1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util;
27
28 import java.io.IOException;
29 import java.io.InvalidObjectException;
30 import java.io.Serializable;
31 import java.lang.reflect.ParameterizedType;
32 import java.lang.reflect.Type;
33 import java.util.function.BiConsumer;
34 import java.util.function.BiFunction;
35 import java.util.function.Consumer;
36 import java.util.function.Function;
37 import jdk.internal.access.SharedSecrets;
38
39 /**
40 * Hash table based implementation of the {@code Map} interface. This
41 * implementation provides all of the optional map operations, and permits
42 * {@code null} values and the {@code null} key. (The {@code HashMap}
43 * class is roughly equivalent to {@code Hashtable}, except that it is
44 * unsynchronized and permits nulls.) This class makes no guarantees as to
45 * the order of the map; in particular, it does not guarantee that the order
46 * will remain constant over time.
47 *
48 * <p>This implementation provides constant-time performance for the basic
49 * operations ({@code get} and {@code put}), assuming the hash function
50 * disperses the elements properly among the buckets. Iteration over
51 * collection views requires time proportional to the "capacity" of the
52 * {@code HashMap} instance (the number of buckets) plus its size (the number
53 * of key-value mappings). Thus, it's very important not to set the initial
54 * capacity too high (or the load factor too low) if iteration performance is
55 * important.
56 *
57 * <p>An instance of {@code HashMap} has two parameters that affect its
58 * performance: <i>initial capacity</i> and <i>load factor</i>. The
59 * <i>capacity</i> is the number of buckets in the hash table, and the initial
60 * capacity is simply the capacity at the time the hash table is created. The
61 * <i>load factor</i> is a measure of how full the hash table is allowed to
62 * get before its capacity is automatically increased. When the number of
63 * entries in the hash table exceeds the product of the load factor and the
64 * current capacity, the hash table is <i>rehashed</i> (that is, internal data
65 * structures are rebuilt) so that the hash table has approximately twice the
66 * number of buckets.
67 *
68 * <p>As a general rule, the default load factor (.75) offers a good
69 * tradeoff between time and space costs. Higher values decrease the
70 * space overhead but increase the lookup cost (reflected in most of
71 * the operations of the {@code HashMap} class, including
72 * {@code get} and {@code put}). The expected number of entries in
73 * the map and its load factor should be taken into account when
74 * setting its initial capacity, so as to minimize the number of
75 * rehash operations. If the initial capacity is greater than the
76 * maximum number of entries divided by the load factor, no rehash
77 * operations will ever occur.
78 *
79 * <p>If many mappings are to be stored in a {@code HashMap}
80 * instance, creating it with a sufficiently large capacity will allow
81 * the mappings to be stored more efficiently than letting it perform
82 * automatic rehashing as needed to grow the table. Note that using
83 * many keys with the same {@code hashCode()} is a sure way to slow
84 * down performance of any hash table. To ameliorate impact, when keys
85 * are {@link Comparable}, this class may use comparison order among
86 * keys to help break ties.
87 *
88 * <p><strong>Note that this implementation is not synchronized.</strong>
89 * If multiple threads access a hash map concurrently, and at least one of
90 * the threads modifies the map structurally, it <i>must</i> be
91 * synchronized externally. (A structural modification is any operation
92 * that adds or deletes one or more mappings; merely changing the value
93 * associated with a key that an instance already contains is not a
94 * structural modification.) This is typically accomplished by
95 * synchronizing on some object that naturally encapsulates the map.
96 *
97 * If no such object exists, the map should be "wrapped" using the
98 * {@link Collections#synchronizedMap Collections.synchronizedMap}
99 * method. This is best done at creation time, to prevent accidental
100 * unsynchronized access to the map:<pre>
101 * Map m = Collections.synchronizedMap(new HashMap(...));</pre>
102 *
103 * <p>The iterators returned by all of this class's "collection view methods"
104 * are <i>fail-fast</i>: if the map is structurally modified at any time after
105 * the iterator is created, in any way except through the iterator's own
106 * {@code remove} method, the iterator will throw a
107 * {@link ConcurrentModificationException}. Thus, in the face of concurrent
108 * modification, the iterator fails quickly and cleanly, rather than risking
109 * arbitrary, non-deterministic behavior at an undetermined time in the
110 * future.
111 *
112 * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
113 * as it is, generally speaking, impossible to make any hard guarantees in the
114 * presence of unsynchronized concurrent modification. Fail-fast iterators
115 * throw {@code ConcurrentModificationException} on a best-effort basis.
116 * Therefore, it would be wrong to write a program that depended on this
117 * exception for its correctness: <i>the fail-fast behavior of iterators
118 * should be used only to detect bugs.</i>
119 *
120 * <p>This class is a member of the
121 * <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework">
122 * Java Collections Framework</a>.
123 *
124 * @param <K> the type of keys maintained by this map
125 * @param <V> the type of mapped values
126 *
127 * @author Doug Lea
128 * @author Josh Bloch
129 * @author Arthur van Hoff
130 * @author Neal Gafter
131 * @see Object#hashCode()
132 * @see Collection
133 * @see Map
134 * @see TreeMap
135 * @see Hashtable
136 * @since 1.2
137 */
138 public class HashMap<K,V> extends AbstractMap<K,V>
139 implements Map<K,V>, Cloneable, Serializable {
140
141 private static final long serialVersionUID = 362498820763181265L;
142
143 /*
144 * Implementation notes.
