1 /* 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. Oracle designates this 7 * particular file as subject to the "Classpath" exception as provided 8 * by Oracle in the LICENSE file that accompanied this code. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 */ 24 25 /* 26 * This file is available under and governed by the GNU General Public 27 * License version 2 only, as published by the Free Software Foundation. 28 * However, the following notice accompanied the original version of this 29 * file: 30 * 31 * Written by Doug Lea with assistance from members of JCP JSR-166 32 * Expert Group and released to the public domain, as explained at 33 * http://creativecommons.org/publicdomain/zero/1.0/ 34 */ 35 36 package java.util.concurrent; 37 38 import java.io.ObjectStreamField; 39 import java.io.Serializable; 40 import java.lang.reflect.ParameterizedType; 41 import java.lang.reflect.Type; 42 import java.util.AbstractMap; 43 import java.util.Arrays; 44 import java.util.Collection; 45 import java.util.Comparator; 46 import java.util.ConcurrentModificationException; 47 import java.util.Enumeration; 48 import java.util.HashMap; 49 import java.util.Hashtable; 50 import java.util.Iterator; 51 import java.util.Map; 52 import java.util.NoSuchElementException; 53 import java.util.Set; 54 import java.util.Spliterator; 55 import java.util.concurrent.ConcurrentMap; 56 import java.util.concurrent.ForkJoinPool; 57 import java.util.concurrent.atomic.AtomicReference; 58 import java.util.concurrent.locks.LockSupport; 59 import java.util.concurrent.locks.ReentrantLock; 60 import java.util.function.BiConsumer; 61 import java.util.function.BiFunction; 62 import java.util.function.BinaryOperator; 63 import java.util.function.Consumer; 64 import java.util.function.DoubleBinaryOperator; 65 import java.util.function.Function; 66 import java.util.function.IntBinaryOperator; 67 import java.util.function.LongBinaryOperator; 68 import java.util.function.ToDoubleBiFunction; 69 import java.util.function.ToDoubleFunction; 70 import java.util.function.ToIntBiFunction; 71 import java.util.function.ToIntFunction; 72 import java.util.function.ToLongBiFunction; 73 import java.util.function.ToLongFunction; 74 import java.util.stream.Stream; 75 76 /** 77 * A hash table supporting full concurrency of retrievals and 78 * high expected concurrency for updates. This class obeys the 79 * same functional specification as {@link java.util.Hashtable}, and 80 * includes versions of methods corresponding to each method of 81 * {@code Hashtable}. However, even though all operations are 82 * thread-safe, retrieval operations do <em>not</em> entail locking, 83 * and there is <em>not</em> any support for locking the entire table 84 * in a way that prevents all access. This class is fully 85 * interoperable with {@code Hashtable} in programs that rely on its 86 * thread safety but not on its synchronization details. 87 * 88 * <p>Retrieval operations (including {@code get}) generally do not 89 * block, so may overlap with update operations (including {@code put} 90 * and {@code remove}). Retrievals reflect the results of the most 91 * recently <em>completed</em> update operations holding upon their 92 * onset. (More formally, an update operation for a given key bears a 93 * <em>happens-before</em> relation with any (non-null) retrieval for 94 * that key reporting the updated value.) For aggregate operations 95 * such as {@code putAll} and {@code clear}, concurrent retrievals may 96 * reflect insertion or removal of only some entries. Similarly, 97 * Iterators and Enumerations return elements reflecting the state of 98 * the hash table at some point at or since the creation of the 99 * iterator/enumeration. They do <em>not</em> throw {@link 100 * ConcurrentModificationException}. However, iterators are designed 101 * to be used by only one thread at a time. Bear in mind that the 102 * results of aggregate status methods including {@code size}, {@code 103 * isEmpty}, and {@code containsValue} are typically useful only when 104 * a map is not undergoing concurrent updates in other threads. 105 * Otherwise the results of these methods reflect transient states 106 * that may be adequate for monitoring or estimation purposes, but not 107 * for program control. 108 * 109 * <p>The table is dynamically expanded when there are too many 110 * collisions (i.e., keys that have distinct hash codes but fall into 111 * the same slot modulo the table size), with the expected average 112 * effect of maintaining roughly two bins per mapping (corresponding 113 * to a 0.75 load factor threshold for resizing). There may be much 114 * variance around this average as mappings are added and removed, but 115 * overall, this maintains a commonly accepted time/space tradeoff for 116 * hash tables. However, resizing this or any other kind of hash 117 * table may be a relatively slow operation. When possible, it is a 118 * good idea to provide a size estimate as an optional {@code 119 * initialCapacity} constructor argument. An additional optional 120 * {@code loadFactor} constructor argument provides a further means of 121 * customizing initial table capacity by specifying the table density 122 * to be used in calculating the amount of space to allocate for the 123 * given number of elements. Also, for compatibility with previous 124 * versions of this class, constructors may optionally specify an 125 * expected {@code concurrencyLevel} as an additional hint for 126 * internal sizing. Note that using many keys with exactly the same 127 * {@code hashCode()} is a sure way to slow down performance of any 128 * hash table. To ameliorate impact, when keys are {@link Comparable}, 129 * this class may use comparison order among keys to help break ties. 130 * 131 * <p>A {@link Set} projection of a ConcurrentHashMap may be created 132 * (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed 133 * (using {@link #keySet(Object)} when only keys are of interest, and the 134 * mapped values are (perhaps transiently) not used or all take the 135 * same mapping value. 136 * 137 * <p>A ConcurrentHashMap can be used as scalable frequency map (a 138 * form of histogram or multiset) by using {@link 139 * java.util.concurrent.atomic.LongAdder} values and initializing via 140 * {@link #computeIfAbsent computeIfAbsent}. For example, to add a count 141 * to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use 142 * {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();} 143 * 144 * <p>This class and its views and iterators implement all of the 145 * <em>optional</em> methods of the {@link Map} and {@link Iterator} 146 * interfaces. 147 * 148 * <p>Like {@link Hashtable} but unlike {@link HashMap}, this class 149 * does <em>not</em> allow {@code null} to be used as a key or value. 150 * 151 * <p>ConcurrentHashMaps support a set of sequential and parallel bulk 152 * operations that, unlike most {@link Stream} methods, are designed 153 * to be safely, and often sensibly, applied even with maps that are 154 * being concurrently updated by other threads; for example, when 155 * computing a snapshot summary of the values in a shared registry. 156 * There are three kinds of operation, each with four forms, accepting 157 * functions with Keys, Values, Entries, and (Key, Value) arguments 158 * and/or return values. Because the elements of a ConcurrentHashMap 159 * are not ordered in any particular way, and may be processed in 160 * different orders in different parallel executions, the correctness 161 * of supplied functions should not depend on any ordering, or on any 162 * other objects or values that may transiently change while 163 * computation is in progress; and except for forEach actions, should 164 * ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry} 165 * objects do not support method {@code setValue}. 166 * 167 * <ul> 168 * <li> forEach: Perform a given action on each element. 169 * A variant form applies a given transformation on each element 170 * before performing the action.</li> 171 * 172 * <li> search: Return the first available non-null result of 173 * applying a given function on each element; skipping further 174 * search when a result is found.</li> 175 * 176 * <li> reduce: Accumulate each element. The supplied reduction 177 * function cannot rely on ordering (more formally, it should be 178 * both associative and commutative). There are five variants: 179 * 180 * <ul> 181 * 182 * <li> Plain reductions. (There is not a form of this method for 183 * (key, value) function arguments since there is no corresponding 184 * return type.)</li> 185 * 186 * <li> Mapped reductions that accumulate the results of a given 187 * function applied to each element.</li> 188 * 189 * <li> Reductions to scalar doubles, longs, and ints, using a 190 * given basis value.</li> 191 * 192 * </ul> 193 * </li> 194 * </ul> 195 * 196 * <p>These bulk operations accept a {@code parallelismThreshold} 197 * argument. Methods proceed sequentially if the current map size is 198 * estimated to be less than the given threshold. Using a value of 199 * {@code Long.MAX_VALUE} suppresses all parallelism. Using a value 200 * of {@code 1} results in maximal parallelism by partitioning into 201 * enough subtasks to fully utilize the {@link 202 * ForkJoinPool#commonPool()} that is used for all parallel 203 * computations. Normally, you would initially choose one of these 204 * extreme values, and then measure performance of using in-between 205 * values that trade off overhead versus throughput. 206 * 207 * <p>The concurrency properties of bulk operations follow 208 * from those of ConcurrentHashMap: Any non-null result returned 209 * from {@code get(key)} and related access methods bears a 210 * happens-before relation with the associated insertion or 211 * update. The result of any bulk operation reflects the 212 * composition of these per-element relations (but is not 213 * necessarily atomic with respect to the map as a whole unless it 214 * is somehow known to be quiescent). Conversely, because keys 215 * and values in the map are never null, null serves as a reliable 216 * atomic indicator of the current lack of any result. To 217 * maintain this property, null serves as an implicit basis for 218 * all non-scalar reduction operations. For the double, long, and 219 * int versions, the basis should be one that, when combined with 220 * any other value, returns that other value (more formally, it 221 * should be the identity element for the reduction). Most common 222 * reductions have these properties; for example, computing a sum 223 * with basis 0 or a minimum with basis MAX_VALUE. 224 * 225 * <p>Search and transformation functions provided as arguments 226 * should similarly return null to indicate the lack of any result 227 * (in which case it is not used). In the case of mapped 228 * reductions, this also enables transformations to serve as 229 * filters, returning null (or, in the case of primitive 230 * specializations, the identity basis) if the element should not 231 * be combined. You can create compound transformations and 232 * filterings by composing them yourself under this "null means 233 * there is nothing there now" rule before using them in search or 234 * reduce operations. 235 * 236 * <p>Methods accepting and/or returning Entry arguments maintain 237 * key-value associations. They may be useful for example when 238 * finding the key for the greatest value. Note that "plain" Entry 239 * arguments can be supplied using {@code new 240 * AbstractMap.SimpleEntry(k,v)}. 241 * 242 * <p>Bulk operations may complete abruptly, throwing an 243 * exception encountered in the application of a supplied 244 * function. Bear in mind when handling such exceptions that other 245 * concurrently executing functions could also have thrown 246 * exceptions, or would have done so if the first exception had 247 * not occurred. 248 * 249 * <p>Speedups for parallel compared to sequential forms are common 250 * but not guaranteed. Parallel operations involving brief functions 251 * on small maps may execute more slowly than sequential forms if the 252 * underlying work to parallelize the computation is more expensive 253 * than the computation itself. Similarly, parallelization may not 254 * lead to much actual parallelism if all processors are busy 255 * performing unrelated tasks. 256 * 257 * <p>All arguments to all task methods must be non-null. 258 * 259 * <p>This class is a member of the 260 * <a href="{@docRoot}/../technotes/guides/collections/index.html"> 261 * Java Collections Framework</a>. 262 * 263 * @since 1.5 264 * @author Doug Lea 265 * @param <K> the type of keys maintained by this map 266 * @param <V> the type of mapped values 267 */ 268 public class ConcurrentHashMap<K,V> extends AbstractMap<K,V> 269 implements ConcurrentMap<K,V>, Serializable { 270 private static final long serialVersionUID = 7249069246763182397L; 271 272 /* 273 * Overview: 274 * 275 * The primary design goal of this hash table is to maintain 276 * concurrent readability (typically method get(), but also 277 * iterators and related methods) while minimizing update 278 * contention. Secondary goals are to keep space consumption about 279 * the same or better than java.util.HashMap, and to support high 280 * initial insertion rates on an empty table by many threads. 281 * 282 * This map usually acts as a binned (bucketed) hash table. Each 283 * key-value mapping is held in a Node. Most nodes are instances 284 * of the basic Node class with hash, key, value, and next 285 * fields. However, various subclasses exist: TreeNodes are 286 * arranged in balanced trees, not lists. TreeBins hold the roots 287 * of sets of TreeNodes. ForwardingNodes are placed at the heads 288 * of bins during resizing. ReservationNodes are used as 289 * placeholders while establishing values in computeIfAbsent and 290 * related methods. The types TreeBin, ForwardingNode, and 291 * ReservationNode do not hold normal user keys, values, or 292 * hashes, and are readily distinguishable during search etc 293 * because they have negative hash fields and null key and value 294 * fields. (These special nodes are either uncommon or transient, 295 * so the impact of carrying around some unused fields is 296 * insignificant.) 297 * 298 * The table is lazily initialized to a power-of-two size upon the 299 * first insertion. Each bin in the table normally contains a 300 * list of Nodes (most often, the list has only zero or one Node). 301 * Table accesses require volatile/atomic reads, writes, and 302 * CASes. Because there is no other way to arrange this without 303 * adding further indirections, we use intrinsics 304 * (sun.misc.Unsafe) operations. 305 * 306 * We use the top (sign) bit of Node hash fields for control 307 * purposes -- it is available anyway because of addressing 308 * constraints. Nodes with negative hash fields are specially 309 * handled or ignored in map methods. 310 * 311 * Insertion (via put or its variants) of the first node in an 312 * empty bin is performed by just CASing it to the bin. This is 313 * by far the most common case for put operations under most 314 * key/hash distributions. Other update operations (insert, 315 * delete, and replace) require locks. We do not want to waste 316 * the space required to associate a distinct lock object with 317 * each bin, so instead use the first node of a bin list itself as 318 * a lock. Locking support for these locks relies on builtin 319 * "synchronized" monitors. 320 * 321 * Using the first node of a list as a lock does not by itself 322 * suffice though: When a node is locked, any update must first 323 * validate that it is still the first node after locking it, and 324 * retry if not. Because new nodes are always appended to lists, 325 * once a node is first in a bin, it remains first until deleted 326 * or the bin becomes invalidated (upon resizing). 327 * 328 * The main disadvantage of per-bin locks is that other update 329 * operations on other nodes in a bin list protected by the same 330 * lock can stall, for example when user equals() or mapping 331 * functions take a long time. However, statistically, under 332 * random hash codes, this is not a common problem. Ideally, the 333 * frequency of nodes in bins follows a Poisson distribution 334 * (http://en.wikipedia.org/wiki/Poisson_distribution) with a 335 * parameter of about 0.5 on average, given the resizing threshold 336 * of 0.75, although with a large variance because of resizing 337 * granularity. Ignoring variance, the expected occurrences of 338 * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The 339 * first values are: 340 * 341 * 0: 0.60653066 342 * 1: 0.30326533 343 * 2: 0.07581633 344 * 3: 0.01263606 345 * 4: 0.00157952 346 * 5: 0.00015795 347 * 6: 0.00001316 348 * 7: 0.00000094 349 * 8: 0.00000006 350 * more: less than 1 in ten million 351 * 352 * Lock contention probability for two threads accessing distinct 353 * elements is roughly 1 / (8 * #elements) under random hashes. 354 * 355 * Actual hash code distributions encountered in practice 356 * sometimes deviate significantly from uniform randomness. This 357 * includes the case when N > (1<<30), so some keys MUST collide. 358 * Similarly for dumb or hostile usages in which multiple keys are 359 * designed to have identical hash codes or ones that differs only 360 * in masked-out high bits. So we use a secondary strategy that 361 * applies when the number of nodes in a bin exceeds a 362 * threshold. These TreeBins use a balanced tree to hold nodes (a 363 * specialized form of red-black trees), bounding search time to 364 * O(log N). Each search step in a TreeBin is at least twice as 365 * slow as in a regular list, but given that N cannot exceed 366 * (1<<64) (before running out of addresses) this bounds search 367 * steps, lock hold times, etc, to reasonable constants (roughly 368 * 100 nodes inspected per operation worst case) so long as keys 369 * are Comparable (which is very common -- String, Long, etc). 370 * TreeBin nodes (TreeNodes) also maintain the same "next" 371 * traversal pointers as regular nodes, so can be traversed in 372 * iterators in the same way. 373 * 374 * The table is resized when occupancy exceeds a percentage 375 * threshold (nominally, 0.75, but see below). Any thread 376 * noticing an overfull bin may assist in resizing after the 377 * initiating thread allocates and sets up the replacement 378 * array. However, rather than stalling, these other threads may 379 * proceed with insertions etc. The use of TreeBins shields us 380 * from the worst case effects of overfilling while resizes are in 381 * progress. Resizing proceeds by transferring bins, one by one, 382 * from the table to the next table. To enable concurrency, the 383 * next table must be (incrementally) prefilled with place-holders 384 * serving as reverse forwarders to the old table. Because we are 385 * using power-of-two expansion, the elements from each bin must 386 * either stay at same index, or move with a power of two 387 * offset. We eliminate unnecessary node creation by catching 388 * cases where old nodes can be reused because their next fields 389 * won't change. On average, only about one-sixth of them need 390 * cloning when a table doubles. The nodes they replace will be 391 * garbage collectable as soon as they are no longer referenced by 392 * any reader thread that may be in the midst of concurrently 393 * traversing table. Upon transfer, the old table bin contains 394 * only a special forwarding node (with hash field "MOVED") that 395 * contains the next table as its key. On encountering a 396 * forwarding node, access and update operations restart, using 397 * the new table. 398 * 399 * Each bin transfer requires its bin lock, which can stall 400 * waiting for locks while resizing. However, because other 401 * threads can join in and help resize rather than contend for 402 * locks, average aggregate waits become shorter as resizing 403 * progresses. The transfer operation must also ensure that all 404 * accessible bins in both the old and new table are usable by any 405 * traversal. This is arranged by proceeding from the last bin 406 * (table.length - 1) up towards the first. Upon seeing a 407 * forwarding node, traversals (see class Traverser) arrange to 408 * move to the new table without revisiting nodes. However, to 409 * ensure that no intervening nodes are skipped, bin splitting can 410 * only begin after the associated reverse-forwarders are in 411 * place. 412 * 413 * The traversal scheme also applies to partial traversals of 414 * ranges of bins (via an alternate Traverser constructor) 415 * to support partitioned aggregate operations. Also, read-only 416 * operations give up if ever forwarded to a null table, which 417 * provides support for shutdown-style clearing, which is also not 418 * currently implemented. 419 * 420 * Lazy table initialization minimizes footprint until first use, 421 * and also avoids resizings when the first operation is from a 422 * putAll, constructor with map argument, or deserialization. 423 * These cases attempt to override the initial capacity settings, 424 * but harmlessly fail to take effect in cases of races. 425 * 426 * The element count is maintained using a specialization of 427 * LongAdder. We need to incorporate a specialization rather than 428 * just use a LongAdder in order to access implicit 429 * contention-sensing that leads to creation of multiple 430 * CounterCells. The counter mechanics avoid contention on 431 * updates but can encounter cache thrashing if read too 432 * frequently during concurrent access. To avoid reading so often, 433 * resizing under contention is attempted only upon adding to a 434 * bin already holding two or more nodes. Under uniform hash 435 * distributions, the probability of this occurring at threshold 436 * is around 13%, meaning that only about 1 in 8 puts check 437 * threshold (and after resizing, many fewer do so). 438 * 439 * TreeBins use a special form of comparison for search and 440 * related operations (which is the main reason we cannot use 441 * existing collections such as TreeMaps). TreeBins contain 442 * Comparable elements, but may contain others, as well as 443 * elements that are Comparable but not necessarily Comparable for 444 * the same T, so we cannot invoke compareTo among them. To handle 445 * this, the tree is ordered primarily by hash value, then by 446 * Comparable.compareTo order if applicable. On lookup at a node, 447 * if elements are not comparable or compare as 0 then both left 448 * and right children may need to be searched in the case of tied 449 * hash values. (This corresponds to the full list search that 450 * would be necessary if all elements were non-Comparable and had 451 * tied hashes.) On insertion, to keep a total ordering (or as 452 * close as is required here) across rebalancings, we compare 453 * classes and identityHashCodes as tie-breakers. The red-black 454 * balancing code is updated from pre-jdk-collections 455 * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java) 456 * based in turn on Cormen, Leiserson, and Rivest "Introduction to 457 * Algorithms" (CLR). 458 * 459 * TreeBins also require an additional locking mechanism. While 460 * list traversal is always possible by readers even during 461 * updates, tree traversal is not, mainly because of tree-rotations 462 * that may change the root node and/or its linkages. TreeBins 463 * include a simple read-write lock mechanism parasitic on the 464 * main bin-synchronization strategy: Structural adjustments 465 * associated with an insertion or removal are already bin-locked 466 * (and so cannot conflict with other writers) but must wait for 467 * ongoing readers to finish. Since there can be only one such 468 * waiter, we use a simple scheme using a single "waiter" field to 469 * block writers. However, readers need never block. If the root 470 * lock is held, they proceed along the slow traversal path (via 471 * next-pointers) until the lock becomes available or the list is 472 * exhausted, whichever comes first. These cases are not fast, but 473 * maximize aggregate expected throughput. 474 * 475 * Maintaining API and serialization compatibility with previous 476 * versions of this class introduces several oddities. Mainly: We 477 * leave untouched but unused constructor arguments refering to 478 * concurrencyLevel. We accept a loadFactor constructor argument, 479 * but apply it only to initial table capacity (which is the only 480 * time that we can guarantee to honor it.) We also declare an 481 * unused "Segment" class that is instantiated in minimal form 482 * only when serializing. 483 * 484 * Also, solely for compatibility with previous versions of this 485 * class, it extends AbstractMap, even though all of its methods 486 * are overridden, so it is just useless baggage. 487 * 488 * This file is organized to make things a little easier to follow 489 * while reading than they might otherwise: First the main static 490 * declarations and utilities, then fields, then main public 491 * methods (with a few factorings of multiple public methods into 492 * internal ones), then sizing methods, trees, traversers, and 493 * bulk operations. 494 */ 495 496 /* ---------------- Constants -------------- */ 497 498 /** 499 * The largest possible table capacity. This value must be 500 * exactly 1<<30 to stay within Java array allocation and indexing 501 * bounds for power of two table sizes, and is further required 502 * because the top two bits of 32bit hash fields are used for 503 * control purposes. 504 */ 505 private static final int MAXIMUM_CAPACITY = 1 << 30; 506 507 /** 508 * The default initial table capacity. Must be a power of 2 509 * (i.e., at least 1) and at most MAXIMUM_CAPACITY. 510 */ 511 private static final int DEFAULT_CAPACITY = 16; 512 513 /** 514 * The largest possible (non-power of two) array size. 515 * Needed by toArray and related methods. 516 */ 517 static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; 518 519 /** 520 * The default concurrency level for this table. Unused but 521 * defined for compatibility with previous versions of this class. 522 */ 523 private static final int DEFAULT_CONCURRENCY_LEVEL = 16; 524 525 /** 526 * The load factor for this table. Overrides of this value in 527 * constructors affect only the initial table capacity. The 528 * actual floating point value isn't normally used -- it is 529 * simpler to use expressions such as {@code n - (n >>> 2)} for 530 * the associated resizing threshold. 