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 26package java.util; 27 28import java.io.IOException; 29import java.io.InvalidObjectException; 30import java.io.Serializable; 31import java.lang.reflect.ParameterizedType; 32import java.lang.reflect.Type; 33import java.util.function.BiConsumer; 34import java.util.function.BiFunction; 35import java.util.function.Consumer; 36import java.util.function.Function; 37 38/** 39 * Hash table based implementation of the {@code Map} interface. This 40 * implementation provides all of the optional map operations, and permits 41 * {@code null} values and the {@code null} key. (The {@code HashMap} 42 * class is roughly equivalent to {@code Hashtable}, 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 ({@code get} and {@code put}), 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 * {@code HashMap} 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 {@code HashMap} 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 {@code HashMap} class, including 71 * {@code get} and {@code put}). 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 {@code HashMap} 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 * {@code remove} 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 {@code ConcurrentModificationException} 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}/java/util/package-summary.html#CollectionsFramework"> 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 */ 137public 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; ParameterizedType p; 348 if ((c = x.getClass()) == String.class) // bypass checks 349 return c; 350 if ((ts = c.getGenericInterfaces()) != null) { 351 for (Type t : ts) { 352 if ((t 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 {@code HashMap} 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 {@code HashMap} 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 {@code HashMap} 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 {@code HashMap} with the same mappings as the 480 * specified {@code Map}. The {@code HashMap} is created with 481 * default load factor (0.75) and an initial capacity sufficient to 482 * hold the mappings in the specified {@code Map}. 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 {@code true} if this map contains no key-value mappings. 530 * 531 * @return {@code true} 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 {@code true} 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 {@code true} 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 {@code key}, or 606 * {@code null} if there was no mapping for {@code key}. 607 * (A {@code null} return can also indicate that the map 608 * previously associated {@code null} with {@code key}.) 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 {@code key}, or 792 * {@code null} if there was no mapping for {@code key}. 793 * (A {@code null} return can also indicate that the map 794 * previously associated {@code null} with {@code key}.) 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 {@code true} 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 {@code true} 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 (Node<K, V> e : tab) { 879 for (; 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 {@code remove} 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 * {@code Iterator.remove}, {@code Set.remove}, 898 * {@code removeAll}, {@code retainAll}, and {@code clear} 899 * operations. It does not support the {@code add} or {@code addAll} 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 = keySet; 906 if (ks == null) { 907 ks = new KeySet(); 908 keySet = ks; 909 } 910 return ks; 911 } 912 913 final class KeySet extends AbstractSet<K> { 914 public final int size() { return size; } 915 public final void clear() { HashMap.this.clear(); } 916 public final Iterator<K> iterator() { return new KeyIterator(); } 917 public final boolean contains(Object o) { return containsKey(o); } 918 public final boolean remove(Object key) { 919 return removeNode(hash(key), key, null, false, true) != null; 920 } 921 public final Spliterator<K> spliterator() { 922 return new KeySpliterator<>(HashMap.this, 0, -1, 0, 0); 923 } 924 public final void forEach(Consumer<? super K> action) { 925 Node<K,V>[] tab; 926 if (action == null) 927 throw new NullPointerException(); 928 if (size > 0 && (tab = table) != null) { 929 int mc = modCount; 930 for (Node<K, V> e : tab) { 931 for (; e != null; e = e.next) 932 action.accept(e.key); 933 } 934 if (modCount != mc) 935 throw new ConcurrentModificationException(); 936 } 937 } 938 } 939 940 /** 941 * Returns a {@link Collection} view of the values contained in this map. 942 * The collection is backed by the map, so changes to the map are 943 * reflected in the collection, and vice-versa. If the map is 944 * modified while an iteration over the collection is in progress 945 * (except through the iterator's own {@code remove} operation), 946 * the results of the iteration are undefined. The collection 947 * supports element removal, which removes the corresponding 948 * mapping from the map, via the {@code Iterator.remove}, 949 * {@code Collection.remove}, {@code removeAll}, 950 * {@code retainAll} and {@code clear} operations. It does not 951 * support the {@code add} or {@code addAll} operations. 