145 *
146 * This map usually acts as a binned (bucketed) hash table, but
147 * when bins get too large, they are transformed into bins of
148 * TreeNodes, each structured similarly to those in
149 * java.util.TreeMap. Most methods try to use normal bins, but
150 * relay to TreeNode methods when applicable (simply by checking
151 * instanceof a node). Bins of TreeNodes may be traversed and
152 * used like any others, but additionally support faster lookup
153 * when overpopulated. However, since the vast majority of bins in
154 * normal use are not overpopulated, checking for existence of
155 * tree bins may be delayed in the course of table methods.
156 *
157 * Tree bins (i.e., bins whose elements are all TreeNodes) are
158 * ordered primarily by hashCode, but in the case of ties, if two
159 * elements are of the same "class C implements Comparable<C>",
160 * type then their compareTo method is used for ordering. (We
161 * conservatively check generic types via reflection to validate
162 * this -- see method comparableClassFor). The added complexity
163 * of tree bins is worthwhile in providing worst-case O(log n)
164 * operations when keys either have distinct hashes or are
165 * orderable, Thus, performance degrades gracefully under
166 * accidental or malicious usages in which hashCode() methods
167 * return values that are poorly distributed, as well as those in
168 * which many keys share a hashCode, so long as they are also
169 * Comparable. (If neither of these apply, we may waste about a
170 * factor of two in time and space compared to taking no
171 * precautions. But the only known cases stem from poor user
172 * programming practices that are already so slow that this makes
173 * little difference.)
174 *
175 * Because TreeNodes are about twice the size of regular nodes, we
176 * use them only when bins contain enough nodes to warrant use
177 * (see TREEIFY_THRESHOLD). And when they become too small (due to
178 * removal or resizing) they are converted back to plain bins. In
179 * usages with well-distributed user hashCodes, tree bins are
180 * rarely used. Ideally, under random hashCodes, the frequency of
181 * nodes in bins follows a Poisson distribution
182 * (http://en.wikipedia.org/wiki/Poisson_distribution) with a
183 * parameter of about 0.5 on average for the default resizing
184 * threshold of 0.75, although with a large variance because of
185 * resizing granularity. Ignoring variance, the expected
186 * occurrences of list size k are (exp(-0.5) * pow(0.5, k) /
187 * factorial(k)). The first values are:
188 *
189 * 0: 0.60653066
190 * 1: 0.30326533
191 * 2: 0.07581633
192 * 3: 0.01263606
193 * 4: 0.00157952
194 * 5: 0.00015795
195 * 6: 0.00001316
196 * 7: 0.00000094
197 * 8: 0.00000006
198 * more: less than 1 in ten million
199 *
200 * The root of a tree bin is normally its first node. However,
201 * sometimes (currently only upon Iterator.remove), the root might
202 * be elsewhere, but can be recovered following parent links
203 * (method TreeNode.root()).
204 *
205 * All applicable internal methods accept a hash code as an
206 * argument (as normally supplied from a public method), allowing
207 * them to call each other without recomputing user hashCodes.
208 * Most internal methods also accept a "tab" argument, that is
209 * normally the current table, but may be a new or old one when
210 * resizing or converting.
211 *
212 * When bin lists are treeified, split, or untreeified, we keep
213 * them in the same relative access/traversal order (i.e., field
214 * Node.next) to better preserve locality, and to slightly
215 * simplify handling of splits and traversals that invoke
216 * iterator.remove. When using comparators on insertion, to keep a
217 * total ordering (or as close as is required here) across
218 * rebalancings, we compare classes and identityHashCodes as
219 * tie-breakers.
220 *
221 * The use and transitions among plain vs tree modes is
222 * complicated by the existence of subclass LinkedHashMap. See
223 * below for hook methods defined to be invoked upon insertion,
224 * removal and access that allow LinkedHashMap internals to
225 * otherwise remain independent of these mechanics. (This also
226 * requires that a map instance be passed to some utility methods
227 * that may create new nodes.)
228 *
229 * The concurrent-programming-like SSA-based coding style helps
230 * avoid aliasing errors amid all of the twisty pointer operations.
231 */
232
233 /**
234 * The default initial capacity - MUST be a power of two.
235 */
236 static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // aka 16
237
238 /**
239 * The maximum capacity, used if a higher value is implicitly specified
240 * by either of the constructors with arguments.
241 * MUST be a power of two <= 1<<30.
242 */
243 static final int MAXIMUM_CAPACITY = 1 << 30;
244
245 /**
246 * The load factor used when none specified in constructor.
247 */
248 static final float DEFAULT_LOAD_FACTOR = 0.75f;
249
250 /**
251 * The bin count threshold for using a tree rather than list for a
252 * bin. Bins are converted to trees when adding an element to a
253 * bin with at least this many nodes. The value must be greater
254 * than 2 and should be at least 8 to mesh with assumptions in
255 * tree removal about conversion back to plain bins upon
256 * shrinkage.
