· 8 years ago · Jul 08, 2018, 03:52 PM
1* Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
2 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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23 */
24
25package java.util;
26
27import java.io.IOException;
28import java.io.InvalidObjectException;
29import java.io.Serializable;
30import java.lang.reflect.ParameterizedType;
31import java.lang.reflect.Type;
32import java.util.function.BiConsumer;
33import java.util.function.BiFunction;
34import java.util.function.Consumer;
35import java.util.function.Function;
36import jdk.internal.misc.SharedSecrets;
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 * Saves this map to a stream (that is, serializes it).
1398 *
1399 * @param s the stream
1400 * @throws IOException if an I/O error occurs
1401 * @serialData The <i>capacity</i> of the HashMap (the length of the
1402 * bucket array) is emitted (int), followed by the
1403 * <i>size</i> (an int, the number of key-value
1404 * mappings), followed by the key (Object) and value (Object)
1405 * for each key-value mapping. The key-value mappings are
1406 * emitted in no particular order.
1407 */
1408 private void writeObject(java.io.ObjectOutputStream s)
1409 throws IOException {
1410 int buckets = capacity();
1411 // Write out the threshold, loadfactor, and any hidden stuff
1412 s.defaultWriteObject();
1413 s.writeInt(buckets);
1414 s.writeInt(size);
1415 internalWriteEntries(s);
1416 }
1417
1418 /**
1419 * Reconstitutes this map from a stream (that is, deserializes it).
1420 * @param s the stream
1421 * @throws ClassNotFoundException if the class of a serialized object
1422 * could not be found
1423 * @throws IOException if an I/O error occurs
1424 */
1425 private void readObject(java.io.ObjectInputStream s)
1426 throws IOException, ClassNotFoundException {
1427 // Read in the threshold (ignored), loadfactor, and any hidden stuff
1428 s.defaultReadObject();
1429 reinitialize();
1430 if (loadFactor <= 0 || Float.isNaN(loadFactor))
1431 throw new InvalidObjectException("Illegal load factor: " +
1432 loadFactor);
1433 s.readInt(); // Read and ignore number of buckets
1434 int mappings = s.readInt(); // Read number of mappings (size)
1435 if (mappings < 0)
1436 throw new InvalidObjectException("Illegal mappings count: " +
1437 mappings);
1438 else if (mappings > 0) { // (if zero, use defaults)
1439 // Size the table using given load factor only if within
1440 // range of 0.25...4.0
1441 float lf = Math.min(Math.max(0.25f, loadFactor), 4.0f);
1442 float fc = (float)mappings / lf + 1.0f;
1443 int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ?
1444 DEFAULT_INITIAL_CAPACITY :
1445 (fc >= MAXIMUM_CAPACITY) ?
1446 MAXIMUM_CAPACITY :
1447 tableSizeFor((int)fc));
1448 float ft = (float)cap * lf;
1449 threshold = ((cap < MAXIMUM_CAPACITY && ft < MAXIMUM_CAPACITY) ?
1450 (int)ft : Integer.MAX_VALUE);
1451
1452 // Check Map.Entry[].class since it's the nearest public type to
1453 // what we're actually creating.
1454 SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Map.Entry[].class, cap);
1455 @SuppressWarnings({"rawtypes","unchecked"})
1456 Node<K,V>[] tab = (Node<K,V>[])new Node[cap];
1457 table = tab;
1458
1459 // Read the keys and values, and put the mappings in the HashMap
1460 for (int i = 0; i < mappings; i++) {
1461 @SuppressWarnings("unchecked")
1462 K key = (K) s.readObject();
1463 @SuppressWarnings("unchecked")
1464 V value = (V) s.readObject();
1465 putVal(hash(key), key, value, false, false);
1466 }
1467 }
1468 }
1469
1470 /* ------------------------------------------------------------ */
1471 // iterators
1472
1473 abstract class HashIterator {
1474 Node<K,V> next; // next entry to return
1475 Node<K,V> current; // current entry
1476 int expectedModCount; // for fast-fail
1477 int index; // current slot
1478
1479 HashIterator() {
1480 expectedModCount = modCount;
1481 Node<K,V>[] t = table;
1482 current = next = null;
1483 index = 0;
1484 if (t != null && size > 0) { // advance to first entry
1485 do {} while (index < t.length && (next = t[index++]) == null);
1486 }
1487 }
1488
1489 public final boolean hasNext() {
1490 return next != null;
1491 }
1492
1493 final Node<K,V> nextNode() {
1494 Node<K,V>[] t;
1495 Node<K,V> e = next;
