1 /* 2 * Copyright (c) 2000, 2018, 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.lang.reflect.Array; 29 import java.util.function.BiConsumer; 30 import java.util.function.BiFunction; 31 import java.util.function.Consumer; 32 import jdk.internal.access.SharedSecrets; 33 34 /** 35 * This class implements the {@code Map} interface with a hash table, using 36 * reference-equality in place of object-equality when comparing keys (and 37 * values). In other words, in an {@code IdentityHashMap}, two keys 38 * {@code k1} and {@code k2} are considered equal if and only if 39 * {@code (k1==k2)}. (In normal {@code Map} implementations (like 40 * {@code HashMap}) two keys {@code k1} and {@code k2} are considered equal 41 * if and only if {@code (k1==null ? k2==null : k1.equals(k2))}.) 42 * 43 * <p><b>This class is <i>not</i> a general-purpose {@code Map} 44 * implementation! While this class implements the {@code Map} interface, it 45 * intentionally violates {@code Map's} general contract, which mandates the 46 * use of the {@code equals} method when comparing objects. This class is 47 * designed for use only in the rare cases wherein reference-equality 48 * semantics are required.</b> 49 * 50 * <p>A typical use of this class is <i>topology-preserving object graph 51 * transformations</i>, such as serialization or deep-copying. To perform such 52 * a transformation, a program must maintain a "node table" that keeps track 53 * of all the object references that have already been processed. The node 54 * table must not equate distinct objects even if they happen to be equal. 55 * Another typical use of this class is to maintain <i>proxy objects</i>. For 56 * example, a debugging facility might wish to maintain a proxy object for 57 * each object in the program being debugged. 58 * 59 * <p>This class provides all of the optional map operations, and permits 60 * {@code null} values and the {@code null} key. This class makes no 61 * guarantees as to the order of the map; in particular, it does not guarantee 62 * that the order will remain constant over time. 63 * 64 * <p>This class provides constant-time performance for the basic 65 * operations ({@code get} and {@code put}), assuming the system 66 * identity hash function ({@link System#identityHashCode(Object)}) 67 * disperses elements properly among the buckets. 68 * 69 * <p>This class has one tuning parameter (which affects performance but not 70 * semantics): <i>expected maximum size</i>. This parameter is the maximum 71 * number of key-value mappings that the map is expected to hold. Internally, 72 * this parameter is used to determine the number of buckets initially 73 * comprising the hash table. The precise relationship between the expected 74 * maximum size and the number of buckets is unspecified. 75 * 76 * <p>If the size of the map (the number of key-value mappings) sufficiently 77 * exceeds the expected maximum size, the number of buckets is increased. 78 * Increasing the number of buckets ("rehashing") may be fairly expensive, so 79 * it pays to create identity hash maps with a sufficiently large expected 80 * maximum size. On the other hand, iteration over collection views requires 81 * time proportional to the number of buckets in the hash table, so it 82 * pays not to set the expected maximum size too high if you are especially 83 * concerned with iteration performance or memory usage. 84 * 85 * <p><strong>Note that this implementation is not synchronized.</strong> 86 * If multiple threads access an identity hash map concurrently, and at 87 * least one of the threads modifies the map structurally, it <i>must</i> 88 * be synchronized externally. (A structural modification is any operation 89 * that adds or deletes one or more mappings; merely changing the value 90 * associated with a key that an instance already contains is not a 91 * structural modification.) This is typically accomplished by 92 * synchronizing on some object that naturally encapsulates the map. 93 * 94 * If no such object exists, the map should be "wrapped" using the 95 * {@link Collections#synchronizedMap Collections.synchronizedMap} 96 * method. This is best done at creation time, to prevent accidental 97 * unsynchronized access to the map:<pre> 98 * Map m = Collections.synchronizedMap(new IdentityHashMap(...));</pre> 99 * 100 * <p>The iterators returned by the {@code iterator} method of the 101 * collections returned by all of this class's "collection view 102 * methods" are <i>fail-fast</i>: if the map is structurally modified 103 * at any time after the iterator is created, in any way except 104 * through the iterator's own {@code remove} method, the iterator 105 * will throw a {@link ConcurrentModificationException}. Thus, in the 106 * face of concurrent modification, the iterator fails quickly and 107 * cleanly, rather than risking arbitrary, non-deterministic behavior 108 * at an undetermined time in the future. 109 * 110 * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed 111 * as it is, generally speaking, impossible to make any hard guarantees in the 112 * presence of unsynchronized concurrent modification. Fail-fast iterators 113 * throw {@code ConcurrentModificationException} on a best-effort basis. 114 * Therefore, it would be wrong to write a program that depended on this 115 * exception for its correctness: <i>fail-fast iterators should be used only 116 * to detect bugs.</i> 117 * 118 * <p>Implementation note: This is a simple <i>linear-probe</i> hash table, 119 * as described for example in texts by Sedgewick and Knuth. The array 120 * alternates holding keys and values. (This has better locality for large 121 * tables than does using separate arrays.) For many JRE implementations 122 * and operation mixes, this class will yield better performance than 123 * {@link HashMap} (which uses <i>chaining</i> rather than linear-probing). 124 * 125 * <p>This class is a member of the 126 * <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework"> 127 * Java Collections Framework</a>. 128 * 129 * @see System#identityHashCode(Object) 130 * @see Object#hashCode() 131 * @see Collection 132 * @see Map 133 * @see HashMap 134 * @see TreeMap 135 * @author Doug Lea and Josh Bloch 136 * @since 1.4 137 */ 138 139 public class IdentityHashMap<K,V> 140 extends AbstractMap<K,V> 141 implements Map<K,V>, java.io.Serializable, Cloneable 142 { 143 /** 144 * The initial capacity used by the no-args constructor. 145 * MUST be a power of two. The value 32 corresponds to the 146 * (specified) expected maximum size of 21, given a load factor 147 * of 2/3. 