257 */
258 static final int TREEIFY_THRESHOLD = 8;
259
260 /**
261 * The bin count threshold for untreeifying a (split) bin during a
262 * resize operation. Should be less than TREEIFY_THRESHOLD, and at
263 * most 6 to mesh with shrinkage detection under removal.
264 */
265 static final int UNTREEIFY_THRESHOLD = 6;
266
267 /**
268 * The smallest table capacity for which bins may be treeified.
269 * (Otherwise the table is resized if too many nodes in a bin.)
270 * Should be at least 4 * TREEIFY_THRESHOLD to avoid conflicts
271 * between resizing and treeification thresholds.
272 */
273 static final int MIN_TREEIFY_CAPACITY = 64;
274
275 /**
276 * Basic hash bin node, used for most entries. (See below for
277 * TreeNode subclass, and in LinkedHashMap for its Entry subclass.)
278 */
279 static class Node<K,V> implements Map.Entry<K,V> {
280 final int hash;
281 final K key;
282 V value;
283 Node<K,V> next;
284
285 Node(int hash, K key, V value, Node<K,V> next) {
286 this.hash = hash;
287 this.key = key;
288 this.value = value;
289 this.next = next;
290 }
291
292 public final K getKey() { return key; }
293 public final V getValue() { return value; }
294 public final String toString() { return key + "=" + value; }
295
296 public final int hashCode() {
297 return Objects.hashCode(key) ^ Objects.hashCode(value);
298 }
299
300 public final V setValue(V newValue) {
301 V oldValue = value;
302 value = newValue;
303 return oldValue;
304 }
305
306 public final boolean equals(Object o) {
307 if (o == this)
308 return true;
309 if (o instanceof Map.Entry) {
310 Map.Entry<?,?> e = (Map.Entry<?,?>)o;
311 if (Objects.equals(key, e.getKey()) &&
312 Objects.equals(value, e.getValue()))
313 return true;
314 }
315 return false;
316 }
317 }
318
319 /* ---------------- Static utilities -------------- */
320
321 /**
322 * Computes key.hashCode() and spreads (XORs) higher bits of hash
323 * to lower. Because the table uses power-of-two masking, sets of
324 * hashes that vary only in bits above the current mask will
325 * always collide. (Among known examples are sets of Float keys
326 * holding consecutive whole numbers in small tables.) So we
327 * apply a transform that spreads the impact of higher bits
328 * downward. There is a tradeoff between speed, utility, and
329 * quality of bit-spreading. Because many common sets of hashes
330 * are already reasonably distributed (so don't benefit from
331 * spreading), and because we use trees to handle large sets of
332 * collisions in bins, we just XOR some shifted bits in the
333 * cheapest possible way to reduce systematic lossage, as well as
334 * to incorporate impact of the highest bits that would otherwise
335 * never be used in index calculations because of table bounds.
336 */
337 static final int hash(Object key) {
338 int h;
339 return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
340 }
341
342 /**
343 * Returns x's Class if it is of the form "class C implements
344 * Comparable<C>", else null.
345 */
346 static Class<?> comparableClassFor(Object x) {
347 if (x instanceof Comparable) {
348 Class<?> c; Type[] ts, as; ParameterizedType p;
349 if ((c = x.getClass()) == String.class) // bypass checks
350 return c;
351 if ((ts = c.getGenericInterfaces()) != null) {
352 for (Type t : ts) {
353 if ((t instanceof ParameterizedType) &&
354 ((p = (ParameterizedType) t).getRawType() ==
355 Comparable.class) &&
356 (as = p.getActualTypeArguments()) != null &&
357 as.length == 1 && as[0] == c) // type arg is c
358 return c;
359 }
360 }
361 }
362 return null;
363 }
364
365 /**
366 * Returns k.compareTo(x) if x matches kc (k's screened comparable
367 * class), else 0.
368 */
369 @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
370 static int compareComparables(Class<?> kc, Object k, Object x) {
371 return (x == null || x.getClass() != kc ? 0 :
372 ((Comparable)k).compareTo(x));
373 }
374
375 /**
376 * Returns a power of two size for the given target capacity.
377 */
378 static final int tableSizeFor(int cap) {
379 int n = -1 >>> Integer.numberOfLeadingZeros(cap - 1);
380 return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
381 }
382
383 /* ---------------- Fields -------------- */
384
385 /**
386 * The table, initialized on first use, and resized as
387 * necessary. When allocated, length is always a power of two.
388 * (We also tolerate length zero in some operations to allow
389 * bootstrapping mechanics that are currently not needed.)
390 */
391 transient Node<K,V>[] table;
392
393 /**
394 * Holds cached entrySet(). Note that AbstractMap fields are used
395 * for keySet() and values().
396 */
397 transient Set<Map.Entry<K,V>> entrySet;
398
399 /**
400 * The number of key-value mappings contained in this map.
401 */
402 transient int size;
403
404 /**
405 * The number of times this HashMap has been structurally modified
406 * Structural modifications are those that change the number of mappings in
407 * the HashMap or otherwise modify its internal structure (e.g.,
408 * rehash). This field is used to make iterators on Collection-views of
409 * the HashMap fail-fast. (See ConcurrentModificationException).