1496 if (modCount != expectedModCount)
1497 throw new ConcurrentModificationException();
1498 if (e == null)
1499 throw new NoSuchElementException();
1500 if ((next = (current = e).next) == null && (t = table) != null) {
1501 do {} while (index < t.length && (next = t[index++]) == null);
1502 }
1503 return e;
1504 }
1505
1506 public final void remove() {
1507 Node<K,V> p = current;
1508 if (p == null)
1509 throw new IllegalStateException();
1510 if (modCount != expectedModCount)
1511 throw new ConcurrentModificationException();
1512 current = null;
1513 removeNode(p.hash, p.key, null, false, false);
1514 expectedModCount = modCount;
1515 }
1516 }
1517
1518 final class KeyIterator extends HashIterator
1519 implements Iterator<K> {
1520 public final K next() { return nextNode().key; }
1521 }
1522
1523 final class ValueIterator extends HashIterator
1524 implements Iterator<V> {
1525 public final V next() { return nextNode().value; }
1526 }
1527
1528 final class EntryIterator extends HashIterator
1529 implements Iterator<Map.Entry<K,V>> {
1530 public final Map.Entry<K,V> next() { return nextNode(); }
1531 }
1532
1533 /* ------------------------------------------------------------ */
1534 // spliterators
1535
1536 static class HashMapSpliterator<K,V> {
1537 final HashMap<K,V> map;
1538 Node<K,V> current; // current node
1539 int index; // current index, modified on advance/split
1540 int fence; // one past last index
1541 int est; // size estimate
1542 int expectedModCount; // for comodification checks
1543
1544 HashMapSpliterator(HashMap<K,V> m, int origin,
1545 int fence, int est,
1546 int expectedModCount) {
1547 this.map = m;
1548 this.index = origin;
1549 this.fence = fence;
1550 this.est = est;
1551 this.expectedModCount = expectedModCount;
1552 }
1553
1554 final int getFence() { // initialize fence and size on first use
1555 int hi;
1556 if ((hi = fence) < 0) {
1557 HashMap<K,V> m = map;
1558 est = m.size;
1559 expectedModCount = m.modCount;
1560 Node<K,V>[] tab = m.table;
1561 hi = fence = (tab == null) ? 0 : tab.length;
1562 }
1563 return hi;
1564 }
1565
1566 public final long estimateSize() {
1567 getFence(); // force init
1568 return (long) est;
1569 }
1570 }
1571
1572 static final class KeySpliterator<K,V>
1573 extends HashMapSpliterator<K,V>
1574 implements Spliterator<K> {
1575 KeySpliterator(HashMap<K,V> m, int origin, int fence, int est,
1576 int expectedModCount) {
1577 super(m, origin, fence, est, expectedModCount);
1578 }
1579
1580 public KeySpliterator<K,V> trySplit() {
1581 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1582 return (lo >= mid || current != null) ? null :
1583 new KeySpliterator<>(map, lo, index = mid, est >>>= 1,
1584 expectedModCount);
1585 }
1586
1587 public void forEachRemaining(Consumer<? super K> action) {
1588 int i, hi, mc;
1589 if (action == null)
1590 throw new NullPointerException();
1591 HashMap<K,V> m = map;
1592 Node<K,V>[] tab = m.table;
1593 if ((hi = fence) < 0) {
1594 mc = expectedModCount = m.modCount;
1595 hi = fence = (tab == null) ? 0 : tab.length;
1596 }
1597 else
1598 mc = expectedModCount;
1599 if (tab != null && tab.length >= hi &&
1600 (i = index) >= 0 && (i < (index = hi) || current != null)) {
1601 Node<K,V> p = current;
1602 current = null;
1603 do {
1604 if (p == null)
1605 p = tab[i++];
1606 else {
1607 action.accept(p.key);
1608 p = p.next;
1609 }
1610 } while (p != null || i < hi);
1611 if (m.modCount != mc)
1612 throw new ConcurrentModificationException();
1613 }
1614 }
1615
1616 public boolean tryAdvance(Consumer<? super K> action) {
1617 int hi;
1618 if (action == null)
1619 throw new NullPointerException();
1620 Node<K,V>[] tab = map.table;
1621 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
1622 while (current != null || index < hi) {
1623 if (current == null)
1624 current = tab[index++];
1625 else {
1626 K k = current.key;
1627 current = current.next;
1628 action.accept(k);
1629 if (map.modCount != expectedModCount)
1630 throw new ConcurrentModificationException();
1631 return true;
1632 }
1633 }
1634 }
1635 return false;
1636 }
1637
1638 public int characteristics() {
1639 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
1640 Spliterator.DISTINCT;
1641 }
1642 }
1643
1644 static final class ValueSpliterator<K,V>
