1 /* 2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.util; 27 28 import java.io.IOException; 29 import java.io.InvalidObjectException; 30 import java.io.Serializable; 31 import java.lang.reflect.ParameterizedType; 32 import java.lang.reflect.Type; 33 import java.util.function.BiConsumer; 34 import java.util.function.BiFunction; 35 import java.util.function.Consumer; 36 import java.util.function.Function; 37 38 /** 39 * Hash table based implementation of the <tt>Map</tt> interface. This 40 * implementation provides all of the optional map operations, and permits 41 * <tt>null</tt> values and the <tt>null</tt> key. (The <tt>HashMap</tt> 42 * class is roughly equivalent to <tt>Hashtable</tt>, except that it is 43 * unsynchronized and permits nulls.) This class makes no guarantees as to 44 * the order of the map; in particular, it does not guarantee that the order 45 * will remain constant over time. 46 * 47 * <p>This implementation provides constant-time performance for the basic 48 * operations (<tt>get</tt> and <tt>put</tt>), assuming the hash function 49 * disperses the elements properly among the buckets. Iteration over 50 * collection views requires time proportional to the "capacity" of the 51 * <tt>HashMap</tt> instance (the number of buckets) plus its size (the number 52 * of key-value mappings). Thus, it's very important not to set the initial 53 * capacity too high (or the load factor too low) if iteration performance is 54 * important. 55 * 56 * <p>An instance of <tt>HashMap</tt> has two parameters that affect its 57 * performance: <i>initial capacity</i> and <i>load factor</i>. The 58 * <i>capacity</i> is the number of buckets in the hash table, and the initial 59 * capacity is simply the capacity at the time the hash table is created. The 60 * <i>load factor</i> is a measure of how full the hash table is allowed to 61 * get before its capacity is automatically increased. When the number of 62 * entries in the hash table exceeds the product of the load factor and the 63 * current capacity, the hash table is <i>rehashed</i> (that is, internal data 64 * structures are rebuilt) so that the hash table has approximately twice the 65 * number of buckets. 66 * 67 * <p>As a general rule, the default load factor (.75) offers a good 68 * tradeoff between time and space costs. Higher values decrease the 69 * space overhead but increase the lookup cost (reflected in most of 70 * the operations of the <tt>HashMap</tt> class, including 71 * <tt>get</tt> and <tt>put</tt>). The expected number of entries in 72 * the map and its load factor should be taken into account when 73 * setting its initial capacity, so as to minimize the number of 74 * rehash operations. If the initial capacity is greater than the 75 * maximum number of entries divided by the load factor, no rehash 76 * operations will ever occur. 77 * 78 * <p>If many mappings are to be stored in a <tt>HashMap</tt> 79 * instance, creating it with a sufficiently large capacity will allow 80 * the mappings to be stored more efficiently than letting it perform 81 * automatic rehashing as needed to grow the table. Note that using 82 * many keys with the same {@code hashCode()} is a sure way to slow 83 * down performance of any hash table. To ameliorate impact, when keys 84 * are {@link Comparable}, this class may use comparison order among 85 * keys to help break ties. 86 * 87 * <p><strong>Note that this implementation is not synchronized.</strong> 88 * If multiple threads access a hash map concurrently, and at least one of 89 * the threads modifies the map structurally, it <i>must</i> be 90 * synchronized externally. (A structural modification is any operation 91 * that adds or deletes one or more mappings; merely changing the value 92 * associated with a key that an instance already contains is not a 93 * structural modification.) This is typically accomplished by 94 * synchronizing on some object that naturally encapsulates the map. 95 * 96 * If no such object exists, the map should be "wrapped" using the 97 * {@link Collections#synchronizedMap Collections.synchronizedMap} 98 * method. This is best done at creation time, to prevent accidental 99 * unsynchronized access to the map:<pre> 100 * Map m = Collections.synchronizedMap(new HashMap(...));</pre> 101 * 102 * <p>The iterators returned by all of this class's "collection view methods" 103 * are <i>fail-fast</i>: if the map is structurally modified at any time after 104 * the iterator is created, in any way except through the iterator's own 105 * <tt>remove</tt> method, the iterator will throw a 106 * {@link ConcurrentModificationException}. Thus, in the face of concurrent 107 * modification, the iterator fails quickly and cleanly, rather than risking 108 * arbitrary, non-deterministic behavior at an undetermined time in the 109 * future. 110 * 111 * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed 112 * as it is, generally speaking, impossible to make any hard guarantees in the 113 * presence of unsynchronized concurrent modification. Fail-fast iterators 114 * throw <tt>ConcurrentModificationException</tt> on a best-effort basis. 115 * Therefore, it would be wrong to write a program that depended on this 116 * exception for its correctness: <i>the fail-fast behavior of iterators 117 * should be used only to detect bugs.</i> 118 * 119 * <p>This class is a member of the 120 * <a href="{@docRoot}/../technotes/guides/collections/index.html"> 121 * Java Collections Framework</a>. 122 * 123 * @param <K> the type of keys maintained by this map 124 * @param <V> the type of mapped values 125 * 126 * @author Doug Lea 127 * @author Josh Bloch 128 * @author Arthur van Hoff 129 * @author Neal Gafter 130 * @see Object#hashCode() 131 * @see Collection 132 * @see Map 133 * @see TreeMap 134 * @see Hashtable 135 * @since 1.2 136 */ 137 public class HashMap<K,V> extends AbstractMap<K,V> 138 implements Map<K,V>, Cloneable, Serializable { 139 140 private static final long serialVersionUID = 362498820763181265L; 141 142 /* 143 * Implementation notes. 144 * 145 * This map usually acts as a binned (bucketed) hash table, but 146 * when bins get too large, they are transformed into bins of 147 * TreeNodes, each structured similarly to those in 148 * java.util.TreeMap. Most methods try to use normal bins, but 149 * relay to TreeNode methods when applicable (simply by checking 150 * instanceof a node). Bins of TreeNodes may be traversed and 151 * used like any others, but additionally support faster lookup 152 * when overpopulated. However, since the vast majority of bins in 153 * normal use are not overpopulated, checking for existence of 154 * tree bins may be delayed in the course of table methods. 155 * 156 * Tree bins (i.e., bins whose elements are all TreeNodes) are 157 * ordered primarily by hashCode, but in the case of ties, if two 158 * elements are of the same "class C implements Comparable<C>", 159 * type then their compareTo method is used for ordering. (We 160 * conservatively check generic types via reflection to validate 161 * this -- see method comparableClassFor). The added complexity 162 * of tree bins is worthwhile in providing worst-case O(log n) 163 * operations when keys either have distinct hashes or are 164 * orderable, Thus, performance degrades gracefully under 165 * accidental or malicious usages in which hashCode() methods 166 * return values that are poorly distributed, as well as those in 167 * which many keys share a hashCode, so long as they are also 168 * Comparable. (If neither of these apply, we may waste about a 169 * factor of two in time and space compared to taking no 170 * precautions. But the only known cases stem from poor user 171 * programming practices that are already so slow that this makes 172 * little difference.) 173 * 174 * Because TreeNodes are about twice the size of regular nodes, we 175 * use them only when bins contain enough nodes to warrant use 176 * (see TREEIFY_THRESHOLD). And when they become too small (due to 177 * removal or resizing) they are converted back to plain bins. In 178 * usages with well-distributed user hashCodes, tree bins are 179 * rarely used. Ideally, under random hashCodes, the frequency of 180 * nodes in bins follows a Poisson distribution 181 * (http://en.wikipedia.org/wiki/Poisson_distribution) with a 182 * parameter of about 0.5 on average for the default resizing 183 * threshold of 0.75, although with a large variance because of 184 * resizing granularity. Ignoring variance, the expected 185 * occurrences of list size k are (exp(-0.5) * pow(0.5, k) / 186 * factorial(k)). The first values are: 187 * 188 * 0: 0.60653066 189 * 1: 0.30326533 190 * 2: 0.07581633 191 * 3: 0.01263606 192 * 4: 0.00157952 193 * 5: 0.00015795 194 * 6: 0.00001316 195 * 7: 0.00000094 196 * 8: 0.00000006 197 * more: less than 1 in ten million 198 * 199 * The root of a tree bin is normally its first node. However, 200 * sometimes (currently only upon Iterator.remove), the root might 201 * be elsewhere, but can be recovered following parent links 202 * (method TreeNode.root()). 203 * 204 * All applicable internal methods accept a hash code as an 205 * argument (as normally supplied from a public method), allowing 206 * them to call each other without recomputing user hashCodes. 