952 * 953 * @return a view of the values contained in this map 954 */ 955 public Collection<V> values() { 956 Collection<V> vs = values; 957 if (vs == null) { 958 vs = new Values(); 959 values = vs; 960 } 961 return vs; 962 } 963 964 final class Values extends AbstractCollection<V> { 965 public final int size() { return size; } 966 public final void clear() { HashMap.this.clear(); } 967 public final Iterator<V> iterator() { return new ValueIterator(); } 968 public final boolean contains(Object o) { return containsValue(o); } 969 public final Spliterator<V> spliterator() { 970 return new ValueSpliterator<>(HashMap.this, 0, -1, 0, 0); 971 } 972 public final void forEach(Consumer<? super V> action) { 973 Node<K,V>[] tab; 974 if (action == null) 975 throw new NullPointerException(); 976 if (size > 0 && (tab = table) != null) { 977 int mc = modCount; 978 for (Node<K, V> e : tab) { 979 for (; e != null; e = e.next) 980 action.accept(e.value); 981 } 982 if (modCount != mc) 983 throw new ConcurrentModificationException(); 984 } 985 } 986 } 987 988 /** 989 * Returns a {@link Set} view of the mappings contained in this map. 990 * The set is backed by the map, so changes to the map are 991 * reflected in the set, and vice-versa. If the map is modified 992 * while an iteration over the set is in progress (except through 993 * the iterator's own {@code remove} operation, or through the 994 * {@code setValue} operation on a map entry returned by the 995 * iterator) the results of the iteration are undefined. The set 996 * supports element removal, which removes the corresponding 997 * mapping from the map, via the {@code Iterator.remove}, 998 * {@code Set.remove}, {@code removeAll}, {@code retainAll} and 999 * {@code clear} operations. It does not support the 1000 * {@code add} or {@code addAll} operations. 1001 * 1002 * @return a set view of the mappings contained in this map 1003 */ 1004 public Set<Map.Entry<K,V>> entrySet() { 1005 Set<Map.Entry<K,V>> es; 1006 return (es = entrySet) == null ? (entrySet = new EntrySet()) : es; 1007 } 1008 1009 final class EntrySet extends AbstractSet<Map.Entry<K,V>> { 1010 public final int size() { return size; } 1011 public final void clear() { HashMap.this.clear(); } 1012 public final Iterator<Map.Entry<K,V>> iterator() { 1013 return new EntryIterator(); 1014 } 1015 public final boolean contains(Object o) { 1016 if (!(o instanceof Map.Entry)) 1017 return false; 1018 Map.Entry<?,?> e = (Map.Entry<?,?>) o; 1019 Object key = e.getKey(); 1020 Node<K,V> candidate = getNode(hash(key), key); 1021 return candidate != null && candidate.equals(e); 1022 } 1023 public final boolean remove(Object o) { 1024 if (o instanceof Map.Entry) { 1025 Map.Entry<?,?> e = (Map.Entry<?,?>) o; 1026 Object key = e.getKey(); 1027 Object value = e.getValue(); 1028 return removeNode(hash(key), key, value, true, true) != null; 1029 } 1030 return false; 1031 } 1032 public final Spliterator<Map.Entry<K,V>> spliterator() { 1033 return new EntrySpliterator<>(HashMap.this, 0, -1, 0, 0); 1034 } 1035 public final void forEach(Consumer<? super Map.Entry<K,V>> action) { 1036 Node<K,V>[] tab; 1037 if (action == null) 1038 throw new NullPointerException(); 1039 if (size > 0 && (tab = table) != null) { 1040 int mc = modCount; 1041 for (Node<K, V> e : tab) { 1042 for (; e != null; e = e.next) 1043 action.accept(e); 1044 } 1045 if (modCount != mc) 1046 throw new ConcurrentModificationException(); 1047 } 1048 } 1049 } 1050 1051 // Overrides of JDK8 Map extension methods 1052 1053 @Override 1054 public V getOrDefault(Object key, V defaultValue) { 1055 Node<K,V> e; 1056 return (e = getNode(hash(key), key)) == null ? defaultValue : e.value; 1057 } 1058 1059 @Override 1060 public V putIfAbsent(K key, V value) { 1061 return putVal(hash(key), key, value, true, true); 1062 } 1063 1064 @Override 1065 public boolean remove(Object key, Object value) { 1066 return removeNode(hash(key), key, value, true, true) != null; 1067 } 1068 1069 @Override 1070 public boolean replace(K key, V oldValue, V newValue) { 1071 Node<K,V> e; V v; 1072 if ((e = getNode(hash(key), key)) != null && 1073 ((v = e.value) == oldValue || (v != null && v.equals(oldValue)))) { 1074 e.value = newValue; 1075 afterNodeAccess(e); 1076 return true; 1077 } 1078 return false; 1079 } 1080 1081 @Override 1082 public V replace(K key, V value) { 1083 Node<K,V> e; 1084 if ((e = getNode(hash(key), key)) != null) { 1085 V oldValue = e.value; 1086 e.value = value; 1087 afterNodeAccess(e); 1088 return oldValue; 1089 } 1090 return null; 1091 } 1092 1093 /** 1094 * {@inheritDoc} 1095 * 1096 * <p>This method will, on a best-effort basis, throw a 1097 * {@link ConcurrentModificationException} if it is detected that the 1098 * mapping function modifies this map during computation. 1099 * 1100 * @throws ConcurrentModificationException if it is detected that the 1101 * mapping function modified this map 1102 */ 1103 @Override 1104 public V computeIfAbsent(K key, 1105 Function<? super K, ? extends V> mappingFunction) { 1106 if (mappingFunction == null) 1107 throw new NullPointerException(); 1108 int hash = hash(key); 1109 Node<K,V>[] tab; Node<K,V> first; int n, i; 1110 int binCount = 0; 1111 TreeNode<K,V> t = null; 1112 Node<K,V> old = null; 1113 if (size > threshold || (tab = table) == null || 1114 (n = tab.length) == 0) 1115 n = (tab = resize()).length; 1116 if ((first = tab[i = (n - 1) & hash]) != null) { 1117 if (first instanceof TreeNode) 1118 old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key); 1119 else { 1120 Node<K,V> e = first; K k; 1121 do { 1122 if (e.hash == hash && 1123 ((k = e.key) == key || (key != null && key.equals(k)))) { 1124 old = e; 1125 break; 1126 } 1127 ++binCount; 1128 } while ((e = e.next) != null); 1129 } 1130 V oldValue; 1131 if (old != null && (oldValue = old.value) != null) { 1132 afterNodeAccess(old); 1133 return oldValue; 1134 } 1135 } 1136 int mc = modCount; 1137 V v = mappingFunction.apply(key); 1138 if (mc != modCount) { throw new ConcurrentModificationException(); } 1139 if (v == null) { 1140 return null; 1141 } else if (old != null) { 1142 old.value = v; 1143 afterNodeAccess(old); 1144 return v; 1145 } 1146 else if (t != null) 1147 t.putTreeVal(this, tab, hash, key, v); 1148 else { 1149 tab[i] = newNode(hash, key, v, first); 1150 if (binCount >= TREEIFY_THRESHOLD - 1) 1151 treeifyBin(tab, hash); 1152 } 1153 modCount = mc + 1; 1154 ++size; 1155 afterNodeInsertion(true); 1156 return v; 1157 } 1158 1159 /** 1160 * {@inheritDoc} 1161 * 1162 * <p>This method will, on a best-effort basis, throw a 1163 * {@link ConcurrentModificationException} if it is detected that the 1164 * remapping function modifies this map during computation. 