1645 extends HashMapSpliterator<K,V>
1646 implements Spliterator<V> {
1647 ValueSpliterator(HashMap<K,V> m, int origin, int fence, int est,
1648 int expectedModCount) {
1649 super(m, origin, fence, est, expectedModCount);
1650 }
1651
1652 public ValueSpliterator<K,V> trySplit() {
1653 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1654 return (lo >= mid || current != null) ? null :
1655 new ValueSpliterator<>(map, lo, index = mid, est >>>= 1,
1656 expectedModCount);
1657 }
1658
1659 public void forEachRemaining(Consumer<? super V> action) {
1660 int i, hi, mc;
1661 if (action == null)
1662 throw new NullPointerException();
1663 HashMap<K,V> m = map;
1664 Node<K,V>[] tab = m.table;
1665 if ((hi = fence) < 0) {
1666 mc = expectedModCount = m.modCount;
1667 hi = fence = (tab == null) ? 0 : tab.length;
1668 }
1669 else
1670 mc = expectedModCount;
1671 if (tab != null && tab.length >= hi &&
1672 (i = index) >= 0 && (i < (index = hi) || current != null)) {
1673 Node<K,V> p = current;
1674 current = null;
1675 do {
1676 if (p == null)
1677 p = tab[i++];
1678 else {
1679 action.accept(p.value);
1680 p = p.next;
1681 }
1682 } while (p != null || i < hi);
1683 if (m.modCount != mc)
1684 throw new ConcurrentModificationException();
1685 }
1686 }
1687
1688 public boolean tryAdvance(Consumer<? super V> action) {
1689 int hi;
1690 if (action == null)
1691 throw new NullPointerException();
1692 Node<K,V>[] tab = map.table;
1693 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
1694 while (current != null || index < hi) {
1695 if (current == null)
1696 current = tab[index++];
1697 else {
1698 V v = current.value;
1699 current = current.next;
1700 action.accept(v);
1701 if (map.modCount != expectedModCount)
1702 throw new ConcurrentModificationException();
1703 return true;
1704 }
1705 }
1706 }
1707 return false;
1708 }
1709
1710 public int characteristics() {
1711 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0);
1712 }
1713 }
1714
1715 static final class EntrySpliterator<K,V>
1716 extends HashMapSpliterator<K,V>
1717 implements Spliterator<Map.Entry<K,V>> {
1718 EntrySpliterator(HashMap<K,V> m, int origin, int fence, int est,
1719 int expectedModCount) {
1720 super(m, origin, fence, est, expectedModCount);
1721 }
1722
1723 public EntrySpliterator<K,V> trySplit() {
1724 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1725 return (lo >= mid || current != null) ? null :
1726 new EntrySpliterator<>(map, lo, index = mid, est >>>= 1,
1727 expectedModCount);
1728 }
1729
1730 public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
1731 int i, hi, mc;
1732 if (action == null)
1733 throw new NullPointerException();
1734 HashMap<K,V> m = map;
1735 Node<K,V>[] tab = m.table;
1736 if ((hi = fence) < 0) {
1737 mc = expectedModCount = m.modCount;
1738 hi = fence = (tab == null) ? 0 : tab.length;
1739 }
1740 else
1741 mc = expectedModCount;
1742 if (tab != null && tab.length >= hi &&
1743 (i = index) >= 0 && (i < (index = hi) || current != null)) {
1744 Node<K,V> p = current;
1745 current = null;
1746 do {
1747 if (p == null)
1748 p = tab[i++];
1749 else {
1750 action.accept(p);
1751 p = p.next;
1752 }
1753 } while (p != null || i < hi);
1754 if (m.modCount != mc)
1755 throw new ConcurrentModificationException();
1756 }
1757 }
1758
1759 public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
1760 int hi;
1761 if (action == null)
1762 throw new NullPointerException();
1763 Node<K,V>[] tab = map.table;
1764 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
1765 while (current != null || index < hi) {
1766 if (current == null)
1767 current = tab[index++];
1768 else {
1769 Node<K,V> e = current;
1770 current = current.next;
1771 action.accept(e);
1772 if (map.modCount != expectedModCount)
1773 throw new ConcurrentModificationException();
1774 return true;
1775 }
1776 }
1777 }
1778 return false;
1779 }
1780
1781 public int characteristics() {
1782 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
1783 Spliterator.DISTINCT;
1784 }
1785 }
1786
1787 /* ------------------------------------------------------------ */
1788 // LinkedHashMap support
1789
1790
1791 /*
1792 * The following package-protected methods are designed to be
1793 * overridden by LinkedHashMap, but not by any other subclass.