207 * Most internal methods also accept a "tab" argument, that is 208 * normally the current table, but may be a new or old one when 209 * resizing or converting. 210 * 211 * When bin lists are treeified, split, or untreeified, we keep 212 * them in the same relative access/traversal order (i.e., field 213 * Node.next) to better preserve locality, and to slightly 214 * simplify handling of splits and traversals that invoke 215 * iterator.remove. When using comparators on insertion, to keep a 216 * total ordering (or as close as is required here) across 217 * rebalancings, we compare classes and identityHashCodes as 218 * tie-breakers. 219 * 220 * The use and transitions among plain vs tree modes is 221 * complicated by the existence of subclass LinkedHashMap. See 222 * below for hook methods defined to be invoked upon insertion, 223 * removal and access that allow LinkedHashMap internals to 224 * otherwise remain independent of these mechanics. (This also 225 * requires that a map instance be passed to some utility methods 226 * that may create new nodes.) 227 * 228 * The concurrent-programming-like SSA-based coding style helps 229 * avoid aliasing errors amid all of the twisty pointer operations. 230 */ 231 232 /** 233 * The default initial capacity - MUST be a power of two. 234 */ 235 static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // aka 16 236 237 /** 238 * The maximum capacity, used if a higher value is implicitly specified 239 * by either of the constructors with arguments. 240 * MUST be a power of two <= 1<<30. 241 */ 242 static final int MAXIMUM_CAPACITY = 1 << 30; 243 244 /** 245 * The load factor used when none specified in constructor. 246 */ 247 static final float DEFAULT_LOAD_FACTOR = 0.75f; 248 249 /** 250 * The bin count threshold for using a tree rather than list for a 251 * bin. Bins are converted to trees when adding an element to a 252 * bin with at least this many nodes. The value must be greater 253 * than 2 and should be at least 8 to mesh with assumptions in 254 * tree removal about conversion back to plain bins upon 255 * shrinkage. 256 */ 257 static final int TREEIFY_THRESHOLD = 8; 258 259 /** 260 * The bin count threshold for untreeifying a (split) bin during a 261 * resize operation. Should be less than TREEIFY_THRESHOLD, and at 262 * most 6 to mesh with shrinkage detection under removal. 263 */ 264 static final int UNTREEIFY_THRESHOLD = 6; 265 266 /** 267 * The smallest table capacity for which bins may be treeified. 268 * (Otherwise the table is resized if too many nodes in a bin.) 269 * Should be at least 4 * TREEIFY_THRESHOLD to avoid conflicts 270 * between resizing and treeification thresholds. 271 */ 272 static final int MIN_TREEIFY_CAPACITY = 64; 273 274 /** 275 * Basic hash bin node, used for most entries. (See below for 276 * TreeNode subclass, and in LinkedHashMap for its Entry subclass.) 277 */ 278 static class Node<K,V> implements Map.Entry<K,V> { 279 final int hash; 280 final K key; 281 V value; 282 Node<K,V> next; 283 284 Node(int hash, K key, V value, Node<K,V> next) { 285 this.hash = hash; 286 this.key = key; 287 this.value = value; 288 this.next = next; 289 } 290 291 public final K getKey() { return key; } 292 public final V getValue() { return value; } 293 public final String toString() { return key + "=" + value; } 294 295 public final int hashCode() { 296 return Objects.hashCode(key) ^ Objects.hashCode(value); 297 } 298 299 public final V setValue(V newValue) { 300 V oldValue = value; 301 value = newValue; 302 return oldValue; 303 } 304 305 public final boolean equals(Object o) { 306 if (o == this) 307 return true; 308 if (o instanceof Map.Entry) { 309 Map.Entry<?,?> e = (Map.Entry<?,?>)o; 310 if (Objects.equals(key, e.getKey()) && 311 Objects.equals(value, e.getValue())) 312 return true; 313 } 314 return false; 315 } 316 } 317 318 /* ---------------- Static utilities -------------- */ 319 320 /** 321 * Computes key.hashCode() and spreads (XORs) higher bits of hash 322 * to lower. Because the table uses power-of-two masking, sets of 323 * hashes that vary only in bits above the current mask will 324 * always collide. (Among known examples are sets of Float keys 325 * holding consecutive whole numbers in small tables.) So we 326 * apply a transform that spreads the impact of higher bits 327 * downward. There is a tradeoff between speed, utility, and 328 * quality of bit-spreading. Because many common sets of hashes 329 * are already reasonably distributed (so don't benefit from 330 * spreading), and because we use trees to handle large sets of 331 * collisions in bins, we just XOR some shifted bits in the 332 * cheapest possible way to reduce systematic lossage, as well as 333 * to incorporate impact of the highest bits that would otherwise 334 * never be used in index calculations because of table bounds. 335 */ 336 static final int hash(Object key) { 337 int h; 338 return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16); 339 } 340 341 /** 342 * Returns x's Class if it is of the form "class C implements 343 * Comparable<C>", else null. 344 */ 345 static Class<?> comparableClassFor(Object x) { 346 if (x instanceof Comparable) { 347 Class<?> c; Type[] ts, as; Type t; ParameterizedType p; 348 if ((c = x.getClass()) == String.class) // bypass checks 349 return c; 350 if ((ts = c.getGenericInterfaces()) != null) { 351 for (int i = 0; i < ts.length; ++i) { 352 if (((t = ts[i]) instanceof ParameterizedType) && 353 ((p = (ParameterizedType)t).getRawType() == 354 Comparable.class) && 355 (as = p.getActualTypeArguments()) != null && 356 as.length == 1 && as[0] == c) // type arg is c 357 return c; 358 } 359 } 360 } 361 return null; 362 } 363 364 /** 365 * Returns k.compareTo(x) if x matches kc (k's screened comparable 366 * class), else 0. 367 */ 368 @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable 369 static int compareComparables(Class<?> kc, Object k, Object x) { 370 return (x == null || x.getClass() != kc ? 0 : 371 ((Comparable)k).compareTo(x)); 372 } 373 374 /** 375 * Returns a power of two size for the given target capacity. 376 */ 377 static final int tableSizeFor(int cap) { 378 int n = cap - 1; 379 n |= n >>> 1; 380 n |= n >>> 2; 381 n |= n >>> 4; 382 n |= n >>> 8; 383 n |= n >>> 16; 384 return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1; 385 } 386 387 /* ---------------- Fields -------------- */ 388 389 /** 390 * The table, initialized on first use, and resized as 391 * necessary. When allocated, length is always a power of two. 392 * (We also tolerate length zero in some operations to allow 393 * bootstrapping mechanics that are currently not needed.) 394 */ 395 transient Node<K,V>[] table; 396 397 /** 398 * Holds cached entrySet(). Note that AbstractMap fields are used 399 * for keySet() and values(). 400 */ 401 transient Set<Map.Entry<K,V>> entrySet; 402 403 /** 404 * The number of key-value mappings contained in this map. 405 */ 406 transient int size; 407 408 /** 409 * The number of times this HashMap has been structurally modified 410 * Structural modifications are those that change the number of mappings in 411 * the HashMap or otherwise modify its internal structure (e.g., 412 * rehash). This field is used to make iterators on Collection-views of 413 * the HashMap fail-fast. (See ConcurrentModificationException). 414 */ 415 transient int modCount; 416 417 /** 418 * The next size value at which to resize (capacity * load factor). 419 * 420 * @serial 421 */ 422 // (The javadoc description is true upon serialization. 423 // Additionally, if the table array has not been allocated, this 424 // field holds the initial array capacity, or zero signifying 425 // DEFAULT_INITIAL_CAPACITY.) 426 int threshold; 427 428 /** 429 * The load factor for the hash table. 430 * 431 * @serial 432 */ 433 final float loadFactor; 434 435 /* ---------------- Public operations -------------- */ 436 437 /** 438 * Constructs an empty <tt>HashMap</tt> with the specified initial 439 * capacity and load factor. 440 * 441 * @param initialCapacity the initial capacity 442 * @param loadFactor the load factor 443 * @throws IllegalArgumentException if the initial capacity is negative 444 * or the load factor is nonpositive 445 */ 446 public HashMap(int initialCapacity, float loadFactor) { 447 if (initialCapacity < 0) 448 throw new IllegalArgumentException("Illegal initial capacity: " + 449 initialCapacity); 450 if (initialCapacity > MAXIMUM_CAPACITY) 451 initialCapacity = MAXIMUM_CAPACITY; 452 if (loadFactor <= 0 || Float.isNaN(loadFactor)) 453 throw new IllegalArgumentException("Illegal load factor: " + 454 loadFactor); 455 this.loadFactor = loadFactor; 456 this.threshold = tableSizeFor(initialCapacity); 457 } 458 459 /** 460 * Constructs an empty <tt>HashMap</tt> with the specified initial 461 * capacity and the default load factor (0.75). 462 * 463 * @param initialCapacity the initial capacity. 464 * @throws IllegalArgumentException if the initial capacity is negative. 465 */ 466 public HashMap(int initialCapacity) { 467 this(initialCapacity, DEFAULT_LOAD_FACTOR); 468 } 469 470 /** 471 * Constructs an empty <tt>HashMap</tt> with the default initial capacity 472 * (16) and the default load factor (0.75). 