531 */ 532 private static final float LOAD_FACTOR = 0.75f; 533 534 /** 535 * The bin count threshold for using a tree rather than list for a 536 * bin. Bins are converted to trees when adding an element to a 537 * bin with at least this many nodes. The value must be greater 538 * than 2, and should be at least 8 to mesh with assumptions in 539 * tree removal about conversion back to plain bins upon 540 * shrinkage. 541 */ 542 static final int TREEIFY_THRESHOLD = 8; 543 544 /** 545 * The bin count threshold for untreeifying a (split) bin during a 546 * resize operation. Should be less than TREEIFY_THRESHOLD, and at 547 * most 6 to mesh with shrinkage detection under removal. 548 */ 549 static final int UNTREEIFY_THRESHOLD = 6; 550 551 /** 552 * The smallest table capacity for which bins may be treeified. 553 * (Otherwise the table is resized if too many nodes in a bin.) 554 * The value should be at least 4 * TREEIFY_THRESHOLD to avoid 555 * conflicts between resizing and treeification thresholds. 556 */ 557 static final int MIN_TREEIFY_CAPACITY = 64; 558 559 /** 560 * Minimum number of rebinnings per transfer step. Ranges are 561 * subdivided to allow multiple resizer threads. This value 562 * serves as a lower bound to avoid resizers encountering 563 * excessive memory contention. The value should be at least 564 * DEFAULT_CAPACITY. 565 */ 566 private static final int MIN_TRANSFER_STRIDE = 16; 567 568 /* 569 * Encodings for Node hash fields. See above for explanation. 570 */ 571 static final int MOVED = -1; // hash for forwarding nodes 572 static final int TREEBIN = -2; // hash for roots of trees 573 static final int RESERVED = -3; // hash for transient reservations 574 static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash 575 576 /** Number of CPUS, to place bounds on some sizings */ 577 static final int NCPU = Runtime.getRuntime().availableProcessors(); 578 579 /** For serialization compatibility. */ 580 private static final ObjectStreamField[] serialPersistentFields = { 581 new ObjectStreamField("segments", Segment[].class), 582 new ObjectStreamField("segmentMask", Integer.TYPE), 583 new ObjectStreamField("segmentShift", Integer.TYPE) 584 }; 585 586 /* ---------------- Nodes -------------- */ 587 588 /** 589 * Key-value entry. This class is never exported out as a 590 * user-mutable Map.Entry (i.e., one supporting setValue; see 591 * MapEntry below), but can be used for read-only traversals used 592 * in bulk tasks. Subclasses of Node with a negative hash field 593 * are special, and contain null keys and values (but are never 594 * exported). Otherwise, keys and vals are never null. 595 */ 596 static class Node<K,V> implements Map.Entry<K,V> { 597 final int hash; 598 final K key; 599 volatile V val; 600 volatile Node<K,V> next; 601 602 Node(int hash, K key, V val, Node<K,V> next) { 603 this.hash = hash; 604 this.key = key; 605 this.val = val; 606 this.next = next; 607 } 608 609 public final K getKey() { return key; } 610 public final V getValue() { return val; } 611 public final int hashCode() { return key.hashCode() ^ val.hashCode(); } 612 public final String toString(){ return key + "=" + val; } 613 public final V setValue(V value) { 614 throw new UnsupportedOperationException(); 615 } 616 617 public final boolean equals(Object o) { 618 Object k, v, u; Map.Entry<?,?> e; 619 return ((o instanceof Map.Entry) && 620 (k = (e = (Map.Entry<?,?>)o).getKey()) != null && 621 (v = e.getValue()) != null && 622 (k == key || k.equals(key)) && 623 (v == (u = val) || v.equals(u))); 624 } 625 626 /** 627 * Virtualized support for map.get(); overridden in subclasses. 628 */ 629 Node<K,V> find(int h, Object k) { 630 Node<K,V> e = this; 631 if (k != null) { 632 do { 633 K ek; 634 if (e.hash == h && 635 ((ek = e.key) == k || (ek != null && k.equals(ek)))) 636 return e; 637 } while ((e = e.next) != null); 638 } 639 return null; 640 } 641 } 642 643 /* ---------------- Static utilities -------------- */ 644 645 /** 646 * Spreads (XORs) higher bits of hash to lower and also forces top 647 * bit to 0. Because the table uses power-of-two masking, sets of 648 * hashes that vary only in bits above the current mask will 649 * always collide. (Among known examples are sets of Float keys 650 * holding consecutive whole numbers in small tables.) So we 651 * apply a transform that spreads the impact of higher bits 652 * downward. There is a tradeoff between speed, utility, and 653 * quality of bit-spreading. Because many common sets of hashes 654 * are already reasonably distributed (so don't benefit from 655 * spreading), and because we use trees to handle large sets of 656 * collisions in bins, we just XOR some shifted bits in the 657 * cheapest possible way to reduce systematic lossage, as well as 658 * to incorporate impact of the highest bits that would otherwise 659 * never be used in index calculations because of table bounds. 660 */ 661 static final int spread(int h) { 662 return (h ^ (h >>> 16)) & HASH_BITS; 663 } 664 665 /** 666 * Returns a power of two table size for the given desired capacity. 667 * See Hackers Delight, sec 3.2 668 */ 669 private static final int tableSizeFor(int c) { 670 int n = c - 1; 671 n |= n >>> 1; 672 n |= n >>> 2; 673 n |= n >>> 4; 674 n |= n >>> 8; 675 n |= n >>> 16; 676 return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1; 677 } 678 679 /** 680 * Returns x's Class if it is of the form "class C implements 681 * Comparable<C>", else null. 682 */ 683 static Class<?> comparableClassFor(Object x) { 684 if (x instanceof Comparable) { 685 Class<?> c; Type[] ts, as; Type t; ParameterizedType p; 686 if ((c = x.getClass()) == String.class) // bypass checks 687 return c; 688 if ((ts = c.getGenericInterfaces()) != null) { 689 for (int i = 0; i < ts.length; ++i) { 690 if (((t = ts[i]) instanceof ParameterizedType) && 691 ((p = (ParameterizedType)t).getRawType() == 692 Comparable.class) && 693 (as = p.getActualTypeArguments()) != null && 694 as.length == 1 && as[0] == c) // type arg is c 695 return c; 696 } 697 } 698 } 699 return null; 700 } 701 702 /** 703 * Returns k.compareTo(x) if x matches kc (k's screened comparable 704 * class), else 0. 705 */ 706 @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable 707 static int compareComparables(Class<?> kc, Object k, Object x) { 708 return (x == null || x.getClass() != kc ? 0 : 709 ((Comparable)k).compareTo(x)); 710 } 711 712 /* ---------------- Table element access -------------- */ 713 714 /* 715 * Volatile access methods are used for table elements as well as 716 * elements of in-progress next table while resizing. All uses of 717 * the tab arguments must be null checked by callers. All callers 718 * also paranoically precheck that tab's length is not zero (or an 719 * equivalent check), thus ensuring that any index argument taking 720 * the form of a hash value anded with (length - 1) is a valid 721 * index. Note that, to be correct wrt arbitrary concurrency 722 * errors by users, these checks must operate on local variables, 723 * which accounts for some odd-looking inline assignments below. 724 * Note that calls to setTabAt always occur within locked regions, 725 * and so in principle require only release ordering, not need 726 * full volatile semantics, but are currently coded as volatile 727 * writes to be conservative. 728 */ 729 730 @SuppressWarnings("unchecked") 731 static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) { 732 return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE); 733 } 734 735 static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i, 736 Node<K,V> c, Node<K,V> v) { 737 return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v); 738 } 739 740 static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) { 741 U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v); 742 } 743 744 /* ---------------- Fields -------------- */ 745 746 /** 747 * The array of bins. Lazily initialized upon first insertion. 748 * Size is always a power of two. Accessed directly by iterators. 749 */ 750 transient volatile Node<K,V>[] table; 751 752 /** 753 * The next table to use; non-null only while resizing. 754 */ 755 private transient volatile Node<K,V>[] nextTable; 756 757 /** 758 * Base counter value, used mainly when there is no contention, 759 * but also as a fallback during table initialization 760 * races. Updated via CAS. 761 */ 762 private transient volatile long baseCount; 763 764 /** 765 * Table initialization and resizing control. When negative, the 766 * table is being initialized or resized: -1 for initialization, 767 * else -(1 + the number of active resizing threads). Otherwise, 768 * when table is null, holds the initial table size to use upon 769 * creation, or 0 for default. After initialization, holds the 770 * next element count value upon which to resize the table. 771 */ 772 private transient volatile int sizeCtl; 773 774 /** 775 * The next table index (plus one) to split while resizing. 776 */ 777 private transient volatile int transferIndex; 778 779 /** 780 * The least available table index to split while resizing. 781 */ 782 private transient volatile int transferOrigin; 783 784 /** 785 * Spinlock (locked via CAS) used when resizing and/or creating CounterCells. 786 */ 787 private transient volatile int cellsBusy; 788 789 /** 790 * Table of counter cells. When non-null, size is a power of 2. 791 */ 792 private transient volatile CounterCell[] counterCells; 793 794 // views 795 private transient KeySetView<K,V> keySet; 796 private transient ValuesView<K,V> values; 797 private transient EntrySetView<K,V> entrySet; 798 799 800 /* ---------------- Public operations -------------- */ 801 802 /** 803 * Creates a new, empty map with the default initial table size (16). 804 */ 805 public ConcurrentHashMap() { 806 } 807 808 /** 809 * Creates a new, empty map with an initial table size 810 * accommodating the specified number of elements without the need 811 * to dynamically resize. 812 * 813 * @param initialCapacity The implementation performs internal 814 * sizing to accommodate this many elements. 815 * @throws IllegalArgumentException if the initial capacity of 816 * elements is negative 817 */ 818 public ConcurrentHashMap(int initialCapacity) { 819 if (initialCapacity < 0) 820 throw new IllegalArgumentException(); 821 int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ? 822 MAXIMUM_CAPACITY : 823 tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1)); 824 this.sizeCtl = cap; 825 } 826 827 /** 828 * Creates a new map with the same mappings as the given map. 829 * 830 * @param m the map 831 */ 832 public ConcurrentHashMap(Map<? extends K, ? extends V> m) { 833 this.sizeCtl = DEFAULT_CAPACITY; 834 putAll(m); 835 } 836 837 /** 838 * Creates a new, empty map with an initial table size based on 839 * the given number of elements ({@code initialCapacity}) and 840 * initial table density ({@code loadFactor}). 841 * 842 * @param initialCapacity the initial capacity. The implementation 843 * performs internal sizing to accommodate this many elements, 844 * given the specified load factor. 845 * @param loadFactor the load factor (table density) for 846 * establishing the initial table size 847 * @throws IllegalArgumentException if the initial capacity of 848 * elements is negative or the load factor is nonpositive 849 * 850 * @since 1.6 851 */ 852 public ConcurrentHashMap(int initialCapacity, float loadFactor) { 853 this(initialCapacity, loadFactor, 1); 854 } 855 856 /** 857 * Creates a new, empty map with an initial table size based on 858 * the given number of elements ({@code initialCapacity}), table 859 * density ({@code loadFactor}), and number of concurrently 860 * updating threads ({@code concurrencyLevel}). 861 * 862 * @param initialCapacity the initial capacity. The implementation 863 * performs internal sizing to accommodate this many elements, 864 * given the specified load factor. 865 * @param loadFactor the load factor (table density) for 866 * establishing the initial table size 867 * @param concurrencyLevel the estimated number of concurrently 868 * updating threads. The implementation may use this value as 869 * a sizing hint. 870 * @throws IllegalArgumentException if the initial capacity is 871 * negative or the load factor or concurrencyLevel are 872 * nonpositive 873 */ 874 public ConcurrentHashMap(int initialCapacity, 875 float loadFactor, int concurrencyLevel) { 876 if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) 877 throw new IllegalArgumentException(); 878 if (initialCapacity < concurrencyLevel) // Use at least as many bins 879 initialCapacity = concurrencyLevel; // as estimated threads 880 long size = (long)(1.0 + (long)initialCapacity / loadFactor); 881 int cap = (size >= (long)MAXIMUM_CAPACITY) ? 882 MAXIMUM_CAPACITY : tableSizeFor((int)size); 883 this.sizeCtl = cap; 884 } 885 886 // Original (since JDK1.2) Map methods 887 888 /** 889 * {@inheritDoc} 890 */ 891 public int size() { 892 long n = sumCount(); 893 return ((n < 0L) ? 0 : 894 (n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE : 895 (int)n); 896 } 897 898 /** 899 * {@inheritDoc} 900 */ 901 public boolean isEmpty() { 902 return sumCount() <= 0L; // ignore transient negative values 903 } 904 905 /** 906 * Returns the value to which the specified key is mapped, 907 * or {@code null} if this map contains no mapping for the key. 908 * 909 * <p>More formally, if this map contains a mapping from a key 910 * {@code k} to a value {@code v} such that {@code key.equals(k)}, 911 * then this method returns {@code v}; otherwise it returns 912 * {@code null}. (There can be at most one such mapping.) 913 * 914 * @throws NullPointerException if the specified key is null 915 */ 916 public V get(Object key) { 917 Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek; 918 int h = spread(key.hashCode()); 919 if ((tab = table) != null && (n = tab.length) > 0 && 920 (e = tabAt(tab, (n - 1) & h)) != null) { 921 if ((eh = e.hash) == h) { 922 if ((ek = e.key) == key || (ek != null && key.equals(ek))) 923 return e.val; 924 } 925 else if (eh < 0) 926 return (p = e.find(h, key)) != null ? p.val : null; 927 while ((e = e.next) != null) { 928 if (e.hash == h && 929 ((ek = e.key) == key || (ek != null && key.equals(ek)))) 930 return e.val; 931 } 932 } 933 return null; 934 } 935 936 /** 937 * Tests if the specified object is a key in this table. 938 * 939 * @param key possible key 940 * @return {@code true} if and only if the specified object 941 * is a key in this table, as determined by the 942 * {@code equals} method; {@code false} otherwise 943 * @throws NullPointerException if the specified key is null 944 */ 945 public boolean containsKey(Object key) { 946 return get(key) != null; 947 } 948 949 /** 950 * Returns {@code true} if this map maps one or more keys to the 951 * specified value. Note: This method may require a full traversal 952 * of the map, and is much slower than method {@code containsKey}. 953 * 954 * @param value value whose presence in this map is to be tested 955 * @return {@code true} if this map maps one or more keys to the 956 * specified value 957 * @throws NullPointerException if the specified value is null 958 */ 959 public boolean containsValue(Object value) { 960 if (value == null) 961 throw new NullPointerException(); 962 Node<K,V>[] t; 963 if ((t = table) != null) { 964 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 965 for (Node<K,V> p; (p = it.advance()) != null; ) { 966 V v; 967 if ((v = p.val) == value || (v != null && value.equals(v))) 968 return true; 969 } 970 } 971 return false; 972 } 973 974 /** 975 * Maps the specified key to the specified value in this table. 976 * Neither the key nor the value can be null. 977 * 978 * <p>The value can be retrieved by calling the {@code get} method 979 * with a key that is equal to the original key. 980 * 981 * @param key key with which the specified value is to be associated 982 * @param value value to be associated with the specified key 983 * @return the previous value associated with {@code key}, or 984 * {@code null} if there was no mapping for {@code key} 985 * @throws NullPointerException if the specified key or value is null 986 */ 987 public V put(K key, V value) { 988 return putVal(key, value, false); 989 } 990 991 /** Implementation for put and putIfAbsent */ 992 final V putVal(K key, V value, boolean onlyIfAbsent) { 993 if (key == null || value == null) throw new NullPointerException(); 994 int hash = spread(key.hashCode()); 995 int binCount = 0; 996 for (Node<K,V>[] tab = table;;) { 997 Node<K,V> f; int n, i, fh; 998 if (tab == null || (n = tab.length) == 0) 999 tab = initTable(); 1000 else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) { 1001 if (casTabAt(tab, i, null, 1002 new Node<K,V>(hash, key, value, null))) 1003 break; // no lock when adding to empty bin 1004 } 1005 else if ((fh = f.hash) == MOVED) 1006 tab = helpTransfer(tab, f); 1007 else { 1008 V oldVal = null; 1009 synchronized (f) { 1010 if (tabAt(tab, i) == f) { 1011 if (fh >= 0) { 1012 binCount = 1; 1013 for (Node<K,V> e = f;; ++binCount) { 1014 K ek; 1015 if (e.hash == hash && 1016 ((ek = e.key) == key || 1017 (ek != null && key.equals(ek)))) { 1018 oldVal = e.val; 1019 if (!onlyIfAbsent) 1020 e.val = value; 1021 break; 1022 } 1023 Node<K,V> pred = e; 1024 if ((e = e.next) == null) { 1025 pred.next = new Node<K,V>(hash, key, 1026 value, null); 1027 break; 1028 } 1029 } 1030 } 1031 else if (f instanceof TreeBin) { 1032 Node<K,V> p; 1033 binCount = 2; 1034 if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key, 1035 value)) != null) { 1036 oldVal = p.val; 1037 if (!onlyIfAbsent) 1038 p.val = value; 1039 } 1040 } 1041 } 1042 } 1043 if (binCount != 0) { 1044 if (binCount >= TREEIFY_THRESHOLD) 1045 treeifyBin(tab, i); 1046 if (oldVal != null) 1047 return oldVal; 1048 break; 1049 } 1050 } 1051 } 1052 addCount(1L, binCount); 1053 return null; 1054 } 1055 1056 /** 1057 * Copies all of the mappings from the specified map to this one. 1058 * These mappings replace any mappings that this map had for any of the 1059 * keys currently in the specified map. 1060 * 1061 * @param m mappings to be stored in this map 1062 */ 1063 public void putAll(Map<? extends K, ? extends V> m) { 1064 tryPresize(m.size()); 1065 for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) 1066 putVal(e.getKey(), e.getValue(), false); 1067 } 1068 1069 /** 1070 * Removes the key (and its corresponding value) from this map. 1071 * This method does nothing if the key is not in the map. 1072 * 1073 * @param key the key that needs to be removed 1074 * @return the previous value associated with {@code key}, or 1075 * {@code null} if there was no mapping for {@code key} 1076 * @throws NullPointerException if the specified key is null 1077 */ 1078 public V remove(Object key) { 1079 return replaceNode(key, null, null); 1080 } 1081 1082 /** 1083 * Implementation for the four public remove/replace methods: 1084 * Replaces node value with v, conditional upon match of cv if 1085 * non-null. If resulting value is null, delete. 1086 */ 1087 final V replaceNode(Object key, V value, Object cv) { 1088 int hash = spread(key.hashCode()); 1089 for (Node<K,V>[] tab = table;;) { 1090 Node<K,V> f; int n, i, fh; 1091 if (tab == null || (n = tab.length) == 0 || 1092 (f = tabAt(tab, i = (n - 1) & hash)) == null) 1093 break; 1094 else if ((fh = f.hash) == MOVED) 1095 tab = helpTransfer(tab, f); 1096 else { 1097 V oldVal = null; 1098 boolean validated = false; 1099 synchronized (f) { 1100 if (tabAt(tab, i) == f) { 1101 if (fh >= 0) { 1102 validated = true; 1103 for (Node<K,V> e = f, pred = null;;) { 1104 K ek; 1105 if (e.hash == hash && 1106 ((ek = e.key) == key || 1107 (ek != null && key.equals(ek)))) { 1108 V ev = e.val; 1109 if (cv == null || cv == ev || 1110 (ev != null && cv.equals(ev))) { 1111 oldVal = ev; 1112 if (value != null) 1113 e.val = value; 1114 else if (pred != null) 1115 pred.next = e.next; 1116 else 1117 setTabAt(tab, i, e.next); 1118 } 1119 break; 1120 } 1121 pred = e; 1122 if ((e = e.next) == null) 1123 break; 1124 } 1125 } 1126 else if (f instanceof TreeBin) { 1127 validated = true; 1128 TreeBin<K,V> t = (TreeBin<K,V>)f; 1129 TreeNode<K,V> r, p; 1130 if ((r = t.root) != null && 1131 (p = r.findTreeNode(hash, key, null)) != null) { 1132 V pv = p.val; 1133 if (cv == null || cv == pv || 1134 (pv != null && cv.equals(pv))) { 1135 oldVal = pv; 1136 if (value != null) 1137 p.val = value; 1138 else if (t.removeTreeNode(p)) 1139 setTabAt(tab, i, untreeify(t.first)); 1140 } 1141 } 1142 } 1143 } 1144 } 1145 if (validated) { 1146 if (oldVal != null) { 1147 if (value == null) 1148 addCount(-1L, -1); 1149 return oldVal; 1150 } 1151 break; 1152 } 1153 } 1154 } 1155 return null; 1156 } 1157 1158 /** 1159 * Removes all of the mappings from this map. 1160 */ 1161 public void clear() { 1162 long delta = 0L; // negative number of deletions 1163 int i = 0; 1164 Node<K,V>[] tab = table; 1165 while (tab != null && i < tab.length) { 1166 int fh; 1167 Node<K,V> f = tabAt(tab, i); 1168 if (f == null) 1169 ++i; 1170 else if ((fh = f.hash) == MOVED) { 1171 tab = helpTransfer(tab, f); 1172 i = 0; // restart 1173 } 1174 else { 1175 synchronized (f) { 1176 if (tabAt(tab, i) == f) { 1177 Node<K,V> p = (fh >= 0 ? f : 1178 (f instanceof TreeBin) ? 1179 ((TreeBin<K,V>)f).first : null); 1180 while (p != null) { 1181 --delta; 1182 p = p.next; 1183 } 1184 setTabAt(tab, i++, null); 1185 } 1186 } 1187 } 1188 } 1189 if (delta != 0L) 1190 addCount(delta, -1); 1191 } 1192 1193 /** 1194 * Returns a {@link Set} view of the keys contained in this map. 1195 * The set is backed by the map, so changes to the map are 1196 * reflected in the set, and vice-versa. The set supports element 1197 * removal, which removes the corresponding mapping from this map, 1198 * via the {@code Iterator.remove}, {@code Set.remove}, 1199 * {@code removeAll}, {@code retainAll}, and {@code clear} 1200 * operations. It does not support the {@code add} or 1201 * {@code addAll} operations. 1202 * 1203 * <p>The view's {@code iterator} is a "weakly consistent" iterator 1204 * that will never throw {@link ConcurrentModificationException}, 1205 * and guarantees to traverse elements as they existed upon 1206 * construction of the iterator, and may (but is not guaranteed to) 1207 * reflect any modifications subsequent to construction. 1208 * 1209 * @return the set view 1210 */ 1211 public KeySetView<K,V> keySet() { 1212 KeySetView<K,V> ks; 1213 return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null)); 1214 } 1215 1216 /** 1217 * Returns a {@link Collection} view of the values contained in this map. 1218 * The collection is backed by the map, so changes to the map are 1219 * reflected in the collection, and vice-versa. The collection 1220 * supports element removal, which removes the corresponding 1221 * mapping from this map, via the {@code Iterator.remove}, 1222 * {@code Collection.remove}, {@code removeAll}, 1223 * {@code retainAll}, and {@code clear} operations. It does not 1224 * support the {@code add} or {@code addAll} operations. 1225 * 1226 * <p>The view's {@code iterator} is a "weakly consistent" iterator 1227 * that will never throw {@link ConcurrentModificationException}, 1228 * and guarantees to traverse elements as they existed upon 1229 * construction of the iterator, and may (but is not guaranteed to) 1230 * reflect any modifications subsequent to construction. 1231 * 1232 * @return the collection view 1233 */ 1234 public Collection<V> values() { 1235 ValuesView<K,V> vs; 1236 return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this)); 1237 } 1238 1239 /** 1240 * Returns a {@link Set} view of the mappings contained in this map. 1241 * The set is backed by the map, so changes to the map are 1242 * reflected in the set, and vice-versa. The set supports element 1243 * removal, which removes the corresponding mapping from the map, 1244 * via the {@code Iterator.remove}, {@code Set.remove}, 1245 * {@code removeAll}, {@code retainAll}, and {@code clear} 1246 * operations. 1247 * 1248 * <p>The view's {@code iterator} is a "weakly consistent" iterator 1249 * that will never throw {@link ConcurrentModificationException}, 1250 * and guarantees to traverse elements as they existed upon 1251 * construction of the iterator, and may (but is not guaranteed to) 1252 * reflect any modifications subsequent to construction. 1253 * 1254 * @return the set view 1255 */ 1256 public Set<Map.Entry<K,V>> entrySet() { 1257 EntrySetView<K,V> es; 1258 return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this)); 1259 } 1260 1261 /** 1262 * Returns the hash code value for this {@link Map}, i.e., 1263 * the sum of, for each key-value pair in the map, 1264 * {@code key.hashCode() ^ value.hashCode()}. 1265 * 1266 * @return the hash code value for this map 1267 */ 1268 public int hashCode() { 1269 int h = 0; 1270 Node<K,V>[] t; 1271 if ((t = table) != null) { 1272 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1273 for (Node<K,V> p; (p = it.advance()) != null; ) 1274 h += p.key.hashCode() ^ p.val.hashCode(); 1275 } 1276 return h; 1277 } 1278 1279 /** 1280 * Returns a string representation of this map. The string 1281 * representation consists of a list of key-value mappings (in no 1282 * particular order) enclosed in braces ("{@code {}}"). Adjacent 1283 * mappings are separated by the characters {@code ", "} (comma 1284 * and space). Each key-value mapping is rendered as the key 1285 * followed by an equals sign ("{@code =}") followed by the 1286 * associated value. 1287 * 1288 * @return a string representation of this map 1289 */ 1290 public String toString() { 1291 Node<K,V>[] t; 1292 int f = (t = table) == null ? 0 : t.length; 1293 Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f); 1294 StringBuilder sb = new StringBuilder(); 1295 sb.append('{'); 1296 Node<K,V> p; 1297 if ((p = it.advance()) != null) { 1298 for (;;) { 1299 K k = p.key; 1300 V v = p.val; 1301 sb.append(k == this ? "(this Map)" : k); 1302 sb.append('='); 1303 sb.append(v == this ? "(this Map)" : v); 1304 if ((p = it.advance()) == null) 1305 break; 1306 sb.append(',').append(' '); 1307 } 1308 } 1309 return sb.append('}').toString(); 1310 } 1311 1312 /** 1313 * Compares the specified object with this map for equality. 1314 * Returns {@code true} if the given object is a map with the same 1315 * mappings as this map. This operation may return misleading 1316 * results if either map is concurrently modified during execution 1317 * of this method. 