410 */
411 transient int modCount;
412
413 /**
414 * The next size value at which to resize (capacity * load factor).
415 *
416 * @serial
417 */
418 // (The javadoc description is true upon serialization.
419 // Additionally, if the table array has not been allocated, this
420 // field holds the initial array capacity, or zero signifying
421 // DEFAULT_INITIAL_CAPACITY.)
422 int threshold;
423
424 /**
425 * The load factor for the hash table.
426 *
427 * @serial
428 */
429 final float loadFactor;
430
431 /* ---------------- Public operations -------------- */
432
433 /**
434 * Constructs an empty {@code HashMap} with the specified initial
435 * capacity and load factor.
436 *
437 * @param initialCapacity the initial capacity
438 * @param loadFactor the load factor
439 * @throws IllegalArgumentException if the initial capacity is negative
440 * or the load factor is nonpositive
441 */
442 public HashMap(int initialCapacity, float loadFactor) {
443 if (initialCapacity < 0)
444 throw new IllegalArgumentException("Illegal initial capacity: " +
445 initialCapacity);
446 if (initialCapacity > MAXIMUM_CAPACITY)
447 initialCapacity = MAXIMUM_CAPACITY;
448 if (loadFactor <= 0 || Float.isNaN(loadFactor))
449 throw new IllegalArgumentException("Illegal load factor: " +
450 loadFactor);
451 this.loadFactor = loadFactor;
452 this.threshold = tableSizeFor(initialCapacity);
453 }
454
455 /**
456 * Constructs an empty {@code HashMap} with the specified initial
457 * capacity and the default load factor (0.75).
458 *
459 * @param initialCapacity the initial capacity.
460 * @throws IllegalArgumentException if the initial capacity is negative.
461 */
462 public HashMap(int initialCapacity) {
463 this(initialCapacity, DEFAULT_LOAD_FACTOR);
464 }
465
466 /**
467 * Constructs an empty {@code HashMap} with the default initial capacity
468 * (16) and the default load factor (0.75).
469 */
470 public HashMap() {
471 this.loadFactor = DEFAULT_LOAD_FACTOR; // all other fields defaulted
472 }
473
474 /**
475 * Constructs a new {@code HashMap} with the same mappings as the
476 * specified {@code Map}. The {@code HashMap} is created with
477 * default load factor (0.75) and an initial capacity sufficient to
478 * hold the mappings in the specified {@code Map}.
479 *
480 * @param m the map whose mappings are to be placed in this map
481 * @throws NullPointerException if the specified map is null
482 */
483 public HashMap(Map<? extends K, ? extends V> m) {
484 this.loadFactor = DEFAULT_LOAD_FACTOR;
485 putMapEntries(m, false);
486 }
487
488 /**
489 * Implements Map.putAll and Map constructor.
490 *
491 * @param m the map
492 * @param evict false when initially constructing this map, else
493 * true (relayed to method afterNodeInsertion).
494 */
495 final void putMapEntries(Map<? extends K, ? extends V> m, boolean evict) {
496 int s = m.size();
497 if (s > 0) {
498 if (table == null) { // pre-size
499 float ft = ((float)s / loadFactor) + 1.0F;
500 int t = ((ft < (float)MAXIMUM_CAPACITY) ?
501 (int)ft : MAXIMUM_CAPACITY);
502 if (t > threshold)
503 threshold = tableSizeFor(t);
504 } else {
505 // Because of linked-list buckets constraints, we cannot
506 // expand all at once, but can reduce total resize
507 // effort by repeated doubling now vs later
508 while (table.length < MAXIMUM_CAPACITY && s > threshold) {
509 resize();
510 }
511 }
512 for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
513 K key = e.getKey();
514 V value = e.getValue();
515 putVal(hash(key), key, value, false, evict);
516 }
517 }
518 }
519
520 /**
521 * Returns the number of key-value mappings in this map.
522 *
523 * @return the number of key-value mappings in this map
524 */
525 public int size() {
526 return size;
527 }
528
529 /**
530 * Returns {@code true} if this map contains no key-value mappings.
531 *
532 * @return {@code true} if this map contains no key-value mappings
533 */
534 public boolean isEmpty() {
535 return size == 0;
536 }
537
538 /**
539 * Returns the value to which the specified key is mapped,
540 * or {@code null} if this map contains no mapping for the key.
541 *
542 * <p>More formally, if this map contains a mapping from a key
543 * {@code k} to a value {@code v} such that {@code (key==null ? k==null :
544 * key.equals(k))}, then this method returns {@code v}; otherwise
545 * it returns {@code null}. (There can be at most one such mapping.)
546 *
547 * <p>A return value of {@code null} does not <i>necessarily</i>
548 * indicate that the map contains no mapping for the key; it's also
549 * possible that the map explicitly maps the key to {@code null}.
550 * The {@link #containsKey containsKey} operation may be used to
551 * distinguish these two cases.