473 */ 474 public HashMap() { 475 this.loadFactor = DEFAULT_LOAD_FACTOR; // all other fields defaulted 476 } 477 478 /** 479 * Constructs a new <tt>HashMap</tt> with the same mappings as the 480 * specified <tt>Map</tt>. The <tt>HashMap</tt> is created with 481 * default load factor (0.75) and an initial capacity sufficient to 482 * hold the mappings in the specified <tt>Map</tt>. 483 * 484 * @param m the map whose mappings are to be placed in this map 485 * @throws NullPointerException if the specified map is null 486 */ 487 public HashMap(Map<? extends K, ? extends V> m) { 488 this.loadFactor = DEFAULT_LOAD_FACTOR; 489 putMapEntries(m, false); 490 } 491 492 /** 493 * Implements Map.putAll and Map constructor 494 * 495 * @param m the map 496 * @param evict false when initially constructing this map, else 497 * true (relayed to method afterNodeInsertion). 498 */ 499 final void putMapEntries(Map<? extends K, ? extends V> m, boolean evict) { 500 int s = m.size(); 501 if (s > 0) { 502 if (table == null) { // pre-size 503 float ft = ((float)s / loadFactor) + 1.0F; 504 int t = ((ft < (float)MAXIMUM_CAPACITY) ? 505 (int)ft : MAXIMUM_CAPACITY); 506 if (t > threshold) 507 threshold = tableSizeFor(t); 508 } 509 else if (s > threshold) 510 resize(); 511 for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) { 512 K key = e.getKey(); 513 V value = e.getValue(); 514 putVal(hash(key), key, value, false, evict); 515 } 516 } 517 } 518 519 /** 520 * Returns the number of key-value mappings in this map. 521 * 522 * @return the number of key-value mappings in this map 523 */ 524 public int size() { 525 return size; 526 } 527 528 /** 529 * Returns <tt>true</tt> if this map contains no key-value mappings. 530 * 531 * @return <tt>true</tt> if this map contains no key-value mappings 532 */ 533 public boolean isEmpty() { 534 return size == 0; 535 } 536 537 /** 538 * Returns the value to which the specified key is mapped, 539 * or {@code null} if this map contains no mapping for the key. 540 * 541 * <p>More formally, if this map contains a mapping from a key 542 * {@code k} to a value {@code v} such that {@code (key==null ? k==null : 543 * key.equals(k))}, then this method returns {@code v}; otherwise 544 * it returns {@code null}. (There can be at most one such mapping.) 545 * 546 * <p>A return value of {@code null} does not <i>necessarily</i> 547 * indicate that the map contains no mapping for the key; it's also 548 * possible that the map explicitly maps the key to {@code null}. 549 * The {@link #containsKey containsKey} operation may be used to 550 * distinguish these two cases. 551 * 552 * @see #put(Object, Object) 553 */ 554 public V get(Object key) { 555 Node<K,V> e; 556 return (e = getNode(hash(key), key)) == null ? null : e.value; 557 } 558 559 /** 560 * Implements Map.get and related methods 561 * 562 * @param hash hash for key 563 * @param key the key 564 * @return the node, or null if none 565 */ 566 final Node<K,V> getNode(int hash, Object key) { 567 Node<K,V>[] tab; Node<K,V> first, e; int n; K k; 568 if ((tab = table) != null && (n = tab.length) > 0 && 569 (first = tab[(n - 1) & hash]) != null) { 570 if (first.hash == hash && // always check first node 571 ((k = first.key) == key || (key != null && key.equals(k)))) 572 return first; 573 if ((e = first.next) != null) { 574 if (first instanceof TreeNode) 575 return ((TreeNode<K,V>)first).getTreeNode(hash, key); 576 do { 577 if (e.hash == hash && 578 ((k = e.key) == key || (key != null && key.equals(k)))) 579 return e; 580 } while ((e = e.next) != null); 581 } 582 } 583 return null; 584 } 585 586 /** 587 * Returns <tt>true</tt> if this map contains a mapping for the 588 * specified key. 589 * 590 * @param key The key whose presence in this map is to be tested 591 * @return <tt>true</tt> if this map contains a mapping for the specified 592 * key. 593 */ 594 public boolean containsKey(Object key) { 595 return getNode(hash(key), key) != null; 596 } 597 598 /** 599 * Associates the specified value with the specified key in this map. 600 * If the map previously contained a mapping for the key, the old 601 * value is replaced. 602 * 603 * @param key key with which the specified value is to be associated 604 * @param value value to be associated with the specified key 605 * @return the previous value associated with <tt>key</tt>, or 606 * <tt>null</tt> if there was no mapping for <tt>key</tt>. 607 * (A <tt>null</tt> return can also indicate that the map 608 * previously associated <tt>null</tt> with <tt>key</tt>.) 609 */ 610 public V put(K key, V value) { 611 return putVal(hash(key), key, value, false, true); 612 } 613 614 /** 615 * Implements Map.put and related methods 616 * 617 * @param hash hash for key 618 * @param key the key 619 * @param value the value to put 620 * @param onlyIfAbsent if true, don't change existing value 621 * @param evict if false, the table is in creation mode. 622 * @return previous value, or null if none 623 */ 624 final V putVal(int hash, K key, V value, boolean onlyIfAbsent, 625 boolean evict) { 626 Node<K,V>[] tab; Node<K,V> p; int n, i; 627 if ((tab = table) == null || (n = tab.length) == 0) 628 n = (tab = resize()).length; 629 if ((p = tab[i = (n - 1) & hash]) == null) 630 tab[i] = newNode(hash, key, value, null); 631 else { 632 Node<K,V> e; K k; 633 if (p.hash == hash && 634 ((k = p.key) == key || (key != null && key.equals(k)))) 635 e = p; 636 else if (p instanceof TreeNode) 637 e = ((TreeNode<K,V>)p).putTreeVal(this, tab, hash, key, value); 638 else { 639 for (int binCount = 0; ; ++binCount) { 640 if ((e = p.next) == null) { 641 p.next = newNode(hash, key, value, null); 642 if (binCount >= TREEIFY_THRESHOLD - 1) // -1 for 1st 643 treeifyBin(tab, hash); 644 break; 645 } 646 if (e.hash == hash && 647 ((k = e.key) == key || (key != null && key.equals(k)))) 648 break; 649 p = e; 650 } 651 } 652 if (e != null) { // existing mapping for key 653 V oldValue = e.value; 654 if (!onlyIfAbsent || oldValue == null) 655 e.value = value; 656 afterNodeAccess(e); 657 return oldValue; 658 } 659 } 660 ++modCount; 661 if (++size > threshold) 662 resize(); 663 afterNodeInsertion(evict); 664 return null; 665 } 666 667 /** 668 * Initializes or doubles table size. If null, allocates in 669 * accord with initial capacity target held in field threshold. 670 * Otherwise, because we are using power-of-two expansion, the 671 * elements from each bin must either stay at same index, or move 672 * with a power of two offset in the new table. 673 * 674 * @return the table 675 */ 676 final Node<K,V>[] resize() { 677 Node<K,V>[] oldTab = table; 678 int oldCap = (oldTab == null) ? 0 : oldTab.length; 679 int oldThr = threshold; 680 int newCap, newThr = 0; 681 if (oldCap > 0) { 682 if (oldCap >= MAXIMUM_CAPACITY) { 683 threshold = Integer.MAX_VALUE; 684 return oldTab; 685 } 686 else if ((newCap = oldCap << 1) < MAXIMUM_CAPACITY && 687 oldCap >= DEFAULT_INITIAL_CAPACITY) 688 newThr = oldThr << 1; // double threshold 689 } 690 else if (oldThr > 0) // initial capacity was placed in threshold 691 newCap = oldThr; 692 else { // zero initial threshold signifies using defaults 693 newCap = DEFAULT_INITIAL_CAPACITY; 694 newThr = (int)(DEFAULT_LOAD_FACTOR * DEFAULT_INITIAL_CAPACITY); 695 } 696 if (newThr == 0) { 697 float ft = (float)newCap * loadFactor; 698 newThr = (newCap < MAXIMUM_CAPACITY && ft < (float)MAXIMUM_CAPACITY ? 699 (int)ft : Integer.MAX_VALUE); 700 } 701 threshold = newThr; 702 @SuppressWarnings({"rawtypes","unchecked"}) 703 Node<K,V>[] newTab = (Node<K,V>[])new Node[newCap]; 704 table = newTab; 705 if (oldTab != null) { 706 for (int j = 0; j < oldCap; ++j) { 707 Node<K,V> e; 708 if ((e = oldTab[j]) != null) { 709 oldTab[j] = null; 710 if (e.next == null) 711 newTab[e.hash & (newCap - 1)] = e; 712 else if (e instanceof TreeNode) 713 ((TreeNode<K,V>)e).split(this, newTab, j, oldCap); 714 else { // preserve order 715 Node<K,V> loHead = null, loTail = null; 716 Node<K,V> hiHead = null, hiTail = null; 717 Node<K,V> next; 718 do { 719 next = e.next; 720 if ((e.hash & oldCap) == 0) { 721 if (loTail == null) 722 loHead = e; 723 else 724 loTail.next = e; 725 loTail = e; 726 } 727 else { 728 if (hiTail == null) 729 hiHead = e; 730 else 731 hiTail.next = e; 732 hiTail = e; 733 } 734 } while ((e = next) != null); 735 if (loTail != null) { 736 loTail.next = null; 737 newTab[j] = loHead; 738 } 739 if (hiTail != null) { 740 hiTail.next = null; 741 newTab[j + oldCap] = hiHead; 742 } 743 } 744 } 745 } 746 } 747 return newTab; 748 } 749 750 /** 751 * Replaces all linked nodes in bin at index for given hash unless 752 * table is too small, in which case resizes instead. 753 */ 754 final void treeifyBin(Node<K,V>[] tab, int hash) { 755 int n, index; Node<K,V> e; 756 if (tab == null || (n = tab.length) < MIN_TREEIFY_CAPACITY) 757 resize(); 758 else if ((e = tab[index = (n - 1) & hash]) != null) { 759 TreeNode<K,V> hd = null, tl = null; 760 do { 761 TreeNode<K,V> p = replacementTreeNode(e, null); 762 if (tl == null) 763 hd = p; 764 else { 765 p.prev = tl; 766 tl.next = p; 767 } 768 tl = p; 769 } while ((e = e.next) != null); 770 if ((tab[index] = hd) != null) 771 hd.treeify(tab); 772 } 773 } 774 775 /** 776 * Copies all of the mappings from the specified map to this map. 777 * These mappings will replace any mappings that this map had for 778 * any of the keys currently in the specified map. 779 * 780 * @param m mappings to be stored in this map 781 * @throws NullPointerException if the specified map is null 782 */ 783 public void putAll(Map<? extends K, ? extends V> m) { 784 putMapEntries(m, true); 785 } 786 787 /** 788 * Removes the mapping for the specified key from this map if present. 