1794 * Nearly all other internal methods are also package-protected
1795 * but are declared final, so can be used by LinkedHashMap, view
1796 * classes, and HashSet.
1797 */
1798
1799 // Create a regular (non-tree) node
1800 Node<K,V> newNode(int hash, K key, V value, Node<K,V> next) {
1801 return new Node<>(hash, key, value, next);
1802 }
1803
1804 // For conversion from TreeNodes to plain nodes
1805 Node<K,V> replacementNode(Node<K,V> p, Node<K,V> next) {
1806 return new Node<>(p.hash, p.key, p.value, next);
1807 }
1808
1809 // Create a tree bin node
1810 TreeNode<K,V> newTreeNode(int hash, K key, V value, Node<K,V> next) {
1811 return new TreeNode<>(hash, key, value, next);
1812 }
1813
1814 // For treeifyBin
1815 TreeNode<K,V> replacementTreeNode(Node<K,V> p, Node<K,V> next) {
1816 return new TreeNode<>(p.hash, p.key, p.value, next);
1817 }
1818
1819 /**
1820 * Reset to initial default state. Called by clone and readObject.
1821 */
1822 void reinitialize() {
1823 table = null;
1824 entrySet = null;
1825 keySet = null;
1826 values = null;
1827 modCount = 0;
1828 threshold = 0;
1829 size = 0;
1830 }
1831
1832 // Callbacks to allow LinkedHashMap post-actions
1833 void afterNodeAccess(Node<K,V> p) { }
1834 void afterNodeInsertion(boolean evict) { }
1835 void afterNodeRemoval(Node<K,V> p) { }
1836
1837 // Called only from writeObject, to ensure compatible ordering.
1838 void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException {
1839 Node<K,V>[] tab;
1840 if (size > 0 && (tab = table) != null) {
1841 for (Node<K,V> e : tab) {
1842 for (; e != null; e = e.next) {
1843 s.writeObject(e.key);
1844 s.writeObject(e.value);
1845 }
1846 }
1847 }
1848 }
1849
1850 /* ------------------------------------------------------------ */
1851 // Tree bins
1852
1853 /**
1854 * Entry for Tree bins. Extends LinkedHashMap.Entry (which in turn
1855 * extends Node) so can be used as extension of either regular or
1856 * linked node.
1857 */
1858 static final class TreeNode<K,V> extends LinkedHashMap.Entry<K,V> {
1859 TreeNode<K,V> parent; // red-black tree links
1860 TreeNode<K,V> left;
1861 TreeNode<K,V> right;
1862 TreeNode<K,V> prev; // needed to unlink next upon deletion
1863 boolean red;
1864 TreeNode(int hash, K key, V val, Node<K,V> next) {
1865 super(hash, key, val, next);
1866 }
1867
1868 /**
1869 * Returns root of tree containing this node.
1870 */
1871 final TreeNode<K,V> root() {
1872 for (TreeNode<K,V> r = this, p;;) {
1873 if ((p = r.parent) == null)
1874 return r;
1875 r = p;
1876 }
1877 }
1878
1879 /**
1880 * Ensures that the given root is the first node of its bin.
1881 */
1882 static <K,V> void moveRootToFront(Node<K,V>[] tab, TreeNode<K,V> root) {
1883 int n;
1884 if (root != null && tab != null && (n = tab.length) > 0) {
1885 int index = (n - 1) & root.hash;
1886 TreeNode<K,V> first = (TreeNode<K,V>)tab[index];
1887 if (root != first) {
1888 Node<K,V> rn;
1889 tab[index] = root;
1890 TreeNode<K,V> rp = root.prev;
1891 if ((rn = root.next) != null)
1892 ((TreeNode<K,V>)rn).prev = rp;
1893 if (rp != null)
1894 rp.next = rn;
1895 if (first != null)
1896 first.prev = root;
1897 root.next = first;
1898 root.prev = null;
1899 }
1900 assert checkInvariants(root);
1901 }
1902 }
1903
1904 /**
1905 * Finds the node starting at root p with the given hash and key.