552 *
553 * @see #put(Object, Object)
554 */
555 public V get(Object key) {
556 Node<K,V> e;
557 return (e = getNode(hash(key), key)) == null ? null : e.value;
558 }
559
560 /**
561 * Implements Map.get and related methods.
562 *
563 * @param hash hash for key
564 * @param key the key
565 * @return the node, or null if none
566 */
567 final Node<K,V> getNode(int hash, Object key) {
568 Node<K,V>[] tab; Node<K,V> first, e; int n; K k;
569 if ((tab = table) != null && (n = tab.length) > 0 &&
570 (first = tab[(n - 1) & hash]) != null) {
571 if (first.hash == hash && // always check first node
572 ((k = first.key) == key || (key != null && key.equals(k))))
573 return first;
574 if ((e = first.next) != null) {
575 if (first instanceof TreeNode)
576 return ((TreeNode<K,V>)first).getTreeNode(hash, key);
577 do {
578 if (e.hash == hash &&
579 ((k = e.key) == key || (key != null && key.equals(k))))
580 return e;
581 } while ((e = e.next) != null);
582 }
583 }
584 return null;
585 }
586
587 /**
588 * Returns {@code true} if this map contains a mapping for the
589 * specified key.
590 *
591 * @param key The key whose presence in this map is to be tested
592 * @return {@code true} if this map contains a mapping for the specified
593 * key.
594 */
595 public boolean containsKey(Object key) {
596 return getNode(hash(key), key) != null;
597 }
598
599 /**
600 * Associates the specified value with the specified key in this map.
601 * If the map previously contained a mapping for the key, the old
602 * value is replaced.
603 *
604 * @param key key with which the specified value is to be associated
605 * @param value value to be associated with the specified key
606 * @return the previous value associated with {@code key}, or
607 * {@code null} if there was no mapping for {@code key}.
608 * (A {@code null} return can also indicate that the map
609 * previously associated {@code null} with {@code key}.)
610 */
611 public V put(K key, V value) {
612 return putVal(hash(key), key, value, false, true);
613 }
614
615 /**
616 * Implements Map.put and related methods.
617 *
618 * @param hash hash for key
619 * @param key the key
620 * @param value the value to put
621 * @param onlyIfAbsent if true, don't change existing value
622 * @param evict if false, the table is in creation mode.
623 * @return previous value, or null if none
624 */
625 final V putVal(int hash, K key, V value, boolean onlyIfAbsent,
626 boolean evict) {
627 Node<K,V>[] tab; Node<K,V> p; int n, i;
628 if ((tab = table) == null || (n = tab.length) == 0)
629 n = (tab = resize()).length;
630 if ((p = tab[i = (n - 1) & hash]) == null)
631 tab[i] = newNode(hash, key, value, null);
632 else {
633 Node<K,V> e; K k;
634 if (p.hash == hash &&
635 ((k = p.key) == key || (key != null && key.equals(k))))
636 e = p;
637 else if (p instanceof TreeNode)
638 e = ((TreeNode<K,V>)p).putTreeVal(this, tab, hash, key, value);
639 else {
640 for (int binCount = 0; ; ++binCount) {
641 if ((e = p.next) == null) {
642 p.next = newNode(hash, key, value, null);
643 if (binCount >= TREEIFY_THRESHOLD - 1) // -1 for 1st
644 treeifyBin(tab, hash);
645 break;
646 }
647 if (e.hash == hash &&
648 ((k = e.key) == key || (key != null && key.equals(k))))
649 break;
650 p = e;
651 }
652 }
653 if (e != null) { // existing mapping for key
654 V oldValue = e.value;
655 if (!onlyIfAbsent || oldValue == null)
656 e.value = value;
657 afterNodeAccess(e);
658 return oldValue;
659 }
660 }
661 ++modCount;
662 if (++size > threshold)
663 resize();
664 afterNodeInsertion(evict);
665 return null;
666 }
667
668 /**
669 * Initializes or doubles table size. If null, allocates in
670 * accord with initial capacity target held in field threshold.
671 * Otherwise, because we are using power-of-two expansion, the
672 * elements from each bin must either stay at same index, or move
673 * with a power of two offset in the new table.
674 *
675 * @return the table
676 */
677 final Node<K,V>[] resize() {
678 Node<K,V>[] oldTab = table;
679 int oldCap = (oldTab == null) ? 0 : oldTab.length;
680 int oldThr = threshold;
681 int newCap, newThr = 0;
682 if (oldCap > 0) {
683 if (oldCap >= MAXIMUM_CAPACITY) {
684 threshold = Integer.MAX_VALUE;
685 return oldTab;
686 }
687 else if ((newCap = oldCap << 1) < MAXIMUM_CAPACITY &&
688 oldCap >= DEFAULT_INITIAL_CAPACITY)
689 newThr = oldThr << 1; // double threshold
690 }
691 else if (oldThr > 0) // initial capacity was placed in threshold
692 newCap = oldThr;
693 else { // zero initial threshold signifies using defaults
694 newCap = DEFAULT_INITIAL_CAPACITY;
695 newThr = (int)(DEFAULT_LOAD_FACTOR * DEFAULT_INITIAL_CAPACITY);
696 }
697 if (newThr == 0) {
698 float ft = (float)newCap * loadFactor;
699 newThr = (newCap < MAXIMUM_CAPACITY && ft < (float)MAXIMUM_CAPACITY ?