148 */ 149 private static final int DEFAULT_CAPACITY = 32; 150 151 /** 152 * The minimum capacity, used if a lower value is implicitly specified 153 * by either of the constructors with arguments. The value 4 corresponds 154 * to an expected maximum size of 2, given a load factor of 2/3. 155 * MUST be a power of two. 156 */ 157 private static final int MINIMUM_CAPACITY = 4; 158 159 /** 160 * The maximum capacity, used if a higher value is implicitly specified 161 * by either of the constructors with arguments. 162 * MUST be a power of two <= 1<<29. 163 * 164 * In fact, the map can hold no more than MAXIMUM_CAPACITY-1 items 165 * because it has to have at least one slot with the key == null 166 * in order to avoid infinite loops in get(), put(), remove() 167 */ 168 private static final int MAXIMUM_CAPACITY = 1 << 29; 169 170 /** 171 * The table, resized as necessary. Length MUST always be a power of two. 172 */ 173 transient Object[] table; // non-private to simplify nested class access 174 175 /** 176 * The number of key-value mappings contained in this identity hash map. 177 * 178 * @serial 179 */ 180 int size; 181 182 /** 183 * The number of modifications, to support fast-fail iterators 184 */ 185 transient int modCount; 186 187 /** 188 * Value representing null keys inside tables. 189 */ 190 static final Object NULL_KEY = new Object(); 191 192 /** 193 * Use NULL_KEY for key if it is null. 194 */ 195 private static Object maskNull(Object key) { 196 return (key == null ? NULL_KEY : key); 197 } 198 199 /** 200 * Returns internal representation of null key back to caller as null. 201 */ 202 static final Object unmaskNull(Object key) { 203 return (key == NULL_KEY ? null : key); 204 } 205 206 /** 207 * Constructs a new, empty identity hash map with a default expected 208 * maximum size (21). 209 */ 210 public IdentityHashMap() { 211 init(DEFAULT_CAPACITY); 212 } 213 214 /** 215 * Constructs a new, empty map with the specified expected maximum size. 216 * Putting more than the expected number of key-value mappings into 217 * the map may cause the internal data structure to grow, which may be 218 * somewhat time-consuming. 219 * 220 * @param expectedMaxSize the expected maximum size of the map 221 * @throws IllegalArgumentException if {@code expectedMaxSize} is negative 222 */ 223 public IdentityHashMap(int expectedMaxSize) { 224 if (expectedMaxSize < 0) 225 throw new IllegalArgumentException("expectedMaxSize is negative: " 226 + expectedMaxSize); 227 init(capacity(expectedMaxSize)); 228 } 229 230 /** 231 * Returns the appropriate capacity for the given expected maximum size. 232 * Returns the smallest power of two between MINIMUM_CAPACITY and 233 * MAXIMUM_CAPACITY, inclusive, that is greater than (3 * 234 * expectedMaxSize)/2, if such a number exists. Otherwise returns 235 * MAXIMUM_CAPACITY. 236 */ 237 private static int capacity(int expectedMaxSize) { 238 // assert expectedMaxSize >= 0; 239 return 240 (expectedMaxSize > MAXIMUM_CAPACITY / 3) ? MAXIMUM_CAPACITY : 241 (expectedMaxSize <= 2 * MINIMUM_CAPACITY / 3) ? MINIMUM_CAPACITY : 242 Integer.highestOneBit(expectedMaxSize + (expectedMaxSize << 1)); 243 } 244 245 /** 246 * Initializes object to be an empty map with the specified initial 247 * capacity, which is assumed to be a power of two between 248 * MINIMUM_CAPACITY and MAXIMUM_CAPACITY inclusive. 249 */ 250 private void init(int initCapacity) { 251 // assert (initCapacity & -initCapacity) == initCapacity; // power of 2 252 // assert initCapacity >= MINIMUM_CAPACITY; 253 // assert initCapacity <= MAXIMUM_CAPACITY; 254 255 table = new Object[2 * initCapacity]; 256 } 257 258 /** 259 * Constructs a new identity hash map containing the keys-value mappings 260 * in the specified map. 261 * 262 * @param m the map whose mappings are to be placed into this map 263 * @throws NullPointerException if the specified map is null 264 */ 265 public IdentityHashMap(Map<? extends K, ? extends V> m) { 266 // Allow for a bit of growth 267 this((int) ((1 + m.size()) * 1.1)); 268 putAll(m); 269 } 270 271 /** 272 * Returns the number of key-value mappings in this identity hash map. 273 * 274 * @return the number of key-value mappings in this map 275 */ 276 public int size() { 277 return size; 278 } 279 280 /** 281 * Returns {@code true} if this identity hash map contains no key-value 282 * mappings. 283 * 284 * @return {@code true} if this identity hash map contains no key-value 285 * mappings 286 */ 287 public boolean isEmpty() { 288 return size == 0; 289 } 290 291 /** 292 * Returns index for Object x. 293 */ 294 private static int hash(Object x, int length) { 295 int h = System.identityHashCode(x); 296 // Multiply by -127, and left-shift to use least bit as part of hash 297 return ((h << 1) - (h << 8)) & (length - 1); 298 } 299 300 /** 301 * Circularly traverses table of size len. 302 */ 303 private static int nextKeyIndex(int i, int len) { 304 return (i + 2 < len ? i + 2 : 0); 305 } 306 307 /** 308 * Returns the value to which the specified key is mapped, 309 * or {@code null} if this map contains no mapping for the key. 310 * 311 * <p>More formally, if this map contains a mapping from a key 312 * {@code k} to a value {@code v} such that {@code (key == k)}, 313 * then this method returns {@code v}; otherwise it returns 314 * {@code null}. (There can be at most one such mapping.) 315 * 316 * <p>A return value of {@code null} does not <i>necessarily</i> 317 * indicate that the map contains no mapping for the key; it's also 318 * possible that the map explicitly maps the key to {@code null}. 319 * The {@link #containsKey containsKey} operation may be used to 320 * distinguish these two cases. 