1906 * The kc argument caches comparableClassFor(key) upon first use
1907 * comparing keys.
1908 */
1909 final TreeNode<K,V> find(int h, Object k, Class<?> kc) {
1910 TreeNode<K,V> p = this;
1911 do {
1912 int ph, dir; K pk;
1913 TreeNode<K,V> pl = p.left, pr = p.right, q;
1914 if ((ph = p.hash) > h)
1915 p = pl;
1916 else if (ph < h)
1917 p = pr;
1918 else if ((pk = p.key) == k || (k != null && k.equals(pk)))
1919 return p;
1920 else if (pl == null)
1921 p = pr;
1922 else if (pr == null)
1923 p = pl;
1924 else if ((kc != null ||
1925 (kc = comparableClassFor(k)) != null) &&
1926 (dir = compareComparables(kc, k, pk)) != 0)
1927 p = (dir < 0) ? pl : pr;
1928 else if ((q = pr.find(h, k, kc)) != null)
1929 return q;
1930 else
1931 p = pl;
1932 } while (p != null);
1933 return null;
1934 }
1935
1936 /**
1937 * Calls find for root node.
1938 */
1939 final TreeNode<K,V> getTreeNode(int h, Object k) {
1940 return ((parent != null) ? root() : this).find(h, k, null);
1941 }
1942
1943 /**
1944 * Tie-breaking utility for ordering insertions when equal
1945 * hashCodes and non-comparable. We don't require a total
1946 * order, just a consistent insertion rule to maintain
1947 * equivalence across rebalancings. Tie-breaking further than
1948 * necessary simplifies testing a bit.
1949 */
1950 static int tieBreakOrder(Object a, Object b) {
1951 int d;
1952 if (a == null || b == null ||
1953 (d = a.getClass().getName().
1954 compareTo(b.getClass().getName())) == 0)
1955 d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
1956 -1 : 1);
1957 return d;
1958 }
1959
1960 /**
1961 * Forms tree of the nodes linked from this node.
1962 */
1963 final void treeify(Node<K,V>[] tab) {
1964 TreeNode<K,V> root = null;
1965 for (TreeNode<K,V> x = this, next; x != null; x = next) {
1966 next = (TreeNode<K,V>)x.next;
1967 x.left = x.right = null;
1968 if (root == null) {
1969 x.parent = null;
1970 x.red = false;
1971 root = x;
1972 }
1973 else {
1974 K k = x.key;
1975 int h = x.hash;
1976 Class<?> kc = null;
1977 for (TreeNode<K,V> p = root;;) {
1978 int dir, ph;
1979 K pk = p.key;
1980 if ((ph = p.hash) > h)
1981 dir = -1;
1982 else if (ph < h)
1983 dir = 1;
1984 else if ((kc == null &&
1985 (kc = comparableClassFor(k)) == null) ||
1986 (dir = compareComparables(kc, k, pk)) == 0)
1987 dir = tieBreakOrder(k, pk);
1988
1989 TreeNode<K,V> xp = p;
1990 if ((p = (dir <= 0) ? p.left : p.right) == null) {
1991 x.parent = xp;
1992 if (dir <= 0)
1993 xp.left = x;
1994 else
1995 xp.right = x;
1996 root = balanceInsertion(root, x);
1997 break;
1998 }
1999 }
2000 }
2001 }
2002 moveRootToFront(tab, root);
2003 }
2004
2005 /**
2006 * Returns a list of non-TreeNodes replacing those linked from
2007 * this node.
2008 */
2009 final Node<K,V> untreeify(HashMap<K,V> map) {
2010 Node<K,V> hd = null, tl = null;
2011 for (Node<K,V> q = this; q != null; q = q.next) {
2012 Node<K,V> p = map.replacementNode(q, null);
2013 if (tl == null)
2014 hd = p;
2015 else
2016 tl.next = p;
2017 tl = p;
2018 }
2019 return hd;
2020 }
2021
2022 /**
2023 * Tree version of putVal.