1318 * 1319 * @param o object to be compared for equality with this map 1320 * @return {@code true} if the specified object is equal to this map 1321 */ 1322 public boolean equals(Object o) { 1323 if (o != this) { 1324 if (!(o instanceof Map)) 1325 return false; 1326 Map<?,?> m = (Map<?,?>) o; 1327 Node<K,V>[] t; 1328 int f = (t = table) == null ? 0 : t.length; 1329 Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f); 1330 for (Node<K,V> p; (p = it.advance()) != null; ) { 1331 V val = p.val; 1332 Object v = m.get(p.key); 1333 if (v == null || (v != val && !v.equals(val))) 1334 return false; 1335 } 1336 for (Map.Entry<?,?> e : m.entrySet()) { 1337 Object mk, mv, v; 1338 if ((mk = e.getKey()) == null || 1339 (mv = e.getValue()) == null || 1340 (v = get(mk)) == null || 1341 (mv != v && !mv.equals(v))) 1342 return false; 1343 } 1344 } 1345 return true; 1346 } 1347 1348 /** 1349 * Stripped-down version of helper class used in previous version, 1350 * declared for the sake of serialization compatibility 1351 */ 1352 static class Segment<K,V> extends ReentrantLock implements Serializable { 1353 private static final long serialVersionUID = 2249069246763182397L; 1354 final float loadFactor; 1355 Segment(float lf) { this.loadFactor = lf; } 1356 } 1357 1358 /** 1359 * Saves the state of the {@code ConcurrentHashMap} instance to a 1360 * stream (i.e., serializes it). 1361 * @param s the stream 1362 * @throws java.io.IOException if an I/O error occurs 1363 * @serialData 1364 * the key (Object) and value (Object) 1365 * for each key-value mapping, followed by a null pair. 1366 * The key-value mappings are emitted in no particular order. 1367 */ 1368 private void writeObject(java.io.ObjectOutputStream s) 1369 throws java.io.IOException { 1370 // For serialization compatibility 1371 // Emulate segment calculation from previous version of this class 1372 int sshift = 0; 1373 int ssize = 1; 1374 while (ssize < DEFAULT_CONCURRENCY_LEVEL) { 1375 ++sshift; 1376 ssize <<= 1; 1377 } 1378 int segmentShift = 32 - sshift; 1379 int segmentMask = ssize - 1; 1380 @SuppressWarnings("unchecked") Segment<K,V>[] segments = (Segment<K,V>[]) 1381 new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL]; 1382 for (int i = 0; i < segments.length; ++i) 1383 segments[i] = new Segment<K,V>(LOAD_FACTOR); 1384 s.putFields().put("segments", segments); 1385 s.putFields().put("segmentShift", segmentShift); 1386 s.putFields().put("segmentMask", segmentMask); 1387 s.writeFields(); 1388 1389 Node<K,V>[] t; 1390 if ((t = table) != null) { 1391 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1392 for (Node<K,V> p; (p = it.advance()) != null; ) { 1393 s.writeObject(p.key); 1394 s.writeObject(p.val); 1395 } 1396 } 1397 s.writeObject(null); 1398 s.writeObject(null); 1399 segments = null; // throw away 1400 } 1401 1402 /** 1403 * Reconstitutes the instance from a stream (that is, deserializes it). 1404 * @param s the stream 1405 * @throws ClassNotFoundException if the class of a serialized object 1406 * could not be found 1407 * @throws java.io.IOException if an I/O error occurs 1408 */ 1409 private void readObject(java.io.ObjectInputStream s) 1410 throws java.io.IOException, ClassNotFoundException { 1411 /* 1412 * To improve performance in typical cases, we create nodes 1413 * while reading, then place in table once size is known. 1414 * However, we must also validate uniqueness and deal with 1415 * overpopulated bins while doing so, which requires 1416 * specialized versions of putVal mechanics. 1417 */ 1418 sizeCtl = -1; // force exclusion for table construction 1419 s.defaultReadObject(); 1420 long size = 0L; 1421 Node<K,V> p = null; 1422 for (;;) { 1423 @SuppressWarnings("unchecked") K k = (K) s.readObject(); 1424 @SuppressWarnings("unchecked") V v = (V) s.readObject(); 1425 if (k != null && v != null) { 1426 p = new Node<K,V>(spread(k.hashCode()), k, v, p); 1427 ++size; 1428 } 1429 else 1430 break; 1431 } 1432 if (size == 0L) 1433 sizeCtl = 0; 1434 else { 1435 int n; 1436 if (size >= (long)(MAXIMUM_CAPACITY >>> 1)) 1437 n = MAXIMUM_CAPACITY; 1438 else { 1439 int sz = (int)size; 1440 n = tableSizeFor(sz + (sz >>> 1) + 1); 1441 } 1442 @SuppressWarnings({"rawtypes","unchecked"}) 1443 Node<K,V>[] tab = (Node<K,V>[])new Node[n]; 1444 int mask = n - 1; 1445 long added = 0L; 1446 while (p != null) { 1447 boolean insertAtFront; 1448 Node<K,V> next = p.next, first; 1449 int h = p.hash, j = h & mask; 1450 if ((first = tabAt(tab, j)) == null) 1451 insertAtFront = true; 1452 else { 1453 K k = p.key; 1454 if (first.hash < 0) { 1455 TreeBin<K,V> t = (TreeBin<K,V>)first; 1456 if (t.putTreeVal(h, k, p.val) == null) 1457 ++added; 1458 insertAtFront = false; 1459 } 1460 else { 1461 int binCount = 0; 1462 insertAtFront = true; 1463 Node<K,V> q; K qk; 1464 for (q = first; q != null; q = q.next) { 1465 if (q.hash == h && 1466 ((qk = q.key) == k || 1467 (qk != null && k.equals(qk)))) { 1468 insertAtFront = false; 1469 break; 1470 } 1471 ++binCount; 1472 } 1473 if (insertAtFront && binCount >= TREEIFY_THRESHOLD) { 1474 insertAtFront = false; 1475 ++added; 1476 p.next = first; 1477 TreeNode<K,V> hd = null, tl = null; 1478 for (q = p; q != null; q = q.next) { 1479 TreeNode<K,V> t = new TreeNode<K,V> 1480 (q.hash, q.key, q.val, null, null); 1481 if ((t.prev = tl) == null) 1482 hd = t; 1483 else 1484 tl.next = t; 1485 tl = t; 1486 } 1487 setTabAt(tab, j, new TreeBin<K,V>(hd)); 1488 } 1489 } 1490 } 1491 if (insertAtFront) { 1492 ++added; 1493 p.next = first; 1494 setTabAt(tab, j, p); 1495 } 1496 p = next; 1497 } 1498 table = tab; 1499 sizeCtl = n - (n >>> 2); 1500 baseCount = added; 1501 } 1502 } 1503 1504 // ConcurrentMap methods 1505 1506 /** 1507 * {@inheritDoc} 1508 * 1509 * @return the previous value associated with the specified key, 1510 * or {@code null} if there was no mapping for the key 1511 * @throws NullPointerException if the specified key or value is null 1512 */ 1513 public V putIfAbsent(K key, V value) { 1514 return putVal(key, value, true); 1515 } 1516 1517 /** 1518 * {@inheritDoc} 1519 * 1520 * @throws NullPointerException if the specified key is null 1521 */ 1522 public boolean remove(Object key, Object value) { 1523 if (key == null) 1524 throw new NullPointerException(); 1525 return value != null && replaceNode(key, null, value) != null; 1526 } 1527 1528 /** 1529 * {@inheritDoc} 1530 * 1531 * @throws NullPointerException if any of the arguments are null 1532 */ 1533 public boolean replace(K key, V oldValue, V newValue) { 1534 if (key == null || oldValue == null || newValue == null) 1535 throw new NullPointerException(); 1536 return replaceNode(key, newValue, oldValue) != null; 1537 } 1538 1539 /** 1540 * {@inheritDoc} 1541 * 1542 * @return the previous value associated with the specified key, 1543 * or {@code null} if there was no mapping for the key 1544 * @throws NullPointerException if the specified key or value is null 1545 */ 1546 public V replace(K key, V value) { 1547 if (key == null || value == null) 1548 throw new NullPointerException(); 1549 return replaceNode(key, value, null); 1550 } 1551 1552 // Overrides of JDK8+ Map extension method defaults 1553 1554 /** 1555 * Returns the value to which the specified key is mapped, or the 1556 * given default value if this map contains no mapping for the 1557 * key. 1558 * 1559 * @param key the key whose associated value is to be returned 1560 * @param defaultValue the value to return if this map contains 1561 * no mapping for the given key 1562 * @return the mapping for the key, if present; else the default value 1563 * @throws NullPointerException if the specified key is null 1564 */ 1565 public V getOrDefault(Object key, V defaultValue) { 1566 V v; 1567 return (v = get(key)) == null ? defaultValue : v; 1568 } 1569 1570 public void forEach(BiConsumer<? super K, ? super V> action) { 1571 if (action == null) throw new NullPointerException(); 1572 Node<K,V>[] t; 1573 if ((t = table) != null) { 1574 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1575 for (Node<K,V> p; (p = it.advance()) != null; ) { 1576 action.accept(p.key, p.val); 1577 } 1578 } 1579 } 1580 1581 public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) { 1582 if (function == null) throw new NullPointerException(); 1583 Node<K,V>[] t; 1584 if ((t = table) != null) { 1585 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1586 for (Node<K,V> p; (p = it.advance()) != null; ) { 1587 V oldValue = p.val; 1588 for (K key = p.key;;) { 1589 V newValue = function.apply(key, oldValue); 1590 if (newValue == null) 1591 throw new NullPointerException(); 1592 if (replaceNode(key, newValue, oldValue) != null || 1593 (oldValue = get(key)) == null) 1594 break; 1595 } 1596 } 1597 } 1598 } 1599 1600 /** 1601 * If the specified key is not already associated with a value, 1602 * attempts to compute its value using the given mapping function 1603 * and enters it into this map unless {@code null}. The entire 1604 * method invocation is performed atomically, so the function is 1605 * applied at most once per key. Some attempted update operations 1606 * on this map by other threads may be blocked while computation 1607 * is in progress, so the computation should be short and simple, 1608 * and must not attempt to update any other mappings of this map. 1609 * 1610 * @param key key with which the specified value is to be associated 1611 * @param mappingFunction the function to compute a value 1612 * @return the current (existing or computed) value associated with 1613 * the specified key, or null if the computed value is null 1614 * @throws NullPointerException if the specified key or mappingFunction 1615 * is null 1616 * @throws IllegalStateException if the computation detectably 1617 * attempts a recursive update to this map that would 1618 * otherwise never complete 1619 * @throws RuntimeException or Error if the mappingFunction does so, 1620 * in which case the mapping is left unestablished 1621 */ 1622 public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) { 1623 if (key == null || mappingFunction == null) 1624 throw new NullPointerException(); 1625 int h = spread(key.hashCode()); 1626 V val = null; 1627 int binCount = 0; 1628 for (Node<K,V>[] tab = table;;) { 1629 Node<K,V> f; int n, i, fh; 1630 if (tab == null || (n = tab.length) == 0) 1631 tab = initTable(); 1632 else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { 1633 Node<K,V> r = new ReservationNode<K,V>(); 1634 synchronized (r) { 1635 if (casTabAt(tab, i, null, r)) { 1636 binCount = 1; 1637 Node<K,V> node = null; 1638 try { 1639 if ((val = mappingFunction.apply(key)) != null) 1640 node = new Node<K,V>(h, key, val, null); 1641 } finally { 1642 setTabAt(tab, i, node); 1643 } 1644 } 1645 } 1646 if (binCount != 0) 1647 break; 1648 } 1649 else if ((fh = f.hash) == MOVED) 1650 tab = helpTransfer(tab, f); 1651 else { 1652 boolean added = false; 1653 synchronized (f) { 1654 if (tabAt(tab, i) == f) { 1655 if (fh >= 0) { 1656 binCount = 1; 1657 for (Node<K,V> e = f;; ++binCount) { 1658 K ek; V ev; 1659 if (e.hash == h && 1660 ((ek = e.key) == key || 1661 (ek != null && key.equals(ek)))) { 1662 val = e.val; 1663 break; 1664 } 1665 Node<K,V> pred = e; 1666 if ((e = e.next) == null) { 1667 if ((val = mappingFunction.apply(key)) != null) { 1668 added = true; 1669 pred.next = new Node<K,V>(h, key, val, null); 1670 } 1671 break; 1672 } 1673 } 1674 } 1675 else if (f instanceof TreeBin) { 1676 binCount = 2; 1677 TreeBin<K,V> t = (TreeBin<K,V>)f; 1678 TreeNode<K,V> r, p; 1679 if ((r = t.root) != null && 1680 (p = r.findTreeNode(h, key, null)) != null) 1681 val = p.val; 1682 else if ((val = mappingFunction.apply(key)) != null) { 1683 added = true; 1684 t.putTreeVal(h, key, val); 1685 } 1686 } 1687 } 1688 } 1689 if (binCount != 0) { 1690 if (binCount >= TREEIFY_THRESHOLD) 1691 treeifyBin(tab, i); 1692 if (!added) 1693 return val; 1694 break; 1695 } 1696 } 1697 } 1698 if (val != null) 1699 addCount(1L, binCount); 1700 return val; 1701 } 1702 1703 /** 1704 * If the value for the specified key is present, attempts to 1705 * compute a new mapping given the key and its current mapped 1706 * value. The entire method invocation is performed atomically. 1707 * Some attempted update operations on this map by other threads 1708 * may be blocked while computation is in progress, so the 1709 * computation should be short and simple, and must not attempt to 1710 * update any other mappings of this map. 1711 * 1712 * @param key key with which a value may be associated 1713 * @param remappingFunction the function to compute a value 1714 * @return the new value associated with the specified key, or null if none 1715 * @throws NullPointerException if the specified key or remappingFunction 1716 * is null 1717 * @throws IllegalStateException if the computation detectably 1718 * attempts a recursive update to this map that would 1719 * otherwise never complete 1720 * @throws RuntimeException or Error if the remappingFunction does so, 1721 * in which case the mapping is unchanged 1722 */ 1723 public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) { 1724 if (key == null || remappingFunction == null) 1725 throw new NullPointerException(); 1726 int h = spread(key.hashCode()); 1727 V val = null; 1728 int delta = 0; 1729 int binCount = 0; 1730 for (Node<K,V>[] tab = table;;) { 1731 Node<K,V> f; int n, i, fh; 1732 if (tab == null || (n = tab.length) == 0) 1733 tab = initTable(); 1734 else if ((f = tabAt(tab, i = (n - 1) & h)) == null) 1735 break; 1736 else if ((fh = f.hash) == MOVED) 1737 tab = helpTransfer(tab, f); 1738 else { 1739 synchronized (f) { 1740 if (tabAt(tab, i) == f) { 1741 if (fh >= 0) { 1742 binCount = 1; 1743 for (Node<K,V> e = f, pred = null;; ++binCount) { 1744 K ek; 1745 if (e.hash == h && 1746 ((ek = e.key) == key || 1747 (ek != null && key.equals(ek)))) { 1748 val = remappingFunction.apply(key, e.val); 1749 if (val != null) 1750 e.val = val; 1751 else { 1752 delta = -1; 1753 Node<K,V> en = e.next; 1754 if (pred != null) 1755 pred.next = en; 1756 else 1757 setTabAt(tab, i, en); 1758 } 1759 break; 1760 } 1761 pred = e; 1762 if ((e = e.next) == null) 1763 break; 1764 } 1765 } 1766 else if (f instanceof TreeBin) { 1767 binCount = 2; 1768 TreeBin<K,V> t = (TreeBin<K,V>)f; 1769 TreeNode<K,V> r, p; 1770 if ((r = t.root) != null && 1771 (p = r.findTreeNode(h, key, null)) != null) { 1772 val = remappingFunction.apply(key, p.val); 1773 if (val != null) 1774 p.val = val; 1775 else { 1776 delta = -1; 1777 if (t.removeTreeNode(p)) 1778 setTabAt(tab, i, untreeify(t.first)); 1779 } 1780 } 1781 } 1782 } 1783 } 1784 if (binCount != 0) 1785 break; 1786 } 1787 } 1788 if (delta != 0) 1789 addCount((long)delta, binCount); 1790 return val; 1791 } 1792 1793 /** 1794 * Attempts to compute a mapping for the specified key and its 1795 * current mapped value (or {@code null} if there is no current 1796 * mapping). The entire method invocation is performed atomically. 1797 * Some attempted update operations on this map by other threads 1798 * may be blocked while computation is in progress, so the 1799 * computation should be short and simple, and must not attempt to 1800 * update any other mappings of this Map. 1801 * 1802 * @param key key with which the specified value is to be associated 1803 * @param remappingFunction the function to compute a value 1804 * @return the new value associated with the specified key, or null if none 1805 * @throws NullPointerException if the specified key or remappingFunction 1806 * is null 1807 * @throws IllegalStateException if the computation detectably 1808 * attempts a recursive update to this map that would 1809 * otherwise never complete 1810 * @throws RuntimeException or Error if the remappingFunction does so, 1811 * in which case the mapping is unchanged 1812 */ 1813 public V compute(K key, 1814 BiFunction<? super K, ? super V, ? extends V> remappingFunction) { 1815 if (key == null || remappingFunction == null) 1816 throw new NullPointerException(); 1817 int h = spread(key.hashCode()); 1818 V val = null; 1819 int delta = 0; 1820 int binCount = 0; 1821 for (Node<K,V>[] tab = table;;) { 1822 Node<K,V> f; int n, i, fh; 1823 if (tab == null || (n = tab.length) == 0) 1824 tab = initTable(); 1825 else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { 1826 Node<K,V> r = new ReservationNode<K,V>(); 1827 synchronized (r) { 1828 if (casTabAt(tab, i, null, r)) { 1829 binCount = 1; 1830 Node<K,V> node = null; 1831 try { 1832 if ((val = remappingFunction.apply(key, null)) != null) { 1833 delta = 1; 1834 node = new Node<K,V>(h, key, val, null); 1835 } 1836 } finally { 1837 setTabAt(tab, i, node); 1838 } 1839 } 1840 } 1841 if (binCount != 0) 1842 break; 1843 } 1844 else if ((fh = f.hash) == MOVED) 1845 tab = helpTransfer(tab, f); 1846 else { 1847 synchronized (f) { 1848 if (tabAt(tab, i) == f) { 1849 if (fh >= 0) { 1850 binCount = 1; 1851 for (Node<K,V> e = f, pred = null;; ++binCount) { 1852 K ek; 1853 if (e.hash == h && 1854 ((ek = e.key) == key || 1855 (ek != null && key.equals(ek)))) { 1856 val = remappingFunction.apply(key, e.val); 1857 if (val != null) 1858 e.val = val; 1859 else { 1860 delta = -1; 1861 Node<K,V> en = e.next; 1862 if (pred != null) 1863 pred.next = en; 1864 else 1865 setTabAt(tab, i, en); 1866 } 1867 break; 1868 } 1869 pred = e; 1870 if ((e = e.next) == null) { 1871 val = remappingFunction.apply(key, null); 1872 if (val != null) { 1873 delta = 1; 1874 pred.next = 1875 new Node<K,V>(h, key, val, null); 1876 } 1877 break; 1878 } 1879 } 1880 } 1881 else if (f instanceof TreeBin) { 1882 binCount = 1; 1883 TreeBin<K,V> t = (TreeBin<K,V>)f; 1884 TreeNode<K,V> r, p; 1885 if ((r = t.root) != null) 1886 p = r.findTreeNode(h, key, null); 1887 else 1888 p = null; 1889 V pv = (p == null) ? null : p.val; 1890 val = remappingFunction.apply(key, pv); 1891 if (val != null) { 1892 if (p != null) 1893 p.val = val; 1894 else { 1895 delta = 1; 1896 t.putTreeVal(h, key, val); 1897 } 1898 } 1899 else if (p != null) { 1900 delta = -1; 1901 if (t.removeTreeNode(p)) 1902 setTabAt(tab, i, untreeify(t.first)); 1903 } 1904 } 1905 } 1906 } 1907 if (binCount != 0) { 1908 if (binCount >= TREEIFY_THRESHOLD) 1909 treeifyBin(tab, i); 1910 break; 1911 } 1912 } 1913 } 1914 if (delta != 0) 1915 addCount((long)delta, binCount); 1916 return val; 1917 } 1918 1919 /** 1920 * If the specified key is not already associated with a 1921 * (non-null) value, associates it with the given value. 1922 * Otherwise, replaces the value with the results of the given 1923 * remapping function, or removes if {@code null}. The entire 1924 * method invocation is performed atomically. Some attempted 1925 * update operations on this map by other threads may be blocked 1926 * while computation is in progress, so the computation should be 1927 * short and simple, and must not attempt to update any other 1928 * mappings of this Map. 1929 * 1930 * @param key key with which the specified value is to be associated 1931 * @param value the value to use if absent 1932 * @param remappingFunction the function to recompute a value if present 1933 * @return the new value associated with the specified key, or null if none 1934 * @throws NullPointerException if the specified key or the 1935 * remappingFunction is null 1936 * @throws RuntimeException or Error if the remappingFunction does so, 1937 * in which case the mapping is unchanged 1938 */ 1939 public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) { 1940 if (key == null || value == null || remappingFunction == null) 1941 throw new NullPointerException(); 1942 int h = spread(key.hashCode()); 1943 V val = null; 1944 int delta = 0; 1945 int binCount = 0; 1946 for (Node<K,V>[] tab = table;;) { 1947 Node<K,V> f; int n, i, fh; 1948 if (tab == null || (n = tab.length) == 0) 1949 tab = initTable(); 1950 else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { 1951 if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) { 1952 delta = 1; 1953 val = value; 1954 break; 1955 } 1956 } 1957 else if ((fh = f.hash) == MOVED) 1958 tab = helpTransfer(tab, f); 1959 else { 1960 synchronized (f) { 1961 if (tabAt(tab, i) == f) { 1962 if (fh >= 0) { 1963 binCount = 1; 1964 for (Node<K,V> e = f, pred = null;; ++binCount) { 1965 K ek; 1966 if (e.hash == h && 1967 ((ek = e.key) == key || 1968 (ek != null && key.equals(ek)))) { 1969 val = remappingFunction.apply(e.val, value); 1970 if (val != null) 1971 e.val = val; 1972 else { 1973 delta = -1; 1974 Node<K,V> en = e.next; 1975 if (pred != null) 1976 pred.next = en; 1977 else 1978 setTabAt(tab, i, en); 1979 } 1980 break; 1981 } 1982 pred = e; 1983 if ((e = e.next) == null) { 1984 delta = 1; 1985 val = value; 1986 pred.next = 1987 new Node<K,V>(h, key, val, null); 1988 break; 1989 } 1990 } 1991 } 1992 else if (f instanceof TreeBin) { 1993 binCount = 2; 1994 TreeBin<K,V> t = (TreeBin<K,V>)f; 1995 TreeNode<K,V> r = t.root; 1996 TreeNode<K,V> p = (r == null) ? null : 1997 r.findTreeNode(h, key, null); 1998 val = (p == null) ? value : 1999 remappingFunction.apply(p.val, value); 2000 if (val != null) { 2001 if (p != null) 2002 p.val = val; 2003 else { 2004 delta = 1; 2005 t.putTreeVal(h, key, val); 2006 } 2007 } 2008 else if (p != null) { 2009 delta = -1; 2010 if (t.removeTreeNode(p)) 2011 setTabAt(tab, i, untreeify(t.first)); 2012 } 2013 } 2014 } 2015 } 2016 if (binCount != 0) { 2017 if (binCount >= TREEIFY_THRESHOLD) 2018 treeifyBin(tab, i); 2019 break; 2020 } 2021 } 2022 } 2023 if (delta != 0) 2024 addCount((long)delta, binCount); 2025 return val; 2026 } 2027 2028 // Hashtable legacy methods 2029 2030 /** 2031 * Legacy method testing if some key maps into the specified value 2032 * in this table. This method is identical in functionality to 2033 * {@link #containsValue(Object)}, and exists solely to ensure 2034 * full compatibility with class {@link java.util.Hashtable}, 2035 * which supported this method prior to introduction of the 2036 * Java Collections framework. 2037 * 2038 * @param value a value to search for 2039 * @return {@code true} if and only if some key maps to the 2040 * {@code value} argument in this table as 2041 * determined by the {@code equals} method; 2042 * {@code false} otherwise 2043 * @throws NullPointerException if the specified value is null 2044 */ 2045 public boolean contains(Object value) { 2046 return containsValue(value); 2047 } 2048 2049 /** 2050 * Returns an enumeration of the keys in this table. 2051 * 2052 * @return an enumeration of the keys in this table 2053 * @see #keySet() 2054 */ 2055 public Enumeration<K> keys() { 2056 Node<K,V>[] t; 2057 int f = (t = table) == null ? 0 : t.length; 2058 return new KeyIterator<K,V>(t, f, 0, f, this); 2059 } 2060 2061 /** 2062 * Returns an enumeration of the values in this table. 2063 * 2064 * @return an enumeration of the values in this table 2065 * @see #values() 2066 */ 2067 public Enumeration<V> elements() { 2068 Node<K,V>[] t; 2069 int f = (t = table) == null ? 0 : t.length; 2070 return new ValueIterator<K,V>(t, f, 0, f, this); 2071 } 2072 2073 // ConcurrentHashMap-only methods 2074 2075 /** 2076 * Returns the number of mappings. This method should be used 2077 * instead of {@link #size} because a ConcurrentHashMap may 2078 * contain more mappings than can be represented as an int. The 2079 * value returned is an estimate; the actual count may differ if 2080 * there are concurrent insertions or removals. 2081 * 2082 * @return the number of mappings 2083 * @since 1.8 2084 */ 2085 public long mappingCount() { 2086 long n = sumCount(); 2087 return (n < 0L) ? 0L : n; // ignore transient negative values 2088 } 2089 2090 /** 2091 * Creates a new {@link Set} backed by a ConcurrentHashMap 2092 * from the given type to {@code Boolean.TRUE}. 2093 * 2094 * @param <K> the element type of the returned set 2095 * @return the new set 2096 * @since 1.8 2097 */ 2098 public static <K> KeySetView<K,Boolean> newKeySet() { 2099 return new KeySetView<K,Boolean> 2100 (new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE); 2101 } 2102 2103 /** 2104 * Creates a new {@link Set} backed by a ConcurrentHashMap 2105 * from the given type to {@code Boolean.TRUE}. 2106 * 2107 * @param initialCapacity The implementation performs internal 2108 * sizing to accommodate this many elements. 2109 * @param <K> the element type of the returned set 2110 * @return the new set 2111 * @throws IllegalArgumentException if the initial capacity of 2112 * elements is negative 2113 * @since 1.8 2114 */ 2115 public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) { 2116 return new KeySetView<K,Boolean> 2117 (new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE); 2118 } 2119 2120 /** 2121 * Returns a {@link Set} view of the keys in this map, using the 2122 * given common mapped value for any additions (i.e., {@link 2123 * Collection#add} and {@link Collection#addAll(Collection)}). 2124 * This is of course only appropriate if it is acceptable to use 2125 * the same value for all additions from this view. 2126 * 2127 * @param mappedValue the mapped value to use for any additions 2128 * @return the set view 2129 * @throws NullPointerException if the mappedValue is null 2130 */ 2131 public KeySetView<K,V> keySet(V mappedValue) { 2132 if (mappedValue == null) 2133 throw new NullPointerException(); 2134 return new KeySetView<K,V>(this, mappedValue); 2135 } 2136 2137 /* ---------------- Special Nodes -------------- */ 2138 2139 /** 2140 * A node inserted at head of bins during transfer operations. 2141 */ 2142 static final class ForwardingNode<K,V> extends Node<K,V> { 2143 final Node<K,V>[] nextTable; 2144 ForwardingNode(Node<K,V>[] tab) { 2145 super(MOVED, null, null, null); 2146 this.nextTable = tab; 2147 } 2148 2149 Node<K,V> find(int h, Object k) { 2150 // loop to avoid arbitrarily deep recursion on forwarding nodes 2151 outer: for (Node<K,V>[] tab = nextTable;;) { 2152 Node<K,V> e; int n; 2153 if (k == null || tab == null || (n = tab.length) == 0 || 2154 (e = tabAt(tab, (n - 1) & h)) == null) 2155 return null; 2156 for (;;) { 2157 int eh; K ek; 2158 if ((eh = e.hash) == h && 2159 ((ek = e.key) == k || (ek != null && k.equals(ek)))) 2160 return e; 2161 if (eh < 0) { 2162 if (e instanceof ForwardingNode) { 2163 tab = ((ForwardingNode<K,V>)e).nextTable; 2164 continue outer; 2165 } 2166 else 2167 return e.find(h, k); 2168 } 2169 if ((e = e.next) == null) 2170 return null; 2171 } 2172 } 2173 } 2174 } 2175 2176 /** 2177 * A place-holder node used in computeIfAbsent and compute 2178 */ 2179 static final class ReservationNode<K,V> extends Node<K,V> { 2180 ReservationNode() { 2181 super(RESERVED, null, null, null); 2182 } 2183 2184 Node<K,V> find(int h, Object k) { 2185 return null; 2186 } 2187 } 2188 2189 /* ---------------- Table Initialization and Resizing -------------- */ 2190 2191 /** 2192 * Initializes table, using the size recorded in sizeCtl. 