321 * 322 * @see #put(Object, Object) 323 */ 324 @SuppressWarnings("unchecked") 325 public V get(Object key) { 326 Object k = maskNull(key); 327 Object[] tab = table; 328 int len = tab.length; 329 int i = hash(k, len); 330 while (true) { 331 Object item = tab[i]; 332 if (item == k) 333 return (V) tab[i + 1]; 334 if (item == null) 335 return null; 336 i = nextKeyIndex(i, len); 337 } 338 } 339 340 /** 341 * Tests whether the specified object reference is a key in this identity 342 * hash map. 343 * 344 * @param key possible key 345 * @return {@code true} if the specified object reference is a key 346 * in this map 347 * @see #containsValue(Object) 348 */ 349 public boolean containsKey(Object key) { 350 Object k = maskNull(key); 351 Object[] tab = table; 352 int len = tab.length; 353 int i = hash(k, len); 354 while (true) { 355 Object item = tab[i]; 356 if (item == k) 357 return true; 358 if (item == null) 359 return false; 360 i = nextKeyIndex(i, len); 361 } 362 } 363 364 /** 365 * Tests whether the specified object reference is a value in this identity 366 * hash map. 367 * 368 * @param value value whose presence in this map is to be tested 369 * @return {@code true} if this map maps one or more keys to the 370 * specified object reference 371 * @see #containsKey(Object) 372 */ 373 public boolean containsValue(Object value) { 374 Object[] tab = table; 375 for (int i = 1; i < tab.length; i += 2) 376 if (tab[i] == value && tab[i - 1] != null) 377 return true; 378 379 return false; 380 } 381 382 /** 383 * Tests if the specified key-value mapping is in the map. 384 * 385 * @param key possible key 386 * @param value possible value 387 * @return {@code true} if and only if the specified key-value 388 * mapping is in the map 389 */ 390 private boolean containsMapping(Object key, Object value) { 391 Object k = maskNull(key); 392 Object[] tab = table; 393 int len = tab.length; 394 int i = hash(k, len); 395 while (true) { 396 Object item = tab[i]; 397 if (item == k) 398 return tab[i + 1] == value; 399 if (item == null) 400 return false; 401 i = nextKeyIndex(i, len); 402 } 403 } 404 405 /** 406 * Associates the specified value with the specified key in this identity 407 * hash map. If the map previously contained a mapping for the key, the 408 * old value is replaced. 409 * 410 * @param key the key with which the specified value is to be associated 411 * @param value the value to be associated with the specified key 412 * @return the previous value associated with {@code key}, or 413 * {@code null} if there was no mapping for {@code key}. 414 * (A {@code null} return can also indicate that the map 415 * previously associated {@code null} with {@code key}.) 416 * @see Object#equals(Object) 417 * @see #get(Object) 418 * @see #containsKey(Object) 419 */ 420 public V put(K key, V value) { 421 final Object k = maskNull(key); 422 423 retryAfterResize: for (;;) { 424 final Object[] tab = table; 425 final int len = tab.length; 426 int i = hash(k, len); 427 428 for (Object item; (item = tab[i]) != null; 429 i = nextKeyIndex(i, len)) { 430 if (item == k) { 431 @SuppressWarnings("unchecked") 432 V oldValue = (V) tab[i + 1]; 433 tab[i + 1] = value; 434 return oldValue; 435 } 436 } 437 438 final int s = size + 1; 439 // Use optimized form of 3 * s. 440 // Next capacity is len, 2 * current capacity. 441 if (s + (s << 1) > len && resize(len)) 442 continue retryAfterResize; 443 444 modCount++; 445 tab[i] = k; 446 tab[i + 1] = value; 447 size = s; 448 return null; 449 } 450 } 451 452 /** 453 * Resizes the table if necessary to hold given capacity. 454 * 455 * @param newCapacity the new capacity, must be a power of two. 456 * @return whether a resize did in fact take place 457 */ 458 private boolean resize(int newCapacity) { 459 // assert (newCapacity & -newCapacity) == newCapacity; // power of 2 460 int newLength = newCapacity * 2; 461 462 Object[] oldTable = table; 463 int oldLength = oldTable.length; 464 if (oldLength == 2 * MAXIMUM_CAPACITY) { // can't expand any further 465 if (size == MAXIMUM_CAPACITY - 1) 466 throw new IllegalStateException("Capacity exhausted."); 467 return false; 468 } 469 if (oldLength >= newLength) 470 return false; 471 472 Object[] newTable = new Object[newLength]; 473 474 for (int j = 0; j < oldLength; j += 2) { 475 Object key = oldTable[j]; 476 if (key != null) { 477 Object value = oldTable[j+1]; 478 oldTable[j] = null; 479 oldTable[j+1] = null; 480 int i = hash(key, newLength); 481 while (newTable[i] != null) 482 i = nextKeyIndex(i, newLength); 483 newTable[i] = key; 484 newTable[i + 1] = value; 485 } 486 } 487 table = newTable; 488 return true; 489 } 490 491 /** 492 * Copies all of the mappings from the specified map to this map. 493 * These mappings will replace any mappings that this map had for 494 * any of the keys currently in the specified map. 495 * 496 * @param m mappings to be stored in this map 497 * @throws NullPointerException if the specified map is null 498 */ 499 public void putAll(Map<? extends K, ? extends V> m) { 500 int n = m.size(); 501 if (n == 0) 502 return; 503 if (n > size) 504 resize(capacity(n)); // conservatively pre-expand 505 506 for (Entry<? extends K, ? extends V> e : m.entrySet()) 507 put(e.getKey(), e.getValue()); 508 } 509 510 /** 511 * Removes the mapping for this key from this map if present. 512 * 513 * @param key key whose mapping is to be removed from the map 514 * @return the previous value associated with {@code key}, or 515 * {@code null} if there was no mapping for {@code key}. 516 * (A {@code null} return can also indicate that the map 517 * previously associated {@code null} with {@code key}.) 518 */ 519 public V remove(Object key) { 520 Object k = maskNull(key); 521 Object[] tab = table; 522 int len = tab.length; 523 int i = hash(k, len); 524 525 while (true) { 526 Object item = tab[i]; 527 if (item == k) { 528 modCount++; 529 size--; 530 @SuppressWarnings("unchecked") 531 V oldValue = (V) tab[i + 1]; 532 tab[i + 1] = null; 533 tab[i] = null; 534 closeDeletion(i); 535 return oldValue; 536 } 537 if (item == null) 538 return null; 539 i = nextKeyIndex(i, len); 540 } 541 } 542 543 /** 544 * Removes the specified key-value mapping from the map if it is present. 545 * 546 * @param key possible key 547 * @param value possible value 548 * @return {@code true} if and only if the specified key-value 549 * mapping was in the map 550 */ 551 private boolean removeMapping(Object key, Object value) { 552 Object k = maskNull(key); 553 Object[] tab = table; 554 int len = tab.length; 555 int i = hash(k, len); 556 557 while (true) { 558 Object item = tab[i]; 559 if (item == k) { 560 if (tab[i + 1] != value) 561 return false; 562 modCount++; 563 size--; 564 tab[i] = null; 565 tab[i + 1] = null; 566 closeDeletion(i); 567 return true; 568 } 569 if (item == null) 570 return false; 571 i = nextKeyIndex(i, len); 572 } 573 } 574 575 /** 576 * Rehash all possibly-colliding entries following a 577 * deletion. This preserves the linear-probe 578 * collision properties required by get, put, etc. 579 * 580 * @param d the index of a newly empty deleted slot 581 */ 582 private void closeDeletion(int d) { 583 // Adapted from Knuth Section 6.4 Algorithm R 584 Object[] tab = table; 585 int len = tab.length; 586 587 // Look for items to swap into newly vacated slot 588 // starting at index immediately following deletion, 589 // and continuing until a null slot is seen, indicating 590 // the end of a run of possibly-colliding keys. 591 Object item; 592 for (int i = nextKeyIndex(d, len); (item = tab[i]) != null; 593 i = nextKeyIndex(i, len) ) { 594 // The following test triggers if the item at slot i (which 595 // hashes to be at slot r) should take the spot vacated by d. 596 // If so, we swap it in, and then continue with d now at the 597 // newly vacated i. This process will terminate when we hit 598 // the null slot at the end of this run. 599 // The test is messy because we are using a circular table. 