700 (int)ft : Integer.MAX_VALUE);
701 }
702 threshold = newThr;
703 @SuppressWarnings({"rawtypes","unchecked"})
704 Node<K,V>[] newTab = (Node<K,V>[])new Node[newCap];
705 table = newTab;
706 if (oldTab != null) {
707 for (int j = 0; j < oldCap; ++j) {
708 Node<K,V> e;
709 if ((e = oldTab[j]) != null) {
710 oldTab[j] = null;
711 if (e.next == null)
712 newTab[e.hash & (newCap - 1)] = e;
713 else if (e instanceof TreeNode)
714 ((TreeNode<K,V>)e).split(this, newTab, j, oldCap);
715 else { // preserve order
716 Node<K,V> loHead = null, loTail = null;
717 Node<K,V> hiHead = null, hiTail = null;
718 Node<K,V> next;
719 do {
720 next = e.next;
721 if ((e.hash & oldCap) == 0) {
722 if (loTail == null)
723 loHead = e;
724 else
725 loTail.next = e;
726 loTail = e;
727 }
728 else {
729 if (hiTail == null)
730 hiHead = e;
731 else
732 hiTail.next = e;
733 hiTail = e;
734 }
735 } while ((e = next) != null);
736 if (loTail != null) {
737 loTail.next = null;
738 newTab[j] = loHead;
739 }
740 if (hiTail != null) {
741 hiTail.next = null;
742 newTab[j + oldCap] = hiHead;
743 }
744 }
745 }
746 }
747 }
748 return newTab;
749 }
750
751 /**
752 * Replaces all linked nodes in bin at index for given hash unless
753 * table is too small, in which case resizes instead.
754 */
755 final void treeifyBin(Node<K,V>[] tab, int hash) {
756 int n, index; Node<K,V> e;
757 if (tab == null || (n = tab.length) < MIN_TREEIFY_CAPACITY)
758 resize();
759 else if ((e = tab[index = (n - 1) & hash]) != null) {
760 TreeNode<K,V> hd = null, tl = null;
761 do {
762 TreeNode<K,V> p = replacementTreeNode(e, null);
763 if (tl == null)
764 hd = p;
765 else {
766 p.prev = tl;
767 tl.next = p;
768 }
769 tl = p;
770 } while ((e = e.next) != null);
771 if ((tab[index] = hd) != null)
772 hd.treeify(tab);
773 }
774 }
775
776 /**
777 * Copies all of the mappings from the specified map to this map.
778 * These mappings will replace any mappings that this map had for
779 * any of the keys currently in the specified map.
780 *
781 * @param m mappings to be stored in this map
782 * @throws NullPointerException if the specified map is null
783 */
784 public void putAll(Map<? extends K, ? extends V> m) {
785 putMapEntries(m, true);
786 }
787
788 /**
789 * Removes the mapping for the specified key from this map if present.
790 *
791 * @param key key whose mapping is to be removed from the map
792 * @return the previous value associated with {@code key}, or
793 * {@code null} if there was no mapping for {@code key}.
794 * (A {@code null} return can also indicate that the map
795 * previously associated {@code null} with {@code key}.)
796 */
797 public V remove(Object key) {
798 Node<K,V> e;
799 return (e = removeNode(hash(key), key, null, false, true)) == null ?
800 null : e.value;
801 }
802
803 /**
804 * Implements Map.remove and related methods.
805 *
806 * @param hash hash for key
807 * @param key the key
808 * @param value the value to match if matchValue, else ignored
809 * @param matchValue if true only remove if value is equal
810 * @param movable if false do not move other nodes while removing
811 * @return the node, or null if none
812 */
813 final Node<K,V> removeNode(int hash, Object key, Object value,
814 boolean matchValue, boolean movable) {
815 Node<K,V>[] tab; Node<K,V> p; int n, index;
816 if ((tab = table) != null && (n = tab.length) > 0 &&
817 (p = tab[index = (n - 1) & hash]) != null) {
818 Node<K,V> node = null, e; K k; V v;
819 if (p.hash == hash &&
820 ((k = p.key) == key || (key != null && key.equals(k))))
821 node = p;
822 else if ((e = p.next) != null) {
823 if (p instanceof TreeNode)
824 node = ((TreeNode<K,V>)p).getTreeNode(hash, key);
825 else {
826 do {
827 if (e.hash == hash &&
828 ((k = e.key) == key ||
829 (key != null && key.equals(k)))) {
830 node = e;
831 break;
832 }
833 p = e;
834 } while ((e = e.next) != null);
835 }
836 }
837 if (node != null && (!matchValue || (v = node.value) == value ||
838 (value != null && value.equals(v)))) {
839 if (node instanceof TreeNode)
840 ((TreeNode<K,V>)node).removeTreeNode(this, tab, movable);
841 else if (node == p)
842 tab[index] = node.next;
843 else
844 p.next = node.next;
845 ++modCount;
846 --size;
847 afterNodeRemoval(node);
848 return node;
849 }
850 }
851 return null;
852 }
853
854 /**
855 * Removes all of the mappings from this map.