2193 */ 2194 private final Node<K,V>[] initTable() { 2195 Node<K,V>[] tab; int sc; 2196 while ((tab = table) == null || tab.length == 0) { 2197 if ((sc = sizeCtl) < 0) 2198 Thread.yield(); // lost initialization race; just spin 2199 else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { 2200 try { 2201 if ((tab = table) == null || tab.length == 0) { 2202 int n = (sc > 0) ? sc : DEFAULT_CAPACITY; 2203 @SuppressWarnings({"rawtypes","unchecked"}) 2204 Node<K,V>[] nt = (Node<K,V>[])new Node[n]; 2205 table = tab = nt; 2206 sc = n - (n >>> 2); 2207 } 2208 } finally { 2209 sizeCtl = sc; 2210 } 2211 break; 2212 } 2213 } 2214 return tab; 2215 } 2216 2217 /** 2218 * Adds to count, and if table is too small and not already 2219 * resizing, initiates transfer. If already resizing, helps 2220 * perform transfer if work is available. Rechecks occupancy 2221 * after a transfer to see if another resize is already needed 2222 * because resizings are lagging additions. 2223 * 2224 * @param x the count to add 2225 * @param check if <0, don't check resize, if <= 1 only check if uncontended 2226 */ 2227 private final void addCount(long x, int check) { 2228 CounterCell[] as; long b, s; 2229 if ((as = counterCells) != null || 2230 !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) { 2231 CounterCell a; long v; int m; 2232 boolean uncontended = true; 2233 if (as == null || (m = as.length - 1) < 0 || 2234 (a = as[ThreadLocalRandom.getProbe() & m]) == null || 2235 !(uncontended = 2236 U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) { 2237 fullAddCount(x, uncontended); 2238 return; 2239 } 2240 if (check <= 1) 2241 return; 2242 s = sumCount(); 2243 } 2244 if (check >= 0) { 2245 Node<K,V>[] tab, nt; int sc; 2246 while (s >= (long)(sc = sizeCtl) && (tab = table) != null && 2247 tab.length < MAXIMUM_CAPACITY) { 2248 if (sc < 0) { 2249 if (sc == -1 || transferIndex <= transferOrigin || 2250 (nt = nextTable) == null) 2251 break; 2252 if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1)) 2253 transfer(tab, nt); 2254 } 2255 else if (U.compareAndSwapInt(this, SIZECTL, sc, -2)) 2256 transfer(tab, null); 2257 s = sumCount(); 2258 } 2259 } 2260 } 2261 2262 /** 2263 * Helps transfer if a resize is in progress. 2264 */ 2265 final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) { 2266 Node<K,V>[] nextTab; int sc; 2267 if ((f instanceof ForwardingNode) && 2268 (nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) { 2269 if (nextTab == nextTable && tab == table && 2270 transferIndex > transferOrigin && (sc = sizeCtl) < -1 && 2271 U.compareAndSwapInt(this, SIZECTL, sc, sc - 1)) 2272 transfer(tab, nextTab); 2273 return nextTab; 2274 } 2275 return table; 2276 } 2277 2278 /** 2279 * Tries to presize table to accommodate the given number of elements. 2280 * 2281 * @param size number of elements (doesn't need to be perfectly accurate) 2282 */ 2283 private final void tryPresize(int size) { 2284 int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : 2285 tableSizeFor(size + (size >>> 1) + 1); 2286 int sc; 2287 while ((sc = sizeCtl) >= 0) { 2288 Node<K,V>[] tab = table; int n; 2289 if (tab == null || (n = tab.length) == 0) { 2290 n = (sc > c) ? sc : c; 2291 if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { 2292 try { 2293 if (table == tab) { 2294 @SuppressWarnings({"rawtypes","unchecked"}) 2295 Node<K,V>[] nt = (Node<K,V>[])new Node[n]; 2296 table = nt; 2297 sc = n - (n >>> 2); 2298 } 2299 } finally { 2300 sizeCtl = sc; 2301 } 2302 } 2303 } 2304 else if (c <= sc || n >= MAXIMUM_CAPACITY) 2305 break; 2306 else if (tab == table && 2307 U.compareAndSwapInt(this, SIZECTL, sc, -2)) 2308 transfer(tab, null); 2309 } 2310 } 2311 2312 /** 2313 * Moves and/or copies the nodes in each bin to new table. See 2314 * above for explanation. 2315 */ 2316 private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) { 2317 int n = tab.length, stride; 2318 if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE) 2319 stride = MIN_TRANSFER_STRIDE; // subdivide range 2320 if (nextTab == null) { // initiating 2321 try { 2322 @SuppressWarnings({"rawtypes","unchecked"}) 2323 Node<K,V>[] nt = (Node<K,V>[])new Node[n << 1]; 2324 nextTab = nt; 2325 } catch (Throwable ex) { // try to cope with OOME 2326 sizeCtl = Integer.MAX_VALUE; 2327 return; 2328 } 2329 nextTable = nextTab; 2330 transferOrigin = n; 2331 transferIndex = n; 2332 ForwardingNode<K,V> rev = new ForwardingNode<K,V>(tab); 2333 for (int k = n; k > 0;) { // progressively reveal ready slots 2334 int nextk = (k > stride) ? k - stride : 0; 2335 for (int m = nextk; m < k; ++m) 2336 nextTab[m] = rev; 2337 for (int m = n + nextk; m < n + k; ++m) 2338 nextTab[m] = rev; 2339 U.putOrderedInt(this, TRANSFERORIGIN, k = nextk); 2340 } 2341 } 2342 int nextn = nextTab.length; 2343 ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab); 2344 boolean advance = true; 2345 boolean finishing = false; // to ensure sweep before committing nextTab 2346 for (int i = 0, bound = 0;;) { 2347 int nextIndex, nextBound, fh; Node<K,V> f; 2348 while (advance) { 2349 if (--i >= bound || finishing) 2350 advance = false; 2351 else if ((nextIndex = transferIndex) <= transferOrigin) { 2352 i = -1; 2353 advance = false; 2354 } 2355 else if (U.compareAndSwapInt 2356 (this, TRANSFERINDEX, nextIndex, 2357 nextBound = (nextIndex > stride ? 2358 nextIndex - stride : 0))) { 2359 bound = nextBound; 2360 i = nextIndex - 1; 2361 advance = false; 2362 } 2363 } 2364 if (i < 0 || i >= n || i + n >= nextn) { 2365 if (finishing) { 2366 nextTable = null; 2367 table = nextTab; 2368 sizeCtl = (n << 1) - (n >>> 1); 2369 return; 2370 } 2371 for (int sc;;) { 2372 if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) { 2373 if (sc != -1) 2374 return; 2375 finishing = advance = true; 2376 i = n; // recheck before commit 2377 break; 2378 } 2379 } 2380 } 2381 else if ((f = tabAt(tab, i)) == null) { 2382 if (casTabAt(tab, i, null, fwd)) { 2383 setTabAt(nextTab, i, null); 2384 setTabAt(nextTab, i + n, null); 2385 advance = true; 2386 } 2387 } 2388 else if ((fh = f.hash) == MOVED) 2389 advance = true; // already processed 2390 else { 2391 synchronized (f) { 2392 if (tabAt(tab, i) == f) { 2393 Node<K,V> ln, hn; 2394 if (fh >= 0) { 2395 int runBit = fh & n; 2396 Node<K,V> lastRun = f; 2397 for (Node<K,V> p = f.next; p != null; p = p.next) { 2398 int b = p.hash & n; 2399 if (b != runBit) { 2400 runBit = b; 2401 lastRun = p; 2402 } 2403 } 2404 if (runBit == 0) { 2405 ln = lastRun; 2406 hn = null; 2407 } 2408 else { 2409 hn = lastRun; 2410 ln = null; 2411 } 2412 for (Node<K,V> p = f; p != lastRun; p = p.next) { 2413 int ph = p.hash; K pk = p.key; V pv = p.val; 2414 if ((ph & n) == 0) 2415 ln = new Node<K,V>(ph, pk, pv, ln); 2416 else 2417 hn = new Node<K,V>(ph, pk, pv, hn); 2418 } 2419 setTabAt(nextTab, i, ln); 2420 setTabAt(nextTab, i + n, hn); 2421 setTabAt(tab, i, fwd); 2422 advance = true; 2423 } 2424 else if (f instanceof TreeBin) { 2425 TreeBin<K,V> t = (TreeBin<K,V>)f; 2426 TreeNode<K,V> lo = null, loTail = null; 2427 TreeNode<K,V> hi = null, hiTail = null; 2428 int lc = 0, hc = 0; 2429 for (Node<K,V> e = t.first; e != null; e = e.next) { 2430 int h = e.hash; 2431 TreeNode<K,V> p = new TreeNode<K,V> 2432 (h, e.key, e.val, null, null); 2433 if ((h & n) == 0) { 2434 if ((p.prev = loTail) == null) 2435 lo = p; 2436 else 2437 loTail.next = p; 2438 loTail = p; 2439 ++lc; 2440 } 2441 else { 2442 if ((p.prev = hiTail) == null) 2443 hi = p; 2444 else 2445 hiTail.next = p; 2446 hiTail = p; 2447 ++hc; 2448 } 2449 } 2450 ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) : 2451 (hc != 0) ? new TreeBin<K,V>(lo) : t; 2452 hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) : 2453 (lc != 0) ? new TreeBin<K,V>(hi) : t; 2454 setTabAt(nextTab, i, ln); 2455 setTabAt(nextTab, i + n, hn); 2456 setTabAt(tab, i, fwd); 2457 advance = true; 2458 } 2459 } 2460 } 2461 } 2462 } 2463 } 2464 2465 /* ---------------- Counter support -------------- */ 2466 2467 /** 2468 * A padded cell for distributing counts. Adapted from LongAdder 2469 * and Striped64. See their internal docs for explanation. 2470 */ 2471 @sun.misc.Contended static final class CounterCell { 2472 volatile long value; 2473 CounterCell(long x) { value = x; } 2474 } 2475 2476 final long sumCount() { 2477 CounterCell[] as = counterCells; CounterCell a; 2478 long sum = baseCount; 2479 if (as != null) { 2480 for (int i = 0; i < as.length; ++i) { 2481 if ((a = as[i]) != null) 2482 sum += a.value; 2483 } 2484 } 2485 return sum; 2486 } 2487 2488 // See LongAdder version for explanation 2489 private final void fullAddCount(long x, boolean wasUncontended) { 2490 int h; 2491 if ((h = ThreadLocalRandom.getProbe()) == 0) { 2492 ThreadLocalRandom.localInit(); // force initialization 2493 h = ThreadLocalRandom.getProbe(); 2494 wasUncontended = true; 2495 } 2496 boolean collide = false; // True if last slot nonempty 2497 for (;;) { 2498 CounterCell[] as; CounterCell a; int n; long v; 2499 if ((as = counterCells) != null && (n = as.length) > 0) { 2500 if ((a = as[(n - 1) & h]) == null) { 2501 if (cellsBusy == 0) { // Try to attach new Cell 2502 CounterCell r = new CounterCell(x); // Optimistic create 2503 if (cellsBusy == 0 && 2504 U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { 2505 boolean created = false; 2506 try { // Recheck under lock 2507 CounterCell[] rs; int m, j; 2508 if ((rs = counterCells) != null && 2509 (m = rs.length) > 0 && 2510 rs[j = (m - 1) & h] == null) { 2511 rs[j] = r; 2512 created = true; 2513 } 2514 } finally { 2515 cellsBusy = 0; 2516 } 2517 if (created) 2518 break; 2519 continue; // Slot is now non-empty 2520 } 2521 } 2522 collide = false; 2523 } 2524 else if (!wasUncontended) // CAS already known to fail 2525 wasUncontended = true; // Continue after rehash 2526 else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x)) 2527 break; 2528 else if (counterCells != as || n >= NCPU) 2529 collide = false; // At max size or stale 2530 else if (!collide) 2531 collide = true; 2532 else if (cellsBusy == 0 && 2533 U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { 2534 try { 2535 if (counterCells == as) {// Expand table unless stale 2536 CounterCell[] rs = new CounterCell[n << 1]; 2537 for (int i = 0; i < n; ++i) 2538 rs[i] = as[i]; 2539 counterCells = rs; 2540 } 2541 } finally { 2542 cellsBusy = 0; 2543 } 2544 collide = false; 2545 continue; // Retry with expanded table 2546 } 2547 h = ThreadLocalRandom.advanceProbe(h); 2548 } 2549 else if (cellsBusy == 0 && counterCells == as && 2550 U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { 2551 boolean init = false; 2552 try { // Initialize table 2553 if (counterCells == as) { 2554 CounterCell[] rs = new CounterCell[2]; 2555 rs[h & 1] = new CounterCell(x); 2556 counterCells = rs; 2557 init = true; 2558 } 2559 } finally { 2560 cellsBusy = 0; 2561 } 2562 if (init) 2563 break; 2564 } 2565 else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x)) 2566 break; // Fall back on using base 2567 } 2568 } 2569 2570 /* ---------------- Conversion from/to TreeBins -------------- */ 2571 2572 /** 2573 * Replaces all linked nodes in bin at given index unless table is 2574 * too small, in which case resizes instead. 2575 */ 2576 private final void treeifyBin(Node<K,V>[] tab, int index) { 2577 Node<K,V> b; int n, sc; 2578 if (tab != null) { 2579 if ((n = tab.length) < MIN_TREEIFY_CAPACITY) { 2580 if (tab == table && (sc = sizeCtl) >= 0 && 2581 U.compareAndSwapInt(this, SIZECTL, sc, -2)) 2582 transfer(tab, null); 2583 } 2584 else if ((b = tabAt(tab, index)) != null && b.hash >= 0) { 2585 synchronized (b) { 2586 if (tabAt(tab, index) == b) { 2587 TreeNode<K,V> hd = null, tl = null; 2588 for (Node<K,V> e = b; e != null; e = e.next) { 2589 TreeNode<K,V> p = 2590 new TreeNode<K,V>(e.hash, e.key, e.val, 2591 null, null); 2592 if ((p.prev = tl) == null) 2593 hd = p; 2594 else 2595 tl.next = p; 2596 tl = p; 2597 } 2598 setTabAt(tab, index, new TreeBin<K,V>(hd)); 2599 } 2600 } 2601 } 2602 } 2603 } 2604 2605 /** 2606 * Returns a list on non-TreeNodes replacing those in given list. 2607 */ 2608 static <K,V> Node<K,V> untreeify(Node<K,V> b) { 2609 Node<K,V> hd = null, tl = null; 2610 for (Node<K,V> q = b; q != null; q = q.next) { 2611 Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null); 2612 if (tl == null) 2613 hd = p; 2614 else 2615 tl.next = p; 2616 tl = p; 2617 } 2618 return hd; 2619 } 2620 2621 /* ---------------- TreeNodes -------------- */ 2622 2623 /** 2624 * Nodes for use in TreeBins 2625 */ 2626 static final class TreeNode<K,V> extends Node<K,V> { 2627 TreeNode<K,V> parent; // red-black tree links 2628 TreeNode<K,V> left; 2629 TreeNode<K,V> right; 2630 TreeNode<K,V> prev; // needed to unlink next upon deletion 2631 boolean red; 2632 2633 TreeNode(int hash, K key, V val, Node<K,V> next, 2634 TreeNode<K,V> parent) { 2635 super(hash, key, val, next); 2636 this.parent = parent; 2637 } 2638 2639 Node<K,V> find(int h, Object k) { 2640 return findTreeNode(h, k, null); 2641 } 2642 2643 /** 2644 * Returns the TreeNode (or null if not found) for the given key 2645 * starting at given root. 2646 */ 2647 final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) { 2648 if (k != null) { 2649 TreeNode<K,V> p = this; 2650 do { 2651 int ph, dir; K pk; TreeNode<K,V> q; 2652 TreeNode<K,V> pl = p.left, pr = p.right; 2653 if ((ph = p.hash) > h) 2654 p = pl; 2655 else if (ph < h) 2656 p = pr; 2657 else if ((pk = p.key) == k || (pk != null && k.equals(pk))) 2658 return p; 2659 else if (pl == null) 2660 p = pr; 2661 else if (pr == null) 2662 p = pl; 2663 else if ((kc != null || 2664 (kc = comparableClassFor(k)) != null) && 2665 (dir = compareComparables(kc, k, pk)) != 0) 2666 p = (dir < 0) ? pl : pr; 2667 else if ((q = pr.findTreeNode(h, k, kc)) != null) 2668 return q; 2669 else 2670 p = pl; 2671 } while (p != null); 2672 } 2673 return null; 2674 } 2675 } 2676 2677 /* ---------------- TreeBins -------------- */ 2678 2679 /** 2680 * TreeNodes used at the heads of bins. TreeBins do not hold user 2681 * keys or values, but instead point to list of TreeNodes and 2682 * their root. They also maintain a parasitic read-write lock 2683 * forcing writers (who hold bin lock) to wait for readers (who do 2684 * not) to complete before tree restructuring operations. 2685 */ 2686 static final class TreeBin<K,V> extends Node<K,V> { 2687 TreeNode<K,V> root; 2688 volatile TreeNode<K,V> first; 2689 volatile Thread waiter; 2690 volatile int lockState; 2691 // values for lockState 2692 static final int WRITER = 1; // set while holding write lock 2693 static final int WAITER = 2; // set when waiting for write lock 2694 static final int READER = 4; // increment value for setting read lock 2695 2696 /** 2697 * Tie-breaking utility for ordering insertions when equal 2698 * hashCodes and non-comparable. We don't require a total 2699 * order, just a consistent insertion rule to maintain 2700 * equivalence across rebalancings. Tie-breaking further than 2701 * necessary simplifies testing a bit. 2702 */ 2703 static int tieBreakOrder(Object a, Object b) { 2704 int d; 2705 if (a == null || b == null || 2706 (d = a.getClass().getName(). 2707 compareTo(b.getClass().getName())) == 0) 2708 d = (System.identityHashCode(a) <= System.identityHashCode(b) ? 2709 -1 : 1); 2710 return d; 2711 } 2712 2713 /** 2714 * Creates bin with initial set of nodes headed by b. 2715 */ 2716 TreeBin(TreeNode<K,V> b) { 2717 super(TREEBIN, null, null, null); 2718 this.first = b; 2719 TreeNode<K,V> r = null; 2720 for (TreeNode<K,V> x = b, next; x != null; x = next) { 2721 next = (TreeNode<K,V>)x.next; 2722 x.left = x.right = null; 2723 if (r == null) { 2724 x.parent = null; 2725 x.red = false; 2726 r = x; 2727 } 2728 else { 2729 K k = x.key; 2730 int h = x.hash; 2731 Class<?> kc = null; 2732 for (TreeNode<K,V> p = r;;) { 2733 int dir, ph; 2734 K pk = p.key; 2735 if ((ph = p.hash) > h) 2736 dir = -1; 2737 else if (ph < h) 2738 dir = 1; 2739 else if ((kc == null && 2740 (kc = comparableClassFor(k)) == null) || 2741 (dir = compareComparables(kc, k, pk)) == 0) 2742 dir = tieBreakOrder(k, pk); 2743 TreeNode<K,V> xp = p; 2744 if ((p = (dir <= 0) ? p.left : p.right) == null) { 2745 x.parent = xp; 2746 if (dir <= 0) 2747 xp.left = x; 2748 else 2749 xp.right = x; 2750 r = balanceInsertion(r, x); 2751 break; 2752 } 2753 } 2754 } 2755 } 2756 this.root = r; 2757 assert checkInvariants(root); 2758 } 2759 2760 /** 2761 * Acquires write lock for tree restructuring. 2762 */ 2763 private final void lockRoot() { 2764 if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER)) 2765 contendedLock(); // offload to separate method 2766 } 2767 2768 /** 2769 * Releases write lock for tree restructuring. 2770 */ 2771 private final void unlockRoot() { 2772 lockState = 0; 2773 } 2774 2775 /** 2776 * Possibly blocks awaiting root lock. 2777 */ 2778 private final void contendedLock() { 2779 boolean waiting = false; 2780 for (int s;;) { 2781 if (((s = lockState) & WRITER) == 0) { 2782 if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) { 2783 if (waiting) 2784 waiter = null; 2785 return; 2786 } 2787 } 2788 else if ((s | WAITER) == 0) { 2789 if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) { 2790 waiting = true; 2791 waiter = Thread.currentThread(); 2792 } 2793 } 2794 else if (waiting) 2795 LockSupport.park(this); 2796 } 2797 } 2798 2799 /** 2800 * Returns matching node or null if none. Tries to search 2801 * using tree comparisons from root, but continues linear 2802 * search when lock not available. 2803 */ 2804 final Node<K,V> find(int h, Object k) { 2805 if (k != null) { 2806 for (Node<K,V> e = first; e != null; e = e.next) { 2807 int s; K ek; 2808 if (((s = lockState) & (WAITER|WRITER)) != 0) { 2809 if (e.hash == h && 2810 ((ek = e.key) == k || (ek != null && k.equals(ek)))) 2811 return e; 2812 } 2813 else if (U.compareAndSwapInt(this, LOCKSTATE, s, 2814 s + READER)) { 2815 TreeNode<K,V> r, p; 2816 try { 2817 p = ((r = root) == null ? null : 2818 r.findTreeNode(h, k, null)); 2819 } finally { 2820 Thread w; 2821 if (U.getAndAddInt(this, LOCKSTATE, -READER) == 2822 (READER|WAITER) && (w = waiter) != null) 2823 LockSupport.unpark(w); 2824 } 2825 return p; 2826 } 2827 } 2828 } 2829 return null; 2830 } 2831 2832 /** 2833 * Finds or adds a node. 2834 * @return null if added 2835 */ 2836 final TreeNode<K,V> putTreeVal(int h, K k, V v) { 2837 Class<?> kc = null; 2838 boolean searched = false; 2839 for (TreeNode<K,V> p = root;;) { 2840 int dir, ph; K pk; 2841 if (p == null) { 2842 first = root = new TreeNode<K,V>(h, k, v, null, null); 2843 break; 2844 } 2845 else if ((ph = p.hash) > h) 2846 dir = -1; 2847 else if (ph < h) 2848 dir = 1; 2849 else if ((pk = p.key) == k || (pk != null && k.equals(pk))) 2850 return p; 2851 else if ((kc == null && 2852 (kc = comparableClassFor(k)) == null) || 2853 (dir = compareComparables(kc, k, pk)) == 0) { 2854 if (!searched) { 2855 TreeNode<K,V> q, ch; 2856 searched = true; 2857 if (((ch = p.left) != null && 2858 (q = ch.findTreeNode(h, k, kc)) != null) || 2859 ((ch = p.right) != null && 2860 (q = ch.findTreeNode(h, k, kc)) != null)) 2861 return q; 2862 } 2863 dir = tieBreakOrder(k, pk); 2864 } 2865 2866 TreeNode<K,V> xp = p; 2867 if ((p = (dir <= 0) ? p.left : p.right) == null) { 2868 TreeNode<K,V> x, f = first; 2869 first = x = new TreeNode<K,V>(h, k, v, f, xp); 2870 if (f != null) 2871 f.prev = x; 2872 if (dir <= 0) 2873 xp.left = x; 2874 else 2875 xp.right = x; 2876 if (!xp.red) 2877 x.red = true; 2878 else { 2879 lockRoot(); 2880 try { 2881 root = balanceInsertion(root, x); 2882 } finally { 2883 unlockRoot(); 2884 } 2885 } 2886 break; 2887 } 2888 } 2889 assert checkInvariants(root); 2890 return null; 2891 } 2892 2893 /** 2894 * Removes the given node, that must be present before this 2895 * call. This is messier than typical red-black deletion code 2896 * because we cannot swap the contents of an interior node 2897 * with a leaf successor that is pinned by "next" pointers 2898 * that are accessible independently of lock. So instead we 2899 * swap the tree linkages. 2900 * 2901 * @return true if now too small, so should be untreeified 2902 */ 2903 final boolean removeTreeNode(TreeNode<K,V> p) { 2904 TreeNode<K,V> next = (TreeNode<K,V>)p.next; 2905 TreeNode<K,V> pred = p.prev; // unlink traversal pointers 2906 TreeNode<K,V> r, rl; 2907 if (pred == null) 2908 first = next; 2909 else 2910 pred.next = next; 2911 if (next != null) 2912 next.prev = pred; 2913 if (first == null) { 2914 root = null; 2915 return true; 2916 } 2917 if ((r = root) == null || r.right == null || // too small 2918 (rl = r.left) == null || rl.left == null) 2919 return true; 2920 lockRoot(); 2921 try { 2922 TreeNode<K,V> replacement; 2923 TreeNode<K,V> pl = p.left; 2924 TreeNode<K,V> pr = p.right; 2925 if (pl != null && pr != null) { 2926 TreeNode<K,V> s = pr, sl; 2927 while ((sl = s.left) != null) // find successor 2928 s = sl; 2929 boolean c = s.red; s.red = p.red; p.red = c; // swap colors 2930 TreeNode<K,V> sr = s.right; 2931 TreeNode<K,V> pp = p.parent; 2932 if (s == pr) { // p was s's direct parent 2933 p.parent = s; 2934 s.right = p; 2935 } 2936 else { 2937 TreeNode<K,V> sp = s.parent; 2938 if ((p.parent = sp) != null) { 2939 if (s == sp.left) 2940 sp.left = p; 2941 else 2942 sp.right = p; 2943 } 2944 if ((s.right = pr) != null) 2945 pr.parent = s; 2946 } 2947 p.left = null; 2948 if ((p.right = sr) != null) 2949 sr.parent = p; 2950 if ((s.left = pl) != null) 2951 pl.parent = s; 2952 if ((s.parent = pp) == null) 2953 r = s; 2954 else if (p == pp.left) 2955 pp.left = s; 2956 else 2957 pp.right = s; 2958 if (sr != null) 2959 replacement = sr; 2960 else 2961 replacement = p; 2962 } 2963 else if (pl != null) 2964 replacement = pl; 2965 else if (pr != null) 2966 replacement = pr; 2967 else 2968 replacement = p; 2969 if (replacement != p) { 2970 TreeNode<K,V> pp = replacement.parent = p.parent; 2971 if (pp == null) 2972 r = replacement; 2973 else if (p == pp.left) 2974 pp.left = replacement; 2975 else 2976 pp.right = replacement; 2977 p.left = p.right = p.parent = null; 2978 } 2979 2980 root = (p.red) ? r : balanceDeletion(r, replacement); 2981 2982 if (p == replacement) { // detach pointers 2983 TreeNode<K,V> pp; 2984 if ((pp = p.parent) != null) { 2985 if (p == pp.left) 2986 pp.left = null; 2987 else if (p == pp.right) 2988 pp.right = null; 2989 p.parent = null; 2990 } 2991 } 2992 } finally { 2993 unlockRoot(); 2994 } 2995 assert checkInvariants(root); 2996 return false; 2997 } 2998 2999 /* ------------------------------------------------------------ */ 3000 // Red-black tree methods, all adapted from CLR 3001 3002 static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root, 3003 TreeNode<K,V> p) { 3004 TreeNode<K,V> r, pp, rl; 3005 if (p != null && (r = p.right) != null) { 3006 if ((rl = p.right = r.left) != null) 3007 rl.parent = p; 3008 if ((pp = r.parent = p.parent) == null) 3009 (root = r).red = false; 3010 else if (pp.left == p) 3011 pp.left = r; 3012 else 3013 pp.right = r; 3014 r.left = p; 3015 p.parent = r; 3016 } 3017 return root; 3018 } 3019 3020 static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root, 3021 TreeNode<K,V> p) { 3022 TreeNode<K,V> l, pp, lr; 3023 if (p != null && (l = p.left) != null) { 3024 if ((lr = p.left = l.right) != null) 3025 lr.parent = p; 3026 if ((pp = l.parent = p.parent) == null) 3027 (root = l).red = false; 3028 else if (pp.right == p) 3029 pp.right = l; 3030 else 3031 pp.left = l; 3032 l.right = p; 3033 p.parent = l; 3034 } 3035 return root; 3036 } 3037 3038 static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root, 3039 TreeNode<K,V> x) { 3040 x.red = true; 3041 for (TreeNode<K,V> xp, xpp, xppl, xppr;;) { 3042 if ((xp = x.parent) == null) { 3043 x.red = false; 3044 return x; 3045 } 3046 else if (!xp.red || (xpp = xp.parent) == null) 3047 return root; 3048 if (xp == (xppl = xpp.left)) { 3049 if ((xppr = xpp.right) != null && xppr.red) { 3050 xppr.red = false; 3051 xp.red = false; 3052 xpp.red = true; 3053 x = xpp; 3054 } 3055 else { 3056 if (x == xp.right) { 3057 root = rotateLeft(root, x = xp); 3058 xpp = (xp = x.parent) == null ? null : xp.parent; 3059 } 3060 if (xp != null) { 3061 xp.red = false; 3062 if (xpp != null) { 3063 xpp.red = true; 3064 root = rotateRight(root, xpp); 3065 } 3066 } 3067 } 3068 } 3069 else { 3070 if (xppl != null && xppl.red) { 3071 xppl.red = false; 3072 xp.red = false; 3073 xpp.red = true; 3074 x = xpp; 3075 } 3076 else { 3077 if (x == xp.left) { 3078 root = rotateRight(root, x = xp); 3079 xpp = (xp = x.parent) == null ? null : xp.parent; 3080 } 3081 if (xp != null) { 3082 xp.red = false; 3083 if (xpp != null) { 3084 xpp.red = true; 3085 root = rotateLeft(root, xpp); 3086 } 3087 } 3088 } 3089 } 3090 } 3091 } 3092 3093 static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root, 3094 TreeNode<K,V> x) { 3095 for (TreeNode<K,V> xp, xpl, xpr;;) { 3096 if (x == null || x == root) 3097 return root; 3098 else if ((xp = x.parent) == null) { 3099 x.red = false; 3100 return x; 3101 } 3102 else if (x.red) { 3103 x.red = false; 3104 return root; 3105 } 3106 else if ((xpl = xp.left) == x) { 3107 if ((xpr = xp.right) != null && xpr.red) { 3108 xpr.red = false; 3109 xp.red = true; 3110 root = rotateLeft(root, xp); 3111 xpr = (xp = x.parent) == null ? null : xp.right; 3112 } 3113 if (xpr == null) 3114 x = xp; 3115 else { 3116 TreeNode<K,V> sl = xpr.left, sr = xpr.right; 3117 if ((sr == null || !sr.red) && 3118 (sl == null || !sl.red)) { 3119 xpr.red = true; 3120 x = xp; 3121 } 3122 else { 3123 if (sr == null || !sr.red) { 3124 if (sl != null) 3125 sl.red = false; 3126 xpr.red = true; 3127 root = rotateRight(root, xpr); 3128 xpr = (xp = x.parent) == null ? 3129 null : xp.right; 3130 } 3131 if (xpr != null) { 3132 xpr.red = (xp == null) ? false : xp.red; 3133 if ((sr = xpr.right) != null) 3134 sr.red = false; 3135 } 3136 if (xp != null) { 3137 xp.red = false; 3138 root = rotateLeft(root, xp); 3139 } 3140 x = root; 3141 } 3142 } 3143 } 3144 else { // symmetric 3145 if (xpl != null && xpl.red) { 3146 xpl.red = false; 3147 xp.red = true; 3148 root = rotateRight(root, xp); 3149 xpl = (xp = x.parent) == null ? null : xp.left; 3150 } 3151 if (xpl == null) 3152 x = xp; 3153 else { 3154 TreeNode<K,V> sl = xpl.left, sr = xpl.right; 3155 if ((sl == null || !sl.red) && 3156 (sr == null || !sr.red)) { 3157 xpl.red = true; 3158 x = xp; 3159 } 3160 else { 3161 if (sl == null || !sl.red) { 3162 if (sr != null) 3163 sr.red = false; 3164 xpl.red = true; 3165 root = rotateLeft(root, xpl); 3166 xpl = (xp = x.parent) == null ? 