600 int r = hash(item, len); 601 if ((i < r && (r <= d || d <= i)) || (r <= d && d <= i)) { 602 tab[d] = item; 603 tab[d + 1] = tab[i + 1]; 604 tab[i] = null; 605 tab[i + 1] = null; 606 d = i; 607 } 608 } 609 } 610 611 /** 612 * Removes all of the mappings from this map. 613 * The map will be empty after this call returns. 614 */ 615 public void clear() { 616 modCount++; 617 Object[] tab = table; 618 for (int i = 0; i < tab.length; i++) 619 tab[i] = null; 620 size = 0; 621 } 622 623 /** 624 * Compares the specified object with this map for equality. Returns 625 * {@code true} if the given object is also a map and the two maps 626 * represent identical object-reference mappings. More formally, this 627 * map is equal to another map {@code m} if and only if 628 * {@code this.entrySet().equals(m.entrySet())}. 629 * 630 * <p><b>Owing to the reference-equality-based semantics of this map it is 631 * possible that the symmetry and transitivity requirements of the 632 * {@code Object.equals} contract may be violated if this map is compared 633 * to a normal map. However, the {@code Object.equals} contract is 634 * guaranteed to hold among {@code IdentityHashMap} instances.</b> 635 * 636 * @param o object to be compared for equality with this map 637 * @return {@code true} if the specified object is equal to this map 638 * @see Object#equals(Object) 639 */ 640 public boolean equals(Object o) { 641 if (o == this) { 642 return true; 643 } else if (o instanceof IdentityHashMap) { 644 IdentityHashMap<?,?> m = (IdentityHashMap<?,?>) o; 645 if (m.size() != size) 646 return false; 647 648 Object[] tab = m.table; 649 for (int i = 0; i < tab.length; i+=2) { 650 Object k = tab[i]; 651 if (k != null && !containsMapping(k, tab[i + 1])) 652 return false; 653 } 654 return true; 655 } else if (o instanceof Map) { 656 Map<?,?> m = (Map<?,?>)o; 657 return entrySet().equals(m.entrySet()); 658 } else { 659 return false; // o is not a Map 660 } 661 } 662 663 /** 664 * Returns the hash code value for this map. The hash code of a map is 665 * defined to be the sum of the hash codes of each entry in the map's 666 * {@code entrySet()} view. This ensures that {@code m1.equals(m2)} 667 * implies that {@code m1.hashCode()==m2.hashCode()} for any two 668 * {@code IdentityHashMap} instances {@code m1} and {@code m2}, as 669 * required by the general contract of {@link Object#hashCode}. 670 * 671 * <p><b>Owing to the reference-equality-based semantics of the 672 * {@code Map.Entry} instances in the set returned by this map's 673 * {@code entrySet} method, it is possible that the contractual 674 * requirement of {@code Object.hashCode} mentioned in the previous 675 * paragraph will be violated if one of the two objects being compared is 676 * an {@code IdentityHashMap} instance and the other is a normal map.</b> 677 * 678 * @return the hash code value for this map 679 * @see Object#equals(Object) 680 * @see #equals(Object) 681 */ 682 public int hashCode() { 683 int result = 0; 684 Object[] tab = table; 685 for (int i = 0; i < tab.length; i +=2) { 686 Object key = tab[i]; 687 if (key != null) { 688 Object k = unmaskNull(key); 689 result += System.identityHashCode(k) ^ 690 System.identityHashCode(tab[i + 1]); 691 } 692 } 693 return result; 694 } 695 696 /** 697 * Returns a shallow copy of this identity hash map: the keys and values 698 * themselves are not cloned. 699 * 700 * @return a shallow copy of this map 701 */ 702 public Object clone() { 703 try { 704 IdentityHashMap<?,?> m = (IdentityHashMap<?,?>) super.clone(); 705 m.entrySet = null; 706 m.table = table.clone(); 707 return m; 708 } catch (CloneNotSupportedException e) { 709 throw new InternalError(e); 710 } 711 } 712 713 private abstract class IdentityHashMapIterator<T> implements Iterator<T> { 714 int index = (size != 0 ? 0 : table.length); // current slot. 715 int expectedModCount = modCount; // to support fast-fail 716 int lastReturnedIndex = -1; // to allow remove() 717 boolean indexValid; // To avoid unnecessary next computation 718 Object[] traversalTable = table; // reference to main table or copy 719 720 public boolean hasNext() { 721 Object[] tab = traversalTable; 722 for (int i = index; i < tab.length; i+=2) { 723 Object key = tab[i]; 724 if (key != null) { 725 index = i; 726 return indexValid = true; 727 } 728 } 729 index = tab.length; 730 return false; 731 } 732 733 protected int nextIndex() { 734 if (modCount != expectedModCount) 735 throw new ConcurrentModificationException(); 736 if (!indexValid && !hasNext()) 737 throw new NoSuchElementException(); 738 739 indexValid = false; 740 lastReturnedIndex = index; 741 index += 2; 742 return lastReturnedIndex; 743 } 744 745 public void remove() { 746 if (lastReturnedIndex == -1) 747 throw new IllegalStateException(); 748 if (modCount != expectedModCount) 749 throw new ConcurrentModificationException(); 750 751 expectedModCount = ++modCount; 752 int deletedSlot = lastReturnedIndex; 753 lastReturnedIndex = -1; 754 // back up index to revisit new contents after deletion 755 index = deletedSlot; 756 indexValid = false; 757 758 // Removal code proceeds as in closeDeletion except that 759 // it must catch the rare case where an element already 760 // seen is swapped into a vacant slot that will be later 761 // traversed by this iterator. We cannot allow future 762 // next() calls to return it again. The likelihood of 763 // this occurring under 2/3 load factor is very slim, but 764 // when it does happen, we must make a copy of the rest of 765 // the table to use for the rest of the traversal. Since 766 // this can only happen when we are near the end of the table, 767 // even in these rare cases, this is not very expensive in 768 // time or space. 769 770 Object[] tab = traversalTable; 771 int len = tab.length; 772 773 int d = deletedSlot; 774 Object key = tab[d]; 775 tab[d] = null; // vacate the slot 776 tab[d + 1] = null; 777 778 // If traversing a copy, remove in real table. 