1165 * 1166 * @throws ConcurrentModificationException if it is detected that the 1167 * remapping function modified this map 1168 */ 1169 @Override 1170 public V computeIfPresent(K key, 1171 BiFunction<? super K, ? super V, ? extends V> remappingFunction) { 1172 if (remappingFunction == null) 1173 throw new NullPointerException(); 1174 Node<K,V> e; V oldValue; 1175 int hash = hash(key); 1176 if ((e = getNode(hash, key)) != null && 1177 (oldValue = e.value) != null) { 1178 int mc = modCount; 1179 V v = remappingFunction.apply(key, oldValue); 1180 if (mc != modCount) { throw new ConcurrentModificationException(); } 1181 if (v != null) { 1182 e.value = v; 1183 afterNodeAccess(e); 1184 return v; 1185 } 1186 else 1187 removeNode(hash, key, null, false, true); 1188 } 1189 return null; 1190 } 1191 1192 /** 1193 * {@inheritDoc} 1194 * 1195 * <p>This method will, on a best-effort basis, throw a 1196 * {@link ConcurrentModificationException} if it is detected that the 1197 * remapping function modifies this map during computation. 1198 * 1199 * @throws ConcurrentModificationException if it is detected that the 1200 * remapping function modified this map 1201 */ 1202 @Override 1203 public V compute(K key, 1204 BiFunction<? super K, ? super V, ? extends V> remappingFunction) { 1205 if (remappingFunction == null) 1206 throw new NullPointerException(); 1207 int hash = hash(key); 1208 Node<K,V>[] tab; Node<K,V> first; int n, i; 1209 int binCount = 0; 1210 TreeNode<K,V> t = null; 1211 Node<K,V> old = null; 1212 if (size > threshold || (tab = table) == null || 1213 (n = tab.length) == 0) 1214 n = (tab = resize()).length; 1215 if ((first = tab[i = (n - 1) & hash]) != null) { 1216 if (first instanceof TreeNode) 1217 old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key); 1218 else { 1219 Node<K,V> e = first; K k; 1220 do { 1221 if (e.hash == hash && 1222 ((k = e.key) == key || (key != null && key.equals(k)))) { 1223 old = e; 1224 break; 1225 } 1226 ++binCount; 1227 } while ((e = e.next) != null); 1228 } 1229 } 1230 V oldValue = (old == null) ? null : old.value; 1231 int mc = modCount; 1232 V v = remappingFunction.apply(key, oldValue); 1233 if (mc != modCount) { throw new ConcurrentModificationException(); } 1234 if (old != null) { 1235 if (v != null) { 1236 old.value = v; 1237 afterNodeAccess(old); 1238 } 1239 else 1240 removeNode(hash, key, null, false, true); 1241 } 1242 else if (v != null) { 1243 if (t != null) 1244 t.putTreeVal(this, tab, hash, key, v); 1245 else { 1246 tab[i] = newNode(hash, key, v, first); 1247 if (binCount >= TREEIFY_THRESHOLD - 1) 1248 treeifyBin(tab, hash); 1249 } 1250 modCount = mc + 1; 1251 ++size; 1252 afterNodeInsertion(true); 1253 } 1254 return v; 1255 } 1256 1257 /** 1258 * {@inheritDoc} 1259 * 1260 * <p>This method will, on a best-effort basis, throw a 1261 * {@link ConcurrentModificationException} if it is detected that the 1262 * remapping function modifies this map during computation. 1263 * 1264 * @throws ConcurrentModificationException if it is detected that the 1265 * remapping function modified this map 1266 */ 1267 @Override 1268 public V merge(K key, V value, 1269 BiFunction<? super V, ? super V, ? extends V> remappingFunction) { 1270 if (value == null) 1271 throw new NullPointerException(); 1272 if (remappingFunction == null) 1273 throw new NullPointerException(); 1274 int hash = hash(key); 1275 Node<K,V>[] tab; Node<K,V> first; int n, i; 1276 int binCount = 0; 1277 TreeNode<K,V> t = null; 1278 Node<K,V> old = null; 1279 if (size > threshold || (tab = table) == null || 1280 (n = tab.length) == 0) 1281 n = (tab = resize()).length; 1282 if ((first = tab[i = (n - 1) & hash]) != null) { 1283 if (first instanceof TreeNode) 1284 old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key); 1285 else { 1286 Node<K,V> e = first; K k; 1287 do { 1288 if (e.hash == hash && 1289 ((k = e.key) == key || (key != null && key.equals(k)))) { 1290 old = e; 1291 break; 1292 } 1293 ++binCount; 1294 } while ((e = e.next) != null); 1295 } 1296 } 1297 if (old != null) { 1298 V v; 1299 if (old.value != null) { 1300 int mc = modCount; 1301 v = remappingFunction.apply(old.value, value); 1302 if (mc != modCount) { 1303 throw new ConcurrentModificationException(); 1304 } 1305 } else { 1306 v = value; 1307 } 1308 if (v != null) { 1309 old.value = v; 1310 afterNodeAccess(old); 1311 } 1312 else 1313 removeNode(hash, key, null, false, true); 1314 return v; 1315 } 1316 if (value != null) { 1317 if (t != null) 1318 t.putTreeVal(this, tab, hash, key, value); 1319 else { 1320 tab[i] = newNode(hash, key, value, first); 1321 if (binCount >= TREEIFY_THRESHOLD - 1) 1322 treeifyBin(tab, hash); 1323 } 1324 ++modCount; 1325 ++size; 1326 afterNodeInsertion(true); 1327 } 1328 return value; 1329 } 1330 1331 @Override 1332 public void forEach(BiConsumer<? super K, ? super V> action) { 1333 Node<K,V>[] tab; 1334 if (action == null) 1335 throw new NullPointerException(); 1336 if (size > 0 && (tab = table) != null) { 1337 int mc = modCount; 1338 for (Node<K, V> e : tab) { 1339 for (; e != null; e = e.next) 1340 action.accept(e.key, e.value); 1341 } 1342 if (modCount != mc) 1343 throw new ConcurrentModificationException(); 1344 } 1345 } 1346 1347 @Override 1348 public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) { 1349 Node<K,V>[] tab; 1350 if (function == null) 1351 throw new NullPointerException(); 1352 if (size > 0 && (tab = table) != null) { 1353 int mc = modCount; 1354 for (Node<K, V> e : tab) { 1355 for (; e != null; e = e.next) { 1356 e.value = function.apply(e.key, e.value); 1357 } 1358 } 1359 if (modCount != mc) 1360 throw new ConcurrentModificationException(); 1361 } 1362 } 1363 1364 /* ------------------------------------------------------------ */ 1365 // Cloning and serialization 1366 1367 /** 1368 * Returns a shallow copy of this {@code HashMap} instance: the keys and 1369 * values themselves are not cloned. 