856 * The map will be empty after this call returns.
857 */
858 public void clear() {
859 Node<K,V>[] tab;
860 modCount++;
861 if ((tab = table) != null && size > 0) {
862 size = 0;
863 for (int i = 0; i < tab.length; ++i)
864 tab[i] = null;
865 }
866 }
867
868 /**
869 * Returns {@code true} if this map maps one or more keys to the
870 * specified value.
871 *
872 * @param value value whose presence in this map is to be tested
873 * @return {@code true} if this map maps one or more keys to the
874 * specified value
875 */
876 public boolean containsValue(Object value) {
877 Node<K,V>[] tab; V v;
878 if ((tab = table) != null && size > 0) {
879 for (Node<K,V> e : tab) {
880 for (; e != null; e = e.next) {
881 if ((v = e.value) == value ||
882 (value != null && value.equals(v)))
883 return true;
884 }
885 }
886 }
887 return false;
888 }
889
890 /**
891 * Returns a {@link Set} view of the keys contained in this map.
892 * The set is backed by the map, so changes to the map are
893 * reflected in the set, and vice-versa. If the map is modified
894 * while an iteration over the set is in progress (except through
895 * the iterator's own {@code remove} operation), the results of
896 * the iteration are undefined. The set supports element removal,
897 * which removes the corresponding mapping from the map, via the
898 * {@code Iterator.remove}, {@code Set.remove},
899 * {@code removeAll}, {@code retainAll}, and {@code clear}
900 * operations. It does not support the {@code add} or {@code addAll}
901 * operations.
902 *
903 * @return a set view of the keys contained in this map
904 */
905 public Set<K> keySet() {
906 Set<K> ks = keySet;
907 if (ks == null) {
908 ks = new KeySet();
909 keySet = ks;
910 }
911 return ks;
912 }
913
914 final class KeySet extends AbstractSet<K> {
915 public final int size() { return size; }
916 public final void clear() { HashMap.this.clear(); }
917 public final Iterator<K> iterator() { return new KeyIterator(); }
918 public final boolean contains(Object o) { return containsKey(o); }
919 public final boolean remove(Object key) {
920 return removeNode(hash(key), key, null, false, true) != null;
921 }
922 public final Spliterator<K> spliterator() {
923 return new KeySpliterator<>(HashMap.this, 0, -1, 0, 0);
924 }
925 public final void forEach(Consumer<? super K> action) {
926 Node<K,V>[] tab;
927 if (action == null)
928 throw new NullPointerException();
929 if (size > 0 && (tab = table) != null) {
930 int mc = modCount;
931 for (Node<K,V> e : tab) {
932 for (; e != null; e = e.next)
933 action.accept(e.key);
934 }
935 if (modCount != mc)
936 throw new ConcurrentModificationException();
937 }
938 }
939 }
940
941 /**
942 * Returns a {@link Collection} view of the values contained in this map.
943 * The collection is backed by the map, so changes to the map are
944 * reflected in the collection, and vice-versa. If the map is
945 * modified while an iteration over the collection is in progress
946 * (except through the iterator's own {@code remove} operation),
947 * the results of the iteration are undefined. The collection
948 * supports element removal, which removes the corresponding
949 * mapping from the map, via the {@code Iterator.remove},
950 * {@code Collection.remove}, {@code removeAll},
951 * {@code retainAll} and {@code clear} operations. It does not
952 * support the {@code add} or {@code addAll} operations.
953 *
954 * @return a view of the values contained in this map
955 */
956 public Collection<V> values() {
957 Collection<V> vs = values;
958 if (vs == null) {
959 vs = new Values();
960 values = vs;
961 }
962 return vs;
963 }
964
965 final class Values extends AbstractCollection<V> {
966 public final int size() { return size; }
967 public final void clear() { HashMap.this.clear(); }
968 public final Iterator<V> iterator() { return new ValueIterator(); }
969 public final boolean contains(Object o) { return containsValue(o); }
970 public final Spliterator<V> spliterator() {
971 return new ValueSpliterator<>(HashMap.this, 0, -1, 0, 0);
972 }
973 public final void forEach(Consumer<? super V> action) {
974 Node<K,V>[] tab;
975 if (action == null)
976 throw new NullPointerException();
977 if (size > 0 && (tab = table) != null) {
978 int mc = modCount;
979 for (Node<K,V> e : tab) {
980 for (; e != null; e = e.next)
981 action.accept(e.value);
982 }
983 if (modCount != mc)
984 throw new ConcurrentModificationException();
985 }
986 }
987 }
988
989 /**
990 * Returns a {@link Set} view of the mappings contained in this map.
991 * The set is backed by the map, so changes to the map are
992 * reflected in the set, and vice-versa. If the map is modified
993 * while an iteration over the set is in progress (except through
994 * the iterator's own {@code remove} operation, or through the
995 * {@code setValue} operation on a map entry returned by the
996 * iterator) the results of the iteration are undefined. The set
997 * supports element removal, which removes the corresponding
998 * mapping from the map, via the {@code Iterator.remove},
999 * {@code Set.remove}, {@code removeAll}, {@code retainAll} and
1000 * {@code clear} operations. It does not support the
1001 * {@code add} or {@code addAll} operations.