779 // We can skip gap-closure on copy. 780 if (tab != IdentityHashMap.this.table) { 781 IdentityHashMap.this.remove(key); 782 expectedModCount = modCount; 783 return; 784 } 785 786 size--; 787 788 Object item; 789 for (int i = nextKeyIndex(d, len); (item = tab[i]) != null; 790 i = nextKeyIndex(i, len)) { 791 int r = hash(item, len); 792 // See closeDeletion for explanation of this conditional 793 if ((i < r && (r <= d || d <= i)) || 794 (r <= d && d <= i)) { 795 796 // If we are about to swap an already-seen element 797 // into a slot that may later be returned by next(), 798 // then clone the rest of table for use in future 799 // next() calls. It is OK that our copy will have 800 // a gap in the "wrong" place, since it will never 801 // be used for searching anyway. 802 803 if (i < deletedSlot && d >= deletedSlot && 804 traversalTable == IdentityHashMap.this.table) { 805 int remaining = len - deletedSlot; 806 Object[] newTable = new Object[remaining]; 807 System.arraycopy(tab, deletedSlot, 808 newTable, 0, remaining); 809 traversalTable = newTable; 810 index = 0; 811 } 812 813 tab[d] = item; 814 tab[d + 1] = tab[i + 1]; 815 tab[i] = null; 816 tab[i + 1] = null; 817 d = i; 818 } 819 } 820 } 821 } 822 823 private class KeyIterator extends IdentityHashMapIterator<K> { 824 @SuppressWarnings("unchecked") 825 public K next() { 826 return (K) unmaskNull(traversalTable[nextIndex()]); 827 } 828 } 829 830 private class ValueIterator extends IdentityHashMapIterator<V> { 831 @SuppressWarnings("unchecked") 832 public V next() { 833 return (V) traversalTable[nextIndex() + 1]; 834 } 835 } 836 837 private class EntryIterator 838 extends IdentityHashMapIterator<Map.Entry<K,V>> 839 { 840 private Entry lastReturnedEntry; 841 842 public Map.Entry<K,V> next() { 843 lastReturnedEntry = new Entry(nextIndex()); 844 return lastReturnedEntry; 845 } 846 847 public void remove() { 848 lastReturnedIndex = 849 ((null == lastReturnedEntry) ? -1 : lastReturnedEntry.index); 850 super.remove(); 851 lastReturnedEntry.index = lastReturnedIndex; 852 lastReturnedEntry = null; 853 } 854 855 private class Entry implements Map.Entry<K,V> { 856 private int index; 857 858 private Entry(int index) { 859 this.index = index; 860 } 861 862 @SuppressWarnings("unchecked") 863 public K getKey() { 864 checkIndexForEntryUse(); 865 return (K) unmaskNull(traversalTable[index]); 866 } 867 868 @SuppressWarnings("unchecked") 869 public V getValue() { 870 checkIndexForEntryUse(); 871 return (V) traversalTable[index+1]; 872 } 873 874 @SuppressWarnings("unchecked") 875 public V setValue(V value) { 876 checkIndexForEntryUse(); 877 V oldValue = (V) traversalTable[index+1]; 878 traversalTable[index+1] = value; 879 // if shadowing, force into main table 880 if (traversalTable != IdentityHashMap.this.table) 881 put((K) traversalTable[index], value); 882 return oldValue; 883 } 884 885 public boolean equals(Object o) { 886 if (index < 0) 887 return super.equals(o); 888 889 if (!(o instanceof Map.Entry)) 890 return false; 891 Map.Entry<?,?> e = (Map.Entry<?,?>)o; 892 return (e.getKey() == unmaskNull(traversalTable[index]) && 893 e.getValue() == traversalTable[index+1]); 894 } 895 896 public int hashCode() { 897 if (lastReturnedIndex < 0) 898 return super.hashCode(); 899 900 return (System.identityHashCode(unmaskNull(traversalTable[index])) ^ 901 System.identityHashCode(traversalTable[index+1])); 902 } 903 904 public String toString() { 905 if (index < 0) 906 return super.toString(); 907 908 return (unmaskNull(traversalTable[index]) + "=" 909 + traversalTable[index+1]); 910 } 911 912 private void checkIndexForEntryUse() { 913 if (index < 0) 914 throw new IllegalStateException("Entry was removed"); 915 } 916 } 917 } 918 919 // Views 920 921 /** 922 * This field is initialized to contain an instance of the entry set 923 * view the first time this view is requested. The view is stateless, 924 * so there's no reason to create more than one. 925 */ 926 private transient Set<Map.Entry<K,V>> entrySet; 927 928 /** 929 * Returns an identity-based set view of the keys contained in this map. 930 * The set is backed by the map, so changes to the map are reflected in 931 * the set, and vice-versa. If the map is modified while an iteration 932 * over the set is in progress, the results of the iteration are 933 * undefined. The set supports element removal, which removes the 934 * corresponding mapping from the map, via the {@code Iterator.remove}, 935 * {@code Set.remove}, {@code removeAll}, {@code retainAll}, and 936 * {@code clear} methods. It does not support the {@code add} or 937 * {@code addAll} methods. 938 * 939 * <p><b>While the object returned by this method implements the 940 * {@code Set} interface, it does <i>not</i> obey {@code Set's} general 941 * contract. Like its backing map, the set returned by this method 942 * defines element equality as reference-equality rather than 943 * object-equality. This affects the behavior of its {@code contains}, 944 * {@code remove}, {@code containsAll}, {@code equals}, and 945 * {@code hashCode} methods.</b> 946 * 947 * <p><b>The {@code equals} method of the returned set returns {@code true} 948 * only if the specified object is a set containing exactly the same 949 * object references as the returned set. The symmetry and transitivity 950 * requirements of the {@code Object.equals} contract may be violated if 951 * the set returned by this method is compared to a normal set. However, 952 * the {@code Object.equals} contract is guaranteed to hold among sets 953 * returned by this method.</b> 954 * 955 * <p>The {@code hashCode} method of the returned set returns the sum of 956 * the <i>identity hashcodes</i> of the elements in the set, rather than 957 * the sum of their hashcodes. This is mandated by the change in the 958 * semantics of the {@code equals} method, in order to enforce the 959 * general contract of the {@code Object.hashCode} method among sets 960 * returned by this method. 961 * 962 * @return an identity-based set view of the keys contained in this map 963 * @see Object#equals(Object) 964 * @see System#identityHashCode(Object) 965 */ 966 public Set<K> keySet() { 967 Set<K> ks = keySet; 968 if (ks == null) { 969 ks = new KeySet(); 970 keySet = ks; 971 } 972 return ks; 973 } 974 975 private class KeySet extends AbstractSet<K> { 976 public Iterator<K> iterator() { 977 return new KeyIterator(); 978 } 979 public int size() { 980 return size; 981 } 982 public boolean contains(Object o) { 983 return containsKey(o); 984 } 985 public boolean remove(Object o) { 986 int oldSize = size; 987 IdentityHashMap.this.remove(o); 988 return size != oldSize; 989 } 990 /* 991 * Must revert from AbstractSet's impl to AbstractCollection's, as 992 * the former contains an optimization that results in incorrect 993 * behavior when c is a smaller "normal" (non-identity-based) Set. 994 */ 995 public boolean removeAll(Collection<?