789 * 790 * @param key key whose mapping is to be removed from the map 791 * @return the previous value associated with <tt>key</tt>, or 792 * <tt>null</tt> if there was no mapping for <tt>key</tt>. 793 * (A <tt>null</tt> return can also indicate that the map 794 * previously associated <tt>null</tt> with <tt>key</tt>.) 795 */ 796 public V remove(Object key) { 797 Node<K,V> e; 798 return (e = removeNode(hash(key), key, null, false, true)) == null ? 799 null : e.value; 800 } 801 802 /** 803 * Implements Map.remove and related methods 804 * 805 * @param hash hash for key 806 * @param key the key 807 * @param value the value to match if matchValue, else ignored 808 * @param matchValue if true only remove if value is equal 809 * @param movable if false do not move other nodes while removing 810 * @return the node, or null if none 811 */ 812 final Node<K,V> removeNode(int hash, Object key, Object value, 813 boolean matchValue, boolean movable) { 814 Node<K,V>[] tab; Node<K,V> p; int n, index; 815 if ((tab = table) != null && (n = tab.length) > 0 && 816 (p = tab[index = (n - 1) & hash]) != null) { 817 Node<K,V> node = null, e; K k; V v; 818 if (p.hash == hash && 819 ((k = p.key) == key || (key != null && key.equals(k)))) 820 node = p; 821 else if ((e = p.next) != null) { 822 if (p instanceof TreeNode) 823 node = ((TreeNode<K,V>)p).getTreeNode(hash, key); 824 else { 825 do { 826 if (e.hash == hash && 827 ((k = e.key) == key || 828 (key != null && key.equals(k)))) { 829 node = e; 830 break; 831 } 832 p = e; 833 } while ((e = e.next) != null); 834 } 835 } 836 if (node != null && (!matchValue || (v = node.value) == value || 837 (value != null && value.equals(v)))) { 838 if (node instanceof TreeNode) 839 ((TreeNode<K,V>)node).removeTreeNode(this, tab, movable); 840 else if (node == p) 841 tab[index] = node.next; 842 else 843 p.next = node.next; 844 ++modCount; 845 --size; 846 afterNodeRemoval(node); 847 return node; 848 } 849 } 850 return null; 851 } 852 853 /** 854 * Removes all of the mappings from this map. 855 * The map will be empty after this call returns. 856 */ 857 public void clear() { 858 Node<K,V>[] tab; 859 modCount++; 860 if ((tab = table) != null && size > 0) { 861 size = 0; 862 for (int i = 0; i < tab.length; ++i) 863 tab[i] = null; 864 } 865 } 866 867 /** 868 * Returns <tt>true</tt> if this map maps one or more keys to the 869 * specified value. 870 * 871 * @param value value whose presence in this map is to be tested 872 * @return <tt>true</tt> if this map maps one or more keys to the 873 * specified value 874 */ 875 public boolean containsValue(Object value) { 876 Node<K,V>[] tab; V v; 877 if ((tab = table) != null && size > 0) { 878 for (int i = 0; i < tab.length; ++i) { 879 for (Node<K,V> e = tab[i]; e != null; e = e.next) { 880 if ((v = e.value) == value || 881 (value != null && value.equals(v))) 882 return true; 883 } 884 } 885 } 886 return false; 887 } 888 889 /** 890 * Returns a {@link Set} view of the keys contained in this map. 891 * The set is backed by the map, so changes to the map are 892 * reflected in the set, and vice-versa. If the map is modified 893 * while an iteration over the set is in progress (except through 894 * the iterator's own <tt>remove</tt> operation), the results of 895 * the iteration are undefined. The set supports element removal, 896 * which removes the corresponding mapping from the map, via the 897 * <tt>Iterator.remove</tt>, <tt>Set.remove</tt>, 898 * <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt> 899 * operations. It does not support the <tt>add</tt> or <tt>addAll</tt> 900 * operations. 901 * 902 * @return a set view of the keys contained in this map 903 */ 904 public Set<K> keySet() { 905 Set<K> ks; 906 return (ks = keySet) == null ? (keySet = new KeySet()) : ks; 907 } 908 909 final class KeySet extends AbstractSet<K> { 910 public final int size() { return size; } 911 public final void clear() { HashMap.this.clear(); } 912 public final Iterator<K> iterator() { return new KeyIterator(); } 913 public final boolean contains(Object o) { return containsKey(o); } 914 public final boolean remove(Object key) { 915 return removeNode(hash(key), key, null, false, true) != null; 916 } 917 public final Spliterator<K> spliterator() { 918 return new KeySpliterator<>(HashMap.this, 0, -1, 0, 0); 919 } 920 public final void forEach(Consumer<? super K> action) { 921 Node<K,V>[] tab; 922 if (action == null) 923 throw new NullPointerException(); 924 if (size > 0 && (tab = table) != null) { 925 int mc = modCount; 926 for (int i = 0; i < tab.length; ++i) { 927 for (Node<K,V> e = tab[i]; e != null; e = e.next) 928 action.accept(e.key); 929 } 930 if (modCount != mc) 931 throw new ConcurrentModificationException(); 932 } 933 } 934 } 935 936 /** 937 * Returns a {@link Collection} view of the values contained in this map. 938 * The collection is backed by the map, so changes to the map are 939 * reflected in the collection, and vice-versa. If the map is 940 * modified while an iteration over the collection is in progress 941 * (except through the iterator's own <tt>remove</tt> operation), 942 * the results of the iteration are undefined. The collection 943 * supports element removal, which removes the corresponding 944 * mapping from the map, via the <tt>Iterator.remove</tt>, 945 * <tt>Collection.remove</tt>, <tt>removeAll</tt>, 946 * <tt>retainAll</tt> and <tt>clear</tt> operations. It does not 947 * support the <tt>add</tt> or <tt>addAll</tt> operations. 948 * 949 * @return a view of the values contained in this map 950 */ 951 public Collection<V> values() { 952 Collection<V> vs; 953 return (vs = values) == null ? (values = new Values()) : vs; 954 } 955 956 final class Values extends AbstractCollection<V> { 957 public final int size() { return size; } 958 public final void clear() { HashMap.this.clear(); } 959 public final Iterator<V> iterator() { return new ValueIterator(); } 960 public final boolean contains(Object o) { return containsValue(o); } 961 public final Spliterator<V> spliterator() { 962 return new ValueSpliterator<>(HashMap.this, 0, -1, 0, 0); 963 } 964 public final void forEach(Consumer<? super V> action) { 965 Node<K,V>[] tab; 966 if (action == null) 967 throw new NullPointerException(); 968 if (size > 0 && (tab = table) != null) { 969 int mc = modCount; 970 for (int i = 0; i < tab.length; ++i) { 971 for (Node<K,V> e = tab[i]; e != null; e = e.next) 972 action.accept(e.value); 973 } 974 if (modCount != mc) 975 throw new ConcurrentModificationException(); 976 } 977 } 978 } 979 980 /** 981 * Returns a {@link Set} view of the mappings contained in this map. 982 * The set is backed by the map, so changes to the map are 983 * reflected in the set, and vice-versa. If the map is modified 984 * while an iteration over the set is in progress (except through 985 * the iterator's own <tt>remove</tt> operation, or through the 986 * <tt>setValue</tt> operation on a map entry returned by the 987 * iterator) the results of the iteration are undefined. The set 988 * supports element removal, which removes the corresponding 989 * mapping from the map, via the <tt>Iterator.remove</tt>, 990 * <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt> and 991 * <tt>clear</tt> operations. It does not support the 992 * <tt>add</tt> or <tt>addAll</tt> operations. 993 * 994 * @return a set view of the mappings contained in this map 995 */ 996 public Set<Map.Entry<K,V>> entrySet() { 997 Set<Map.Entry<K,V>> es; 998 return (es = entrySet) == null ? (entrySet = new EntrySet()) : es; 999 } 1000 1001 final class EntrySet extends AbstractSet<Map.Entry<K,V>> { 1002 public final int size() { return size; } 1003 public final void clear() { HashMap.this.clear(); } 1004 public final Iterator<Map.Entry<K,V>> iterator() { 1005 return new EntryIterator(); 1006 } 1007 public final boolean contains(Object o) { 1008 if (!(o instanceof Map.Entry)) 1009 return false; 1010 Map.Entry<?,?> e = (Map.Entry<?,?>) o; 1011 Object key = e.getKey(); 1012 Node<K,V> candidate = getNode(hash(key), key); 1013 return candidate != null && candidate.equals(e); 1014 } 1015 public final boolean remove(Object o) { 1016 if (o instanceof Map.Entry) { 1017 Map.Entry<?,?> e = (Map.Entry<?,?