3167 null : xp.left; 3168 } 3169 if (xpl != null) { 3170 xpl.red = (xp == null) ? false : xp.red; 3171 if ((sl = xpl.left) != null) 3172 sl.red = false; 3173 } 3174 if (xp != null) { 3175 xp.red = false; 3176 root = rotateRight(root, xp); 3177 } 3178 x = root; 3179 } 3180 } 3181 } 3182 } 3183 } 3184 3185 /** 3186 * Recursive invariant check 3187 */ 3188 static <K,V> boolean checkInvariants(TreeNode<K,V> t) { 3189 TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right, 3190 tb = t.prev, tn = (TreeNode<K,V>)t.next; 3191 if (tb != null && tb.next != t) 3192 return false; 3193 if (tn != null && tn.prev != t) 3194 return false; 3195 if (tp != null && t != tp.left && t != tp.right) 3196 return false; 3197 if (tl != null && (tl.parent != t || tl.hash > t.hash)) 3198 return false; 3199 if (tr != null && (tr.parent != t || tr.hash < t.hash)) 3200 return false; 3201 if (t.red && tl != null && tl.red && tr != null && tr.red) 3202 return false; 3203 if (tl != null && !checkInvariants(tl)) 3204 return false; 3205 if (tr != null && !checkInvariants(tr)) 3206 return false; 3207 return true; 3208 } 3209 3210 private static final sun.misc.Unsafe U; 3211 private static final long LOCKSTATE; 3212 static { 3213 try { 3214 U = sun.misc.Unsafe.getUnsafe(); 3215 Class<?> k = TreeBin.class; 3216 LOCKSTATE = U.objectFieldOffset 3217 (k.getDeclaredField("lockState")); 3218 } catch (Exception e) { 3219 throw new Error(e); 3220 } 3221 } 3222 } 3223 3224 /* ----------------Table Traversal -------------- */ 3225 3226 /** 3227 * Encapsulates traversal for methods such as containsValue; also 3228 * serves as a base class for other iterators and spliterators. 3229 * 3230 * Method advance visits once each still-valid node that was 3231 * reachable upon iterator construction. It might miss some that 3232 * were added to a bin after the bin was visited, which is OK wrt 3233 * consistency guarantees. Maintaining this property in the face 3234 * of possible ongoing resizes requires a fair amount of 3235 * bookkeeping state that is difficult to optimize away amidst 3236 * volatile accesses. Even so, traversal maintains reasonable 3237 * throughput. 3238 * 3239 * Normally, iteration proceeds bin-by-bin traversing lists. 3240 * However, if the table has been resized, then all future steps 3241 * must traverse both the bin at the current index as well as at 3242 * (index + baseSize); and so on for further resizings. To 3243 * paranoically cope with potential sharing by users of iterators 3244 * across threads, iteration terminates if a bounds checks fails 3245 * for a table read. 3246 */ 3247 static class Traverser<K,V> { 3248 Node<K,V>[] tab; // current table; updated if resized 3249 Node<K,V> next; // the next entry to use 3250 int index; // index of bin to use next 3251 int baseIndex; // current index of initial table 3252 int baseLimit; // index bound for initial table 3253 final int baseSize; // initial table size 3254 3255 Traverser(Node<K,V>[] tab, int size, int index, int limit) { 3256 this.tab = tab; 3257 this.baseSize = size; 3258 this.baseIndex = this.index = index; 3259 this.baseLimit = limit; 3260 this.next = null; 3261 } 3262 3263 /** 3264 * Advances if possible, returning next valid node, or null if none. 3265 */ 3266 final Node<K,V> advance() { 3267 Node<K,V> e; 3268 if ((e = next) != null) 3269 e = e.next; 3270 for (;;) { 3271 Node<K,V>[] t; int i, n; K ek; // must use locals in checks 3272 if (e != null) 3273 return next = e; 3274 if (baseIndex >= baseLimit || (t = tab) == null || 3275 (n = t.length) <= (i = index) || i < 0) 3276 return next = null; 3277 if ((e = tabAt(t, index)) != null && e.hash < 0) { 3278 if (e instanceof ForwardingNode) { 3279 tab = ((ForwardingNode<K,V>)e).nextTable; 3280 e = null; 3281 continue; 3282 } 3283 else if (e instanceof TreeBin) 3284 e = ((TreeBin<K,V>)e).first; 3285 else 3286 e = null; 3287 } 3288 if ((index += baseSize) >= n) 3289 index = ++baseIndex; // visit upper slots if present 3290 } 3291 } 3292 } 3293 3294 /** 3295 * Base of key, value, and entry Iterators. Adds fields to 3296 * Traverser to support iterator.remove. 3297 */ 3298 static class BaseIterator<K,V> extends Traverser<K,V> { 3299 final ConcurrentHashMap<K,V> map; 3300 Node<K,V> lastReturned; 3301 BaseIterator(Node<K,V>[] tab, int size, int index, int limit, 3302 ConcurrentHashMap<K,V> map) { 3303 super(tab, size, index, limit); 3304 this.map = map; 3305 advance(); 3306 } 3307 3308 public final boolean hasNext() { return next != null; } 3309 public final boolean hasMoreElements() { return next != null; } 3310 3311 public final void remove() { 3312 Node<K,V> p; 3313 if ((p = lastReturned) == null) 3314 throw new IllegalStateException(); 3315 lastReturned = null; 3316 map.replaceNode(p.key, null, null); 3317 } 3318 } 3319 3320 static final class KeyIterator<K,V> extends BaseIterator<K,V> 3321 implements Iterator<K>, Enumeration<K> { 3322 KeyIterator(Node<K,V>[] tab, int index, int size, int limit, 3323 ConcurrentHashMap<K,V> map) { 3324 super(tab, index, size, limit, map); 3325 } 3326 3327 public final K next() { 3328 Node<K,V> p; 3329 if ((p = next) == null) 3330 throw new NoSuchElementException(); 3331 K k = p.key; 3332 lastReturned = p; 3333 advance(); 3334 return k; 3335 } 3336 3337 public final K nextElement() { return next(); } 3338 } 3339 3340 static final class ValueIterator<K,V> extends BaseIterator<K,V> 3341 implements Iterator<V>, Enumeration<V> { 3342 ValueIterator(Node<K,V>[] tab, int index, int size, int limit, 3343 ConcurrentHashMap<K,V> map) { 3344 super(tab, index, size, limit, map); 3345 } 3346 3347 public final V next() { 3348 Node<K,V> p; 3349 if ((p = next) == null) 3350 throw new NoSuchElementException(); 3351 V v = p.val; 3352 lastReturned = p; 3353 advance(); 3354 return v; 3355 } 3356 3357 public final V nextElement() { return next(); } 3358 } 3359 3360 static final class EntryIterator<K,V> extends BaseIterator<K,V> 3361 implements Iterator<Map.Entry<K,V>> { 3362 EntryIterator(Node<K,V>[] tab, int index, int size, int limit, 3363 ConcurrentHashMap<K,V> map) { 3364 super(tab, index, size, limit, map); 3365 } 3366 3367 public final Map.Entry<K,V> next() { 3368 Node<K,V> p; 3369 if ((p = next) == null) 3370 throw new NoSuchElementException(); 3371 K k = p.key; 3372 V v = p.val; 3373 lastReturned = p; 3374 advance(); 3375 return new MapEntry<K,V>(k, v, map); 3376 } 3377 } 3378 3379 /** 3380 * Exported Entry for EntryIterator 3381 */ 3382 static final class MapEntry<K,V> implements Map.Entry<K,V> { 3383 final K key; // non-null 3384 V val; // non-null 3385 final ConcurrentHashMap<K,V> map; 3386 MapEntry(K key, V val, ConcurrentHashMap<K,V> map) { 3387 this.key = key; 3388 this.val = val; 3389 this.map = map; 3390 } 3391 public K getKey() { return key; } 3392 public V getValue() { return val; } 3393 public int hashCode() { return key.hashCode() ^ val.hashCode(); } 3394 public String toString() { return key + "=" + val; } 3395 3396 public boolean equals(Object o) { 3397 Object k, v; Map.Entry<?,?> e; 3398 return ((o instanceof Map.Entry) && 3399 (k = (e = (Map.Entry<?,?>)o).getKey()) != null && 3400 (v = e.getValue()) != null && 3401 (k == key || k.equals(key)) && 3402 (v == val || v.equals(val))); 3403 } 3404 3405 /** 3406 * Sets our entry's value and writes through to the map. The 3407 * value to return is somewhat arbitrary here. Since we do not 3408 * necessarily track asynchronous changes, the most recent 3409 * "previous" value could be different from what we return (or 3410 * could even have been removed, in which case the put will 3411 * re-establish). We do not and cannot guarantee more. 3412 */ 3413 public V setValue(V value) { 3414 if (value == null) throw new NullPointerException(); 3415 V v = val; 3416 val = value; 3417 map.put(key, value); 3418 return v; 3419 } 3420 } 3421 3422 static final class KeySpliterator<K,V> extends Traverser<K,V> 3423 implements Spliterator<K> { 3424 long est; // size estimate 3425 KeySpliterator(Node<K,V>[] tab, int size, int index, int limit, 3426 long est) { 3427 super(tab, size, index, limit); 3428 this.est = est; 3429 } 3430 3431 public Spliterator<K> trySplit() { 3432 int i, f, h; 3433 return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : 3434 new KeySpliterator<K,V>(tab, baseSize, baseLimit = h, 3435 f, est >>>= 1); 3436 } 3437 3438 public void forEachRemaining(Consumer<? super K> action) { 3439 if (action == null) throw new NullPointerException(); 3440 for (Node<K,V> p; (p = advance()) != null;) 3441 action.accept(p.key); 3442 } 3443 3444 public boolean tryAdvance(Consumer<? super K> action) { 3445 if (action == null) throw new NullPointerException(); 3446 Node<K,V> p; 3447 if ((p = advance()) == null) 3448 return false; 3449 action.accept(p.key); 3450 return true; 3451 } 3452 3453 public long estimateSize() { return est; } 3454 3455 public int characteristics() { 3456 return Spliterator.DISTINCT | Spliterator.CONCURRENT | 3457 Spliterator.NONNULL; 3458 } 3459 } 3460 3461 static final class ValueSpliterator<K,V> extends Traverser<K,V> 3462 implements Spliterator<V> { 3463 long est; // size estimate 3464 ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit, 3465 long est) { 3466 super(tab, size, index, limit); 3467 this.est = est; 3468 } 3469 3470 public Spliterator<V> trySplit() { 3471 int i, f, h; 3472 return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : 3473 new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h, 3474 f, est >>>= 1); 3475 } 3476 3477 public void forEachRemaining(Consumer<? super V> action) { 3478 if (action == null) throw new NullPointerException(); 3479 for (Node<K,V> p; (p = advance()) != null;) 3480 action.accept(p.val); 3481 } 3482 3483 public boolean tryAdvance(Consumer<? super V> action) { 3484 if (action == null) throw new NullPointerException(); 3485 Node<K,V> p; 3486 if ((p = advance()) == null) 3487 return false; 3488 action.accept(p.val); 3489 return true; 3490 } 3491 3492 public long estimateSize() { return est; } 3493 3494 public int characteristics() { 3495 return Spliterator.CONCURRENT | Spliterator.NONNULL; 3496 } 3497 } 3498 3499 static final class EntrySpliterator<K,V> extends Traverser<K,V> 3500 implements Spliterator<Map.Entry<K,V>> { 3501 final ConcurrentHashMap<K,V> map; // To export MapEntry 3502 long est; // size estimate 3503 EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit, 3504 long est, ConcurrentHashMap<K,V> map) { 3505 super(tab, size, index, limit); 3506 this.map = map; 3507 this.est = est; 3508 } 3509 3510 public Spliterator<Map.Entry<K,V>> trySplit() { 3511 int i, f, h; 3512 return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : 3513 new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h, 3514 f, est >>>= 1, map); 3515 } 3516 3517 public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) { 3518 if (action == null) throw new NullPointerException(); 3519 for (Node<K,V> p; (p = advance()) != null; ) 3520 action.accept(new MapEntry<K,V>(p.key, p.val, map)); 3521 } 3522 3523 public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) { 3524 if (action == null) throw new NullPointerException(); 3525 Node<K,V> p; 3526 if ((p = advance()) == null) 3527 return false; 3528 action.accept(new MapEntry<K,V>(p.key, p.val, map)); 3529 return true; 3530 } 3531 3532 public long estimateSize() { return est; } 3533 3534 public int characteristics() { 3535 return Spliterator.DISTINCT | Spliterator.CONCURRENT | 3536 Spliterator.NONNULL; 3537 } 3538 } 3539 3540 // Parallel bulk operations 3541 3542 /** 3543 * Computes initial batch value for bulk tasks. The returned value 3544 * is approximately exp2 of the number of times (minus one) to 3545 * split task by two before executing leaf action. This value is 3546 * faster to compute and more convenient to use as a guide to 3547 * splitting than is the depth, since it is used while dividing by 3548 * two anyway. 3549 */ 3550 final int batchFor(long b) { 3551 long n; 3552 if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b) 3553 return 0; 3554 int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4 3555 return (b <= 0L || (n /= b) >= sp) ? sp : (int)n; 3556 } 3557 3558 /** 3559 * Performs the given action for each (key, value). 3560 * 3561 * @param parallelismThreshold the (estimated) number of elements 3562 * needed for this operation to be executed in parallel 3563 * @param action the action 3564 * @since 1.8 3565 */ 3566 public void forEach(long parallelismThreshold, 3567 BiConsumer<? super K,? super V> action) { 3568 if (action == null) throw new NullPointerException(); 3569 new ForEachMappingTask<K,V> 3570 (null, batchFor(parallelismThreshold), 0, 0, table, 3571 action).invoke(); 3572 } 3573 3574 /** 3575 * Performs the given action for each non-null transformation 3576 * of each (key, value). 3577 * 3578 * @param parallelismThreshold the (estimated) number of elements 3579 * needed for this operation to be executed in parallel 3580 * @param transformer a function returning the transformation 3581 * for an element, or null if there is no transformation (in 3582 * which case the action is not applied) 3583 * @param action the action 3584 * @param <U> the return type of the transformer 3585 * @since 1.8 3586 */ 3587 public <U> void forEach(long parallelismThreshold, 3588 BiFunction<? super K, ? super V, ? extends U> transformer, 3589 Consumer<? super U> action) { 3590 if (transformer == null || action == null) 3591 throw new NullPointerException(); 3592 new ForEachTransformedMappingTask<K,V,U> 3593 (null, batchFor(parallelismThreshold), 0, 0, table, 3594 transformer, action).invoke(); 3595 } 3596 3597 /** 3598 * Returns a non-null result from applying the given search 3599 * function on each (key, value), or null if none. Upon 3600 * success, further element processing is suppressed and the 3601 * results of any other parallel invocations of the search 3602 * function are ignored. 3603 * 3604 * @param parallelismThreshold the (estimated) number of elements 3605 * needed for this operation to be executed in parallel 3606 * @param searchFunction a function returning a non-null 3607 * result on success, else null 3608 * @param <U> the return type of the search function 3609 * @return a non-null result from applying the given search 3610 * function on each (key, value), or null if none 3611 * @since 1.8 3612 */ 3613 public <U> U search(long parallelismThreshold, 3614 BiFunction<? super K, ? super V, ? extends U> searchFunction) { 3615 if (searchFunction == null) throw new NullPointerException(); 3616 return new SearchMappingsTask<K,V,U> 3617 (null, batchFor(parallelismThreshold), 0, 0, table, 3618 searchFunction, new AtomicReference<U>()).invoke(); 3619 } 3620 3621 /** 3622 * Returns the result of accumulating the given transformation 3623 * of all (key, value) pairs using the given reducer to 3624 * combine values, or null if none. 3625 * 3626 * @param parallelismThreshold the (estimated) number of elements 3627 * needed for this operation to be executed in parallel 3628 * @param transformer a function returning the transformation 3629 * for an element, or null if there is no transformation (in 3630 * which case it is not combined) 3631 * @param reducer a commutative associative combining function 3632 * @param <U> the return type of the transformer 3633 * @return the result of accumulating the given transformation 3634 * of all (key, value) pairs 3635 * @since 1.8 3636 */ 3637 public <U> U reduce(long parallelismThreshold, 3638 BiFunction<? super K, ? super V, ? extends U> transformer, 3639 BiFunction<? super U, ? super U, ? extends U> reducer) { 3640 if (transformer == null || reducer == null) 3641 throw new NullPointerException(); 3642 return new MapReduceMappingsTask<K,V,U> 3643 (null, batchFor(parallelismThreshold), 0, 0, table, 3644 null, transformer, reducer).invoke(); 3645 } 3646 3647 /** 3648 * Returns the result of accumulating the given transformation 3649 * of all (key, value) pairs using the given reducer to 3650 * combine values, and the given basis as an identity value. 3651 * 3652 * @param parallelismThreshold the (estimated) number of elements 3653 * needed for this operation to be executed in parallel 3654 * @param transformer a function returning the transformation 3655 * for an element 3656 * @param basis the identity (initial default value) for the reduction 3657 * @param reducer a commutative associative combining function 3658 * @return the result of accumulating the given transformation 3659 * of all (key, value) pairs 3660 * @since 1.8 3661 */ 3662 public double reduceToDouble(long parallelismThreshold, 3663 ToDoubleBiFunction<? super K, ? super V> transformer, 3664 double basis, 3665 DoubleBinaryOperator reducer) { 3666 if (transformer == null || reducer == null) 3667 throw new NullPointerException(); 3668 return new MapReduceMappingsToDoubleTask<K,V> 3669 (null, batchFor(parallelismThreshold), 0, 0, table, 3670 null, transformer, basis, reducer).invoke(); 3671 } 3672 3673 /** 3674 * Returns the result of accumulating the given transformation 3675 * of all (key, value) pairs using the given reducer to 3676 * combine values, and the given basis as an identity value. 3677 * 3678 * @param parallelismThreshold the (estimated) number of elements 3679 * needed for this operation to be executed in parallel 3680 * @param transformer a function returning the transformation 3681 * for an element 3682 * @param basis the identity (initial default value) for the reduction 3683 * @param reducer a commutative associative combining function 3684 * @return the result of accumulating the given transformation 3685 * of all (key, value) pairs 3686 * @since 1.8 3687 */ 3688 public long reduceToLong(long parallelismThreshold, 3689 ToLongBiFunction<? super K, ? super V> transformer, 3690 long basis, 3691 LongBinaryOperator reducer) { 3692 if (transformer == null || reducer == null) 3693 throw new NullPointerException(); 3694 return new MapReduceMappingsToLongTask<K,V> 3695 (null, batchFor(parallelismThreshold), 0, 0, table, 3696 null, transformer, basis, reducer).invoke(); 3697 } 3698 3699 /** 3700 * Returns the result of accumulating the given transformation 3701 * of all (key, value) pairs using the given reducer to 3702 * combine values, and the given basis as an identity value. 3703 * 3704 * @param parallelismThreshold the (estimated) number of elements 3705 * needed for this operation to be executed in parallel 3706 * @param transformer a function returning the transformation 3707 * for an element 3708 * @param basis the identity (initial default value) for the reduction 3709 * @param reducer a commutative associative combining function 3710 * @return the result of accumulating the given transformation 3711 * of all (key, value) pairs 3712 * @since 1.8 3713 */ 3714 public int reduceToInt(long parallelismThreshold, 3715 ToIntBiFunction<? super K, ? super V> transformer, 3716 int basis, 3717 IntBinaryOperator reducer) { 3718 if (transformer == null || reducer == null) 3719 throw new NullPointerException(); 3720 return new MapReduceMappingsToIntTask<K,V> 3721 (null, batchFor(parallelismThreshold), 0, 0, table, 3722 null, transformer, basis, reducer).invoke(); 3723 } 3724 3725 /** 3726 * Performs the given action for each key. 3727 * 3728 * @param parallelismThreshold the (estimated) number of elements 3729 * needed for this operation to be executed in parallel 3730 * @param action the action 3731 * @since 1.8 3732 */ 3733 public void forEachKey(long parallelismThreshold, 3734 Consumer<? super K> action) { 3735 if (action == null) throw new NullPointerException(); 3736 new ForEachKeyTask<K,V> 3737 (null, batchFor(parallelismThreshold), 0, 0, table, 3738 action).invoke(); 3739 } 3740 3741 /** 3742 * Performs the given action for each non-null transformation 3743 * of each key. 3744 * 3745 * @param parallelismThreshold the (estimated) number of elements 3746 * needed for this operation to be executed in parallel 3747 * @param transformer a function returning the transformation 3748 * for an element, or null if there is no transformation (in 3749 * which case the action is not applied) 3750 * @param action the action 3751 * @param <U> the return type of the transformer 3752 * @since 1.8 3753 */ 3754 public <U> void forEachKey(long parallelismThreshold, 3755 Function<? super K, ? extends U> transformer, 3756 Consumer<? super U> action) { 3757 if (transformer == null || action == null) 3758 throw new NullPointerException(); 3759 new ForEachTransformedKeyTask<K,V,U> 3760 (null, batchFor(parallelismThreshold), 0, 0, table, 3761 transformer, action).invoke(); 3762 } 3763 3764 /** 3765 * Returns a non-null result from applying the given search 3766 * function on each key, or null if none. Upon success, 3767 * further element processing is suppressed and the results of 3768 * any other parallel invocations of the search function are 3769 * ignored. 3770 * 3771 * @param parallelismThreshold the (estimated) number of elements 3772 * needed for this operation to be executed in parallel 3773 * @param searchFunction a function returning a non-null 3774 * result on success, else null 3775 * @param <U> the return type of the search function 3776 * @return a non-null result from applying the given search 3777 * function on each key, or null if none 3778 * @since 1.8 3779 */ 3780 public <U> U searchKeys(long parallelismThreshold, 3781 Function<? super K, ? extends U> searchFunction) { 3782 if (searchFunction == null) throw new NullPointerException(); 3783 return new SearchKeysTask<K,V,U> 3784 (null, batchFor(parallelismThreshold), 0, 0, table, 3785 searchFunction, new AtomicReference<U>()).invoke(); 3786 } 3787 3788 /** 3789 * Returns the result of accumulating all keys using the given 3790 * reducer to combine values, or null if none. 3791 * 3792 * @param parallelismThreshold the (estimated) number of elements 3793 * needed for this operation to be executed in parallel 3794 * @param reducer a commutative associative combining function 3795 * @return the result of accumulating all keys using the given 3796 * reducer to combine values, or null if none 3797 * @since 1.8 3798 */ 3799 public K reduceKeys(long parallelismThreshold, 3800 BiFunction<? super K, ? super K, ? extends K> reducer) { 3801 if (reducer == null) throw new NullPointerException(); 3802 return new ReduceKeysTask<K,V> 3803 (null, batchFor(parallelismThreshold), 0, 0, table, 3804 null, reducer).invoke(); 3805 } 3806 3807 /** 3808 * Returns the result of accumulating the given transformation 3809 * of all keys using the given reducer to combine values, or 3810 * null if none. 3811 * 3812 * @param parallelismThreshold the (estimated) number of elements 3813 * needed for this operation to be executed in parallel 3814 * @param transformer a function returning the transformation 3815 * for an element, or null if there is no transformation (in 3816 * which case it is not combined) 3817 * @param reducer a commutative associative combining function 3818 * @param <U> the return type of the transformer 3819 * @return the result of accumulating the given transformation 3820 * of all keys 3821 * @since 1.8 3822 */ 3823 public <U> U reduceKeys(long parallelismThreshold, 3824 Function<? super K, ? extends U> transformer, 3825 BiFunction<? super U, ? super U, ? extends U> reducer) { 3826 if (transformer == null || reducer == null) 3827 throw new NullPointerException(); 3828 return new MapReduceKeysTask<K,V,U> 3829 (null, batchFor(parallelismThreshold), 0, 0, table, 3830 null, transformer, reducer).invoke(); 3831 } 3832 3833 /** 3834 * Returns the result of accumulating the given transformation 3835 * of all keys using the given reducer to combine values, and 3836 * the given basis as an identity value. 3837 * 3838 * @param parallelismThreshold the (estimated) number of elements 3839 * needed for this operation to be executed in parallel 3840 * @param transformer a function returning the transformation 3841 * for an element 3842 * @param basis the identity (initial default value) for the reduction 3843 * @param reducer a commutative associative combining function 3844 * @return the result of accumulating the given transformation 3845 * of all keys 3846 * @since 1.8 3847 */ 3848 public double reduceKeysToDouble(long parallelismThreshold, 3849 ToDoubleFunction<? super K> transformer, 3850 double basis, 3851 DoubleBinaryOperator reducer) { 3852 if (transformer == null || reducer == null) 3853 throw new NullPointerException(); 3854 return new MapReduceKeysToDoubleTask<K,V> 3855 (null, batchFor(parallelismThreshold), 0, 0, table, 3856 null, transformer, basis, reducer).invoke(); 3857 } 3858 3859 /** 3860 * Returns the result of accumulating the given transformation 3861 * of all keys using the given reducer to combine values, and 3862 * the given basis as an identity value. 3863 * 3864 * @param parallelismThreshold the (estimated) number of elements 3865 * needed for this operation to be executed in parallel 3866 * @param transformer a function returning the transformation 3867 * for an element 3868 * @param basis the identity (initial default value) for the reduction 3869 * @param reducer a commutative associative combining function 3870 * @return the result of accumulating the given transformation 3871 * of all keys 3872 * @since 1.8 3873 */ 3874 public long reduceKeysToLong(long parallelismThreshold, 3875 ToLongFunction<? super K> transformer, 3876 long basis, 3877 LongBinaryOperator reducer) { 3878 if (transformer == null || reducer == null) 3879 throw new NullPointerException(); 3880 return new MapReduceKeysToLongTask<K,V> 3881 (null, batchFor(parallelismThreshold), 0, 0, table, 3882 null, transformer, basis, reducer).invoke(); 3883 } 3884 3885 /** 3886 * Returns the result of accumulating the given transformation 3887 * of all keys using the given reducer to combine values, and 3888 * the given basis as an identity value. 3889 * 3890 * @param parallelismThreshold the (estimated) number of elements 3891 * needed for this operation to be executed in parallel 3892 * @param transformer a function returning the transformation 3893 * for an element 3894 * @param basis the identity (initial default value) for the reduction 3895 * @param reducer a commutative associative combining function 3896 * @return the result of accumulating the given transformation 3897 * of all keys 3898 * @since 1.8 3899 */ 3900 public int reduceKeysToInt(long parallelismThreshold, 3901 ToIntFunction<? super K> transformer, 3902 int basis, 3903 IntBinaryOperator reducer) { 3904 if (transformer == null || reducer == null) 3905 throw new NullPointerException(); 3906 return new MapReduceKeysToIntTask<K,V> 3907 (null, batchFor(parallelismThreshold), 0, 0, table, 3908 null, transformer, basis, reducer).invoke(); 3909 } 3910 3911 /** 3912 * Performs the given action for each value. 