> c) { 996 Objects.requireNonNull(c); 997 boolean modified = false; 998 for (Iterator<K> i = iterator(); i.hasNext(); ) { 999 if (c.contains(i.next())) { 1000 i.remove(); 1001 modified = true; 1002 } 1003 } 1004 return modified; 1005 } 1006 public void clear() { 1007 IdentityHashMap.this.clear(); 1008 } 1009 public int hashCode() { 1010 int result = 0; 1011 for (K key : this) 1012 result += System.identityHashCode(key); 1013 return result; 1014 } 1015 public Object[] toArray() { 1016 return toArray(new Object[0]); 1017 } 1018 @SuppressWarnings("unchecked") 1019 public <T> T[] toArray(T[] a) { 1020 int expectedModCount = modCount; 1021 int size = size(); 1022 if (a.length < size) 1023 a = (T[]) Array.newInstance(a.getClass().getComponentType(), size); 1024 Object[] tab = table; 1025 int ti = 0; 1026 for (int si = 0; si < tab.length; si += 2) { 1027 Object key; 1028 if ((key = tab[si]) != null) { // key present ? 1029 // more elements than expected -> concurrent modification from other thread 1030 if (ti >= size) { 1031 throw new ConcurrentModificationException(); 1032 } 1033 a[ti++] = (T) unmaskNull(key); // unmask key 1034 } 1035 } 1036 // fewer elements than expected or concurrent modification from other thread detected 1037 if (ti < size || expectedModCount != modCount) { 1038 throw new ConcurrentModificationException(); 1039 } 1040 // final null marker as per spec 1041 if (ti < a.length) { 1042 a[ti] = null; 1043 } 1044 return a; 1045 } 1046 1047 public Spliterator<K> spliterator() { 1048 return new KeySpliterator<>(IdentityHashMap.this, 0, -1, 0, 0); 1049 } 1050 } 1051 1052 /** 1053 * Returns a {@link Collection} view of the values contained in this map. 1054 * The collection is backed by the map, so changes to the map are 1055 * reflected in the collection, and vice-versa. If the map is 1056 * modified while an iteration over the collection is in progress, 1057 * the results of the iteration are undefined. The collection 1058 * supports element removal, which removes the corresponding 1059 * mapping from the map, via the {@code Iterator.remove}, 1060 * {@code Collection.remove}, {@code removeAll}, 1061 * {@code retainAll} and {@code clear} methods. It does not 1062 * support the {@code add} or {@code addAll} methods. 1063 * 1064 * <p><b>While the object returned by this method implements the 1065 * {@code Collection} interface, it does <i>not</i> obey 1066 * {@code Collection's} general contract. Like its backing map, 1067 * the collection returned by this method defines element equality as 1068 * reference-equality rather than object-equality. This affects the 1069 * behavior of its {@code contains}, {@code remove} and 1070 * {@code containsAll} methods.</b> 1071 */ 1072 public Collection<V> values() { 1073 Collection<V> vs = values; 1074 if (vs == null) { 1075 vs = new Values(); 1076 values = vs; 1077 } 1078 return vs; 1079 } 1080 1081 private class Values extends AbstractCollection<V> { 1082 public Iterator<V> iterator() { 1083 return new ValueIterator(); 1084 } 1085 public int size() { 1086 return size; 1087 } 1088 public boolean contains(Object o) { 1089 return containsValue(o); 1090 } 1091 public boolean remove(Object o) { 1092 for (Iterator<V> i = iterator(); i.hasNext(); ) { 1093 if (i.next() == o) { 1094 i.remove(); 1095 return true; 1096 } 1097 } 1098 return false; 1099 } 1100 public void clear() { 1101 IdentityHashMap.this.clear(); 1102 } 1103 public Object[] toArray() { 1104 return toArray(new Object[0]); 1105 } 1106 @SuppressWarnings("unchecked") 1107 public <T> T[] toArray(T[] a) { 1108 int expectedModCount = modCount; 1109 int size = size(); 1110 if (a.length < size) 1111 a = (T[]) Array.newInstance(a.getClass().getComponentType(), size); 1112 Object[] tab = table; 1113 int ti = 0; 1114 for (int si = 0; si < tab.length; si += 2) { 1115 if (tab[si] != null) { // key present ? 1116 // more elements than expected -> concurrent modification from other thread 1117 if (ti >= size) { 1118 throw new ConcurrentModificationException(); 1119 } 1120 a[ti++] = (T) tab[si+1]; // copy value 1121 } 1122 } 1123 // fewer elements than expected or concurrent modification from other thread detected 1124 if (ti < size || expectedModCount != modCount) { 1125 throw new ConcurrentModificationException(); 1126 } 1127 // final null marker as per spec 1128 if (ti < a.length) { 1129 a[ti] = null; 1130 } 1131 return a; 1132 } 1133 1134 public Spliterator<V> spliterator() { 1135 return new ValueSpliterator<>(IdentityHashMap.this, 0, -1, 0, 0); 1136 } 1137 } 1138 1139 /** 1140 * Returns a {@link Set} view of the mappings contained in this map. 1141 * Each element in the returned set is a reference-equality-based 1142 * {@code Map.Entry}. The set is backed by the map, so changes 1143 * to the map are reflected in the set, and vice-versa. If the 1144 * map is modified while an iteration over the set is in progress, 1145 * the results of the iteration are undefined. The set supports 1146 * element removal, which removes the corresponding mapping from 1147 * the map, via the {@code Iterator.remove}, {@code Set.remove}, 1148 * {@code removeAll}, {@code retainAll} and {@code clear} 1149 * methods. It does not support the {@code add} or 1150 * {@code addAll} methods. 1151 * 1152 * <p>Like the backing map, the {@code Map.Entry} objects in the set 1153 * returned by this method define key and value equality as 1154 * reference-equality rather than object-equality. This affects the 1155 * behavior of the {@code equals} and {@code hashCode} methods of these 1156 * {@code Map.Entry} objects. A reference-equality based {@code Map.Entry 1157 * e} is equal to an object {@code o} if and only if {@code o} is a 1158 * {@code Map.Entry} and {@code e.getKey()==o.getKey() && 1159 * e.getValue()==o.getValue()}. To accommodate these equals 1160 * semantics, the {@code hashCode} method returns 1161 * {@code System.identityHashCode(e.getKey()) ^ 1162 * System.identityHashCode(e.getValue())}. 1163 * 1164 * <p><b>Owing to the reference-equality-based semantics of the 1165 * {@code Map.Entry} instances in the set returned by this method, 1166 * it is possible that the symmetry and transitivity requirements of 1167 * the {@link Object#equals(Object)} contract may be violated if any of 1168 * the entries in the set is compared to a normal map entry, or if 1169 * the set returned by this method is compared to a set of normal map 1170 * entries (such as would be returned by a call to this method on a normal 1171 * map). However, the {@code Object.equals} contract is guaranteed to 1172 * hold among identity-based map entries, and among sets of such entries. 