2024 */
2025 final TreeNode<K,V> putTreeVal(HashMap<K,V> map, Node<K,V>[] tab,
2026 int h, K k, V v) {
2027 Class<?> kc = null;
2028 boolean searched = false;
2029 TreeNode<K,V> root = (parent != null) ? root() : this;
2030 for (TreeNode<K,V> p = root;;) {
2031 int dir, ph; K pk;
2032 if ((ph = p.hash) > h)
2033 dir = -1;
2034 else if (ph < h)
2035 dir = 1;
2036 else if ((pk = p.key) == k || (k != null && k.equals(pk)))
2037 return p;
2038 else if ((kc == null &&
2039 (kc = comparableClassFor(k)) == null) ||
2040 (dir = compareComparables(kc, k, pk)) == 0) {
2041 if (!searched) {
2042 TreeNode<K,V> q, ch;
2043 searched = true;
2044 if (((ch = p.left) != null &&
2045 (q = ch.find(h, k, kc)) != null) ||
2046 ((ch = p.right) != null &&
2047 (q = ch.find(h, k, kc)) != null))
2048 return q;
2049 }
2050 dir = tieBreakOrder(k, pk);
2051 }
2052
2053 TreeNode<K,V> xp = p;
2054 if ((p = (dir <= 0) ? p.left : p.right) == null) {
2055 Node<K,V> xpn = xp.next;
2056 TreeNode<K,V> x = map.newTreeNode(h, k, v, xpn);
2057 if (dir <= 0)
2058 xp.left = x;
2059 else
2060 xp.right = x;
2061 xp.next = x;
2062 x.parent = x.prev = xp;
2063 if (xpn != null)
2064 ((TreeNode<K,V>)xpn).prev = x;
2065 moveRootToFront(tab, balanceInsertion(root, x));
2066 return null;
2067 }
2068 }
2069 }
2070
2071 /**
2072 * Removes the given node, that must be present before this call.
2073 * This is messier than typical red-black deletion code because we
2074 * cannot swap the contents of an interior node with a leaf
2075 * successor that is pinned by "next" pointers that are accessible
2076 * independently during traversal. So instead we swap the tree
2077 * linkages. If the current tree appears to have too few nodes,
2078 * the bin is converted back to a plain bin. (The test triggers
2079 * somewhere between 2 and 6 nodes, depending on tree structure).
2080 */
2081 final void removeTreeNode(HashMap<K,V> map, Node<K,V>[] tab,
2082 boolean movable) {
2083 int n;
2084 if (tab == null || (n = tab.length) == 0)
2085 return;
2086 int index = (n - 1) & hash;
2087 TreeNode<K,V> first = (TreeNode<K,V>)tab[index], root = first, rl;
2088 TreeNode<K,V> succ = (TreeNode<K,V>)next, pred = prev;
2089 if (pred == null)
2090 tab[index] = first = succ;
2091 else
2092 pred.next = succ;
2093 if (succ != null)
2094 succ.prev = pred;
2095 if (first == null)
2096 return;
2097 if (root.parent != null)
2098 root = root.root();
2099 if (root == null
2100 || (movable
2101 && (root.right == null
2102 || (rl = root.left) == null
2103 || rl.left == null))) {
2104 tab[index] = first.untreeify(map); // too small
2105 return;
2106 }
2107 TreeNode<K,V> p = this, pl = left, pr = right, replacement;
2108 if (pl != null && pr != null) {
2109 TreeNode<K,V> s = pr, sl;
2110 while ((sl = s.left) != null) // find successor
2111 s = sl;
2112 boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2113 TreeNode<K,V> sr = s.right;
2114 TreeNode<K,V> pp = p.parent;
2115 if (s == pr) { // p was s's direct parent
2116 p.parent = s;
2117 s.right = p;
2118 }
2119 else {
2120 TreeNode<K,V> sp = s.parent;
2121 if ((p.parent = sp) != null) {
2122 if (s == sp.left)
2123 sp.left = p;
2124 else
2125 sp.right = p;
2126 }
2127 if ((s.right = pr) != null)
2128 pr.parent = s;
2129 }
2130 p.left = null;
2131 if ((p.right = sr) != null)
2132 sr.parent = p;
2133 if ((s.left = pl) != null)
2134 pl.parent = s;
2135 if ((s.parent = pp) == null)
2136 root = s;
2137 else if (p == pp.left)
2138 pp.left = s;
2139 else
2140 pp.right = s;
2141 if (sr != null)
2142 replacement = sr;
2143 else
2144 replacement = p;
2145 }
2146 else if (pl != null)
2147 replacement = pl;
2148 else if (pr != null)
2149 replacement = pr;
2150 else
2151 replacement = p;
2152 if (replacement != p) {
2153 TreeNode<K,V> pp = replacement.parent = p.parent;
2154 if (pp == null)
2155 root = replacement;
2156 else if (p == pp.left)
2157 pp.left = replacement;
2158 else
2159 pp.right = replacement;
2160 p.left = p.right = p.parent = null;
2161 }
2162
2163 TreeNode<K,V> r = p.red ? root : balanceDeletion(root, replacement);
2164
2165 if (replacement == p) { // detach
2166 TreeNode<K,V> pp = p.parent;
2167 p.parent = null;
2168 if (pp != null) {
2169 if (p == pp.left)
2170 pp.left = null;
2171 else if (p == pp.right)
2172 pp.right = null;
2173 }
2174 }
2175 if (movable)
2176 moveRootToFront(tab, r);
2177 }
2178
2179 /**
2180 * Splits nodes in a tree bin into lower and upper tree bins,
2181 * or untreeifies if now too small. Called only from resize;
2182 * see above discussion about split bits and indices.