3913 * 3914 * @param parallelismThreshold the (estimated) number of elements 3915 * needed for this operation to be executed in parallel 3916 * @param action the action 3917 * @since 1.8 3918 */ 3919 public void forEachValue(long parallelismThreshold, 3920 Consumer<? super V> action) { 3921 if (action == null) 3922 throw new NullPointerException(); 3923 new ForEachValueTask<K,V> 3924 (null, batchFor(parallelismThreshold), 0, 0, table, 3925 action).invoke(); 3926 } 3927 3928 /** 3929 * Performs the given action for each non-null transformation 3930 * of each value. 3931 * 3932 * @param parallelismThreshold the (estimated) number of elements 3933 * needed for this operation to be executed in parallel 3934 * @param transformer a function returning the transformation 3935 * for an element, or null if there is no transformation (in 3936 * which case the action is not applied) 3937 * @param action the action 3938 * @param <U> the return type of the transformer 3939 * @since 1.8 3940 */ 3941 public <U> void forEachValue(long parallelismThreshold, 3942 Function<? super V, ? extends U> transformer, 3943 Consumer<? super U> action) { 3944 if (transformer == null || action == null) 3945 throw new NullPointerException(); 3946 new ForEachTransformedValueTask<K,V,U> 3947 (null, batchFor(parallelismThreshold), 0, 0, table, 3948 transformer, action).invoke(); 3949 } 3950 3951 /** 3952 * Returns a non-null result from applying the given search 3953 * function on each value, or null if none. Upon success, 3954 * further element processing is suppressed and the results of 3955 * any other parallel invocations of the search function are 3956 * ignored. 3957 * 3958 * @param parallelismThreshold the (estimated) number of elements 3959 * needed for this operation to be executed in parallel 3960 * @param searchFunction a function returning a non-null 3961 * result on success, else null 3962 * @param <U> the return type of the search function 3963 * @return a non-null result from applying the given search 3964 * function on each value, or null if none 3965 * @since 1.8 3966 */ 3967 public <U> U searchValues(long parallelismThreshold, 3968 Function<? super V, ? extends U> searchFunction) { 3969 if (searchFunction == null) throw new NullPointerException(); 3970 return new SearchValuesTask<K,V,U> 3971 (null, batchFor(parallelismThreshold), 0, 0, table, 3972 searchFunction, new AtomicReference<U>()).invoke(); 3973 } 3974 3975 /** 3976 * Returns the result of accumulating all values using the 3977 * given reducer to combine values, or null if none. 3978 * 3979 * @param parallelismThreshold the (estimated) number of elements 3980 * needed for this operation to be executed in parallel 3981 * @param reducer a commutative associative combining function 3982 * @return the result of accumulating all values 3983 * @since 1.8 3984 */ 3985 public V reduceValues(long parallelismThreshold, 3986 BiFunction<? super V, ? super V, ? extends V> reducer) { 3987 if (reducer == null) throw new NullPointerException(); 3988 return new ReduceValuesTask<K,V> 3989 (null, batchFor(parallelismThreshold), 0, 0, table, 3990 null, reducer).invoke(); 3991 } 3992 3993 /** 3994 * Returns the result of accumulating the given transformation 3995 * of all values using the given reducer to combine values, or 3996 * null if none. 3997 * 3998 * @param parallelismThreshold the (estimated) number of elements 3999 * needed for this operation to be executed in parallel 4000 * @param transformer a function returning the transformation 4001 * for an element, or null if there is no transformation (in 4002 * which case it is not combined) 4003 * @param reducer a commutative associative combining function 4004 * @param <U> the return type of the transformer 4005 * @return the result of accumulating the given transformation 4006 * of all values 4007 * @since 1.8 4008 */ 4009 public <U> U reduceValues(long parallelismThreshold, 4010 Function<? super V, ? extends U> transformer, 4011 BiFunction<? super U, ? super U, ? extends U> reducer) { 4012 if (transformer == null || reducer == null) 4013 throw new NullPointerException(); 4014 return new MapReduceValuesTask<K,V,U> 4015 (null, batchFor(parallelismThreshold), 0, 0, table, 4016 null, transformer, reducer).invoke(); 4017 } 4018 4019 /** 4020 * Returns the result of accumulating the given transformation 4021 * of all values using the given reducer to combine values, 4022 * and the given basis as an identity value. 4023 * 4024 * @param parallelismThreshold the (estimated) number of elements 4025 * needed for this operation to be executed in parallel 4026 * @param transformer a function returning the transformation 4027 * for an element 4028 * @param basis the identity (initial default value) for the reduction 4029 * @param reducer a commutative associative combining function 4030 * @return the result of accumulating the given transformation 4031 * of all values 4032 * @since 1.8 4033 */ 4034 public double reduceValuesToDouble(long parallelismThreshold, 4035 ToDoubleFunction<? super V> transformer, 4036 double basis, 4037 DoubleBinaryOperator reducer) { 4038 if (transformer == null || reducer == null) 4039 throw new NullPointerException(); 4040 return new MapReduceValuesToDoubleTask<K,V> 4041 (null, batchFor(parallelismThreshold), 0, 0, table, 4042 null, transformer, basis, reducer).invoke(); 4043 } 4044 4045 /** 4046 * Returns the result of accumulating the given transformation 4047 * of all values using the given reducer to combine values, 4048 * and the given basis as an identity value. 4049 * 4050 * @param parallelismThreshold the (estimated) number of elements 4051 * needed for this operation to be executed in parallel 4052 * @param transformer a function returning the transformation 4053 * for an element 4054 * @param basis the identity (initial default value) for the reduction 4055 * @param reducer a commutative associative combining function 4056 * @return the result of accumulating the given transformation 4057 * of all values 4058 * @since 1.8 4059 */ 4060 public long reduceValuesToLong(long parallelismThreshold, 4061 ToLongFunction<? super V> transformer, 4062 long basis, 4063 LongBinaryOperator reducer) { 4064 if (transformer == null || reducer == null) 4065 throw new NullPointerException(); 4066 return new MapReduceValuesToLongTask<K,V> 4067 (null, batchFor(parallelismThreshold), 0, 0, table, 4068 null, transformer, basis, reducer).invoke(); 4069 } 4070 4071 /** 4072 * Returns the result of accumulating the given transformation 4073 * of all values using the given reducer to combine values, 4074 * and the given basis as an identity value. 4075 * 4076 * @param parallelismThreshold the (estimated) number of elements 4077 * needed for this operation to be executed in parallel 4078 * @param transformer a function returning the transformation 4079 * for an element 4080 * @param basis the identity (initial default value) for the reduction 4081 * @param reducer a commutative associative combining function 4082 * @return the result of accumulating the given transformation 4083 * of all values 4084 * @since 1.8 4085 */ 4086 public int reduceValuesToInt(long parallelismThreshold, 4087 ToIntFunction<? super V> transformer, 4088 int basis, 4089 IntBinaryOperator reducer) { 4090 if (transformer == null || reducer == null) 4091 throw new NullPointerException(); 4092 return new MapReduceValuesToIntTask<K,V> 4093 (null, batchFor(parallelismThreshold), 0, 0, table, 4094 null, transformer, basis, reducer).invoke(); 4095 } 4096 4097 /** 4098 * Performs the given action for each entry. 4099 * 4100 * @param parallelismThreshold the (estimated) number of elements 4101 * needed for this operation to be executed in parallel 4102 * @param action the action 4103 * @since 1.8 4104 */ 4105 public void forEachEntry(long parallelismThreshold, 4106 Consumer<? super Map.Entry<K,V>> action) { 4107 if (action == null) throw new NullPointerException(); 4108 new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table, 4109 action).invoke(); 4110 } 4111 4112 /** 4113 * Performs the given action for each non-null transformation 4114 * of each entry. 4115 * 4116 * @param parallelismThreshold the (estimated) number of elements 4117 * needed for this operation to be executed in parallel 4118 * @param transformer a function returning the transformation 4119 * for an element, or null if there is no transformation (in 4120 * which case the action is not applied) 4121 * @param action the action 4122 * @param <U> the return type of the transformer 4123 * @since 1.8 4124 */ 4125 public <U> void forEachEntry(long parallelismThreshold, 4126 Function<Map.Entry<K,V>, ? extends U> transformer, 4127 Consumer<? super U> action) { 4128 if (transformer == null || action == null) 4129 throw new NullPointerException(); 4130 new ForEachTransformedEntryTask<K,V,U> 4131 (null, batchFor(parallelismThreshold), 0, 0, table, 4132 transformer, action).invoke(); 4133 } 4134 4135 /** 4136 * Returns a non-null result from applying the given search 4137 * function on each entry, or null if none. Upon success, 4138 * further element processing is suppressed and the results of 4139 * any other parallel invocations of the search function are 4140 * ignored. 4141 * 4142 * @param parallelismThreshold the (estimated) number of elements 4143 * needed for this operation to be executed in parallel 4144 * @param searchFunction a function returning a non-null 4145 * result on success, else null 4146 * @param <U> the return type of the search function 4147 * @return a non-null result from applying the given search 4148 * function on each entry, or null if none 4149 * @since 1.8 4150 */ 4151 public <U> U searchEntries(long parallelismThreshold, 4152 Function<Map.Entry<K,V>, ? extends U> searchFunction) { 4153 if (searchFunction == null) throw new NullPointerException(); 4154 return new SearchEntriesTask<K,V,U> 4155 (null, batchFor(parallelismThreshold), 0, 0, table, 4156 searchFunction, new AtomicReference<U>()).invoke(); 4157 } 4158 4159 /** 4160 * Returns the result of accumulating all entries using the 4161 * given reducer to combine values, or null if none. 4162 * 4163 * @param parallelismThreshold the (estimated) number of elements 4164 * needed for this operation to be executed in parallel 4165 * @param reducer a commutative associative combining function 4166 * @return the result of accumulating all entries 4167 * @since 1.8 4168 */ 4169 public Map.Entry<K,V> reduceEntries(long parallelismThreshold, 4170 BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) { 4171 if (reducer == null) throw new NullPointerException(); 4172 return new ReduceEntriesTask<K,V> 4173 (null, batchFor(parallelismThreshold), 0, 0, table, 4174 null, reducer).invoke(); 4175 } 4176 4177 /** 4178 * Returns the result of accumulating the given transformation 4179 * of all entries using the given reducer to combine values, 4180 * or null if none. 4181 * 4182 * @param parallelismThreshold the (estimated) number of elements 4183 * needed for this operation to be executed in parallel 4184 * @param transformer a function returning the transformation 4185 * for an element, or null if there is no transformation (in 4186 * which case it is not combined) 4187 * @param reducer a commutative associative combining function 4188 * @param <U> the return type of the transformer 4189 * @return the result of accumulating the given transformation 4190 * of all entries 4191 * @since 1.8 4192 */ 4193 public <U> U reduceEntries(long parallelismThreshold, 4194 Function<Map.Entry<K,V>, ? extends U> transformer, 4195 BiFunction<? super U, ? super U, ? extends U> reducer) { 4196 if (transformer == null || reducer == null) 4197 throw new NullPointerException(); 4198 return new MapReduceEntriesTask<K,V,U> 4199 (null, batchFor(parallelismThreshold), 0, 0, table, 4200 null, transformer, reducer).invoke(); 4201 } 4202 4203 /** 4204 * Returns the result of accumulating the given transformation 4205 * of all entries using the given reducer to combine values, 4206 * and the given basis as an identity value. 4207 * 4208 * @param parallelismThreshold the (estimated) number of elements 4209 * needed for this operation to be executed in parallel 4210 * @param transformer a function returning the transformation 4211 * for an element 4212 * @param basis the identity (initial default value) for the reduction 4213 * @param reducer a commutative associative combining function 4214 * @return the result of accumulating the given transformation 4215 * of all entries 4216 * @since 1.8 4217 */ 4218 public double reduceEntriesToDouble(long parallelismThreshold, 4219 ToDoubleFunction<Map.Entry<K,V>> transformer, 4220 double basis, 4221 DoubleBinaryOperator reducer) { 4222 if (transformer == null || reducer == null) 4223 throw new NullPointerException(); 4224 return new MapReduceEntriesToDoubleTask<K,V> 4225 (null, batchFor(parallelismThreshold), 0, 0, table, 4226 null, transformer, basis, reducer).invoke(); 4227 } 4228 4229 /** 4230 * Returns the result of accumulating the given transformation 4231 * of all entries using the given reducer to combine values, 4232 * and the given basis as an identity value. 4233 * 4234 * @param parallelismThreshold the (estimated) number of elements 4235 * needed for this operation to be executed in parallel 4236 * @param transformer a function returning the transformation 4237 * for an element 4238 * @param basis the identity (initial default value) for the reduction 4239 * @param reducer a commutative associative combining function 4240 * @return the result of accumulating the given transformation 4241 * of all entries 4242 * @since 1.8 4243 */ 4244 public long reduceEntriesToLong(long parallelismThreshold, 4245 ToLongFunction<Map.Entry<K,V>> transformer, 4246 long basis, 4247 LongBinaryOperator reducer) { 4248 if (transformer == null || reducer == null) 4249 throw new NullPointerException(); 4250 return new MapReduceEntriesToLongTask<K,V> 4251 (null, batchFor(parallelismThreshold), 0, 0, table, 4252 null, transformer, basis, reducer).invoke(); 4253 } 4254 4255 /** 4256 * Returns the result of accumulating the given transformation 4257 * of all entries using the given reducer to combine values, 4258 * and the given basis as an identity value. 4259 * 4260 * @param parallelismThreshold the (estimated) number of elements 4261 * needed for this operation to be executed in parallel 4262 * @param transformer a function returning the transformation 4263 * for an element 4264 * @param basis the identity (initial default value) for the reduction 4265 * @param reducer a commutative associative combining function 4266 * @return the result of accumulating the given transformation 4267 * of all entries 4268 * @since 1.8 4269 */ 4270 public int reduceEntriesToInt(long parallelismThreshold, 4271 ToIntFunction<Map.Entry<K,V>> transformer, 4272 int basis, 4273 IntBinaryOperator reducer) { 4274 if (transformer == null || reducer == null) 4275 throw new NullPointerException(); 4276 return new MapReduceEntriesToIntTask<K,V> 4277 (null, batchFor(parallelismThreshold), 0, 0, table, 4278 null, transformer, basis, reducer).invoke(); 4279 } 4280 4281 4282 /* ----------------Views -------------- */ 4283 4284 /** 4285 * Base class for views. 4286 */ 4287 abstract static class CollectionView<K,V,E> 4288 implements Collection<E>, java.io.Serializable { 4289 private static final long serialVersionUID = 7249069246763182397L; 4290 final ConcurrentHashMap<K,V> map; 4291 CollectionView(ConcurrentHashMap<K,V> map) { this.map = map; } 4292 4293 /** 4294 * Returns the map backing this view. 4295 * 4296 * @return the map backing this view 4297 */ 4298 public ConcurrentHashMap<K,V> getMap() { return map; } 4299 4300 /** 4301 * Removes all of the elements from this view, by removing all 4302 * the mappings from the map backing this view. 4303 */ 4304 public final void clear() { map.clear(); } 4305 public final int size() { return map.size(); } 4306 public final boolean isEmpty() { return map.isEmpty(); } 4307 4308 // implementations below rely on concrete classes supplying these 4309 // abstract methods 4310 /** 4311 * Returns a "weakly consistent" iterator that will never 4312 * throw {@link ConcurrentModificationException}, and 4313 * guarantees to traverse elements as they existed upon 4314 * construction of the iterator, and may (but is not 4315 * guaranteed to) reflect any modifications subsequent to 4316 * construction. 4317 */ 4318 public abstract Iterator<E> iterator(); 4319 public abstract boolean contains(Object o); 4320 public abstract boolean remove(Object o); 4321 4322 private static final String oomeMsg = "Required array size too large"; 4323 4324 public final Object[] toArray() { 4325 long sz = map.mappingCount(); 4326 if (sz > MAX_ARRAY_SIZE) 4327 throw new OutOfMemoryError(oomeMsg); 4328 int n = (int)sz; 4329 Object[] r = new Object[n]; 4330 int i = 0; 4331 for (E e : this) { 4332 if (i == n) { 4333 if (n >= MAX_ARRAY_SIZE) 4334 throw new OutOfMemoryError(oomeMsg); 4335 if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) 4336 n = MAX_ARRAY_SIZE; 4337 else 4338 n += (n >>> 1) + 1; 4339 r = Arrays.copyOf(r, n); 4340 } 4341 r[i++] = e; 4342 } 4343 return (i == n) ? r : Arrays.copyOf(r, i); 4344 } 4345 4346 @SuppressWarnings("unchecked") 4347 public final <T> T[] toArray(T[] a) { 4348 long sz = map.mappingCount(); 4349 if (sz > MAX_ARRAY_SIZE) 4350 throw new OutOfMemoryError(oomeMsg); 4351 int m = (int)sz; 4352 T[] r = (a.length >= m) ? a : 4353 (T[])java.lang.reflect.Array 4354 .newInstance(a.getClass().getComponentType(), m); 4355 int n = r.length; 4356 int i = 0; 4357 for (E e : this) { 4358 if (i == n) { 4359 if (n >= MAX_ARRAY_SIZE) 4360 throw new OutOfMemoryError(oomeMsg); 4361 if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) 4362 n = MAX_ARRAY_SIZE; 4363 else 4364 n += (n >>> 1) + 1; 4365 r = Arrays.copyOf(r, n); 4366 } 4367 r[i++] = (T)e; 4368 } 4369 if (a == r && i < n) { 4370 r[i] = null; // null-terminate 4371 return r; 4372 } 4373 return (i == n) ? r : Arrays.copyOf(r, i); 4374 } 4375 4376 /** 4377 * Returns a string representation of this collection. 4378 * The string representation consists of the string representations 4379 * of the collection's elements in the order they are returned by 4380 * its iterator, enclosed in square brackets ({@code "[]"}). 4381 * Adjacent elements are separated by the characters {@code ", "} 4382 * (comma and space). Elements are converted to strings as by 4383 * {@link String#valueOf(Object)}. 4384 * 4385 * @return a string representation of this collection 4386 */ 4387 public final String toString() { 4388 StringBuilder sb = new StringBuilder(); 4389 sb.append('['); 4390 Iterator<E> it = iterator(); 4391 if (it.hasNext()) { 4392 for (;;) { 4393 Object e = it.next(); 4394 sb.append(e == this ? "(this Collection)" : e); 4395 if (!it.hasNext()) 4396 break; 4397 sb.append(',').append(' '); 4398 } 4399 } 4400 return sb.append(']').toString(); 4401 } 4402 4403 public final boolean containsAll(Collection<?> c) { 4404 if (c != this) { 4405 for (Object e : c) { 4406 if (e == null || !contains(e)) 4407 return false; 4408 } 4409 } 4410 return true; 4411 } 4412 4413 public final boolean removeAll(Collection<?> c) { 4414 boolean modified = false; 4415 for (Iterator<E> it = iterator(); it.hasNext();) { 4416 if (c.contains(it.next())) { 4417 it.remove(); 4418 modified = true; 4419 } 4420 } 4421 return modified; 4422 } 4423 4424 public final boolean retainAll(Collection<?> c) { 4425 boolean modified = false; 4426 for (Iterator<E> it = iterator(); it.hasNext();) { 4427 if (!c.contains(it.next())) { 4428 it.remove(); 4429 modified = true; 4430 } 4431 } 4432 return modified; 4433 } 4434 4435 } 4436 4437 /** 4438 * A view of a ConcurrentHashMap as a {@link Set} of keys, in 4439 * which additions may optionally be enabled by mapping to a 4440 * common value. This class cannot be directly instantiated. 4441 * See {@link #keySet() keySet()}, 4442 * {@link #keySet(Object) keySet(V)}, 4443 * {@link #newKeySet() newKeySet()}, 4444 * {@link #newKeySet(int) newKeySet(int)}. 4445 * 4446 * @since 1.8 4447 */ 4448 public static class KeySetView<K,V> extends CollectionView<K,V,K> 4449 implements Set<K>, java.io.Serializable { 4450 private static final long serialVersionUID = 7249069246763182397L; 4451 private final V value; 4452 KeySetView(ConcurrentHashMap<K,V> map, V value) { // non-public 4453 super(map); 4454 this.value = value; 4455 } 4456 4457 /** 4458 * Returns the default mapped value for additions, 4459 * or {@code null} if additions are not supported. 4460 * 4461 * @return the default mapped value for additions, or {@code null} 4462 * if not supported 4463 */ 4464 public V getMappedValue() { return value; } 4465 4466 /** 4467 * {@inheritDoc} 4468 * @throws NullPointerException if the specified key is null 4469 */ 4470 public boolean contains(Object o) { return map.containsKey(o); } 4471 4472 /** 4473 * Removes the key from this map view, by removing the key (and its 4474 * corresponding value) from the backing map. This method does 4475 * nothing if the key is not in the map. 4476 * 4477 * @param o the key to be removed from the backing map 4478 * @return {@code true} if the backing map contained the specified key 4479 * @throws NullPointerException if the specified key is null 4480 */ 4481 public boolean remove(Object o) { return map.remove(o) != null; } 4482 4483 /** 4484 * @return an iterator over the keys of the backing map 4485 */ 4486 public Iterator<K> iterator() { 4487 Node<K,V>[] t; 4488 ConcurrentHashMap<K,V> m = map; 4489 int f = (t = m.table) == null ? 0 : t.length; 4490 return new KeyIterator<K,V>(t, f, 0, f, m); 4491 } 4492 4493 /** 4494 * Adds the specified key to this set view by mapping the key to 4495 * the default mapped value in the backing map, if defined. 4496 * 4497 * @param e key to be added 4498 * @return {@code true} if this set changed as a result of the call 4499 * @throws NullPointerException if the specified key is null 4500 * @throws UnsupportedOperationException if no default mapped value 4501 * for additions was provided 4502 */ 4503 public boolean add(K e) { 4504 V v; 4505 if ((v = value) == null) 4506 throw new UnsupportedOperationException(); 4507 return map.putVal(e, v, true) == null; 4508 } 4509 4510 /** 4511 * Adds all of the elements in the specified collection to this set, 4512 * as if by calling {@link #add} on each one. 4513 * 4514 * @param c the elements to be inserted into this set 4515 * @return {@code true} if this set changed as a result of the call 4516 * @throws NullPointerException if the collection or any of its 4517 * elements are {@code null} 4518 * @throws UnsupportedOperationException if no default mapped value 4519 * for additions was provided 4520 */ 4521 public boolean addAll(Collection<? extends K> c) { 4522 boolean added = false; 4523 V v; 4524 if ((v = value) == null) 4525 throw new UnsupportedOperationException(); 4526 for (K e : c) { 4527 if (map.putVal(e, v, true) == null) 4528 added = true; 4529 } 4530 return added; 4531 } 4532 4533 public int hashCode() { 4534 int h = 0; 4535 for (K e : this) 4536 h += e.hashCode(); 4537 return h; 4538 } 4539 4540 public boolean equals(Object o) { 4541 Set<?> c; 4542 return ((o instanceof Set) && 4543 ((c = (Set<?>)o) == this || 4544 (containsAll(c) && c.containsAll(this)))); 4545 } 4546 4547 public Spliterator<K> spliterator() { 4548 Node<K,V>[] t; 4549 ConcurrentHashMap<K,V> m = map; 4550 long n = m.sumCount(); 4551 int f = (t = m.table) == null ? 0 : t.length; 4552 return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n); 4553 } 4554 4555 public void forEach(Consumer<? super K> action) { 4556 if (action == null) throw new NullPointerException(); 4557 Node<K,V>[] t; 4558 if ((t = map.table) != null) { 4559 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 4560 for (Node<K,V> p; (p = it.advance()) != null; ) 4561 action.accept(p.key); 4562 } 4563 } 4564 } 4565 4566 /** 4567 * A view of a ConcurrentHashMap as a {@link Collection} of 4568 * values, in which additions are disabled. This class cannot be 4569 * directly instantiated. See {@link #values()}. 4570 */ 4571 static final class ValuesView<K,V> extends CollectionView<K,V,V> 4572 implements Collection<V>, java.io.Serializable { 4573 private static final long serialVersionUID = 2249069246763182397L; 4574 ValuesView(ConcurrentHashMap<K,V> map) { super(map); } 4575 public final boolean contains(Object o) { 4576 return map.containsValue(o); 4577 } 4578 4579 public final boolean remove(Object o) { 4580 if (o != null) { 4581 for (Iterator<V> it = iterator(); it.hasNext();) { 4582 if (o.equals(it.next())) { 4583 it.remove(); 4584 return true; 4585 } 4586 } 4587 } 4588 return false; 4589 } 4590 4591 public final Iterator<V> iterator() { 4592 ConcurrentHashMap<K,V> m = map; 4593 Node<K,V>[] t; 4594 int f = (t = m.table) == null ? 0 : t.length; 4595 return new ValueIterator<K,V>(t, f, 0, f, m); 4596 } 4597 4598 public final boolean add(V e) { 4599 throw new UnsupportedOperationException(); 4600 } 4601 public final boolean addAll(Collection<? extends V> c) { 4602 throw new UnsupportedOperationException(); 4603 } 4604 4605 public Spliterator<V> spliterator() { 4606 Node<K,V>[] t; 4607 ConcurrentHashMap<K,V> m = map; 4608 long n = m.sumCount(); 4609 int f = (t = m.table) == null ? 0 : t.length; 4610 return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n); 4611 } 4612 4613 public void forEach(Consumer<? super V> action) { 4614 if (action == null) throw new NullPointerException(); 4615 Node<K,V>[] t; 4616 if ((t = map.table) != null) { 4617 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 4618 for (Node<K,V> p; (p = it.advance()) != null; ) 4619 action.accept(p.val); 4620 } 4621 } 4622 } 4623 4624 /** 4625 * A view of a ConcurrentHashMap as a {@link Set} of (key, value) 4626 * entries. This class cannot be directly instantiated. See 4627 * {@link #entrySet()}. 4628 */ 4629 static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>> 4630 implements Set<Map.Entry<K,V>>, java.io.Serializable { 4631 private static final long serialVersionUID = 2249069246763182397L; 4632 EntrySetView(ConcurrentHashMap<K,V> map) { super(map); } 4633 4634 public boolean contains(Object o) { 4635 Object k, v, r; Map.Entry<?,?