1370 * 1371 * @return a shallow copy of this map 1372 */ 1373 @SuppressWarnings("unchecked") 1374 @Override 1375 public Object clone() { 1376 HashMap<K,V> result; 1377 try { 1378 result = (HashMap<K,V>)super.clone(); 1379 } catch (CloneNotSupportedException e) { 1380 // this shouldn't happen, since we are Cloneable 1381 throw new InternalError(e); 1382 } 1383 result.reinitialize(); 1384 result.putMapEntries(this, false); 1385 return result; 1386 } 1387 1388 // These methods are also used when serializing HashSets 1389 final float loadFactor() { return loadFactor; } 1390 final int capacity() { 1391 return (table != null) ? table.length : 1392 (threshold > 0) ? threshold : 1393 DEFAULT_INITIAL_CAPACITY; 1394 } 1395 1396 /** 1397 * Save the state of the {@code HashMap} instance to a stream (i.e., 1398 * serialize it). 1399 * 1400 * @serialData The <i>capacity</i> of the HashMap (the length of the 1401 * bucket array) is emitted (int), followed by the 1402 * <i>size</i> (an int, the number of key-value 1403 * mappings), followed by the key (Object) and value (Object) 1404 * for each key-value mapping. The key-value mappings are 1405 * emitted in no particular order. 1406 */ 1407 private void writeObject(java.io.ObjectOutputStream s) 1408 throws IOException { 1409 int buckets = capacity(); 1410 // Write out the threshold, loadfactor, and any hidden stuff 1411 s.defaultWriteObject(); 1412 s.writeInt(buckets); 1413 s.writeInt(size); 1414 internalWriteEntries(s); 1415 } 1416 1417 /** 1418 * Reconstitute the {@code HashMap} instance from a stream (i.e., 1419 * deserialize it). 1420 */ 1421 private void readObject(java.io.ObjectInputStream s) 1422 throws IOException, ClassNotFoundException { 1423 // Read in the threshold (ignored), loadfactor, and any hidden stuff 1424 s.defaultReadObject(); 1425 reinitialize(); 1426 if (loadFactor <= 0 || Float.isNaN(loadFactor)) 1427 throw new InvalidObjectException("Illegal load factor: " + 1428 loadFactor); 1429 s.readInt(); // Read and ignore number of buckets 1430 int mappings = s.readInt(); // Read number of mappings (size) 1431 if (mappings < 0) 1432 throw new InvalidObjectException("Illegal mappings count: " + 1433 mappings); 1434 else if (mappings > 0) { // (if zero, use defaults) 1435 // Size the table using given load factor only if within 1436 // range of 0.25...4.0 1437 float lf = Math.min(Math.max(0.25f, loadFactor), 4.0f); 1438 float fc = (float)mappings / lf + 1.0f; 1439 int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ? 1440 DEFAULT_INITIAL_CAPACITY : 1441 (fc >= MAXIMUM_CAPACITY) ? 1442 MAXIMUM_CAPACITY : 1443 tableSizeFor((int)fc)); 1444 float ft = (float)cap * lf; 1445 threshold = ((cap < MAXIMUM_CAPACITY && ft < MAXIMUM_CAPACITY) ? 1446 (int)ft : Integer.MAX_VALUE); 1447 @SuppressWarnings({"rawtypes","unchecked"}) 1448 Node<K,V>[] tab = (Node<K,V>[])new Node[cap]; 1449 table = tab; 1450 1451 // Read the keys and values, and put the mappings in the HashMap 1452 for (int i = 0; i < mappings; i++) { 1453 @SuppressWarnings("unchecked") 1454 K key = (K) s.readObject(); 1455 @SuppressWarnings("unchecked") 1456 V value = (V) s.readObject(); 1457 putVal(hash(key), key, value, false, false); 1458 } 1459 } 1460 } 1461 1462 /* ------------------------------------------------------------ */ 1463 // iterators 1464 1465 abstract class HashIterator { 1466 Node<K,V> next; // next entry to return 1467 Node<K,V> current; // current entry 1468 int expectedModCount; // for fast-fail 1469 int index; // current slot 1470 1471 HashIterator() { 1472 expectedModCount = modCount; 1473 Node<K,V>[] t = table; 1474 current = next = null; 1475 index = 0; 1476 if (t != null && size > 0) { // advance to first entry 1477 do {} while (index < t.length && (next = t[index++]) == null); 1478 } 1479 } 1480 1481 public final boolean hasNext() { 1482 return next != null; 1483 } 1484 1485 final Node<K,V> nextNode() { 1486 Node<K,V>[] t; 1487 Node<K,V> e = next; 1488 if (modCount != expectedModCount) 1489 throw new ConcurrentModificationException(); 1490 if (e == null) 1491 throw new NoSuchElementException(); 1492 if ((next = (current = e).next) == null && (t = table) != null) { 1493 do {} while (index < t.length && (next = t[index++]) == null); 1494 } 1495 return e; 1496 } 1497 1498 public final void remove() { 1499 Node<K,V> p = current; 1500 if (p == null) 1501 throw new IllegalStateException(); 1502 if (modCount != expectedModCount) 1503 throw new ConcurrentModificationException(); 1504 current = null; 1505 removeNode(p.hash, p.key, null, false, false); 1506 expectedModCount = modCount; 1507 } 1508 } 1509 1510 final class KeyIterator extends HashIterator 1511 implements Iterator<K> { 1512 public final K next() { return nextNode().key; } 1513 } 1514 1515 final class ValueIterator extends HashIterator 1516 implements Iterator<V> { 1517 public final V next() { return nextNode().value; } 1518 } 1519 1520 final class EntryIterator extends HashIterator 1521 implements Iterator<Map.Entry<K,V>> { 1522 public final Map.Entry<K,V> next() { return nextNode(); } 1523 } 1524 1525 /* ------------------------------------------------------------ */ 1526 // spliterators 1527 1528 static class HashMapSpliterator<K,V> { 1529 final HashMap<K,V> map; 1530 Node<K,V> current; // current node 1531 int index; // current index, modified on advance/split 1532 int fence; // one past last index 1533 int est; // size estimate 1534 int expectedModCount; // for comodification checks 1535 1536 HashMapSpliterator(HashMap<K,V> m, int origin, 1537 int fence, int est, 1538 int expectedModCount) { 1539 this.map = m; 1540 this.index = origin; 1541 this.fence = fence; 1542 this.est = est; 1543 this.expectedModCount = expectedModCount; 1544 } 1545 1546 final int getFence() { // initialize fence and size on first use 1547 int hi; 1548 if ((hi = fence) < 0) { 1549 HashMap<K,V> m = map; 1550 est = m.size; 1551 expectedModCount = m.modCount; 1552 Node<K,V>[] tab = m.table; 1553 hi = fence = (tab == null) ? 