2183 *
2184 * @param map the map
2185 * @param tab the table for recording bin heads
2186 * @param index the index of the table being split
2187 * @param bit the bit of hash to split on
2188 */
2189 final void split(HashMap<K,V> map, Node<K,V>[] tab, int index, int bit) {
2190 TreeNode<K,V> b = this;
2191 // Relink into lo and hi lists, preserving order
2192 TreeNode<K,V> loHead = null, loTail = null;
2193 TreeNode<K,V> hiHead = null, hiTail = null;
2194 int lc = 0, hc = 0;
2195 for (TreeNode<K,V> e = b, next; e != null; e = next) {
2196 next = (TreeNode<K,V>)e.next;
2197 e.next = null;
2198 if ((e.hash & bit) == 0) {
2199 if ((e.prev = loTail) == null)
2200 loHead = e;
2201 else
2202 loTail.next = e;
2203 loTail = e;
2204 ++lc;
2205 }
2206 else {
2207 if ((e.prev = hiTail) == null)
2208 hiHead = e;
2209 else
2210 hiTail.next = e;
2211 hiTail = e;
2212 ++hc;
2213 }
2214 }
2215
2216 if (loHead != null) {
2217 if (lc <= UNTREEIFY_THRESHOLD)
2218 tab[index] = loHead.untreeify(map);
2219 else {
2220 tab[index] = loHead;
2221 if (hiHead != null) // (else is already treeified)
2222 loHead.treeify(tab);
2223 }
2224 }
2225 if (hiHead != null) {
2226 if (hc <= UNTREEIFY_THRESHOLD)
2227 tab[index + bit] = hiHead.untreeify(map);
2228 else {
2229 tab[index + bit] = hiHead;
2230 if (loHead != null)
2231 hiHead.treeify(tab);
2232 }
2233 }
2234 }
2235
2236 /* ------------------------------------------------------------ */
2237 // Red-black tree methods, all adapted from CLR
2238
2239 static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
2240 TreeNode<K,V> p) {
2241 TreeNode<K,V> r, pp, rl;
2242 if (p != null && (r = p.right) != null) {
2243 if ((rl = p.right = r.left) != null)
2244 rl.parent = p;
2245 if ((pp = r.parent = p.parent) == null)
2246 (root = r).red = false;
2247 else if (pp.left == p)
2248 pp.left = r;
2249 else
2250 pp.right = r;
2251 r.left = p;
2252 p.parent = r;
2253 }
2254 return root;
2255 }
2256
2257 static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
2258 TreeNode<K,V> p) {
2259 TreeNode<K,V> l, pp, lr;
2260 if (p != null && (l = p.left) != null) {
2261 if ((lr = p.left = l.right) != null)
2262 lr.parent = p;
2263 if ((pp = l.parent = p.parent) == null)
2264 (root = l).red = false;
2265 else if (pp.right == p)
2266 pp.right = l;
2267 else
2268 pp.left = l;
2269 l.right = p;
2270 p.parent = l;
2271 }
2272 return root;
2273 }
2274
2275 static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
2276 TreeNode<K,V> x) {
2277 x.red = true;
2278 for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
2279 if ((xp = x.parent) == null) {
2280 x.red = false;
2281 return x;
2282 }
2283 else if (!xp.red || (xpp = xp.parent) == null)
2284 return root;
2285 if (xp == (xppl = xpp.left)) {
2286 if ((xppr = xpp.right) != null && xppr.red) {
2287 xppr.red = false;
2288 xp.red = false;
2289 xpp.red = true;
2290 x = xpp;
2291 }
2292 else {
2293 if (x == xp.right) {
2294 root = rotateLeft(root, x = xp);
2295 xpp = (xp = x.parent) == null ? null : xp.parent;
2296 }
2297 if (xp != null) {
2298 xp.red = false;
2299 if (xpp != null) {
2300 xpp.red = true;
2301 root = rotateRight(root, xpp);
2302 }
2303 }
2304 }
2305 }
2306 else {
2307 if (xppl != null && xppl.red) {
2308 xppl.red = false;
2309 xp.red = false;