> e; 4636 return ((o instanceof Map.Entry) && 4637 (k = (e = (Map.Entry<?,?>)o).getKey()) != null && 4638 (r = map.get(k)) != null && 4639 (v = e.getValue()) != null && 4640 (v == r || v.equals(r))); 4641 } 4642 4643 public boolean remove(Object o) { 4644 Object k, v; Map.Entry<?,?> e; 4645 return ((o instanceof Map.Entry) && 4646 (k = (e = (Map.Entry<?,?>)o).getKey()) != null && 4647 (v = e.getValue()) != null && 4648 map.remove(k, v)); 4649 } 4650 4651 /** 4652 * @return an iterator over the entries of the backing map 4653 */ 4654 public Iterator<Map.Entry<K,V>> iterator() { 4655 ConcurrentHashMap<K,V> m = map; 4656 Node<K,V>[] t; 4657 int f = (t = m.table) == null ? 0 : t.length; 4658 return new EntryIterator<K,V>(t, f, 0, f, m); 4659 } 4660 4661 public boolean add(Entry<K,V> e) { 4662 return map.putVal(e.getKey(), e.getValue(), false) == null; 4663 } 4664 4665 public boolean addAll(Collection<? extends Entry<K,V>> c) { 4666 boolean added = false; 4667 for (Entry<K,V> e : c) { 4668 if (add(e)) 4669 added = true; 4670 } 4671 return added; 4672 } 4673 4674 public final int hashCode() { 4675 int h = 0; 4676 Node<K,V>[] t; 4677 if ((t = map.table) != null) { 4678 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 4679 for (Node<K,V> p; (p = it.advance()) != null; ) { 4680 h += p.hashCode(); 4681 } 4682 } 4683 return h; 4684 } 4685 4686 public final boolean equals(Object o) { 4687 Set<?> c; 4688 return ((o instanceof Set) && 4689 ((c = (Set<?>)o) == this || 4690 (containsAll(c) && c.containsAll(this)))); 4691 } 4692 4693 public Spliterator<Map.Entry<K,V>> spliterator() { 4694 Node<K,V>[] t; 4695 ConcurrentHashMap<K,V> m = map; 4696 long n = m.sumCount(); 4697 int f = (t = m.table) == null ? 0 : t.length; 4698 return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m); 4699 } 4700 4701 public void forEach(Consumer<? super Map.Entry<K,V>> action) { 4702 if (action == null) throw new NullPointerException(); 4703 Node<K,V>[] t; 4704 if ((t = map.table) != null) { 4705 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 4706 for (Node<K,V> p; (p = it.advance()) != null; ) 4707 action.accept(new MapEntry<K,V>(p.key, p.val, map)); 4708 } 4709 } 4710 4711 } 4712 4713 // ------------------------------------------------------- 4714 4715 /** 4716 * Base class for bulk tasks. Repeats some fields and code from 4717 * class Traverser, because we need to subclass CountedCompleter. 4718 */ 4719 abstract static class BulkTask<K,V,R> extends CountedCompleter<R> { 4720 Node<K,V>[] tab; // same as Traverser 4721 Node<K,V> next; 4722 int index; 4723 int baseIndex; 4724 int baseLimit; 4725 final int baseSize; 4726 int batch; // split control 4727 4728 BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) { 4729 super(par); 4730 this.batch = b; 4731 this.index = this.baseIndex = i; 4732 if ((this.tab = t) == null) 4733 this.baseSize = this.baseLimit = 0; 4734 else if (par == null) 4735 this.baseSize = this.baseLimit = t.length; 4736 else { 4737 this.baseLimit = f; 4738 this.baseSize = par.baseSize; 4739 } 4740 } 4741 4742 /** 4743 * Same as Traverser version 4744 */ 4745 final Node<K,V> advance() { 4746 Node<K,V> e; 4747 if ((e = next) != null) 4748 e = e.next; 4749 for (;;) { 4750 Node<K,V>[] t; int i, n; K ek; // must use locals in checks 4751 if (e != null) 4752 return next = e; 4753 if (baseIndex >= baseLimit || (t = tab) == null || 4754 (n = t.length) <= (i = index) || i < 0) 4755 return next = null; 4756 if ((e = tabAt(t, index)) != null && e.hash < 0) { 4757 if (e instanceof ForwardingNode) { 4758 tab = ((ForwardingNode<K,V>)e).nextTable; 4759 e = null; 4760 continue; 4761 } 4762 else if (e instanceof TreeBin) 4763 e = ((TreeBin<K,V>)e).first; 4764 else 4765 e = null; 4766 } 4767 if ((index += baseSize) >= n) 4768 index = ++baseIndex; // visit upper slots if present 4769 } 4770 } 4771 } 4772 4773 /* 4774 * Task classes. Coded in a regular but ugly format/style to 4775 * simplify checks that each variant differs in the right way from 4776 * others. The null screenings exist because compilers cannot tell 4777 * that we've already null-checked task arguments, so we force 4778 * simplest hoisted bypass to help avoid convoluted traps. 4779 */ 4780 @SuppressWarnings("serial") 4781 static final class ForEachKeyTask<K,V> 4782 extends BulkTask<K,V,Void> { 4783 final Consumer<? super K> action; 4784 ForEachKeyTask 4785 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 4786 Consumer<? super K> action) { 4787 super(p, b, i, f, t); 4788 this.action = action; 4789 } 4790 public final void compute() { 4791 final Consumer<? super K> action; 4792 if ((action = this.action) != null) { 4793 for (int i = baseIndex, f, h; batch > 0 && 4794 (h = ((f = baseLimit) + i) >>> 1) > i;) { 4795 addToPendingCount(1); 4796 new ForEachKeyTask<K,V> 4797 (this, batch >>>= 1, baseLimit = h, f, tab, 4798 action).fork(); 4799 } 4800 for (Node<K,V> p; (p = advance()) != null;) 4801 action.accept(p.key); 4802 propagateCompletion(); 4803 } 4804 } 4805 } 4806 4807 @SuppressWarnings("serial") 4808 static final class ForEachValueTask<K,V> 4809 extends BulkTask<K,V,Void> { 4810 final Consumer<? super V> action; 4811 ForEachValueTask 4812 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 4813 Consumer<? super V> action) { 4814 super(p, b, i, f, t); 4815 this.action = action; 4816 } 4817 public final void compute() { 4818 final Consumer<? super V> action; 4819 if ((action = this.action) != null) { 4820 for (int i = baseIndex, f, h; batch > 0 && 4821 (h = ((f = baseLimit) + i) >>> 1) > i;) { 4822 addToPendingCount(1); 4823 new ForEachValueTask<K,V> 4824 (this, batch >>>= 1, baseLimit = h, f, tab, 4825 action).fork(); 4826 } 4827 for (Node<K,V> p; (p = advance()) != null;) 4828 action.accept(p.val); 4829 propagateCompletion(); 4830 } 4831 } 4832 } 4833 4834 @SuppressWarnings("serial") 4835 static final class ForEachEntryTask<K,V> 4836 extends BulkTask<K,V,Void> { 4837 final Consumer<? super Entry<K,V>> action; 4838 ForEachEntryTask 4839 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 4840 Consumer<? super Entry<K,V>> action) { 4841 super(p, b, i, f, t); 4842 this.action = action; 4843 } 4844 public final void compute() { 4845 final Consumer<? super Entry<K,V>> action; 4846 if ((action = this.action) != null) { 4847 for (int i = baseIndex, f, h; batch > 0 && 4848 (h = ((f = baseLimit) + i) >>> 1) > i;) { 4849 addToPendingCount(1); 4850 new ForEachEntryTask<K,V> 4851 (this, batch >>>= 1, baseLimit = h, f, tab, 4852 action).fork(); 4853 } 4854 for (Node<K,V> p; (p = advance()) != null; ) 4855 action.accept(p); 4856 propagateCompletion(); 4857 } 4858 } 4859 } 4860 4861 @SuppressWarnings("serial") 4862 static final class ForEachMappingTask<K,V> 4863 extends BulkTask<K,V,Void> { 4864 final BiConsumer<? super K, ? super V> action; 4865 ForEachMappingTask 4866 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 4867 BiConsumer<? super K,? super V> action) { 4868 super(p, b, i, f, t); 4869 this.action = action; 4870 } 4871 public final void compute() { 4872 final BiConsumer<? super K, ? super V> action; 4873 if ((action = this.action) != null) { 4874 for (int i = baseIndex, f, h; batch > 0 && 4875 (h = ((f = baseLimit) + i) >>> 1) > i;) { 4876 addToPendingCount(1); 4877 new ForEachMappingTask<K,V> 4878 (this, batch >>>= 1, baseLimit = h, f, tab, 4879 action).fork(); 4880 } 4881 for (Node<K,V> p; (p = advance()) != null; ) 4882 action.accept(p.key, p.val); 4883 propagateCompletion(); 4884 } 4885 } 4886 } 4887 4888 @SuppressWarnings("serial") 4889 static final class ForEachTransformedKeyTask<K,V,U> 4890 extends BulkTask<K,V,Void> { 4891 final Function<? super K, ? extends U> transformer; 4892 final Consumer<? super U> action; 4893 ForEachTransformedKeyTask 4894 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 4895 Function<? super K, ? extends U> transformer, Consumer<? super U> action) { 4896 super(p, b, i, f, t); 4897 this.transformer = transformer; this.action = action; 4898 } 4899 public final void compute() { 4900 final Function<? super K, ? extends U> transformer; 4901 final Consumer<? super U> action; 4902 if ((transformer = this.transformer) != null && 4903 (action = this.action) != null) { 4904 for (int i = baseIndex, f, h; batch > 0 && 4905 (h = ((f = baseLimit) + i) >>> 1) > i;) { 4906 addToPendingCount(1); 4907 new ForEachTransformedKeyTask<K,V,U> 4908 (this, batch >>>= 1, baseLimit = h, f, tab, 4909 transformer, action).fork(); 4910 } 4911 for (Node<K,V> p; (p = advance()) != null; ) { 4912 U u; 4913 if ((u = transformer.apply(p.key)) != null) 4914 action.accept(u); 4915 } 4916 propagateCompletion(); 4917 } 4918 } 4919 } 4920 4921 @SuppressWarnings("serial") 4922 static final class ForEachTransformedValueTask<K,V,U> 4923 extends BulkTask<K,V,Void> { 4924 final Function<? super V, ? extends U> transformer; 4925 final Consumer<? super U> action; 4926 ForEachTransformedValueTask 4927 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 4928 Function<? super V, ? extends U> transformer, Consumer<? super U> action) { 4929 super(p, b, i, f, t); 4930 this.transformer = transformer; this.action = action; 4931 } 4932 public final void compute() { 4933 final Function<? super V, ? extends U> transformer; 4934 final Consumer<? super U> action; 4935 if ((transformer = this.transformer) != null && 4936 (action = this.action) != null) { 4937 for (int i = baseIndex, f, h; batch > 0 && 4938 (h = ((f = baseLimit) + i) >>> 1) > i;) { 4939 addToPendingCount(1); 4940 new ForEachTransformedValueTask<K,V,U> 4941 (this, batch >>>= 1, baseLimit = h, f, tab, 4942 transformer, action).fork(); 4943 } 4944 for (Node<K,V> p; (p = advance()) != null; ) { 4945 U u; 4946 if ((u = transformer.apply(p.val)) != null) 4947 action.accept(u); 4948 } 4949 propagateCompletion(); 4950 } 4951 } 4952 } 4953 4954 @SuppressWarnings("serial") 4955 static final class ForEachTransformedEntryTask<K,V,U> 4956 extends BulkTask<K,V,Void> { 4957 final Function<Map.Entry<K,V>, ? extends U> transformer; 4958 final Consumer<? super U> action; 4959 ForEachTransformedEntryTask 4960 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 4961 Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) { 4962 super(p, b, i, f, t); 4963 this.transformer = transformer; this.action = action; 4964 } 4965 public final void compute() { 4966 final Function<Map.Entry<K,V>, ? extends U> transformer; 4967 final Consumer<? super U> action; 4968 if ((transformer = this.transformer) != null && 4969 (action = this.action) != null) { 4970 for (int i = baseIndex, f, h; batch > 0 && 4971 (h = ((f = baseLimit) + i) >>> 1) > i;) { 4972 addToPendingCount(1); 4973 new ForEachTransformedEntryTask<K,V,U> 4974 (this, batch >>>= 1, baseLimit = h, f, tab, 4975 transformer, action).fork(); 4976 } 4977 for (Node<K,V> p; (p = advance()) != null; ) { 4978 U u; 4979 if ((u = transformer.apply(p)) != null) 4980 action.accept(u); 4981 } 4982 propagateCompletion(); 4983 } 4984 } 4985 } 4986 4987 @SuppressWarnings("serial") 4988 static final class ForEachTransformedMappingTask<K,V,U> 4989 extends BulkTask<K,V,Void> { 4990 final BiFunction<? super K, ? super V, ? extends U> transformer; 4991 final Consumer<? super U> action; 4992 ForEachTransformedMappingTask 4993 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 4994 BiFunction<? super K, ? super V, ? extends U> transformer, 4995 Consumer<? super U> action) { 4996 super(p, b, i, f, t); 4997 this.transformer = transformer; this.action = action; 4998 } 4999 public final void compute() { 5000 final BiFunction<? super K, ? super V, ? extends U> transformer; 5001 final Consumer<? super U> action; 5002 if ((transformer = this.transformer) != null && 5003 (action = this.action) != null) { 5004 for (int i = baseIndex, f, h; batch > 0 && 5005 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5006 addToPendingCount(1); 5007 new ForEachTransformedMappingTask<K,V,U> 5008 (this, batch >>>= 1, baseLimit = h, f, tab, 5009 transformer, action).fork(); 5010 } 5011 for (Node<K,V> p; (p = advance()) != null; ) { 5012 U u; 5013 if ((u = transformer.apply(p.key, p.val)) != null) 5014 action.accept(u); 5015 } 5016 propagateCompletion(); 5017 } 5018 } 5019 } 5020 5021 @SuppressWarnings("serial") 5022 static final class SearchKeysTask<K,V,U> 5023 extends BulkTask<K,V,U> { 5024 final Function<? super K, ? extends U> searchFunction; 5025 final AtomicReference<U> result; 5026 SearchKeysTask 5027 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5028 Function<? super K, ? extends U> searchFunction, 5029 AtomicReference<U> result) { 5030 super(p, b, i, f, t); 5031 this.searchFunction = searchFunction; this.result = result; 5032 } 5033 public final U getRawResult() { return result.get(); } 5034 public final void compute() { 5035 final Function<? super K, ? extends U> searchFunction; 5036 final AtomicReference<U> result; 5037 if ((searchFunction = this.searchFunction) != null && 5038 (result = this.result) != null) { 5039 for (int i = baseIndex, f, h; batch > 0 && 5040 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5041 if (result.get() != null) 5042 return; 5043 addToPendingCount(1); 5044 new SearchKeysTask<K,V,U> 5045 (this, batch >>>= 1, baseLimit = h, f, tab, 5046 searchFunction, result).fork(); 5047 } 5048 while (result.get() == null) { 5049 U u; 5050 Node<K,V> p; 5051 if ((p = advance()) == null) { 5052 propagateCompletion(); 5053 break; 5054 } 5055 if ((u = searchFunction.apply(p.key)) != null) { 5056 if (result.compareAndSet(null, u)) 5057 quietlyCompleteRoot(); 5058 break; 5059 } 5060 } 5061 } 5062 } 5063 } 5064 5065 @SuppressWarnings("serial") 5066 static final class SearchValuesTask<K,V,U> 5067 extends BulkTask<K,V,U> { 5068 final Function<? super V, ? extends U> searchFunction; 5069 final AtomicReference<U> result; 5070 SearchValuesTask 5071 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5072 Function<? super V, ? extends U> searchFunction, 5073 AtomicReference<U> result) { 5074 super(p, b, i, f, t); 5075 this.searchFunction = searchFunction; this.result = result; 5076 } 5077 public final U getRawResult() { return result.get(); } 5078 public final void compute() { 5079 final Function<? super V, ? extends U> searchFunction; 5080 final AtomicReference<U> result; 5081 if ((searchFunction = this.searchFunction) != null && 5082 (result = this.result) != null) { 5083 for (int i = baseIndex, f, h; batch > 0 && 5084 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5085 if (result.get() != null) 5086 return; 5087 addToPendingCount(1); 5088 new SearchValuesTask<K,V,U> 5089 (this, batch >>>= 1, baseLimit = h, f, tab, 5090 searchFunction, result).fork(); 5091 } 5092 while (result.get() == null) { 5093 U u; 5094 Node<K,V> p; 5095 if ((p = advance()) == null) { 5096 propagateCompletion(); 5097 break; 5098 } 5099 if ((u = searchFunction.apply(p.val)) != null) { 5100 if (result.compareAndSet(null, u)) 5101 quietlyCompleteRoot(); 5102 break; 5103 } 5104 } 5105 } 5106 } 5107 } 5108 5109 @SuppressWarnings("serial") 5110 static final class SearchEntriesTask<K,V,U> 5111 extends BulkTask<K,V,U> { 5112 final Function<Entry<K,V>, ? extends U> searchFunction; 5113 final AtomicReference<U> result; 5114 SearchEntriesTask 5115 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5116 Function<Entry<K,V>, ? extends U> searchFunction, 5117 AtomicReference<U> result) { 5118 super(p, b, i, f, t); 5119 this.searchFunction = searchFunction; this.result = result; 5120 } 5121 public final U getRawResult() { return result.get(); } 5122 public final void compute() { 5123 final Function<Entry<K,V>, ? extends U> searchFunction; 5124 final AtomicReference<U> result; 5125 if ((searchFunction = this.searchFunction) != null && 5126 (result = this.result) != null) { 5127 for (int i = baseIndex, f, h; batch > 0 && 5128 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5129 if (result.get() != null) 5130 return; 5131 addToPendingCount(1); 5132 new SearchEntriesTask<K,V,U> 5133 (this, batch >>>= 1, baseLimit = h, f, tab, 5134 searchFunction, result).fork(); 5135 } 5136 while (result.get() == null) { 5137 U u; 5138 Node<K,V> p; 5139 if ((p = advance()) == null) { 5140 propagateCompletion(); 5141 break; 5142 } 5143 if ((u = searchFunction.apply(p)) != null) { 5144 if (result.compareAndSet(null, u)) 5145 quietlyCompleteRoot(); 5146 return; 5147 } 5148 } 5149 } 5150 } 5151 } 5152 5153 @SuppressWarnings("serial") 5154 static final class SearchMappingsTask<K,V,U> 5155 extends BulkTask<K,V,U> { 5156 final BiFunction<? super K, ? super V, ? extends U> searchFunction; 5157 final AtomicReference<U> result; 5158 SearchMappingsTask 5159 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5160 BiFunction<? super K, ? super V, ? extends U> searchFunction, 5161 AtomicReference<U> result) { 5162 super(p, b, i, f, t); 5163 this.searchFunction = searchFunction; this.result = result; 5164 } 5165 public final U getRawResult() { return result.get(); } 5166 public final void compute() { 5167 final BiFunction<? super K, ? super V, ? extends U> searchFunction; 5168 final AtomicReference<U> result; 5169 if ((searchFunction = this.searchFunction) != null && 5170 (result = this.result) != null) { 5171 for (int i = baseIndex, f, h; batch > 0 && 5172 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5173 if (result.get() != null) 5174 return; 5175 addToPendingCount(1); 5176 new SearchMappingsTask<K,V,U> 5177 (this, batch >>>= 1, baseLimit = h, f, tab, 5178 searchFunction, result).fork(); 5179 } 5180 while (result.get() == null) { 5181 U u; 5182 Node<K,V> p; 5183 if ((p = advance()) == null) { 5184 propagateCompletion(); 5185 break; 5186 } 5187 if ((u = searchFunction.apply(p.key, p.val)) != null) { 5188 if (result.compareAndSet(null, u)) 5189 quietlyCompleteRoot(); 5190 break; 5191 } 5192 } 5193 } 5194 } 5195 } 5196 5197 @SuppressWarnings("serial") 5198 static final class ReduceKeysTask<K,V> 5199 extends BulkTask<K,V,K> { 5200 final BiFunction<? super K, ? super K, ? extends K> reducer; 5201 K result; 5202 ReduceKeysTask<K,V> rights, nextRight; 5203 ReduceKeysTask 5204 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5205 ReduceKeysTask<K,V> nextRight, 5206 BiFunction<? super K, ? super K, ? extends K> reducer) { 5207 super(p, b, i, f, t); this.nextRight = nextRight; 5208 this.reducer = reducer; 5209 } 5210 public final K getRawResult() { return result; } 5211 public final void compute() { 5212 final BiFunction<? super K, ? super K, ? extends K> reducer; 5213 if ((reducer = this.reducer) != null) { 5214 for (int i = baseIndex, f, h; batch > 0 && 5215 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5216 addToPendingCount(1); 5217 (rights = new ReduceKeysTask<K,V> 5218 (this, batch >>>= 1, baseLimit = h, f, tab, 5219 rights, reducer)).fork(); 5220 } 5221 K r = null; 5222 for (Node<K,V> p; (p = advance()) != null; ) { 5223 K u = p.key; 5224 r = (r == null) ? u : u == null ? r : reducer.apply(r, u); 5225 } 5226 result = r; 5227 CountedCompleter<?> c; 5228 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5229 @SuppressWarnings("unchecked") ReduceKeysTask<K,V> 5230 t = (ReduceKeysTask<K,V>)c, 5231 s = t.rights; 5232 while (s != null) { 5233 K tr, sr; 5234 if ((sr = s.result) != null) 5235 t.result = (((tr = t.result) == null) ? sr : 5236 reducer.apply(tr, sr)); 5237 s = t.rights = s.nextRight; 5238 } 5239 } 5240 } 5241 } 5242 } 5243 5244 @SuppressWarnings("serial") 5245 static final class ReduceValuesTask<K,V> 5246 extends BulkTask<K,V,V> { 5247 final BiFunction<? super V, ? super V, ? extends V> reducer; 5248 V result; 5249 ReduceValuesTask<K,V> rights, nextRight; 5250 ReduceValuesTask 5251 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5252 ReduceValuesTask<K,V> nextRight, 5253 BiFunction<? super V, ? super V, ? extends V> reducer) { 5254 super(p, b, i, f, t); this.nextRight = nextRight; 5255 this.reducer = reducer; 5256 } 5257 public final V getRawResult() { return result; } 5258 public final void compute() { 5259 final BiFunction<? super V, ? super V, ? extends V> reducer; 5260 if ((reducer = this.reducer) != null) { 5261 for (int i = baseIndex, f, h; batch > 0 && 5262 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5263 addToPendingCount(1); 5264 (rights = new ReduceValuesTask<K,V> 5265 (this, batch >>>= 1, baseLimit = h, f, tab, 5266 rights, reducer)).fork(); 5267 } 5268 V r = null; 5269 for (Node<K,V> p; (p = advance()) != null; ) { 5270 V v = p.val; 5271 r = (r == null) ? v : reducer.apply(r, v); 5272 } 5273 result = r; 5274 CountedCompleter<?> c; 5275 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5276 @SuppressWarnings("unchecked") ReduceValuesTask<K,V> 5277 t = (ReduceValuesTask<K,V>)c, 5278 s = t.rights; 5279 while (s != null) { 5280 V tr, sr; 5281 if ((sr = s.result) != null) 5282 t.result = (((tr = t.result) == null) ? sr : 5283 reducer.apply(tr, sr)); 5284 s = t.rights = s.nextRight; 5285 } 5286 } 5287 } 5288 } 5289 } 5290 5291 @SuppressWarnings("serial") 5292 static final class ReduceEntriesTask<K,V> 5293 extends BulkTask<K,V,Map.Entry<K,V>> { 5294 final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer; 5295 Map.Entry<K,V> result; 5296 ReduceEntriesTask<K,V> rights, nextRight; 5297 ReduceEntriesTask 5298 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5299 ReduceEntriesTask<K,V> nextRight, 5300 BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) { 5301 super(p, b, i, f, t); this.nextRight = nextRight; 5302 this.reducer = reducer; 5303 } 5304 public final Map.Entry<K,V> getRawResult() { return result; } 5305 public final void compute() { 5306 final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer; 5307 if ((reducer = this.reducer) != null) { 5308 for (int i = baseIndex, f, h; batch > 0 && 5309 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5310 addToPendingCount(1); 5311 (rights = new ReduceEntriesTask<K,V> 5312 (this, batch >>>= 1, baseLimit = h, f, tab, 5313 rights, reducer)).fork(); 5314 } 5315 Map.Entry<K,V> r = null; 5316 for (Node<K,V> p; (p = advance()) != null; ) 5317 r = (r == null) ? p : reducer.apply(r, p); 5318 result = r; 5319 CountedCompleter<?> c; 5320 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5321 @SuppressWarnings("unchecked") ReduceEntriesTask<K,V> 5322 t = (ReduceEntriesTask<K,V>)c, 5323 s = t.rights; 5324 while (s != null) { 5325 Map.Entry<K,V> tr, sr; 5326 if ((sr = s.result) != null) 5327 t.result = (((tr = t.result) == null) ? sr : 5328 reducer.apply(tr, sr)); 5329 s = t.rights = s.nextRight; 5330 } 5331 } 5332 } 5333 } 5334 } 5335 5336 @SuppressWarnings("serial") 5337 static final class MapReduceKeysTask<K,V,U> 5338 extends BulkTask<K,V,U> { 5339 final Function<? super K, ? extends U> transformer; 5340 final BiFunction<? super U, ? super U, ? extends U> reducer; 5341 U result; 5342 MapReduceKeysTask<K,V,U> rights, nextRight; 5343 MapReduceKeysTask 5344 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5345 MapReduceKeysTask<K,V,U> nextRight, 5346 Function<? super K, ? extends U> transformer, 5347 BiFunction<? super U, ? super U, ? extends U> reducer) { 5348 super(p, b, i, f, t); this.nextRight = nextRight; 5349 this.transformer = transformer; 5350 this.reducer = reducer; 5351 } 5352 public final U getRawResult() { return result; } 5353 public final void compute() { 5354 final Function<? super K, ? extends U> transformer; 5355 final BiFunction<? super U, ? super U, ? extends U> reducer; 5356 if ((transformer = this.transformer) != null && 5357 (reducer = this.reducer) != null) { 5358 for (int i = baseIndex, f, h; batch > 0 && 5359 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5360 addToPendingCount(1); 5361 (rights = new MapReduceKeysTask<K,V,U> 5362 (this, batch >>>= 1, baseLimit = h, f, tab, 5363 rights, transformer, reducer)).fork(); 5364 } 5365 U r = null; 5366 for (Node<K,V> p; (p = advance()) != null; ) { 5367 U u; 5368 if ((u = transformer.apply(p.key)) != null) 5369 r = (r == null) ? u : reducer.apply(r, u); 5370 } 5371 result = r; 5372 CountedCompleter<?> c; 5373 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5374 @SuppressWarnings("unchecked") MapReduceKeysTask<K,V,U> 5375 t = (MapReduceKeysTask<K,V,U>)c, 5376 s = t.rights; 5377 while (s != null) { 5378 U tr, sr; 5379 if ((sr = s.result) != null) 5380 t.result = (((tr = t.result) == null) ? sr : 5381 reducer.apply(tr, sr)); 5382 s = t.rights = s.nextRight; 5383 } 5384 } 5385 } 5386 } 5387 } 5388 5389 @SuppressWarnings("serial") 5390 static final class MapReduceValuesTask<K,V,U> 5391 extends BulkTask<K,V,U> { 5392 final Function<? super V, ? extends U> transformer; 5393 final BiFunction<? super U, ? super U, ? extends U> reducer; 5394 U result; 5395 MapReduceValuesTask<K,V,U> rights, nextRight; 5396 MapReduceValuesTask 5397 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5398 MapReduceValuesTask<K,V,U> nextRight, 5399 Function<? super V, ? extends U> transformer, 5400 BiFunction<? super U, ? super U, ? extends U> reducer) { 5401 super(p, b, i, f, t); this.nextRight = nextRight; 5402 this.transformer = transformer; 5403 this.reducer = reducer; 5404 } 5405 public final U getRawResult() { return result; } 5406 public final void compute() { 5407 final Function<? super V, ? extends U> transformer; 5408 final BiFunction<? super U, ? super U, ? extends U> reducer; 5409 if ((transformer = this.transformer) != null && 5410 (reducer = this.reducer) != null) { 5411 for (int i = baseIndex, f, h; batch > 0 && 5412 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5413 addToPendingCount(1); 5414 (rights = new MapReduceValuesTask<K,V,U> 5415 (this, batch >>>= 1, baseLimit = h, f, tab, 5416 rights, transformer, reducer)).fork(); 5417 } 5418 U r = null; 5419 for (Node<K,V> p; (p = advance()) != null; ) { 5420 U u; 5421 if ((u = transformer.apply(p.val)) != null) 5422 r = (r == null) ? u : reducer.apply(r, u); 5423 } 5424 result = r; 5425 CountedCompleter<?