0 : tab.length; 1554 } 1555 return hi; 1556 } 1557 1558 public final long estimateSize() { 1559 getFence(); // force init 1560 return (long) est; 1561 } 1562 } 1563 1564 static final class KeySpliterator<K,V> 1565 extends HashMapSpliterator<K,V> 1566 implements Spliterator<K> { 1567 KeySpliterator(HashMap<K,V> m, int origin, int fence, int est, 1568 int expectedModCount) { 1569 super(m, origin, fence, est, expectedModCount); 1570 } 1571 1572 public KeySpliterator<K,V> trySplit() { 1573 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; 1574 return (lo >= mid || current != null) ? null : 1575 new KeySpliterator<>(map, lo, index = mid, est >>>= 1, 1576 expectedModCount); 1577 } 1578 1579 public void forEachRemaining(Consumer<? super K> action) { 1580 int i, hi, mc; 1581 if (action == null) 1582 throw new NullPointerException(); 1583 HashMap<K,V> m = map; 1584 Node<K,V>[] tab = m.table; 1585 if ((hi = fence) < 0) { 1586 mc = expectedModCount = m.modCount; 1587 hi = fence = (tab == null) ? 0 : tab.length; 1588 } 1589 else 1590 mc = expectedModCount; 1591 if (tab != null && tab.length >= hi && 1592 (i = index) >= 0 && (i < (index = hi) || current != null)) { 1593 Node<K,V> p = current; 1594 current = null; 1595 do { 1596 if (p == null) 1597 p = tab[i++]; 1598 else { 1599 action.accept(p.key); 1600 p = p.next; 1601 } 1602 } while (p != null || i < hi); 1603 if (m.modCount != mc) 1604 throw new ConcurrentModificationException(); 1605 } 1606 } 1607 1608 public boolean tryAdvance(Consumer<? super K> action) { 1609 int hi; 1610 if (action == null) 1611 throw new NullPointerException(); 1612 Node<K,V>[] tab = map.table; 1613 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) { 1614 while (current != null || index < hi) { 1615 if (current == null) 1616 current = tab[index++]; 1617 else { 1618 K k = current.key; 1619 current = current.next; 1620 action.accept(k); 1621 if (map.modCount != expectedModCount) 1622 throw new ConcurrentModificationException(); 1623 return true; 1624 } 1625 } 1626 } 1627 return false; 1628 } 1629 1630 public int characteristics() { 1631 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) | 1632 Spliterator.DISTINCT; 1633 } 1634 } 1635 1636 static final class ValueSpliterator<K,V> 1637 extends HashMapSpliterator<K,V> 1638 implements Spliterator<V> { 1639 ValueSpliterator(HashMap<K,V> m, int origin, int fence, int est, 1640 int expectedModCount) { 1641 super(m, origin, fence, est, expectedModCount); 1642 } 1643 1644 public ValueSpliterator<K,V> trySplit() { 1645 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; 1646 return (lo >= mid || current != null) ? null : 1647 new ValueSpliterator<>(map, lo, index = mid, est >>>= 1, 1648 expectedModCount); 1649 } 1650 1651 public void forEachRemaining(Consumer<? super V> action) { 1652 int i, hi, mc; 1653 if (action == null) 1654 throw new NullPointerException(); 1655 HashMap<K,V> m = map; 1656 Node<K,V>[] tab = m.table; 1657 if ((hi = fence) < 0) { 1658 mc = expectedModCount = m.modCount; 1659 hi = fence = (tab == null) ? 0 : tab.length; 1660 } 1661 else 1662 mc = expectedModCount; 1663 if (tab != null && tab.length >= hi && 1664 (i = index) >= 0 && (i < (index = hi) || current != null)) { 1665 Node<K,V> p = current; 1666 current = null; 1667 do { 1668 if (p == null) 1669 p = tab[i++]; 1670 else { 1671 action.accept(p.value); 1672 p = p.next; 1673 } 1674 } while (p != null || i < hi); 1675 if (m.modCount != mc) 1676 throw new ConcurrentModificationException(); 1677 } 1678 } 1679 1680 public boolean tryAdvance(Consumer<? super V> action) { 1681 int hi; 1682 if (action == null) 1683 throw new NullPointerException(); 1684 Node<K,V>[] tab = map.table; 1685 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) { 1686 while (current != null || index < hi) { 1687 if (current == null) 1688 current = tab[index++]; 1689 else { 1690 V v = current.value; 1691 current = current.next; 1692 action.accept(v); 1693 if (map.modCount != expectedModCount) 1694 throw new ConcurrentModificationException(); 1695 return true; 1696 } 1697 } 1698 } 1699 return false; 1700 } 1701 1702 public int characteristics() { 1703 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0); 1704 } 1705 } 1706 1707 static final class EntrySpliterator<K,V> 1708 extends HashMapSpliterator<K,V> 1709 implements Spliterator<Map.Entry<K,V>> { 1710 EntrySpliterator(HashMap<K,V> m, int origin, int fence, int est, 1711 int expectedModCount) { 1712 super(m, origin, fence, est, expectedModCount); 1713 } 1714 1715 public EntrySpliterator<K,V> trySplit() { 1716 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; 1717 return (lo >= mid || current != null) ? null : 1718 new EntrySpliterator<>(map, lo, index = mid, est >>>= 1, 1719 expectedModCount); 1720 } 1721 1722 public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) { 1723 int i, hi, mc; 1724 if (action == null) 1725 throw new NullPointerException(); 1726 HashMap<K,V> m = map; 1727 Node<K,V>[] tab = m.table; 1728 if ((hi = fence) < 0) { 1729 mc = expectedModCount = m.modCount; 1730 hi = fence = (tab == null) ? 0 : tab.length; 1731 } 1732 else 1733 mc = expectedModCount; 1734 if (tab != null && tab.length >= hi && 1735 (i = index) >= 0 && (i < (index = hi) || current != null)) { 1736 Node<K,V> p = current; 1737 current = null; 1738 do { 1739 if (p == null) 1740 p = tab[i++]; 1741 else { 1742 action.accept(p); 1743 p = p.next; 1744 } 1745 } while (p != null || i < hi); 1746 if (m.modCount != mc) 1747 throw new ConcurrentModificationException(); 1748 } 1749 } 1750 1751 public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) { 1752 int hi; 1753 if (action == null) 1754 throw new NullPointerException(); 1755 Node<K,V>[] tab = map.table; 1756 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) { 1757 while (current != null || index < hi) { 1758 if (current == null) 1759 current = tab[index++]; 1760 else { 1761 Node<K,V> e = current; 1762 current = current.next; 1763 action.accept(e); 1764 if (map.modCount != expectedModCount) 1765 throw new ConcurrentModificationException(); 1766 return true; 1767 } 1768 } 1769 } 1770 return false; 1771 } 1772 1773 public int characteristics() { 1774 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) | 1775 Spliterator.DISTINCT; 1776 } 1777 } 1778 1779 /* ------------------------------------------------------------ */ 1780 // LinkedHashMap support 1781 1782 1783 /* 1784 * The following package-protected methods are designed to be 1785 * overridden by LinkedHashMap, but not by any other subclass. 