2310 xpp.red = true;
2311 x = xpp;
2312 }
2313 else {
2314 if (x == xp.left) {
2315 root = rotateRight(root, x = xp);
2316 xpp = (xp = x.parent) == null ? null : xp.parent;
2317 }
2318 if (xp != null) {
2319 xp.red = false;
2320 if (xpp != null) {
2321 xpp.red = true;
2322 root = rotateLeft(root, xpp);
2323 }
2324 }
2325 }
2326 }
2327 }
2328 }
2329
2330 static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
2331 TreeNode<K,V> x) {
2332 for (TreeNode<K,V> xp, xpl, xpr;;) {
2333 if (x == null || x == root)
2334 return root;
2335 else if ((xp = x.parent) == null) {
2336 x.red = false;
2337 return x;
2338 }
2339 else if (x.red) {
2340 x.red = false;
2341 return root;
2342 }
2343 else if ((xpl = xp.left) == x) {
2344 if ((xpr = xp.right) != null && xpr.red) {
2345 xpr.red = false;
2346 xp.red = true;
2347 root = rotateLeft(root, xp);
2348 xpr = (xp = x.parent) == null ? null : xp.right;
2349 }
2350 if (xpr == null)
2351 x = xp;
2352 else {
2353 TreeNode<K,V> sl = xpr.left, sr = xpr.right;
2354 if ((sr == null || !sr.red) &&
2355 (sl == null || !sl.red)) {
2356 xpr.red = true;
2357 x = xp;
2358 }
2359 else {
2360 if (sr == null || !sr.red) {
2361 if (sl != null)
2362 sl.red = false;
2363 xpr.red = true;
2364 root = rotateRight(root, xpr);
2365 xpr = (xp = x.parent) == null ?
2366 null : xp.right;
2367 }
2368 if (xpr != null) {
2369 xpr.red = (xp == null) ? false : xp.red;
2370 if ((sr = xpr.right) != null)
2371 sr.red = false;
2372 }
2373 if (xp != null) {
2374 xp.red = false;
2375 root = rotateLeft(root, xp);
2376 }
2377 x = root;
2378 }
2379 }
2380 }
2381 else { // symmetric
2382 if (xpl != null && xpl.red) {
2383 xpl.red = false;
2384 xp.red = true;
2385 root = rotateRight(root, xp);
2386 xpl = (xp = x.parent) == null ? null : xp.left;
2387 }
2388 if (xpl == null)
2389 x = xp;
2390 else {
2391 TreeNode<K,V> sl = xpl.left, sr = xpl.right;
2392 if ((sl == null || !sl.red) &&
2393 (sr == null || !sr.red)) {
2394 xpl.red = true;
2395 x = xp;
2396 }
2397 else {
2398 if (sl == null || !sl.red) {
2399 if (sr != null)
2400 sr.red = false;
2401 xpl.red = true;
2402 root = rotateLeft(root, xpl);
2403 xpl = (xp = x.parent) == null ?
2404 null : xp.left;
2405 }
2406 if (xpl != null) {
2407 xpl.red = (xp == null) ? false : xp.red;
2408 if ((sl = xpl.left) != null)
2409 sl.red = false;
2410 }
2411 if (xp != null) {
2412 xp.red = false;
2413 root = rotateRight(root, xp);
2414 }
2415 x = root;
2416 }
2417 }
2418 }
2419 }
2420 }
2421
2422 /**
2423 * Recursive invariant check
2424 */
2425 static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
2426 TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
2427 tb = t.prev, tn = (TreeNode<K,V>)t.next;
2428 if (tb != null && tb.next != t)
2429 return false;
2430 if (tn != null && tn.prev != t)
2431 return false;
2432 if (tp != null && t != tp.left && t != tp.right)
2433 return false;
2434 if (tl != null && (tl.parent != t || tl.hash > t.hash))
2435 return false;
2436 if (tr != null && (tr.parent != t || tr.hash < t.hash))
2437 return false;
2438 if (t.red && tl != null && tl.red && tr != null && tr.red)
2439 return false;
2440 if (tl != null && !checkInvariants(tl))
2441 return false;
2442 if (tr != null && !checkInvariants(tr))
2443 return false;
2444 return true;
2445 }
2446 }
2447
2448}