>) o; 1018 Object key = e.getKey(); 1019 Object value = e.getValue(); 1020 return removeNode(hash(key), key, value, true, true) != null; 1021 } 1022 return false; 1023 } 1024 public final Spliterator<Map.Entry<K,V>> spliterator() { 1025 return new EntrySpliterator<>(HashMap.this, 0, -1, 0, 0); 1026 } 1027 public final void forEach(Consumer<? super Map.Entry<K,V>> action) { 1028 Node<K,V>[] tab; 1029 if (action == null) 1030 throw new NullPointerException(); 1031 if (size > 0 && (tab = table) != null) { 1032 int mc = modCount; 1033 for (int i = 0; i < tab.length; ++i) { 1034 for (Node<K,V> e = tab[i]; e != null; e = e.next) 1035 action.accept(e); 1036 } 1037 if (modCount != mc) 1038 throw new ConcurrentModificationException(); 1039 } 1040 } 1041 } 1042 1043 // Overrides of JDK8 Map extension methods 1044 1045 @Override 1046 public V getOrDefault(Object key, V defaultValue) { 1047 Node<K,V> e; 1048 return (e = getNode(hash(key), key)) == null ? defaultValue : e.value; 1049 } 1050 1051 @Override 1052 public V putIfAbsent(K key, V value) { 1053 return putVal(hash(key), key, value, true, true); 1054 } 1055 1056 @Override 1057 public boolean remove(Object key, Object value) { 1058 return removeNode(hash(key), key, value, true, true) != null; 1059 } 1060 1061 @Override 1062 public boolean replace(K key, V oldValue, V newValue) { 1063 Node<K,V> e; V v; 1064 if ((e = getNode(hash(key), key)) != null && 1065 ((v = e.value) == oldValue || (v != null && v.equals(oldValue)))) { 1066 e.value = newValue; 1067 afterNodeAccess(e); 1068 return true; 1069 } 1070 return false; 1071 } 1072 1073 @Override 1074 public V replace(K key, V value) { 1075 Node<K,V> e; 1076 if ((e = getNode(hash(key), key)) != null) { 1077 V oldValue = e.value; 1078 e.value = value; 1079 afterNodeAccess(e); 1080 return oldValue; 1081 } 1082 return null; 1083 } 1084 1085 @Override 1086 public V computeIfAbsent(K key, 1087 Function<? super K, ? extends V> mappingFunction) { 1088 if (mappingFunction == null) 1089 throw new NullPointerException(); 1090 int hash = hash(key); 1091 Node<K,V>[] tab; Node<K,V> first; int n, i; 1092 int binCount = 0; 1093 TreeNode<K,V> t = null; 1094 Node<K,V> old = null; 1095 if (size > threshold || (tab = table) == null || 1096 (n = tab.length) == 0) 1097 n = (tab = resize()).length; 1098 if ((first = tab[i = (n - 1) & hash]) != null) { 1099 if (first instanceof TreeNode) 1100 old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key); 1101 else { 1102 Node<K,V> e = first; K k; 1103 do { 1104 if (e.hash == hash && 1105 ((k = e.key) == key || (key != null && key.equals(k)))) { 1106 old = e; 1107 break; 1108 } 1109 ++binCount; 1110 } while ((e = e.next) != null); 1111 } 1112 V oldValue; 1113 if (old != null && (oldValue = old.value) != null) { 1114 afterNodeAccess(old); 1115 return oldValue; 1116 } 1117 } 1118 V v = mappingFunction.apply(key); 1119 if (old != null) { 1120 old.value = v; 1121 afterNodeAccess(old); 1122 return v; 1123 } 1124 else if (v == null) 1125 return null; 1126 else if (t != null) 1127 t.putTreeVal(this, tab, hash, key, v); 1128 else { 1129 tab[i] = newNode(hash, key, v, first); 1130 if (binCount >= TREEIFY_THRESHOLD - 1) 1131 treeifyBin(tab, hash); 1132 } 1133 ++modCount; 1134 ++size; 1135 afterNodeInsertion(true); 1136 return v; 1137 } 1138 1139 public V computeIfPresent(K key, 1140 BiFunction<? super K, ? super V, ? extends V> remappingFunction) { 1141 if (remappingFunction == null) 1142 throw new NullPointerException(); 1143 Node<K,V> e; V oldValue; 1144 int hash = hash(key); 1145 if ((e = getNode(hash, key)) != null && 1146 (oldValue = e.value) != null) { 1147 V v = remappingFunction.apply(key, oldValue); 1148 if (v != null) { 1149 e.value = v; 1150 afterNodeAccess(e); 1151 return v; 1152 } 1153 else 1154 removeNode(hash, key, null, false, true); 1155 } 1156 return null; 1157 } 1158 1159 @Override 1160 public V compute(K key, 1161 BiFunction<? super K, ? super V, ? extends V> remappingFunction) { 1162 if (remappingFunction == null) 1163 throw new NullPointerException(); 1164 int hash = hash(key); 1165 Node<K,V>[] tab; Node<K,V> first; int n, i; 1166 int binCount = 0; 1167 TreeNode<K,V> t = null; 1168 Node<K,V> old = null; 1169 if (size > threshold || (tab = table) == null || 1170 (n = tab.length) == 0) 1171 n = (tab = resize()).length; 1172 if ((first = tab[i = (n - 1) & hash]) != null) { 1173 if (first instanceof TreeNode) 1174 old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key); 1175 else { 1176 Node<K,V> e = first; K k; 1177 do { 1178 if (e.hash == hash && 1179 ((k = e.key) == key || (key != null && key.equals(k)))) { 1180 old = e; 1181 break; 1182 } 1183 ++binCount; 1184 } while ((e = e.next) != null); 1185 } 1186 } 1187 V oldValue = (old == null) ? null : old.value; 1188 V v = remappingFunction.apply(key, oldValue); 1189 if (old != null) { 1190 if (v != null) { 1191 old.value = v; 1192 afterNodeAccess(old); 1193 } 1194 else 1195 removeNode(hash, key, null, false, true); 1196 } 1197 else if (v != null) { 1198 if (t != null) 1199 t.putTreeVal(this, tab, hash, key, v); 1200 else { 1201 tab[i] = newNode(hash, key, v, first); 1202 if (binCount >= TREEIFY_THRESHOLD - 1) 1203 treeifyBin(tab, hash); 1204 } 1205 ++modCount; 1206 ++size; 1207 afterNodeInsertion(true); 1208 } 1209 return v; 1210 } 1211 1212 @Override 1213 public V merge(K key, V value, 1214 BiFunction<? super V, ? super V, ? extends V> remappingFunction) { 1215 if (remappingFunction == null) 1216 throw new NullPointerException(); 1217 int hash = hash(key); 1218 Node<K,V>[] tab; Node<K,V> first; int n, i; 1219 int binCount = 0; 1220 TreeNode<K,V> t = null; 1221 Node<K,V> old = null; 1222 if (size > threshold || (tab = table) == null || 1223 (n = tab.length) == 0) 1224 n = (tab = resize()).length; 1225 if ((first = tab[i = (n - 1) & hash]) != null) { 1226 if (first instanceof TreeNode) 1227 old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key); 1228 else { 1229 Node<K,V> e = first; K k; 1230 do { 1231 if (e.hash == hash && 1232 ((k = e.key) == key || (key != null && key.equals(k)))) { 1233 old = e; 1234 break; 1235 } 1236 ++binCount; 1237 } while ((e = e.next) != null); 1238 } 1239 } 1240 if (old != null) { 1241 V v; 1242 if (old.value != null) 1243 v = remappingFunction.apply(old.value, value); 1244 else 1245 v = value; 1246 if (v != null) { 1247 old.value = v; 1248 afterNodeAccess(old); 1249 } 1250 else 1251 removeNode(hash, key, null, false, true); 1252 return v; 1253 } 1254 if (value != null) { 1255 if (t != null) 1256 t.putTreeVal(this, tab, hash, key, value); 1257 else { 1258 tab[i] = newNode(hash, key, value, first); 1259 if (binCount >= TREEIFY_THRESHOLD - 1) 1260 treeifyBin(tab, hash); 1261 } 1262 ++modCount; 1263 ++size; 1264 afterNodeInsertion(true); 1265 } 1266 return value; 1267 } 1268 1269 @Override 1270 public void forEach(BiConsumer<? super K, ? super V> action) { 1271 Node<K,V>[] tab; 1272 if (action == null) 1273 throw new NullPointerException(); 1274 if (size > 0 && (tab = table) != null) { 1275 int mc = modCount; 1276 for (int i = 0; i < tab.length; ++i) { 1277 for (Node<K,V> e = tab[i]; e != null; e = e.next) 1278 action.accept(e.key, e.value); 1279 } 1280 if (modCount != mc) 1281 throw new ConcurrentModificationException(); 1282 } 1283 } 1284 1285 @Override 1286 public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) { 1287 Node<K,V>[] tab; 1288 if (function == null) 1289 throw new NullPointerException(); 1290 if (size > 0 && (tab = table) != null) { 1291 int mc = modCount; 1292 for (int i = 0; i < tab.length; ++i) { 1293 for (Node<K,V> e = tab[i]; e != null; e = e.next) { 1294 e.value = function.apply(e.key, e.value); 1295 } 1296 } 1297 if (modCount != mc) 1298 throw new ConcurrentModificationException(); 1299 } 1300 } 1301 1302 /* ------------------------------------------------------------ */ 1303 // Cloning and serialization 1304 1305 /** 1306 * Returns a shallow copy of this <tt>HashMap</tt> instance: the keys and 1307 * values themselves are not cloned. 1308 * 1309 * @return a shallow copy of this map 1310 */ 1311 @SuppressWarnings("unchecked") 1312 @Override 1313 public Object clone() { 1314 HashMap<K,V> result; 1315 try { 1316 result = (HashMap<K,V>)super.clone(); 1317 } catch (CloneNotSupportedException e) { 1318 // this shouldn't happen, since we are Cloneable 1319 throw new InternalError(e); 1320 } 1321 result.reinitialize(); 1322 result.putMapEntries(this, false); 1323 return result; 1324 } 1325 1326 // These methods are also used when serializing HashSets 1327 final float loadFactor() { return loadFactor; } 1328 final int capacity() { 1329 return (table != null) ? table.length : 1330 (threshold > 0) ? threshold : 1331 DEFAULT_INITIAL_CAPACITY; 1332 } 1333 1334 /** 1335 * Save the state of the <tt>HashMap</tt> instance to a stream (i.e., 1336 * serialize it). 1337 * 1338 * @serialData The <i>capacity</i> of the HashMap (the length of the 1339 * bucket array) is emitted (int), followed by the 1340 * <i>size</i> (an int, the number of key-value 1341 * mappings), followed by the key (Object) and value (Object) 1342 * for each key-value mapping. The key-value mappings are 1343 * emitted in no particular order. 1344 */ 1345 private void writeObject(java.io.ObjectOutputStream s) 1346 throws IOException { 1347 int buckets = capacity(); 1348 // Write out the threshold, loadfactor, and any hidden stuff 1349 s.defaultWriteObject(); 1350 s.writeInt(buckets); 1351 s.writeInt(size); 1352 internalWriteEntries(s); 1353 } 1354 1355 /** 1356 * Reconstitute the {@code HashMap} instance from a stream (i.e., 1357 * deserialize it). 1358 */ 1359 private void readObject(java.io.ObjectInputStream s) 1360 throws IOException, ClassNotFoundException { 1361 // Read in the threshold (ignored), loadfactor, and any hidden stuff 1362 s.defaultReadObject(); 1363 reinitialize(); 1364 if (loadFactor <= 0 || Float.isNaN(loadFactor)) 1365 throw new InvalidObjectException("Illegal load factor: " + 1366 loadFactor); 1367 s.readInt(); // Read and ignore number of buckets 1368 int mappings = s.readInt(); // Read number of mappings (size) 1369 if (mappings < 0) 1370 throw new InvalidObjectException("Illegal mappings count: " + 1371 mappings); 1372 else if (mappings > 0) { // (if zero, use defaults) 1373 // Size the table using given load factor only if within 1374 // range of 0.25...4.0 1375 float lf = Math.min(Math.max(0.25f, loadFactor), 4.0f); 1376 float fc = (float)mappings / lf + 1.0f; 1377 int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ? 