1786 * Nearly all other internal methods are also package-protected 1787 * but are declared final, so can be used by LinkedHashMap, view 1788 * classes, and HashSet. 1789 */ 1790 1791 // Create a regular (non-tree) node 1792 Node<K,V> newNode(int hash, K key, V value, Node<K,V> next) { 1793 return new Node<>(hash, key, value, next); 1794 } 1795 1796 // For conversion from TreeNodes to plain nodes 1797 Node<K,V> replacementNode(Node<K,V> p, Node<K,V> next) { 1798 return new Node<>(p.hash, p.key, p.value, next); 1799 } 1800 1801 // Create a tree bin node 1802 TreeNode<K,V> newTreeNode(int hash, K key, V value, Node<K,V> next) { 1803 return new TreeNode<>(hash, key, value, next); 1804 } 1805 1806 // For treeifyBin 1807 TreeNode<K,V> replacementTreeNode(Node<K,V> p, Node<K,V> next) { 1808 return new TreeNode<>(p.hash, p.key, p.value, next); 1809 } 1810 1811 /** 1812 * Reset to initial default state. Called by clone and readObject. 1813 */ 1814 void reinitialize() { 1815 table = null; 1816 entrySet = null; 1817 keySet = null; 1818 values = null; 1819 modCount = 0; 1820 threshold = 0; 1821 size = 0; 1822 } 1823 1824 // Callbacks to allow LinkedHashMap post-actions 1825 void afterNodeAccess(Node<K,V> p) { } 1826 void afterNodeInsertion(boolean evict) { } 1827 void afterNodeRemoval(Node<K,V> p) { } 1828 1829 // Called only from writeObject, to ensure compatible ordering. 1830 void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException { 1831 Node<K,V>[] tab; 1832 if (size > 0 && (tab = table) != null) { 1833 for (Node<K, V> e : tab) { 1834 for (; e != null; e = e.next) { 1835 s.writeObject(e.key); 1836 s.writeObject(e.value); 1837 } 1838 } 1839 } 1840 } 1841 1842 /* ------------------------------------------------------------ */ 1843 // Tree bins 1844 1845 /** 1846 * Entry for Tree bins. Extends LinkedHashMap.Entry (which in turn 1847 * extends Node) so can be used as extension of either regular or 1848 * linked node. 1849 */ 1850 static final class TreeNode<K,V> extends LinkedHashMap.Entry<K,V> { 1851 TreeNode<K,V> parent; // red-black tree links 1852 TreeNode<K,V> left; 1853 TreeNode<K,V> right; 1854 TreeNode<K,V> prev; // needed to unlink next upon deletion 1855 boolean red; 1856 TreeNode(int hash, K key, V val, Node<K,V> next) { 1857 super(hash, key, val, next); 1858 } 1859 1860 /** 1861 * Returns root of tree containing this node. 1862 */ 1863 final TreeNode<K,V> root() { 1864 for (TreeNode<K,V> r = this, p;;) { 1865 if ((p = r.parent) == null) 1866 return r; 1867 r = p; 1868 } 1869 } 1870 1871 /** 1872 * Ensures that the given root is the first node of its bin. 1873 */ 1874 static <K,V> void moveRootToFront(Node<K,V>[] tab, TreeNode<K,V> root) { 1875 int n; 1876 if (root != null && tab != null && (n = tab.length) > 0) { 1877 int index = (n - 1) & root.hash; 1878 TreeNode<K,V> first = (TreeNode<K,V>)tab[index]; 1879 if (root != first) { 1880 Node<K,V> rn; 1881 tab[index] = root; 1882 TreeNode<K,V> rp = root.prev; 1883 if ((rn = root.next) != null) 1884 ((TreeNode<K,V>)rn).prev = rp; 1885 if (rp != null) 1886 rp.next = rn; 1887 if (first != null) 1888 first.prev = root; 1889 root.next = first; 1890 root.prev = null; 1891 } 1892 assert checkInvariants(root); 1893 } 1894 } 1895 1896 /** 1897 * Finds the node starting at root p with the given hash and key. 1898 * The kc argument caches comparableClassFor(key) upon first use 1899 * comparing keys. 1900 */ 1901 final TreeNode<K,V> find(int h, Object k, Class<?> kc) { 1902 TreeNode<K,V> p = this; 1903 do { 1904 int ph, dir; K pk; 1905 TreeNode<K,V> pl = p.left, pr = p.right, q; 1906 if ((ph = p.hash) > h) 1907 p = pl; 1908 else if (ph < h) 1909 p = pr; 1910 else if ((pk = p.key) == k || (k != null && k.equals(pk))) 1911 return p; 1912 else if (pl == null) 1913 p = pr; 1914 else if (pr == null) 1915 p = pl; 1916 else if ((kc != null || 1917 (kc = comparableClassFor(k)) != null) && 1918 (dir = compareComparables(kc, k, pk)) != 0) 1919 p = (dir < 0) ? pl : pr; 1920 else if ((q = pr.find(h, k, kc)) != null) 1921 return q; 1922 else 1923 p = pl; 1924 } while (p != null); 1925 return null; 1926 } 1927 1928 /** 1929 * Calls find for root node. 1930 */ 1931 final TreeNode<K,V> getTreeNode(int h, Object k) { 1932 return ((parent != null) ? root() : this).find(h, k, null); 1933 } 1934 1935 /** 1936 * Tie-breaking utility for ordering insertions when equal 1937 * hashCodes and non-comparable. We don't require a total 1938 * order, just a consistent insertion rule to maintain 1939 * equivalence across rebalancings. Tie-breaking further than 1940 * necessary simplifies testing a bit. 1941 */ 1942 static int tieBreakOrder(Object a, Object b) { 1943 int d; 1944 if (a == null || b == null || 1945 (d = a.getClass().getName(). 1946 compareTo(b.getClass().getName())) == 0) 1947 d = (System.identityHashCode(a) <= System.identityHashCode(b) ? 1948 -1 : 1); 1949 return d; 1950 } 1951 1952 /** 1953 * Forms tree of the nodes linked from this node. 1954 * @return root of tree 1955 */ 1956 final void treeify(Node<K,V>[] tab) { 1957 TreeNode<K,V> root = null; 1958 for (TreeNode<K,V> x = this, next; x != null; x = next) { 1959 next = (TreeNode<K,V>)x.next; 1960 x.left = x.right = null; 1961 if (root == null) { 1962 x.parent = null; 1963 x.red = false; 1964 root = x; 1965 } 1966 else { 1967 K k = x.key; 1968 int h = x.hash; 1969 Class<?