1173 * </b> 1174 * 1175 * @return a set view of the identity-mappings contained in this map 1176 */ 1177 public Set<Map.Entry<K,V>> entrySet() { 1178 Set<Map.Entry<K,V>> es = entrySet; 1179 if (es != null) 1180 return es; 1181 else 1182 return entrySet = new EntrySet(); 1183 } 1184 1185 private class EntrySet extends AbstractSet<Map.Entry<K,V>> { 1186 public Iterator<Map.Entry<K,V>> iterator() { 1187 return new EntryIterator(); 1188 } 1189 public boolean contains(Object o) { 1190 if (!(o instanceof Map.Entry)) 1191 return false; 1192 Map.Entry<?,?> entry = (Map.Entry<?,?>)o; 1193 return containsMapping(entry.getKey(), entry.getValue()); 1194 } 1195 public boolean remove(Object o) { 1196 if (!(o instanceof Map.Entry)) 1197 return false; 1198 Map.Entry<?,?> entry = (Map.Entry<?,?>)o; 1199 return removeMapping(entry.getKey(), entry.getValue()); 1200 } 1201 public int size() { 1202 return size; 1203 } 1204 public void clear() { 1205 IdentityHashMap.this.clear(); 1206 } 1207 /* 1208 * Must revert from AbstractSet's impl to AbstractCollection's, as 1209 * the former contains an optimization that results in incorrect 1210 * behavior when c is a smaller "normal" (non-identity-based) Set. 1211 */ 1212 public boolean removeAll(Collection<?> c) { 1213 Objects.requireNonNull(c); 1214 boolean modified = false; 1215 for (Iterator<Map.Entry<K,V>> i = iterator(); i.hasNext(); ) { 1216 if (c.contains(i.next())) { 1217 i.remove(); 1218 modified = true; 1219 } 1220 } 1221 return modified; 1222 } 1223 1224 public Object[] toArray() { 1225 return toArray(new Object[0]); 1226 } 1227 1228 @SuppressWarnings("unchecked") 1229 public <T> T[] toArray(T[] a) { 1230 int expectedModCount = modCount; 1231 int size = size(); 1232 if (a.length < size) 1233 a = (T[]) Array.newInstance(a.getClass().getComponentType(), size); 1234 Object[] tab = table; 1235 int ti = 0; 1236 for (int si = 0; si < tab.length; si += 2) { 1237 Object key; 1238 if ((key = tab[si]) != null) { // key present ? 1239 // more elements than expected -> concurrent modification from other thread 1240 if (ti >= size) { 1241 throw new ConcurrentModificationException(); 1242 } 1243 a[ti++] = (T) new AbstractMap.SimpleEntry<>(unmaskNull(key), tab[si + 1]); 1244 } 1245 } 1246 // fewer elements than expected or concurrent modification from other thread detected 1247 if (ti < size || expectedModCount != modCount) { 1248 throw new ConcurrentModificationException(); 1249 } 1250 // final null marker as per spec 1251 if (ti < a.length) { 1252 a[ti] = null; 1253 } 1254 return a; 1255 } 1256 1257 public Spliterator<Map.Entry<K,V>> spliterator() { 1258 return new EntrySpliterator<>(IdentityHashMap.this, 0, -1, 0, 0); 1259 } 1260 } 1261 1262 @java.io.Serial 1263 private static final long serialVersionUID = 8188218128353913216L; 1264 1265 /** 1266 * Saves the state of the {@code IdentityHashMap} instance to a stream 1267 * (i.e., serializes it). 1268 * 1269 * @serialData The <i>size</i> of the HashMap (the number of key-value 1270 * mappings) ({@code int}), followed by the key (Object) and 1271 * value (Object) for each key-value mapping represented by the 1272 * IdentityHashMap. The key-value mappings are emitted in no 1273 * particular order. 1274 */ 1275 @java.io.Serial 1276 private void writeObject(java.io.ObjectOutputStream s) 1277 throws java.io.IOException { 1278 // Write out and any hidden stuff 1279 s.defaultWriteObject(); 1280 1281 // Write out size (number of Mappings) 1282 s.writeInt(size); 1283 1284 // Write out keys and values (alternating) 1285 Object[] tab = table; 1286 for (int i = 0; i < tab.length; i += 2) { 1287 Object key = tab[i]; 1288 if (key != null) { 1289 s.writeObject(unmaskNull(key)); 1290 s.writeObject(tab[i + 1]); 1291 } 1292 } 1293 } 1294 1295 /** 1296 * Reconstitutes the {@code IdentityHashMap} instance from a stream (i.e., 1297 * deserializes it). 1298 */ 1299 @java.io.Serial 1300 private void readObject(java.io.ObjectInputStream s) 1301 throws java.io.IOException, ClassNotFoundException { 1302 // Read in any hidden stuff 1303 s.defaultReadObject(); 1304 1305 // Read in size (number of Mappings) 1306 int size = s.readInt(); 1307 if (size < 0) 1308 throw new java.io.StreamCorruptedException 1309 ("Illegal mappings count: " + size); 1310 int cap = capacity(size); 1311 SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Object[].class, cap); 1312 init(cap); 1313 1314 // Read the keys and values, and put the mappings in the table 1315 for (int i=0; i<size; i++) { 1316 @SuppressWarnings("unchecked") 1317 K key = (K) s.readObject(); 1318 @SuppressWarnings("unchecked") 1319 V value = (V) s.readObject(); 1320 putForCreate(key, value); 1321 } 1322 } 1323 1324 /** 1325 * The put method for readObject. It does not resize the table, 1326 * update modCount, etc. 1327 */ 1328 private void putForCreate(K key, V value) 1329 throws java.io.StreamCorruptedException 1330 { 1331 Object k = maskNull(key); 1332 Object[] tab = table; 1333 int len = tab.length; 1334 int i = hash(k, len); 1335 1336 Object item; 1337 while ( (item = tab[i]) != null) { 1338 if (item == k) 1339 throw new java.io.StreamCorruptedException(); 1340 i = nextKeyIndex(i, len); 1341 } 1342 tab[i] = k; 1343 tab[i + 1] = value; 1344 } 1345 1346 @SuppressWarnings("unchecked") 1347 @Override 1348 public void forEach(BiConsumer<? super K, ? super V> action) { 1349 Objects.requireNonNull(action); 1350 int expectedModCount = modCount; 1351 1352 Object[] t = table; 1353 for (int index = 0; index < t.length; index += 2) { 1354 Object k = t[index]; 1355 if (k != null) { 1356 action.accept((K) unmaskNull(k), (V) t[index + 1]); 1357 } 1358 1359 if (modCount != expectedModCount) { 1360 throw new ConcurrentModificationException(); 1361 } 1362 } 1363 } 1364 1365 @SuppressWarnings("unchecked") 1366 @Override 1367 public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) { 1368 Objects.requireNonNull(function); 1369 int expectedModCount = modCount; 1370 1371 Object[] t = table; 1372 for (int index = 0; index < t.length; index += 2) { 1373 Object k = t[index]; 1374 if (k != null) { 1375 t[index + 1] = function.apply((K) unmaskNull(k), (V) t[index + 1]); 1376 } 1377 1378 if (modCount != expectedModCount) { 1379 throw new ConcurrentModificationException(); 1380 } 1381 } 1382 } 1383 1384 /** 1385 * Similar form as array-based Spliterators, but skips blank elements, 1386 * and guestimates size as decreasing by half per split. 