1378 DEFAULT_INITIAL_CAPACITY : 1379 (fc >= MAXIMUM_CAPACITY) ? 1380 MAXIMUM_CAPACITY : 1381 tableSizeFor((int)fc)); 1382 float ft = (float)cap * lf; 1383 threshold = ((cap < MAXIMUM_CAPACITY && ft < MAXIMUM_CAPACITY) ? 1384 (int)ft : Integer.MAX_VALUE); 1385 @SuppressWarnings({"rawtypes","unchecked"}) 1386 Node<K,V>[] tab = (Node<K,V>[])new Node[cap]; 1387 table = tab; 1388 1389 // Read the keys and values, and put the mappings in the HashMap 1390 for (int i = 0; i < mappings; i++) { 1391 @SuppressWarnings("unchecked") 1392 K key = (K) s.readObject(); 1393 @SuppressWarnings("unchecked") 1394 V value = (V) s.readObject(); 1395 putVal(hash(key), key, value, false, false); 1396 } 1397 } 1398 } 1399 1400 /* ------------------------------------------------------------ */ 1401 // iterators 1402 1403 abstract class HashIterator { 1404 Node<K,V> next; // next entry to return 1405 Node<K,V> current; // current entry 1406 int expectedModCount; // for fast-fail 1407 int index; // current slot 1408 1409 HashIterator() { 1410 expectedModCount = modCount; 1411 Node<K,V>[] t = table; 1412 current = next = null; 1413 index = 0; 1414 if (t != null && size > 0) { // advance to first entry 1415 do {} while (index < t.length && (next = t[index++]) == null); 1416 } 1417 } 1418 1419 public final boolean hasNext() { 1420 return next != null; 1421 } 1422 1423 final Node<K,V> nextNode() { 1424 Node<K,V>[] t; 1425 Node<K,V> e = next; 1426 if (modCount != expectedModCount) 1427 throw new ConcurrentModificationException(); 1428 if (e == null) 1429 throw new NoSuchElementException(); 1430 if ((next = (current = e).next) == null && (t = table) != null) { 1431 do {} while (index < t.length && (next = t[index++]) == null); 1432 } 1433 return e; 1434 } 1435 1436 public final void remove() { 1437 Node<K,V> p = current; 1438 if (p == null) 1439 throw new IllegalStateException(); 1440 if (modCount != expectedModCount) 1441 throw new ConcurrentModificationException(); 1442 current = null; 1443 K key = p.key; 1444 removeNode(hash(key), key, null, false, false); 1445 expectedModCount = modCount; 1446 } 1447 } 1448 1449 final class KeyIterator extends HashIterator 1450 implements Iterator<K> { 1451 public final K next() { return nextNode().key; } 1452 } 1453 1454 final class ValueIterator extends HashIterator 1455 implements Iterator<V> { 1456 public final V next() { return nextNode().value; } 1457 } 1458 1459 final class EntryIterator extends HashIterator 1460 implements Iterator<Map.Entry<K,V>> { 1461 public final Map.Entry<K,V> next() { return nextNode(); } 1462 } 1463 1464 /* ------------------------------------------------------------ */ 1465 // spliterators 1466 1467 static class HashMapSpliterator<K,V> { 1468 final HashMap<K,V> map; 1469 Node<K,V> current; // current node 1470 int index; // current index, modified on advance/split 1471 int fence; // one past last index 1472 int est; // size estimate 1473 int expectedModCount; // for comodification checks 1474 1475 HashMapSpliterator(HashMap<K,V> m, int origin, 1476 int fence, int est, 1477 int expectedModCount) { 1478 this.map = m; 1479 this.index = origin; 1480 this.fence = fence; 1481 this.est = est; 1482 this.expectedModCount = expectedModCount; 1483 } 1484 1485 final int getFence() { // initialize fence and size on first use 1486 int hi; 1487 if ((hi = fence) < 0) { 1488 HashMap<K,V> m = map; 1489 est = m.size; 1490 expectedModCount = m.modCount; 1491 Node<K,V>[] tab = m.table; 1492 hi = fence = (tab == null) ? 0 : tab.length; 1493 } 1494 return hi; 1495 } 1496 1497 public final long estimateSize() { 1498 getFence(); // force init 1499 return (long) est; 1500 } 1501 } 1502 1503 static final class KeySpliterator<K,V> 1504 extends HashMapSpliterator<K,V> 1505 implements Spliterator<K> { 1506 KeySpliterator(HashMap<K,V> m, int origin, int fence, int est, 1507 int expectedModCount) { 1508 super(m, origin, fence, est, expectedModCount); 1509 } 1510 1511 public KeySpliterator<K,V> trySplit() { 1512 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; 1513 return (lo >= mid || current != null) ? null : 1514 new KeySpliterator<>(map, lo, index = mid, est >>>= 1, 1515 expectedModCount); 1516 } 1517 1518 public void forEachRemaining(Consumer<? super K> action) { 1519 int i, hi, mc; 1520 if (action == null) 1521 throw new NullPointerException(); 1522 HashMap<K,V> m = map; 1523 Node<K,V>[] tab = m.table; 1524 if ((hi = fence) < 0) { 1525 mc = expectedModCount = m.modCount; 1526 hi = fence = (tab == null) ? 0 : tab.length; 1527 } 1528 else 1529 mc = expectedModCount; 1530 if (tab != null && tab.length >= hi && 1531 (i = index) >= 0 && (i < (index = hi) || current != null)) { 1532 Node<K,V> p = current; 1533 current = null; 1534 do { 1535 if (p == null) 1536 p = tab[i++]; 1537 else { 1538 action.accept(p.key); 1539 p = p.next; 1540 } 1541 } while (p != null || i < hi); 1542 if (m.modCount != mc) 1543 throw new ConcurrentModificationException(); 1544 } 1545 } 1546 1547 public boolean tryAdvance(Consumer<? super K> action) { 1548 int hi; 1549 if (action == null) 1550 throw new NullPointerException(); 1551 Node<K,V>[] tab = map.table; 1552 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) { 1553 while (current != null || index < hi) { 1554 if (current == null) 1555 current = tab[index++]; 1556 else { 1557 K k = current.key; 1558 current = current.next; 1559 action.accept(k); 1560 if (map.modCount != expectedModCount) 1561 throw new ConcurrentModificationException(); 1562 return true; 1563 } 1564 } 1565 } 1566 return false; 1567 } 1568 1569 public int characteristics() { 1570 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) | 1571 Spliterator.DISTINCT; 1572 } 1573 } 1574 1575 static final class ValueSpliterator<K,V> 1576 extends HashMapSpliterator<K,V> 1577 implements Spliterator<V> { 1578 ValueSpliterator(HashMap<K,V> m, int origin, int fence, int est, 1579 int expectedModCount) { 1580 super(m, origin, fence, est, expectedModCount); 1581 } 1582 1583 public ValueSpliterator<K,V> trySplit() { 1584 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; 1585 return (lo >= mid || current != null) ? null : 1586 new ValueSpliterator<>(map, lo, index = mid, est >>>= 1, 1587 expectedModCount); 1588 } 1589 1590 public void forEachRemaining(Consumer<? super V> action) { 1591 int i, hi, mc; 1592 if (action == null) 1593 throw new NullPointerException(); 1594 HashMap<K,V> m = map; 1595 Node<K,V>[] tab = m.table; 1596 if ((hi = fence) < 0) { 1597 mc = expectedModCount = m.modCount; 1598 hi = fence = (tab == null) ? 0 : tab.length; 1599 } 1600 else 1601 mc = expectedModCount; 1602 if (tab != null && tab.length >= hi && 1603 (i = index) >= 0 && (i < (index = hi) || current != null)) { 1604 Node<K,V> p = current; 1605 current = null; 1606 do { 1607 if (p == null) 1608 p = tab[i++]; 1609 else { 1610 action.accept(p.value); 1611 p = p.next; 1612 } 1613 } while (p != null || i < hi); 1614 if (m.modCount != mc) 1615 throw new ConcurrentModificationException(); 1616 } 1617 } 1618 1619 public boolean tryAdvance(Consumer<? super V> action) { 1620 int hi; 1621 if (action == null) 1622 throw new NullPointerException(); 1623 Node<K,V>[] tab = map.table; 1624 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) { 1625 while (current != null || index < hi) { 1626 if (current == null) 1627 current = tab[index++]; 1628 else { 1629 V v = current.value; 1630 current = current.next; 1631 action.accept(v); 1632 if (map.modCount != expectedModCount) 1633 throw new ConcurrentModificationException(); 1634 return true; 1635 } 1636 } 1637 } 1638 return false; 1639 } 1640 1641 public int characteristics() { 1642 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0); 1643 } 1644 } 1645 1646 static final class EntrySpliterator<K,V> 1647 extends HashMapSpliterator<K,V> 1648 implements Spliterator<Map.Entry<K,V>> { 1649 EntrySpliterator(HashMap<K,V> m, int origin, int fence, int est, 1650 int expectedModCount) { 1651 super(m, origin, fence, est, expectedModCount); 1652 } 1653 1654 public EntrySpliterator<K,V> trySplit() { 1655 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; 1656 return (lo >= mid || current != null) ? null : 1657 new EntrySpliterator<>(map, lo, index = mid, est >>>= 1, 1658 expectedModCount); 1659 } 1660 1661 public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) { 1662 int i, hi, mc; 1663 if (action == null) 1664 throw new NullPointerException(); 1665 HashMap<K,V> m = map; 1666 Node<K,V>[] tab = m.table; 1667 if ((hi = fence) < 0) { 1668 mc = expectedModCount = m.modCount; 1669 hi = fence = (tab == null) ? 