> kc = null; 1970 for (TreeNode<K,V> p = root;;) { 1971 int dir, ph; 1972 K pk = p.key; 1973 if ((ph = p.hash) > h) 1974 dir = -1; 1975 else if (ph < h) 1976 dir = 1; 1977 else if ((kc == null && 1978 (kc = comparableClassFor(k)) == null) || 1979 (dir = compareComparables(kc, k, pk)) == 0) 1980 dir = tieBreakOrder(k, pk); 1981 1982 TreeNode<K,V> xp = p; 1983 if ((p = (dir <= 0) ? p.left : p.right) == null) { 1984 x.parent = xp; 1985 if (dir <= 0) 1986 xp.left = x; 1987 else 1988 xp.right = x; 1989 root = balanceInsertion(root, x); 1990 break; 1991 } 1992 } 1993 } 1994 } 1995 moveRootToFront(tab, root); 1996 } 1997 1998 /** 1999 * Returns a list of non-TreeNodes replacing those linked from 2000 * this node. 2001 */ 2002 final Node<K,V> untreeify(HashMap<K,V> map) { 2003 Node<K,V> hd = null, tl = null; 2004 for (Node<K,V> q = this; q != null; q = q.next) { 2005 Node<K,V> p = map.replacementNode(q, null); 2006 if (tl == null) 2007 hd = p; 2008 else 2009 tl.next = p; 2010 tl = p; 2011 } 2012 return hd; 2013 } 2014 2015 /** 2016 * Tree version of putVal. 2017 */ 2018 final TreeNode<K,V> putTreeVal(HashMap<K,V> map, Node<K,V>[] tab, 2019 int h, K k, V v) { 2020 Class<?> kc = null; 2021 boolean searched = false; 2022 TreeNode<K,V> root = (parent != null) ? root() : this; 2023 for (TreeNode<K,V> p = root;;) { 2024 int dir, ph; K pk; 2025 if ((ph = p.hash) > h) 2026 dir = -1; 2027 else if (ph < h) 2028 dir = 1; 2029 else if ((pk = p.key) == k || (k != null && k.equals(pk))) 2030 return p; 2031 else if ((kc == null && 2032 (kc = comparableClassFor(k)) == null) || 2033 (dir = compareComparables(kc, k, pk)) == 0) { 2034 if (!searched) { 2035 TreeNode<K,V> q, ch; 2036 searched = true; 2037 if (((ch = p.left) != null && 2038 (q = ch.find(h, k, kc)) != null) || 2039 ((ch = p.right) != null && 2040 (q = ch.find(h, k, kc)) != null)) 2041 return q; 2042 } 2043 dir = tieBreakOrder(k, pk); 2044 } 2045 2046 TreeNode<K,V> xp = p; 2047 if ((p = (dir <= 0) ? p.left : p.right) == null) { 2048 Node<K,V> xpn = xp.next; 2049 TreeNode<K,V> x = map.newTreeNode(h, k, v, xpn); 2050 if (dir <= 0) 2051 xp.left = x; 2052 else 2053 xp.right = x; 2054 xp.next = x; 2055 x.parent = x.prev = xp; 2056 if (xpn != null) 2057 ((TreeNode<K,V>)xpn).prev = x; 2058 moveRootToFront(tab, balanceInsertion(root, x)); 2059 return null; 2060 } 2061 } 2062 } 2063 2064 /** 2065 * Removes the given node, that must be present before this call. 2066 * This is messier than typical red-black deletion code because we 2067 * cannot swap the contents of an interior node with a leaf 2068 * successor that is pinned by "next" pointers that are accessible 2069 * independently during traversal. So instead we swap the tree 2070 * linkages. If the current tree appears to have too few nodes, 2071 * the bin is converted back to a plain bin. (The test triggers 2072 * somewhere between 2 and 6 nodes, depending on tree structure). 2073 */ 2074 final void removeTreeNode(HashMap<K,V> map, Node<K,V>[] tab, 2075 boolean movable) { 2076 int n; 2077 if (tab == null || (n = tab.length) == 0) 2078 return; 2079 int index = (n - 1) & hash; 2080 TreeNode<K,V> first = (TreeNode<K,V>)tab[index], root = first, rl; 2081 TreeNode<K,V> succ = (TreeNode<K,V>)next, pred = prev; 2082 if (pred == null) 2083 tab[index] = first = succ; 2084 else 2085 pred.next = succ; 2086 if (succ != null) 2087 succ.prev = pred; 2088 if (first == null) 2089 return; 2090 if (root.parent != null) 2091 root = root.root(); 2092 if (root == null || root.right == null || 2093 (rl = root.left) == null || rl.left == null) { 2094 tab[index] = first.untreeify(map); // too small 2095 return; 2096 } 2097 TreeNode<K,V> p = this, pl = left, pr = right, replacement; 2098 if (pl != null && pr != null) { 2099 TreeNode<K,V> s = pr, sl; 2100 while ((sl = s.left) != null) // find successor 2101 s = sl; 2102 boolean c = s.red; s.red = p.red; p.red = c; // swap colors 2103 TreeNode<K,V> sr = s.right; 2104 TreeNode<K,V> pp = p.parent; 2105 if (s == pr) { // p was s's direct parent 2106 p.parent = s; 2107 s.right = p; 2108 } 2109 else { 2110 TreeNode<K,V> sp = s.parent; 2111 if ((p.parent = sp) != null) { 2112 if (s == sp.left) 2113 sp.left = p; 2114 else 2115 sp.right = p; 2116 } 2117 if ((s.right = pr) != null) 2118 pr.parent = s; 2119 } 2120 p.left = null; 2121 if ((p.right = sr) != null) 2122 sr.parent = p; 2123 if ((s.left = pl) != null) 2124 pl.parent = s; 2125 if ((s.parent = pp) == null) 2126 root = s; 2127 else if (p == pp.left) 2128 pp.left = s; 2129 else 2130 pp.right = s; 2131 if (sr != null) 2132 replacement = sr; 2133 else 2134 replacement = p; 2135 } 2136 else if (pl != null) 2137 replacement = pl; 2138 else if (pr != null) 2139 replacement = pr; 2140 else 2141 replacement = p; 2142 if (replacement != p) { 2143 TreeNode<K,V> pp = replacement.parent = p.parent; 2144 if (pp == null) 2145 root = replacement; 2146 else if (p == pp.left) 2147 pp.left = replacement; 2148 else 2149 pp.right = replacement; 2150 p.left = p.right = p.parent = null; 2151 } 2152 2153 TreeNode<K,V> r = p.red ? root : balanceDeletion(root, replacement); 2154 2155 if (replacement == p) { // detach 2156 TreeNode<K,V> pp = p.parent; 2157 p.parent = null; 2158 if (pp != null) { 2159 if (p == pp.left) 2160 pp.left = null; 2161 else if (p == pp.right) 2162 pp.right = null; 2163 } 2164 } 2165 if (movable) 2166 moveRootToFront(tab, r); 2167 } 2168 2169 /** 2170 * Splits nodes in a tree bin into lower and upper tree bins, 2171 * or untreeifies if now too small. Called only from resize; 2172 * see above discussion about split bits and indices. 