> c; 5426 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5427 @SuppressWarnings("unchecked") MapReduceValuesTask<K,V,U> 5428 t = (MapReduceValuesTask<K,V,U>)c, 5429 s = t.rights; 5430 while (s != null) { 5431 U tr, sr; 5432 if ((sr = s.result) != null) 5433 t.result = (((tr = t.result) == null) ? sr : 5434 reducer.apply(tr, sr)); 5435 s = t.rights = s.nextRight; 5436 } 5437 } 5438 } 5439 } 5440 } 5441 5442 @SuppressWarnings("serial") 5443 static final class MapReduceEntriesTask<K,V,U> 5444 extends BulkTask<K,V,U> { 5445 final Function<Map.Entry<K,V>, ? extends U> transformer; 5446 final BiFunction<? super U, ? super U, ? extends U> reducer; 5447 U result; 5448 MapReduceEntriesTask<K,V,U> rights, nextRight; 5449 MapReduceEntriesTask 5450 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5451 MapReduceEntriesTask<K,V,U> nextRight, 5452 Function<Map.Entry<K,V>, ? extends U> transformer, 5453 BiFunction<? super U, ? super U, ? extends U> reducer) { 5454 super(p, b, i, f, t); this.nextRight = nextRight; 5455 this.transformer = transformer; 5456 this.reducer = reducer; 5457 } 5458 public final U getRawResult() { return result; } 5459 public final void compute() { 5460 final Function<Map.Entry<K,V>, ? extends U> transformer; 5461 final BiFunction<? super U, ? super U, ? extends U> reducer; 5462 if ((transformer = this.transformer) != null && 5463 (reducer = this.reducer) != null) { 5464 for (int i = baseIndex, f, h; batch > 0 && 5465 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5466 addToPendingCount(1); 5467 (rights = new MapReduceEntriesTask<K,V,U> 5468 (this, batch >>>= 1, baseLimit = h, f, tab, 5469 rights, transformer, reducer)).fork(); 5470 } 5471 U r = null; 5472 for (Node<K,V> p; (p = advance()) != null; ) { 5473 U u; 5474 if ((u = transformer.apply(p)) != null) 5475 r = (r == null) ? u : reducer.apply(r, u); 5476 } 5477 result = r; 5478 CountedCompleter<?> c; 5479 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5480 @SuppressWarnings("unchecked") MapReduceEntriesTask<K,V,U> 5481 t = (MapReduceEntriesTask<K,V,U>)c, 5482 s = t.rights; 5483 while (s != null) { 5484 U tr, sr; 5485 if ((sr = s.result) != null) 5486 t.result = (((tr = t.result) == null) ? sr : 5487 reducer.apply(tr, sr)); 5488 s = t.rights = s.nextRight; 5489 } 5490 } 5491 } 5492 } 5493 } 5494 5495 @SuppressWarnings("serial") 5496 static final class MapReduceMappingsTask<K,V,U> 5497 extends BulkTask<K,V,U> { 5498 final BiFunction<? super K, ? super V, ? extends U> transformer; 5499 final BiFunction<? super U, ? super U, ? extends U> reducer; 5500 U result; 5501 MapReduceMappingsTask<K,V,U> rights, nextRight; 5502 MapReduceMappingsTask 5503 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5504 MapReduceMappingsTask<K,V,U> nextRight, 5505 BiFunction<? super K, ? super V, ? extends U> transformer, 5506 BiFunction<? super U, ? super U, ? extends U> reducer) { 5507 super(p, b, i, f, t); this.nextRight = nextRight; 5508 this.transformer = transformer; 5509 this.reducer = reducer; 5510 } 5511 public final U getRawResult() { return result; } 5512 public final void compute() { 5513 final BiFunction<? super K, ? super V, ? extends U> transformer; 5514 final BiFunction<? super U, ? super U, ? extends U> reducer; 5515 if ((transformer = this.transformer) != null && 5516 (reducer = this.reducer) != null) { 5517 for (int i = baseIndex, f, h; batch > 0 && 5518 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5519 addToPendingCount(1); 5520 (rights = new MapReduceMappingsTask<K,V,U> 5521 (this, batch >>>= 1, baseLimit = h, f, tab, 5522 rights, transformer, reducer)).fork(); 5523 } 5524 U r = null; 5525 for (Node<K,V> p; (p = advance()) != null; ) { 5526 U u; 5527 if ((u = transformer.apply(p.key, p.val)) != null) 5528 r = (r == null) ? u : reducer.apply(r, u); 5529 } 5530 result = r; 5531 CountedCompleter<?> c; 5532 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5533 @SuppressWarnings("unchecked") MapReduceMappingsTask<K,V,U> 5534 t = (MapReduceMappingsTask<K,V,U>)c, 5535 s = t.rights; 5536 while (s != null) { 5537 U tr, sr; 5538 if ((sr = s.result) != null) 5539 t.result = (((tr = t.result) == null) ? sr : 5540 reducer.apply(tr, sr)); 5541 s = t.rights = s.nextRight; 5542 } 5543 } 5544 } 5545 } 5546 } 5547 5548 @SuppressWarnings("serial") 5549 static final class MapReduceKeysToDoubleTask<K,V> 5550 extends BulkTask<K,V,Double> { 5551 final ToDoubleFunction<? super K> transformer; 5552 final DoubleBinaryOperator reducer; 5553 final double basis; 5554 double result; 5555 MapReduceKeysToDoubleTask<K,V> rights, nextRight; 5556 MapReduceKeysToDoubleTask 5557 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5558 MapReduceKeysToDoubleTask<K,V> nextRight, 5559 ToDoubleFunction<? super K> transformer, 5560 double basis, 5561 DoubleBinaryOperator reducer) { 5562 super(p, b, i, f, t); this.nextRight = nextRight; 5563 this.transformer = transformer; 5564 this.basis = basis; this.reducer = reducer; 5565 } 5566 public final Double getRawResult() { return result; } 5567 public final void compute() { 5568 final ToDoubleFunction<? super K> transformer; 5569 final DoubleBinaryOperator reducer; 5570 if ((transformer = this.transformer) != null && 5571 (reducer = this.reducer) != null) { 5572 double r = this.basis; 5573 for (int i = baseIndex, f, h; batch > 0 && 5574 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5575 addToPendingCount(1); 5576 (rights = new MapReduceKeysToDoubleTask<K,V> 5577 (this, batch >>>= 1, baseLimit = h, f, tab, 5578 rights, transformer, r, reducer)).fork(); 5579 } 5580 for (Node<K,V> p; (p = advance()) != null; ) 5581 r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key)); 5582 result = r; 5583 CountedCompleter<?> c; 5584 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5585 @SuppressWarnings("unchecked") MapReduceKeysToDoubleTask<K,V> 5586 t = (MapReduceKeysToDoubleTask<K,V>)c, 5587 s = t.rights; 5588 while (s != null) { 5589 t.result = reducer.applyAsDouble(t.result, s.result); 5590 s = t.rights = s.nextRight; 5591 } 5592 } 5593 } 5594 } 5595 } 5596 5597 @SuppressWarnings("serial") 5598 static final class MapReduceValuesToDoubleTask<K,V> 5599 extends BulkTask<K,V,Double> { 5600 final ToDoubleFunction<? super V> transformer; 5601 final DoubleBinaryOperator reducer; 5602 final double basis; 5603 double result; 5604 MapReduceValuesToDoubleTask<K,V> rights, nextRight; 5605 MapReduceValuesToDoubleTask 5606 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5607 MapReduceValuesToDoubleTask<K,V> nextRight, 5608 ToDoubleFunction<? super V> transformer, 5609 double basis, 5610 DoubleBinaryOperator reducer) { 5611 super(p, b, i, f, t); this.nextRight = nextRight; 5612 this.transformer = transformer; 5613 this.basis = basis; this.reducer = reducer; 5614 } 5615 public final Double getRawResult() { return result; } 5616 public final void compute() { 5617 final ToDoubleFunction<? super V> transformer; 5618 final DoubleBinaryOperator reducer; 5619 if ((transformer = this.transformer) != null && 5620 (reducer = this.reducer) != null) { 5621 double r = this.basis; 5622 for (int i = baseIndex, f, h; batch > 0 && 5623 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5624 addToPendingCount(1); 5625 (rights = new MapReduceValuesToDoubleTask<K,V> 5626 (this, batch >>>= 1, baseLimit = h, f, tab, 5627 rights, transformer, r, reducer)).fork(); 5628 } 5629 for (Node<K,V> p; (p = advance()) != null; ) 5630 r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val)); 5631 result = r; 5632 CountedCompleter<?> c; 5633 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5634 @SuppressWarnings("unchecked") MapReduceValuesToDoubleTask<K,V> 5635 t = (MapReduceValuesToDoubleTask<K,V>)c, 5636 s = t.rights; 5637 while (s != null) { 5638 t.result = reducer.applyAsDouble(t.result, s.result); 5639 s = t.rights = s.nextRight; 5640 } 5641 } 5642 } 5643 } 5644 } 5645 5646 @SuppressWarnings("serial") 5647 static final class MapReduceEntriesToDoubleTask<K,V> 5648 extends BulkTask<K,V,Double> { 5649 final ToDoubleFunction<Map.Entry<K,V>> transformer; 5650 final DoubleBinaryOperator reducer; 5651 final double basis; 5652 double result; 5653 MapReduceEntriesToDoubleTask<K,V> rights, nextRight; 5654 MapReduceEntriesToDoubleTask 5655 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5656 MapReduceEntriesToDoubleTask<K,V> nextRight, 5657 ToDoubleFunction<Map.Entry<K,V>> transformer, 5658 double basis, 5659 DoubleBinaryOperator reducer) { 5660 super(p, b, i, f, t); this.nextRight = nextRight; 5661 this.transformer = transformer; 5662 this.basis = basis; this.reducer = reducer; 5663 } 5664 public final Double getRawResult() { return result; } 5665 public final void compute() { 5666 final ToDoubleFunction<Map.Entry<K,V>> transformer; 5667 final DoubleBinaryOperator reducer; 5668 if ((transformer = this.transformer) != null && 5669 (reducer = this.reducer) != null) { 5670 double r = this.basis; 5671 for (int i = baseIndex, f, h; batch > 0 && 5672 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5673 addToPendingCount(1); 5674 (rights = new MapReduceEntriesToDoubleTask<K,V> 5675 (this, batch >>>= 1, baseLimit = h, f, tab, 5676 rights, transformer, r, reducer)).fork(); 5677 } 5678 for (Node<K,V> p; (p = advance()) != null; ) 5679 r = reducer.applyAsDouble(r, transformer.applyAsDouble(p)); 5680 result = r; 5681 CountedCompleter<?> c; 5682 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5683 @SuppressWarnings("unchecked") MapReduceEntriesToDoubleTask<K,V> 5684 t = (MapReduceEntriesToDoubleTask<K,V>)c, 5685 s = t.rights; 5686 while (s != null) { 5687 t.result = reducer.applyAsDouble(t.result, s.result); 5688 s = t.rights = s.nextRight; 5689 } 5690 } 5691 } 5692 } 5693 } 5694 5695 @SuppressWarnings("serial") 5696 static final class MapReduceMappingsToDoubleTask<K,V> 5697 extends BulkTask<K,V,Double> { 5698 final ToDoubleBiFunction<? super K, ? super V> transformer; 5699 final DoubleBinaryOperator reducer; 5700 final double basis; 5701 double result; 5702 MapReduceMappingsToDoubleTask<K,V> rights, nextRight; 5703 MapReduceMappingsToDoubleTask 5704 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5705 MapReduceMappingsToDoubleTask<K,V> nextRight, 5706 ToDoubleBiFunction<? super K, ? super V> transformer, 5707 double basis, 5708 DoubleBinaryOperator reducer) { 5709 super(p, b, i, f, t); this.nextRight = nextRight; 5710 this.transformer = transformer; 5711 this.basis = basis; this.reducer = reducer; 5712 } 5713 public final Double getRawResult() { return result; } 5714 public final void compute() { 5715 final ToDoubleBiFunction<? super K, ? super V> transformer; 5716 final DoubleBinaryOperator reducer; 5717 if ((transformer = this.transformer) != null && 5718 (reducer = this.reducer) != null) { 5719 double r = this.basis; 5720 for (int i = baseIndex, f, h; batch > 0 && 5721 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5722 addToPendingCount(1); 5723 (rights = new MapReduceMappingsToDoubleTask<K,V> 5724 (this, batch >>>= 1, baseLimit = h, f, tab, 5725 rights, transformer, r, reducer)).fork(); 5726 } 5727 for (Node<K,V> p; (p = advance()) != null; ) 5728 r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val)); 5729 result = r; 5730 CountedCompleter<?> c; 5731 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5732 @SuppressWarnings("unchecked") MapReduceMappingsToDoubleTask<K,V> 5733 t = (MapReduceMappingsToDoubleTask<K,V>)c, 5734 s = t.rights; 5735 while (s != null) { 5736 t.result = reducer.applyAsDouble(t.result, s.result); 5737 s = t.rights = s.nextRight; 5738 } 5739 } 5740 } 5741 } 5742 } 5743 5744 @SuppressWarnings("serial") 5745 static final class MapReduceKeysToLongTask<K,V> 5746 extends BulkTask<K,V,Long> { 5747 final ToLongFunction<? super K> transformer; 5748 final LongBinaryOperator reducer; 5749 final long basis; 5750 long result; 5751 MapReduceKeysToLongTask<K,V> rights, nextRight; 5752 MapReduceKeysToLongTask 5753 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5754 MapReduceKeysToLongTask<K,V> nextRight, 5755 ToLongFunction<? super K> transformer, 5756 long basis, 5757 LongBinaryOperator reducer) { 5758 super(p, b, i, f, t); this.nextRight = nextRight; 5759 this.transformer = transformer; 5760 this.basis = basis; this.reducer = reducer; 5761 } 5762 public final Long getRawResult() { return result; } 5763 public final void compute() { 5764 final ToLongFunction<? super K> transformer; 5765 final LongBinaryOperator reducer; 5766 if ((transformer = this.transformer) != null && 5767 (reducer = this.reducer) != null) { 5768 long r = this.basis; 5769 for (int i = baseIndex, f, h; batch > 0 && 5770 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5771 addToPendingCount(1); 5772 (rights = new MapReduceKeysToLongTask<K,V> 5773 (this, batch >>>= 1, baseLimit = h, f, tab, 5774 rights, transformer, r, reducer)).fork(); 5775 } 5776 for (Node<K,V> p; (p = advance()) != null; ) 5777 r = reducer.applyAsLong(r, transformer.applyAsLong(p.key)); 5778 result = r; 5779 CountedCompleter<?> c; 5780 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5781 @SuppressWarnings("unchecked") MapReduceKeysToLongTask<K,V> 5782 t = (MapReduceKeysToLongTask<K,V>)c, 5783 s = t.rights; 5784 while (s != null) { 5785 t.result = reducer.applyAsLong(t.result, s.result); 5786 s = t.rights = s.nextRight; 5787 } 5788 } 5789 } 5790 } 5791 } 5792 5793 @SuppressWarnings("serial") 5794 static final class MapReduceValuesToLongTask<K,V> 5795 extends BulkTask<K,V,Long> { 5796 final ToLongFunction<? super V> transformer; 5797 final LongBinaryOperator reducer; 5798 final long basis; 5799 long result; 5800 MapReduceValuesToLongTask<K,V> rights, nextRight; 5801 MapReduceValuesToLongTask 5802 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5803 MapReduceValuesToLongTask<K,V> nextRight, 5804 ToLongFunction<? super V> transformer, 5805 long basis, 5806 LongBinaryOperator reducer) { 5807 super(p, b, i, f, t); this.nextRight = nextRight; 5808 this.transformer = transformer; 5809 this.basis = basis; this.reducer = reducer; 5810 } 5811 public final Long getRawResult() { return result; } 5812 public final void compute() { 5813 final ToLongFunction<? super V> transformer; 5814 final LongBinaryOperator reducer; 5815 if ((transformer = this.transformer) != null && 5816 (reducer = this.reducer) != null) { 5817 long r = this.basis; 5818 for (int i = baseIndex, f, h; batch > 0 && 5819 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5820 addToPendingCount(1); 5821 (rights = new MapReduceValuesToLongTask<K,V> 5822 (this, batch >>>= 1, baseLimit = h, f, tab, 5823 rights, transformer, r, reducer)).fork(); 5824 } 5825 for (Node<K,V> p; (p = advance()) != null; ) 5826 r = reducer.applyAsLong(r, transformer.applyAsLong(p.val)); 5827 result = r; 5828 CountedCompleter<?> c; 5829 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5830 @SuppressWarnings("unchecked") MapReduceValuesToLongTask<K,V> 5831 t = (MapReduceValuesToLongTask<K,V>)c, 5832 s = t.rights; 5833 while (s != null) { 5834 t.result = reducer.applyAsLong(t.result, s.result); 5835 s = t.rights = s.nextRight; 5836 } 5837 } 5838 } 5839 } 5840 } 5841 5842 @SuppressWarnings("serial") 5843 static final class MapReduceEntriesToLongTask<K,V> 5844 extends BulkTask<K,V,Long> { 5845 final ToLongFunction<Map.Entry<K,V>> transformer; 5846 final LongBinaryOperator reducer; 5847 final long basis; 5848 long result; 5849 MapReduceEntriesToLongTask<K,V> rights, nextRight; 5850 MapReduceEntriesToLongTask 5851 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5852 MapReduceEntriesToLongTask<K,V> nextRight, 5853 ToLongFunction<Map.Entry<K,V>> transformer, 5854 long basis, 5855 LongBinaryOperator reducer) { 5856 super(p, b, i, f, t); this.nextRight = nextRight; 5857 this.transformer = transformer; 5858 this.basis = basis; this.reducer = reducer; 5859 } 5860 public final Long getRawResult() { return result; } 5861 public final void compute() { 5862 final ToLongFunction<Map.Entry<K,V>> transformer; 5863 final LongBinaryOperator reducer; 5864 if ((transformer = this.transformer) != null && 5865 (reducer = this.reducer) != null) { 5866 long r = this.basis; 5867 for (int i = baseIndex, f, h; batch > 0 && 5868 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5869 addToPendingCount(1); 5870 (rights = new MapReduceEntriesToLongTask<K,V> 5871 (this, batch >>>= 1, baseLimit = h, f, tab, 5872 rights, transformer, r, reducer)).fork(); 5873 } 5874 for (Node<K,V> p; (p = advance()) != null; ) 5875 r = reducer.applyAsLong(r, transformer.applyAsLong(p)); 5876 result = r; 5877 CountedCompleter<?> c; 5878 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5879 @SuppressWarnings("unchecked") MapReduceEntriesToLongTask<K,V> 5880 t = (MapReduceEntriesToLongTask<K,V>)c, 5881 s = t.rights; 5882 while (s != null) { 5883 t.result = reducer.applyAsLong(t.result, s.result); 5884 s = t.rights = s.nextRight; 5885 } 5886 } 5887 } 5888 } 5889 } 5890 5891 @SuppressWarnings("serial") 5892 static final class MapReduceMappingsToLongTask<K,V> 5893 extends BulkTask<K,V,Long> { 5894 final ToLongBiFunction<? super K, ? super V> transformer; 5895 final LongBinaryOperator reducer; 5896 final long basis; 5897 long result; 5898 MapReduceMappingsToLongTask<K,V> rights, nextRight; 5899 MapReduceMappingsToLongTask 5900 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5901 MapReduceMappingsToLongTask<K,V> nextRight, 5902 ToLongBiFunction<? super K, ? super V> transformer, 5903 long basis, 5904 LongBinaryOperator reducer) { 5905 super(p, b, i, f, t); this.nextRight = nextRight; 5906 this.transformer = transformer; 5907 this.basis = basis; this.reducer = reducer; 5908 } 5909 public final Long getRawResult() { return result; } 5910 public final void compute() { 5911 final ToLongBiFunction<? super K, ? super V> transformer; 5912 final LongBinaryOperator reducer; 5913 if ((transformer = this.transformer) != null && 5914 (reducer = this.reducer) != null) { 5915 long r = this.basis; 5916 for (int i = baseIndex, f, h; batch > 0 && 5917 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5918 addToPendingCount(1); 5919 (rights = new MapReduceMappingsToLongTask<K,V> 5920 (this, batch >>>= 1, baseLimit = h, f, tab, 5921 rights, transformer, r, reducer)).fork(); 5922 } 5923 for (Node<K,V> p; (p = advance()) != null; ) 5924 r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val)); 5925 result = r; 5926 CountedCompleter<?> c; 5927 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5928 @SuppressWarnings("unchecked") MapReduceMappingsToLongTask<K,V> 5929 t = (MapReduceMappingsToLongTask<K,V>)c, 5930 s = t.rights; 5931 while (s != null) { 5932 t.result = reducer.applyAsLong(t.result, s.result); 5933 s = t.rights = s.nextRight; 5934 } 5935 } 5936 } 5937 } 5938 } 5939 5940 @SuppressWarnings("serial") 5941 static final class MapReduceKeysToIntTask<K,V> 5942 extends BulkTask<K,V,Integer> { 5943 final ToIntFunction<? super K> transformer; 5944 final IntBinaryOperator reducer; 5945 final int basis; 5946 int result; 5947 MapReduceKeysToIntTask<K,V> rights, nextRight; 5948 MapReduceKeysToIntTask 5949 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5950 MapReduceKeysToIntTask<K,V> nextRight, 5951 ToIntFunction<? super K> transformer, 5952 int basis, 5953 IntBinaryOperator reducer) { 5954 super(p, b, i, f, t); this.nextRight = nextRight; 5955 this.transformer = transformer; 5956 this.basis = basis; this.reducer = reducer; 5957 } 5958 public final Integer getRawResult() { return result; } 5959 public final void compute() { 5960 final ToIntFunction<? super K> transformer; 5961 final IntBinaryOperator reducer; 5962 if ((transformer = this.transformer) != null && 5963 (reducer = this.reducer) != null) { 5964 int r = this.basis; 5965 for (int i = baseIndex, f, h; batch > 0 && 5966 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5967 addToPendingCount(1); 5968 (rights = new MapReduceKeysToIntTask<K,V> 5969 (this, batch >>>= 1, baseLimit = h, f, tab, 5970 rights, transformer, r, reducer)).fork(); 5971 } 5972 for (Node<K,V> p; (p = advance()) != null; ) 5973 r = reducer.applyAsInt(r, transformer.applyAsInt(p.key)); 5974 result = r; 5975 CountedCompleter<?> c; 5976 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5977 @SuppressWarnings("unchecked") MapReduceKeysToIntTask<K,V> 5978 t = (MapReduceKeysToIntTask<K,V>)c, 5979 s = t.rights; 5980 while (s != null) { 5981 t.result = reducer.applyAsInt(t.result, s.result); 5982 s = t.rights = s.nextRight; 5983 } 5984 } 5985 } 5986 } 5987 } 5988 5989 @SuppressWarnings("serial") 5990 static final class MapReduceValuesToIntTask<K,V> 5991 extends BulkTask<K,V,Integer> { 5992 final ToIntFunction<? super V> transformer; 5993 final IntBinaryOperator reducer; 5994 final int basis; 5995 int result; 5996 MapReduceValuesToIntTask<K,V> rights, nextRight; 5997 MapReduceValuesToIntTask 5998 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5999 MapReduceValuesToIntTask<K,V> nextRight, 6000 ToIntFunction<? super V> transformer, 6001 int basis, 6002 IntBinaryOperator reducer) { 6003 super(p, b, i, f, t); this.nextRight = nextRight; 6004 this.transformer = transformer; 6005 this.basis = basis; this.reducer = reducer; 6006 } 6007 public final Integer getRawResult() { return result; } 6008 public final void compute() { 6009 final ToIntFunction<? super V> transformer; 6010 final IntBinaryOperator reducer; 6011 if ((transformer = this.transformer) != null && 6012 (reducer = this.reducer) != null) { 6013 int r = this.basis; 6014 for (int i = baseIndex, f, h; batch > 0 && 6015 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6016 addToPendingCount(1); 6017 (rights = new MapReduceValuesToIntTask<K,V> 6018 (this, batch >>>= 1, baseLimit = h, f, tab, 6019 rights, transformer, r, reducer)).fork(); 6020 } 6021 for (Node<K,V> p; (p = advance()) != null; ) 6022 r = reducer.applyAsInt(r, transformer.applyAsInt(p.val)); 6023 result = r; 6024 CountedCompleter<?> c; 6025 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6026 @SuppressWarnings("unchecked") MapReduceValuesToIntTask<K,V> 6027 t = (MapReduceValuesToIntTask<K,V>)c, 6028 s = t.rights; 6029 while (s != null) { 6030 t.result = reducer.applyAsInt(t.result, s.result); 6031 s = t.rights = s.nextRight; 6032 } 6033 } 6034 } 6035 } 6036 } 6037 6038 @SuppressWarnings("serial") 6039 static final class MapReduceEntriesToIntTask<K,V> 6040 extends BulkTask<K,V,Integer> { 6041 final ToIntFunction<Map.Entry<K,V>> transformer; 6042 final IntBinaryOperator reducer; 6043 final int basis; 6044 int result; 6045 MapReduceEntriesToIntTask<K,V> rights, nextRight; 6046 MapReduceEntriesToIntTask 6047 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 6048 MapReduceEntriesToIntTask<K,V> nextRight, 6049 ToIntFunction<Map.Entry<K,V>> transformer, 6050 int basis, 6051 IntBinaryOperator reducer) { 6052 super(p, b, i, f, t); this.nextRight = nextRight; 6053 this.transformer = transformer; 6054 this.basis = basis; this.reducer = reducer; 6055 } 6056 public final Integer getRawResult() { return result; } 6057 public final void compute() { 6058 final ToIntFunction<Map.Entry<K,V>> transformer; 6059 final IntBinaryOperator reducer; 6060 if ((transformer = this.transformer) != null && 6061 (reducer = this.reducer) != null) { 6062 int r = this.basis; 6063 for (int i = baseIndex, f, h; batch > 0 && 6064 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6065 addToPendingCount(1); 6066 (rights = new MapReduceEntriesToIntTask<K,V> 6067 (this, batch >>>= 1, baseLimit = h, f, tab, 6068 rights, transformer, r, reducer)).fork(); 6069 } 6070 for (Node<K,V> p; (p = advance()) != null; ) 6071 r = reducer.applyAsInt(r, transformer.applyAsInt(p)); 6072 result = r; 6073 CountedCompleter<?> c; 6074 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6075 @SuppressWarnings("unchecked") MapReduceEntriesToIntTask<K,V> 6076 t = (MapReduceEntriesToIntTask<K,V>)c, 6077 s = t.rights; 6078 while (s != null) { 6079 t.result = reducer.applyAsInt(t.result, s.result); 6080 s = t.rights = s.nextRight; 6081 } 6082 } 6083 } 6084 } 6085 } 6086 6087 @SuppressWarnings("serial") 6088 static final class MapReduceMappingsToIntTask<K,V> 6089 extends BulkTask<K,V,Integer> { 6090 final ToIntBiFunction<? super K, ? super V> transformer; 6091 final IntBinaryOperator reducer; 6092 final int basis; 6093 int result; 6094 MapReduceMappingsToIntTask<K,V> rights, nextRight; 6095 MapReduceMappingsToIntTask 6096 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 6097 MapReduceMappingsToIntTask<K,V> nextRight, 6098 ToIntBiFunction<? super K, ? super V> transformer, 6099 int basis, 6100 IntBinaryOperator reducer) { 6101 super(p, b, i, f, t); this.nextRight = nextRight; 6102 this.transformer = transformer; 6103 this.basis = basis; this.reducer = reducer; 6104 } 6105 public final Integer getRawResult() { return result; } 6106 public final void compute() { 6107 final ToIntBiFunction<? super K, ? super V> transformer; 6108 final IntBinaryOperator reducer; 6109 if ((transformer = this.transformer) != null && 6110 (reducer = this.reducer) != null) { 6111 int r = this.basis; 6112 for (int i = baseIndex, f, h; batch > 0 && 6113 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6114 addToPendingCount(1); 6115 (rights = new MapReduceMappingsToIntTask<K,V> 6116 (this, batch >>>= 1, baseLimit = h, f, tab, 6117 rights, transformer, r, reducer)).fork(); 6118 } 6119 for (Node<K,V> p; (p = advance()) != null; ) 6120 r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val)); 6121 result = r; 6122 CountedCompleter<?> c; 6123 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6124 @SuppressWarnings("unchecked") MapReduceMappingsToIntTask<K,V> 6125 t = (MapReduceMappingsToIntTask<K,V>)c, 6126 s = t.rights; 6127 while (s != null) { 6128 t.result = reducer.applyAsInt(t.result, s.result); 6129 s = t.rights = s.nextRight; 6130 } 6131 } 6132 } 6133 } 6134 } 6135 6136 // Unsafe mechanics 6137 private static final sun.misc.Unsafe U; 6138 private static final long SIZECTL; 6139 private static final long TRANSFERINDEX; 6140 private static final long TRANSFERORIGIN; 6141 private static final long BASECOUNT; 6142 private static final long CELLSBUSY; 6143 private static final long CELLVALUE; 6144 private static final long ABASE; 6145 private static final int ASHIFT; 6146 6147 static { 6148 try { 6149 U = sun.misc.Unsafe.getUnsafe(); 6150 Class<?> k = ConcurrentHashMap.class; 6151 SIZECTL = U.objectFieldOffset 6152 (k.getDeclaredField("sizeCtl")); 6153 TRANSFERINDEX = U.objectFieldOffset 6154 (k.getDeclaredField("transferIndex")); 6155 TRANSFERORIGIN = U.objectFieldOffset 6156 (k.getDeclaredField("transferOrigin")); 6157 BASECOUNT = U.objectFieldOffset 6158 (k.getDeclaredField("baseCount")); 6159 CELLSBUSY = U.objectFieldOffset 6160 (k.getDeclaredField("cellsBusy")); 6161 Class<?> ck = CounterCell.class; 6162 CELLVALUE = U.objectFieldOffset 6163 (ck.getDeclaredField("value")); 6164 Class<?> ak = Node[].class; 6165 ABASE = U.arrayBaseOffset(ak); 6166 int scale = U.arrayIndexScale(ak); 6167 if ((scale & (scale - 1)) != 0) 6168 throw new Error("data type scale not a power of two"); 6169 ASHIFT = 31 - Integer.numberOfLeadingZeros(scale); 6170 } catch (Exception e) { 6171 throw new Error(e); 6172 } 6173 } 6174 }