0 : tab.length; 1670 } 1671 else 1672 mc = expectedModCount; 1673 if (tab != null && tab.length >= hi && 1674 (i = index) >= 0 && (i < (index = hi) || current != null)) { 1675 Node<K,V> p = current; 1676 current = null; 1677 do { 1678 if (p == null) 1679 p = tab[i++]; 1680 else { 1681 action.accept(p); 1682 p = p.next; 1683 } 1684 } while (p != null || i < hi); 1685 if (m.modCount != mc) 1686 throw new ConcurrentModificationException(); 1687 } 1688 } 1689 1690 public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) { 1691 int hi; 1692 if (action == null) 1693 throw new NullPointerException(); 1694 Node<K,V>[] tab = map.table; 1695 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) { 1696 while (current != null || index < hi) { 1697 if (current == null) 1698 current = tab[index++]; 1699 else { 1700 Node<K,V> e = current; 1701 current = current.next; 1702 action.accept(e); 1703 if (map.modCount != expectedModCount) 1704 throw new ConcurrentModificationException(); 1705 return true; 1706 } 1707 } 1708 } 1709 return false; 1710 } 1711 1712 public int characteristics() { 1713 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) | 1714 Spliterator.DISTINCT; 1715 } 1716 } 1717 1718 /* ------------------------------------------------------------ */ 1719 // LinkedHashMap support 1720 1721 1722 /* 1723 * The following package-protected methods are designed to be 1724 * overridden by LinkedHashMap, but not by any other subclass. 1725 * Nearly all other internal methods are also package-protected 1726 * but are declared final, so can be used by LinkedHashMap, view 1727 * classes, and HashSet. 1728 */ 1729 1730 // Create a regular (non-tree) node 1731 Node<K,V> newNode(int hash, K key, V value, Node<K,V> next) { 1732 return new Node<>(hash, key, value, next); 1733 } 1734 1735 // For conversion from TreeNodes to plain nodes 1736 Node<K,V> replacementNode(Node<K,V> p, Node<K,V> next) { 1737 return new Node<>(p.hash, p.key, p.value, next); 1738 } 1739 1740 // Create a tree bin node 1741 TreeNode<K,V> newTreeNode(int hash, K key, V value, Node<K,V> next) { 1742 return new TreeNode<>(hash, key, value, next); 1743 } 1744 1745 // For treeifyBin 1746 TreeNode<K,V> replacementTreeNode(Node<K,V> p, Node<K,V> next) { 1747 return new TreeNode<>(p.hash, p.key, p.value, next); 1748 } 1749 1750 /** 1751 * Reset to initial default state. Called by clone and readObject. 1752 */ 1753 void reinitialize() { 1754 table = null; 1755 entrySet = null; 1756 keySet = null; 1757 values = null; 1758 modCount = 0; 1759 threshold = 0; 1760 size = 0; 1761 } 1762 1763 // Callbacks to allow LinkedHashMap post-actions 1764 void afterNodeAccess(Node<K,V> p) { } 1765 void afterNodeInsertion(boolean evict) { } 1766 void afterNodeRemoval(Node<K,V> p) { } 1767 1768 // Called only from writeObject, to ensure compatible ordering. 1769 void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException { 1770 Node<K,V>[] tab; 1771 if (size > 0 && (tab = table) != null) { 1772 for (int i = 0; i < tab.length; ++i) { 1773 for (Node<K,V> e = tab[i]; e != null; e = e.next) { 1774 s.writeObject(e.key); 1775 s.writeObject(e.value); 1776 } 1777 } 1778 } 1779 } 1780 1781 /* ------------------------------------------------------------ */ 1782 // Tree bins 1783 1784 /** 1785 * Entry for Tree bins. Extends LinkedHashMap.Entry (which in turn 1786 * extends Node) so can be used as extension of either regular or 1787 * linked node. 1788 */ 1789 static final class TreeNode<K,V> extends LinkedHashMap.Entry<K,V> { 1790 TreeNode<K,V> parent; // red-black tree links 1791 TreeNode<K,V> left; 1792 TreeNode<K,V> right; 1793 TreeNode<K,V> prev; // needed to unlink next upon deletion 1794 boolean red; 1795 TreeNode(int hash, K key, V val, Node<K,V> next) { 1796 super(hash, key, val, next); 1797 } 1798 1799 /** 1800 * Returns root of tree containing this node. 1801 */ 1802 final TreeNode<K,V> root() { 1803 for (TreeNode<K,V> r = this, p;;) { 1804 if ((p = r.parent) == null) 1805 return r; 1806 r = p; 1807 } 1808 } 1809 1810 /** 1811 * Ensures that the given root is the first node of its bin. 1812 */ 1813 static <K,V> void moveRootToFront(Node<K,V>[] tab, TreeNode<K,V> root) { 1814 int n; 1815 if (root != null && tab != null && (n = tab.length) > 0) { 1816 int index = (n - 1) & root.hash; 1817 TreeNode<K,V> first = (TreeNode<K,V>)tab[index]; 1818 if (root != first) { 1819 Node<K,V> rn; 1820 tab[index] = root; 1821 TreeNode<K,V> rp = root.prev; 1822 if ((rn = root.next) != null) 1823 ((TreeNode<K,V>)rn).prev = rp; 1824 if (rp != null) 1825 rp.next = rn; 1826 if (first != null) 1827 first.prev = root; 1828 root.next = first; 1829 root.prev = null; 1830 } 1831 assert checkInvariants(root); 1832 } 1833 } 1834 1835 /** 1836 * Finds the node starting at root p with the given hash and key. 1837 * The kc argument caches comparableClassFor(key) upon first use 1838 * comparing keys. 1839 */ 1840 final TreeNode<K,V> find(int h, Object k, Class<?> kc) { 1841 TreeNode<K,V> p = this; 1842 do { 1843 int ph, dir; K pk; 1844 TreeNode<K,V> pl = p.left, pr = p.right, q; 1845 if ((ph = p.hash) > h) 1846 p = pl; 1847 else if (ph < h) 1848 p = pr; 1849 else if ((pk = p.key) == k || (k != null && k.equals(pk))) 1850 return p; 1851 else if (pl == null) 1852 p = pr; 1853 else if (pr == null) 1854 p = pl; 1855 else if ((kc != null || 1856 (kc = comparableClassFor(k)) != null) && 1857 (dir = compareComparables(kc, k, pk)) != 0) 1858 p = (dir < 0) ? pl : pr; 1859 else if ((q = pr.find(h, k, kc)) != null) 1860 return q; 1861 else 1862 p = pl; 1863 } while (p != null); 1864 return null; 1865 } 1866 1867 /** 1868 * Calls find for root node. 1869 */ 1870 final TreeNode<K,V> getTreeNode(int h, Object k) { 1871 return ((parent != null) ? root() : this).find(h, k, null); 1872 } 1873 1874 /** 1875 * Tie-breaking utility for ordering insertions when equal 1876 * hashCodes and non-comparable. We don't require a total 1877 * order, just a consistent insertion rule to maintain 1878 * equivalence across rebalancings. Tie-breaking further than 1879 * necessary simplifies testing a bit. 1880 */ 1881 static int tieBreakOrder(Object a, Object b) { 1882 int d; 1883 if (a == null || b == null || 1884 (d = a.getClass().getName(). 1885 compareTo(b.getClass().getName())) == 0) 1886 d = (System.identityHashCode(a) <= System.identityHashCode(b) ? 1887 -1 : 1); 1888 return d; 1889 } 1890 1891 /** 1892 * Forms tree of the nodes linked from this node. 1893 * @return root of tree 1894 */ 1895 final void treeify(Node<K,V>[] tab) { 1896 TreeNode<K,V> root = null; 1897 for (TreeNode<K,V> x = this, next; x != null; x = next) { 1898 next = (TreeNode<K,V>)x.next; 1899 x.left = x.right = null; 1900 if (root == null) { 1901 x.parent = null; 1902 x.red = false; 1903 root = x; 1904 } 1905 else { 1906 K k = x.key; 1907 int h = x.hash; 1908 Class<?> kc = null; 1909 for (TreeNode<K,V> p = root;;) { 1910 int dir, ph; 1911 K pk = p.key; 1912 if ((ph = p.hash) > h) 1913 dir = -1; 1914 else if (ph < h) 1915 dir = 1; 1916 else if ((kc == null && 1917 (kc = comparableClassFor(k)) == null) || 1918 (dir = compareComparables(kc, k, pk)) == 0) 1919 dir = tieBreakOrder(k, pk); 1920 1921 TreeNode<K,V> xp = p; 1922 if ((p = (dir <= 0) ? p.left : p.right) == null) { 1923 x.parent = xp; 1924 if (dir <= 0) 1925 xp.left = x; 1926 else 1927 xp.right = x; 1928 root = balanceInsertion(root, x); 1929 break; 1930 } 1931 } 1932 } 1933 } 1934 moveRootToFront(tab, root); 1935 } 1936 1937 /** 1938 * Returns a list of non-TreeNodes replacing those linked from 1939 * this node. 1940 */ 1941 final Node<K,V> untreeify(HashMap<K,V> map) { 1942 Node<K,V> hd = null, tl = null; 1943 for (Node<K,V> q = this; q != null; q = q.next) { 1944 Node<K,V> p = map.replacementNode(q, null); 1945 if (tl == null) 1946 hd = p; 1947 else 1948 tl.next = p; 1949 tl = p; 1950 } 1951 return hd; 1952 } 1953 1954 /** 1955 * Tree version of putVal. 1956 */ 1957 final TreeNode<K,V> putTreeVal(HashMap<K,V> map, Node<K,V>[] tab, 1958 int h, K k, V v) { 1959 Class<?> kc = null; 1960 boolean searched = false; 1961 TreeNode<K,V> root = (parent != null) ? root() : this; 1962 for (TreeNode<K,V> p = root;;) { 1963 int dir, ph; K pk; 1964 if ((ph = p.hash) > h) 1965 dir = -1; 1966 else if (ph < h) 1967 dir = 1; 1968 else if ((pk = p.key) == k || (pk != null && k.equals(pk))) 1969 return p; 1970 else if ((kc == null && 1971 (kc = comparableClassFor(k)) == null) || 1972 (dir = compareComparables(kc, k, pk)) == 0) { 1973 if (!searched) { 1974 TreeNode<K,V> q, ch; 1975 searched = true; 1976 if (((ch = p.left) != null && 1977 (q = ch.find(h, k, kc)) != null) || 1978 ((ch = p.right) != null && 1979 (q = ch.find(h, k, kc)) != null)) 1980 return q; 1981 } 1982 dir = tieBreakOrder(k, pk); 1983 } 1984 1985 TreeNode<K,V> xp = p; 1986 if ((p = (dir <= 0) ? p.left : p.right) == null) { 1987 Node<K,V> xpn = xp.next; 1988 TreeNode<K,V> x = map.newTreeNode(h, k, v, xpn); 1989 if (dir <= 0) 1990 xp.left = x; 1991 else 1992 xp.right = x; 1993 xp.next = x; 1994 x.parent = x.prev = xp; 1995 if (xpn != null) 1996 ((TreeNode<K,V>)xpn).prev = x; 1997 moveRootToFront(tab, balanceInsertion(root, x)); 1998 return null; 1999 } 2000 } 2001 } 2002 2003 /** 2004 * Removes the given node, that must be present before this call. 2005 * This is messier than typical red-black deletion code because we 2006 * cannot swap the contents of an interior node with a leaf 2007 * successor that is pinned by "next" pointers that are accessible 2008 * independently during traversal. So instead we swap the tree 2009 * linkages. If the current tree appears to have too few nodes, 2010 * the bin is converted back to a plain bin. (The test triggers 2011 * somewhere between 2 and 6 nodes, depending on tree structure). 