2173 * 2174 * @param map the map 2175 * @param tab the table for recording bin heads 2176 * @param index the index of the table being split 2177 * @param bit the bit of hash to split on 2178 */ 2179 final void split(HashMap<K,V> map, Node<K,V>[] tab, int index, int bit) { 2180 TreeNode<K,V> b = this; 2181 // Relink into lo and hi lists, preserving order 2182 TreeNode<K,V> loHead = null, loTail = null; 2183 TreeNode<K,V> hiHead = null, hiTail = null; 2184 int lc = 0, hc = 0; 2185 for (TreeNode<K,V> e = b, next; e != null; e = next) { 2186 next = (TreeNode<K,V>)e.next; 2187 e.next = null; 2188 if ((e.hash & bit) == 0) { 2189 if ((e.prev = loTail) == null) 2190 loHead = e; 2191 else 2192 loTail.next = e; 2193 loTail = e; 2194 ++lc; 2195 } 2196 else { 2197 if ((e.prev = hiTail) == null) 2198 hiHead = e; 2199 else 2200 hiTail.next = e; 2201 hiTail = e; 2202 ++hc; 2203 } 2204 } 2205 2206 if (loHead != null) { 2207 if (lc <= UNTREEIFY_THRESHOLD) 2208 tab[index] = loHead.untreeify(map); 2209 else { 2210 tab[index] = loHead; 2211 if (hiHead != null) // (else is already treeified) 2212 loHead.treeify(tab); 2213 } 2214 } 2215 if (hiHead != null) { 2216 if (hc <= UNTREEIFY_THRESHOLD) 2217 tab[index + bit] = hiHead.untreeify(map); 2218 else { 2219 tab[index + bit] = hiHead; 2220 if (loHead != null) 2221 hiHead.treeify(tab); 2222 } 2223 } 2224 } 2225 2226 /* ------------------------------------------------------------ */ 2227 // Red-black tree methods, all adapted from CLR 2228 2229 static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root, 2230 TreeNode<K,V> p) { 2231 TreeNode<K,V> r, pp, rl; 2232 if (p != null && (r = p.right) != null) { 2233 if ((rl = p.right = r.left) != null) 2234 rl.parent = p; 2235 if ((pp = r.parent = p.parent) == null) 2236 (root = r).red = false; 2237 else if (pp.left == p) 2238 pp.left = r; 2239 else 2240 pp.right = r; 2241 r.left = p; 2242 p.parent = r; 2243 } 2244 return root; 2245 } 2246 2247 static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root, 2248 TreeNode<K,V> p) { 2249 TreeNode<K,V> l, pp, lr; 2250 if (p != null && (l = p.left) != null) { 2251 if ((lr = p.left = l.right) != null) 2252 lr.parent = p; 2253 if ((pp = l.parent = p.parent) == null) 2254 (root = l).red = false; 2255 else if (pp.right == p) 2256 pp.right = l; 2257 else 2258 pp.left = l; 2259 l.right = p; 2260 p.parent = l; 2261 } 2262 return root; 2263 } 2264 2265 static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root, 2266 TreeNode<K,V> x) { 2267 x.red = true; 2268 for (TreeNode<K,V> xp, xpp, xppl, xppr;;) { 2269 if ((xp = x.parent) == null) { 2270 x.red = false; 2271 return x; 2272 } 2273 else if (!xp.red || (xpp = xp.parent) == null) 2274 return root; 2275 if (xp == (xppl = xpp.left)) { 2276 if ((xppr = xpp.right) != null && xppr.red) { 2277 xppr.red = false; 2278 xp.red = false; 2279 xpp.red = true; 2280 x = xpp; 2281 } 2282 else { 2283 if (x == xp.right) { 2284 root = rotateLeft(root, x = xp); 2285 xpp = (xp = x.parent) == null ? null : xp.parent; 2286 } 2287 if (xp != null) { 2288 xp.red = false; 2289 if (xpp != null) { 2290 xpp.red = true; 2291 root = rotateRight(root, xpp); 2292 } 2293 } 2294 } 2295 } 2296 else { 2297 if (xppl != null && xppl.red) { 2298 xppl.red = false; 2299 xp.red = false; 2300 xpp.red = true; 2301 x = xpp; 2302 } 2303 else { 2304 if (x == xp.left) { 2305 root = rotateRight(root, x = xp); 2306 xpp = (xp = x.parent) == null ? null : xp.parent; 2307 } 2308 if (xp != null) { 2309 xp.red = false; 2310 if (xpp != null) { 2311 xpp.red = true; 2312 root = rotateLeft(root, xpp); 2313 } 2314 } 2315 } 2316 } 2317 } 2318 } 2319 2320 static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root, 2321 TreeNode<K,V> x) { 2322 for (TreeNode<K,V> xp, xpl, xpr;;) { 2323 if (x == null || x == root) 2324 return root; 2325 else if ((xp = x.parent) == null) { 2326 x.red = false; 2327 return x; 2328 } 2329 else if (x.red) { 2330 x.red = false; 2331 return root; 2332 } 2333 else if ((xpl = xp.left) == x) { 2334 if ((xpr = xp.right) != null && xpr.red) { 2335 xpr.red = false; 2336 xp.red = true; 2337 root = rotateLeft(root, xp); 2338 xpr = (xp = x.parent) == null ? null : xp.right; 2339 } 2340 if (xpr == null) 2341 x = xp; 2342 else { 2343 TreeNode<K,V> sl = xpr.left, sr = xpr.right; 2344 if ((sr == null || !sr.red) && 2345 (sl == null || !sl.red)) { 2346 xpr.red = true; 2347 x = xp; 2348 } 2349 else { 2350 if (sr == null || !sr.red) { 2351 if (sl != null) 2352 sl.red = false; 2353 xpr.red = true; 2354 root = rotateRight(root, xpr); 2355 xpr = (xp = x.parent) == null ? 2356 null : xp.right; 2357 } 2358 if (xpr != null) { 2359 xpr.red = (xp == null) ? false : xp.red; 2360 if ((sr = xpr.right) != null) 2361 sr.red = false; 2362 } 2363 if (xp != null) { 2364 xp.red = false; 2365 root = rotateLeft(root, xp); 2366 } 2367 x = root; 2368 } 2369 } 2370 } 2371 else { // symmetric 2372 if (xpl != null && xpl.red) { 2373 xpl.red = false; 2374 xp.red = true; 2375 root = rotateRight(root, xp); 2376 xpl = (xp = x.parent) == null ? null : xp.left; 2377 } 2378 if (xpl == null) 2379 x = xp; 2380 else { 2381 TreeNode<K,V> sl = xpl.left, sr = xpl.right; 2382 if ((sl == null || !sl.red) && 2383 (sr == null || !sr.red)) { 2384 xpl.red = true; 2385 x = xp; 2386 } 2387 else { 2388 if (sl == null || !sl.red) { 2389 if (sr != null) 2390 sr.red = false; 2391 xpl.red = true; 2392 root = rotateLeft(root, xpl); 2393 xpl = (xp = x.parent) == null ? 2394 null : xp.left; 2395 } 2396 if (xpl != null) { 2397 xpl.red = (xp == null) ? false : xp.red; 2398 if ((sl = xpl.left) != null) 2399 sl.red = false; 2400 } 2401 if (xp != null) { 2402 xp.red = false; 2403 root = rotateRight(root, xp); 2404 } 2405 x = root; 2406 } 2407 } 2408 } 2409 } 2410 } 2411 2412 /** 2413 * Recursive invariant check 2414 */ 2415 static <K,V> boolean checkInvariants(TreeNode<K,V> t) { 2416 TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right, 2417 tb = t.prev, tn = (TreeNode<K,V>)t.next; 2418 if (tb != null && tb.next != t) 2419 return false; 2420 if (tn != null && tn.prev != t) 2421 return false; 2422 if (tp != null && t != tp.left && t != tp.right) 2423 return false; 2424 if (tl != null && (tl.parent != t || tl.hash > t.hash)) 2425 return false; 2426 if (tr != null && (tr.parent != t || tr.hash < t.hash)) 2427 return false; 2428 if (t.red && tl != null && tl.red && tr != null && tr.red) 2429 return false; 2430 if (tl != null && !checkInvariants(tl)) 2431 return false; 2432 if (tr != null && !checkInvariants(tr)) 2433 return false; 2434 return true; 2435 } 2436 } 2437 2438} 2439