1387 */ 1388 static class IdentityHashMapSpliterator<K,V> { 1389 final IdentityHashMap<K,V> map; 1390 int index; // current index, modified on advance/split 1391 int fence; // -1 until first use; then one past last index 1392 int est; // size estimate 1393 int expectedModCount; // initialized when fence set 1394 1395 IdentityHashMapSpliterator(IdentityHashMap<K,V> map, int origin, 1396 int fence, int est, int expectedModCount) { 1397 this.map = map; 1398 this.index = origin; 1399 this.fence = fence; 1400 this.est = est; 1401 this.expectedModCount = expectedModCount; 1402 } 1403 1404 final int getFence() { // initialize fence and size on first use 1405 int hi; 1406 if ((hi = fence) < 0) { 1407 est = map.size; 1408 expectedModCount = map.modCount; 1409 hi = fence = map.table.length; 1410 } 1411 return hi; 1412 } 1413 1414 public final long estimateSize() { 1415 getFence(); // force init 1416 return (long) est; 1417 } 1418 } 1419 1420 static final class KeySpliterator<K,V> 1421 extends IdentityHashMapSpliterator<K,V> 1422 implements Spliterator<K> { 1423 KeySpliterator(IdentityHashMap<K,V> map, int origin, int fence, int est, 1424 int expectedModCount) { 1425 super(map, origin, fence, est, expectedModCount); 1426 } 1427 1428 public KeySpliterator<K,V> trySplit() { 1429 int hi = getFence(), lo = index, mid = ((lo + hi) >>> 1) & ~1; 1430 return (lo >= mid) ? null : 1431 new KeySpliterator<>(map, lo, index = mid, est >>>= 1, 1432 expectedModCount); 1433 } 1434 1435 @SuppressWarnings("unchecked") 1436 public void forEachRemaining(Consumer<? super K> action) { 1437 if (action == null) 1438 throw new NullPointerException(); 1439 int i, hi, mc; Object key; 1440 IdentityHashMap<K,V> m; Object[] a; 1441 if ((m = map) != null && (a = m.table) != null && 1442 (i = index) >= 0 && (index = hi = getFence()) <= a.length) { 1443 for (; i < hi; i += 2) { 1444 if ((key = a[i]) != null) 1445 action.accept((K)unmaskNull(key)); 1446 } 1447 if (m.modCount == expectedModCount) 1448 return; 1449 } 1450 throw new ConcurrentModificationException(); 1451 } 1452 1453 @SuppressWarnings("unchecked") 1454 public boolean tryAdvance(Consumer<? super K> action) { 1455 if (action == null) 1456 throw new NullPointerException(); 1457 Object[] a = map.table; 1458 int hi = getFence(); 1459 while (index < hi) { 1460 Object key = a[index]; 1461 index += 2; 1462 if (key != null) { 1463 action.accept((K)unmaskNull(key)); 1464 if (map.modCount != expectedModCount) 1465 throw new ConcurrentModificationException(); 1466 return true; 1467 } 1468 } 1469 return false; 1470 } 1471 1472 public int characteristics() { 1473 return (fence < 0 || est == map.size ? SIZED : 0) | Spliterator.DISTINCT; 1474 } 1475 } 1476 1477 static final class ValueSpliterator<K,V> 1478 extends IdentityHashMapSpliterator<K,V> 1479 implements Spliterator<V> { 1480 ValueSpliterator(IdentityHashMap<K,V> m, int origin, int fence, int est, 1481 int expectedModCount) { 1482 super(m, origin, fence, est, expectedModCount); 1483 } 1484 1485 public ValueSpliterator<K,V> trySplit() { 1486 int hi = getFence(), lo = index, mid = ((lo + hi) >>> 1) & ~1; 1487 return (lo >= mid) ? null : 1488 new ValueSpliterator<>(map, lo, index = mid, est >>>= 1, 1489 expectedModCount); 1490 } 1491 1492 public void forEachRemaining(Consumer<? super V> action) { 1493 if (action == null) 1494 throw new NullPointerException(); 1495 int i, hi, mc; 1496 IdentityHashMap<K,V> m; Object[] a; 1497 if ((m = map) != null && (a = m.table) != null && 1498 (i = index) >= 0 && (index = hi = getFence()) <= a.length) { 1499 for (; i < hi; i += 2) { 1500 if (a[i] != null) { 1501 @SuppressWarnings("unchecked") V v = (V)a[i+1]; 1502 action.accept(v); 1503 } 1504 } 1505 if (m.modCount == expectedModCount) 1506 return; 1507 } 1508 throw new ConcurrentModificationException(); 1509 } 1510 1511 public boolean tryAdvance(Consumer<? super V> action) { 1512 if (action == null) 1513 throw new NullPointerException(); 1514 Object[] a = map.table; 1515 int hi = getFence(); 1516 while (index < hi) { 1517 Object key = a[index]; 1518 @SuppressWarnings("unchecked") V v = (V)a[index+1]; 1519 index += 2; 1520 if (key != null) { 1521 action.accept(v); 1522 if (map.modCount != expectedModCount) 1523 throw new ConcurrentModificationException(); 1524 return true; 1525 } 1526 } 1527 return false; 1528 } 1529 1530 public int characteristics() { 1531 return (fence < 0 || est == map.size ? SIZED : 0); 1532 } 1533 1534 } 1535 1536 static final class EntrySpliterator<K,V> 1537 extends IdentityHashMapSpliterator<K,V> 1538 implements Spliterator<Map.Entry<K,V>> { 1539 EntrySpliterator(IdentityHashMap<K,V> m, int origin, int fence, int est, 1540 int expectedModCount) { 1541 super(m, origin, fence, est, expectedModCount); 1542 } 1543 1544 public EntrySpliterator<K,V> trySplit() { 1545 int hi = getFence(), lo = index, mid = ((lo + hi) >>> 1) & ~1; 1546 return (lo >= mid) ? null : 1547 new EntrySpliterator<>(map, lo, index = mid, est >>>= 1, 1548 expectedModCount); 1549 } 1550 1551 public void forEachRemaining(Consumer<? super Map.Entry<K, V>> action) { 1552 if (action == null) 1553 throw new NullPointerException(); 1554 int i, hi, mc; 1555 IdentityHashMap<K,V> m; Object[] a; 1556 if ((m = map) != null && (a = m.table) != null && 1557 (i = index) >= 0 && (index = hi = getFence()) <= a.length) { 1558 for (; i < hi; i += 2) { 1559 Object key = a[i]; 1560 if (key != null) { 1561 @SuppressWarnings("unchecked") K k = 1562 (K)unmaskNull(key); 1563 @SuppressWarnings("unchecked") V v = (V)a[i+1]; 1564 action.accept 1565 (new AbstractMap.SimpleImmutableEntry<>(k, v)); 1566 1567 } 1568 } 1569 if (m.modCount == expectedModCount) 1570 return; 1571 } 1572 throw new ConcurrentModificationException(); 1573 } 1574 1575 public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) { 1576 if (action == null) 1577 throw new NullPointerException(); 1578 Object[] a = map.table; 1579 int hi = getFence(); 1580 while (index < hi) { 1581 Object key = a[index]; 1582 @SuppressWarnings("unchecked") V v = (V)a[index+1]; 1583 index += 2; 1584 if (key != null) { 1585 @SuppressWarnings("unchecked") K k = 1586 (K)unmaskNull(key); 1587 action.accept 1588 (new AbstractMap.SimpleImmutableEntry<>(k, v)); 1589 if (map.modCount != expectedModCount) 1590 throw new ConcurrentModificationException(); 1591 return true; 1592 } 1593 } 1594 return false; 1595 } 1596 1597 public int characteristics() { 1598 return (fence < 0 || est == map.size ? SIZED : 0) | Spliterator.DISTINCT; 1599 } 1600 } 1601 1602 }