2012 */ 2013 final void removeTreeNode(HashMap<K,V> map, Node<K,V>[] tab, 2014 boolean movable) { 2015 int n; 2016 if (tab == null || (n = tab.length) == 0) 2017 return; 2018 int index = (n - 1) & hash; 2019 TreeNode<K,V> first = (TreeNode<K,V>)tab[index], root = first, rl; 2020 TreeNode<K,V> succ = (TreeNode<K,V>)next, pred = prev; 2021 if (pred == null) 2022 tab[index] = first = succ; 2023 else 2024 pred.next = succ; 2025 if (succ != null) 2026 succ.prev = pred; 2027 if (first == null) 2028 return; 2029 if (root.parent != null) 2030 root = root.root(); 2031 if (root == null || root.right == null || 2032 (rl = root.left) == null || rl.left == null) { 2033 tab[index] = first.untreeify(map); // too small 2034 return; 2035 } 2036 TreeNode<K,V> p = this, pl = left, pr = right, replacement; 2037 if (pl != null && pr != null) { 2038 TreeNode<K,V> s = pr, sl; 2039 while ((sl = s.left) != null) // find successor 2040 s = sl; 2041 boolean c = s.red; s.red = p.red; p.red = c; // swap colors 2042 TreeNode<K,V> sr = s.right; 2043 TreeNode<K,V> pp = p.parent; 2044 if (s == pr) { // p was s's direct parent 2045 p.parent = s; 2046 s.right = p; 2047 } 2048 else { 2049 TreeNode<K,V> sp = s.parent; 2050 if ((p.parent = sp) != null) { 2051 if (s == sp.left) 2052 sp.left = p; 2053 else 2054 sp.right = p; 2055 } 2056 if ((s.right = pr) != null) 2057 pr.parent = s; 2058 } 2059 p.left = null; 2060 if ((p.right = sr) != null) 2061 sr.parent = p; 2062 if ((s.left = pl) != null) 2063 pl.parent = s; 2064 if ((s.parent = pp) == null) 2065 root = s; 2066 else if (p == pp.left) 2067 pp.left = s; 2068 else 2069 pp.right = s; 2070 if (sr != null) 2071 replacement = sr; 2072 else 2073 replacement = p; 2074 } 2075 else if (pl != null) 2076 replacement = pl; 2077 else if (pr != null) 2078 replacement = pr; 2079 else 2080 replacement = p; 2081 if (replacement != p) { 2082 TreeNode<K,V> pp = replacement.parent = p.parent; 2083 if (pp == null) 2084 root = replacement; 2085 else if (p == pp.left) 2086 pp.left = replacement; 2087 else 2088 pp.right = replacement; 2089 p.left = p.right = p.parent = null; 2090 } 2091 2092 TreeNode<K,V> r = p.red ? root : balanceDeletion(root, replacement); 2093 2094 if (replacement == p) { // detach 2095 TreeNode<K,V> pp = p.parent; 2096 p.parent = null; 2097 if (pp != null) { 2098 if (p == pp.left) 2099 pp.left = null; 2100 else if (p == pp.right) 2101 pp.right = null; 2102 } 2103 } 2104 if (movable) 2105 moveRootToFront(tab, r); 2106 } 2107 2108 /** 2109 * Splits nodes in a tree bin into lower and upper tree bins, 2110 * or untreeifies if now too small. Called only from resize; 2111 * see above discussion about split bits and indices. 2112 * 2113 * @param map the map 2114 * @param tab the table for recording bin heads 2115 * @param index the index of the table being split 2116 * @param bit the bit of hash to split on 2117 */ 2118 final void split(HashMap<K,V> map, Node<K,V>[] tab, int index, int bit) { 2119 TreeNode<K,V> b = this; 2120 // Relink into lo and hi lists, preserving order 2121 TreeNode<K,V> loHead = null, loTail = null; 2122 TreeNode<K,V> hiHead = null, hiTail = null; 2123 int lc = 0, hc = 0; 2124 for (TreeNode<K,V> e = b, next; e != null; e = next) { 2125 next = (TreeNode<K,V>)e.next; 2126 e.next = null; 2127 if ((e.hash & bit) == 0) { 2128 if ((e.prev = loTail) == null) 2129 loHead = e; 2130 else 2131 loTail.next = e; 2132 loTail = e; 2133 ++lc; 2134 } 2135 else { 2136 if ((e.prev = hiTail) == null) 2137 hiHead = e; 2138 else 2139 hiTail.next = e; 2140 hiTail = e; 2141 ++hc; 2142 } 2143 } 2144 2145 if (loHead != null) { 2146 if (lc <= UNTREEIFY_THRESHOLD) 2147 tab[index] = loHead.untreeify(map); 2148 else { 2149 tab[index] = loHead; 2150 if (hiHead != null) // (else is already treeified) 2151 loHead.treeify(tab); 2152 } 2153 } 2154 if (hiHead != null) { 2155 if (hc <= UNTREEIFY_THRESHOLD) 2156 tab[index + bit] = hiHead.untreeify(map); 2157 else { 2158 tab[index + bit] = hiHead; 2159 if (loHead != null) 2160 hiHead.treeify(tab); 2161 } 2162 } 2163 } 2164 2165 /* ------------------------------------------------------------ */ 2166 // Red-black tree methods, all adapted from CLR 2167 2168 static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root, 2169 TreeNode<K,V> p) { 2170 TreeNode<K,V> r, pp, rl; 2171 if (p != null && (r = p.right) != null) { 2172 if ((rl = p.right = r.left) != null) 2173 rl.parent = p; 2174 if ((pp = r.parent = p.parent) == null) 2175 (root = r).red = false; 2176 else if (pp.left == p) 2177 pp.left = r; 2178 else 2179 pp.right = r; 2180 r.left = p; 2181 p.parent = r; 2182 } 2183 return root; 2184 } 2185 2186 static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root, 2187 TreeNode<K,V> p) { 2188 TreeNode<K,V> l, pp, lr; 2189 if (p != null && (l = p.left) != null) { 2190 if ((lr = p.left = l.right) != null) 2191 lr.parent = p; 2192 if ((pp = l.parent = p.parent) == null) 2193 (root = l).red = false; 2194 else if (pp.right == p) 2195 pp.right = l; 2196 else 2197 pp.left = l; 2198 l.right = p; 2199 p.parent = l; 2200 } 2201 return root; 2202 } 2203 2204 static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root, 2205 TreeNode<K,V> x) { 2206 x.red = true; 2207 for (TreeNode<K,V> xp, xpp, xppl, xppr;;) { 2208 if ((xp = x.parent) == null) { 2209 x.red = false; 2210 return x; 2211 } 2212 else if (!xp.red || (xpp = xp.parent) == null) 2213 return root; 2214 if (xp == (xppl = xpp.left)) { 2215 if ((xppr = xpp.right) != null && xppr.red) { 2216 xppr.red = false; 2217 xp.red = false; 2218 xpp.red = true; 2219 x = xpp; 2220 } 2221 else { 2222 if (x == xp.right) { 2223 root = rotateLeft(root, x = xp); 2224 xpp = (xp = x.parent) == null ? null : xp.parent; 2225 } 2226 if (xp != null) { 2227 xp.red = false; 2228 if (xpp != null) { 2229 xpp.red = true; 2230 root = rotateRight(root, xpp); 2231 } 2232 } 2233 } 2234 } 2235 else { 2236 if (xppl != null && xppl.red) { 2237 xppl.red = false; 2238 xp.red = false; 2239 xpp.red = true; 2240 x = xpp; 2241 } 2242 else { 2243 if (x == xp.left) { 2244 root = rotateRight(root, x = xp); 2245 xpp = (xp = x.parent) == null ? null : xp.parent; 2246 } 2247 if (xp != null) { 2248 xp.red = false; 2249 if (xpp != null) { 2250 xpp.red = true; 2251 root = rotateLeft(root, xpp); 2252 } 2253 } 2254 } 2255 } 2256 } 2257 } 2258 2259 static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root, 2260 TreeNode<K,V> x) { 2261 for (TreeNode<K,V> xp, xpl, xpr;;) { 2262 if (x == null || x == root) 2263 return root; 2264 else if ((xp = x.parent) == null) { 2265 x.red = false; 2266 return x; 2267 } 2268 else if (x.red) { 2269 x.red = false; 2270 return root; 2271 } 2272 else if ((xpl = xp.left) == x) { 2273 if ((xpr = xp.right) != null && xpr.red) { 2274 xpr.red = false; 2275 xp.red = true; 2276 root = rotateLeft(root, xp); 2277 xpr = (xp = x.parent) == null ? null : xp.right; 2278 } 2279 if (xpr == null) 2280 x = xp; 2281 else { 2282 TreeNode<K,V> sl = xpr.left, sr = xpr.right; 2283 if ((sr == null || !sr.red) && 2284 (sl == null || !sl.red)) { 2285 xpr.red = true; 2286 x = xp; 2287 } 2288 else { 2289 if (sr == null || !sr.red) { 2290 if (sl != null) 2291 sl.red = false; 2292 xpr.red = true; 2293 root = rotateRight(root, xpr); 2294 xpr = (xp = x.parent) == null ? 2295 null : xp.right; 2296 } 2297 if (xpr != null) { 2298 xpr.red = (xp == null) ? false : xp.red; 2299 if ((sr = xpr.right) != null) 2300 sr.red = false; 2301 } 2302 if (xp != null) { 2303 xp.red = false; 2304 root = rotateLeft(root, xp); 2305 } 2306 x = root; 2307 } 2308 } 2309 } 2310 else { // symmetric 2311 if (xpl != null && xpl.red) { 2312 xpl.red = false; 2313 xp.red = true; 2314 root = rotateRight(root, xp); 2315 xpl = (xp = x.parent) == null ? null : xp.left; 2316 } 2317 if (xpl == null) 2318 x = xp; 2319 else { 2320 TreeNode<K,V> sl = xpl.left, sr = xpl.right; 2321 if ((sl == null || !sl.red) && 2322 (sr == null || !sr.red)) { 2323 xpl.red = true; 2324 x = xp; 2325 } 2326 else { 2327 if (sl == null || !sl.red) { 2328 if (sr != null) 2329 sr.red = false; 2330 xpl.red = true; 2331 root = rotateLeft(root, xpl); 2332 xpl = (xp = x.parent) == null ? 2333 null : xp.left; 2334 } 2335 if (xpl != null) { 2336 xpl.red = (xp == null) ? false : xp.red; 2337 if ((sl = xpl.left) != null) 2338 sl.red = false; 2339 } 2340 if (xp != null) { 2341 xp.red = false; 2342 root = rotateRight(root, xp); 2343 } 2344 x = root; 2345 } 2346 } 2347 } 2348 } 2349 } 2350 2351 /** 2352 * Recursive invariant check 2353 */ 2354 static <K,V> boolean checkInvariants(TreeNode<K,V> t) { 2355 TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right, 2356 tb = t.prev, tn = (TreeNode<K,V>)t.next; 2357 if (tb != null && tb.next != t) 2358 return false; 2359 if (tn != null && tn.prev != t) 2360 return false; 2361 if (tp != null && t != tp.left && t != tp.right) 2362 return false; 2363 if (tl != null && (tl.parent != t || tl.hash > t.hash)) 2364 return false; 2365 if (tr != null && (tr.parent != t || tr.hash < t.hash)) 2366 return false; 2367 if (t.red && tl != null && tl.red && tr != null && tr.red) 2368 return false; 2369 if (tl != null && !checkInvariants(tl)) 2370 return false; 2371 if (tr != null && !checkInvariants(tr)) 2372 return false; 2373 return true; 2374 } 2375 } 2376 2377 }