1002 *
1003 * @return a set view of the mappings contained in this map
1004 */
1005 public Set<Map.Entry<K,V>> entrySet() {
1006 Set<Map.Entry<K,V>> es;
1007 return (es = entrySet) == null ? (entrySet = new EntrySet()) : es;
1008 }
1009
1010 final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
1011 public final int size() { return size; }
1012 public final void clear() { HashMap.this.clear(); }
1013 public final Iterator<Map.Entry<K,V>> iterator() {
1014 return new EntryIterator();
1015 }
1016 public final boolean contains(Object o) {
1017 if (!(o instanceof Map.Entry))
1018 return false;
1019 Map.Entry<?,?> e = (Map.Entry<?,?>) o;
1020 Object key = e.getKey();
1021 Node<K,V> candidate = getNode(hash(key), key);
1022 return candidate != null && candidate.equals(e);
1023 }
1024 public final boolean remove(Object o) {
1025 if (o instanceof Map.Entry) {
1026 Map.Entry<?,?> e = (Map.Entry<?,?>) o;
1027 Object key = e.getKey();
1028 Object value = e.getValue();
1029 return removeNode(hash(key), key, value, true, true) != null;
1030 }
1031 return false;
1032 }
1033 public final Spliterator<Map.Entry<K,V>> spliterator() {
1034 return new EntrySpliterator<>(HashMap.this, 0, -1, 0, 0);
1035 }
1036 public final void forEach(Consumer<? super Map.Entry<K,V>> action) {
1037 Node<K,V>[] tab;
1038 if (action == null)
1039 throw new NullPointerException();
1040 if (size > 0 && (tab = table) != null) {
1041 int mc = modCount;
1042 for (Node<K,V> e : tab) {
1043 for (; e != null; e = e.next)
1044 action.accept(e);
1045 }
1046 if (modCount != mc)
1047 throw new ConcurrentModificationException();
1048 }
1049 }
1050 }
1051
1052 // Overrides of JDK8 Map extension methods
1053
1054 @Override
1055 public V getOrDefault(Object key, V defaultValue) {
1056 Node<K,V> e;
1057 return (e = getNode(hash(key), key)) == null ? defaultValue : e.value;
1058 }
1059
1060 @Override
1061 public V putIfAbsent(K key, V value) {
1062 return putVal(hash(key), key, value, true, true);
1063 }
1064
1065 @Override
1066 public boolean remove(Object key, Object value) {
1067 return removeNode(hash(key), key, value, true, true) != null;
1068 }
1069
1070 @Override
1071 public boolean replace(K key, V oldValue, V newValue) {
1072 Node<K,V> e; V v;
1073 if ((e = getNode(hash(key), key)) != null &&
1074 ((v = e.value) == oldValue || (v != null && v.equals(oldValue)))) {
1075 e.value = newValue;
1076 afterNodeAccess(e);
1077 return true;
1078 }
1079 return false;
1080 }
1081
1082 @Override
1083 public V replace(K key, V value) {
1084 Node<K,V> e;
1085 if ((e = getNode(hash(key), key)) != null) {
1086 V oldValue = e.value;
1087 e.value = value;
1088 afterNodeAccess(e);
1089 return oldValue;
1090 }
1091 return null;
1092 }
1093
1094 /**
1095 * {@inheritDoc}
1096 *
1097 * <p>This method will, on a best-effort basis, throw a
1098 * {@link ConcurrentModificationException} if it is detected that the
1099 * mapping function modifies this map during computation.
1100 *
1101 * @throws ConcurrentModificationException if it is detected that the
1102 * mapping function modified this map
1103 */
1104 @Override
1105 public V computeIfAbsent(K key,
1106 Function<? super K, ? extends V> mappingFunction) {
1107 if (mappingFunction == null)
1108 throw new NullPointerException();
1109 int hash = hash(key);
1110 Node<K,V>[] tab; Node<K,V> first; int n, i;
1111 int binCount = 0;
1112 TreeNode<K,V> t = null;
1113 Node<K,V> old = null;
1114 if (size > threshold || (tab = table) == null ||
1115 (n = tab.length) == 0)
1116 n = (tab = resize()).length;
1117 if ((first = tab[i = (n - 1) & hash]) != null) {
1118 if (first instanceof TreeNode)
1119 old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
1120 else {
1121 Node<K,V> e = first; K k;
1122 do {
1123 if (e.hash == hash &&
1124 ((k = e.key) == key || (key != null && key.equals(k)))) {
1125 old = e;
1126 break;
1127 }
1128 ++binCount;
1129 } while ((e = e.next) != null);
1130 }
1131 V oldValue;
1132 if (old != null && (oldValue = old.value) != null) {
1133 afterNodeAccess(old);
1134 return oldValue;
1135 }
1136 }
1137 int mc = modCount;
1138 V v = mappingFunction.apply(key);
1139 if (mc != modCount) { throw new ConcurrentModificationException(); }
1140 if (v == null) {
1141 return null;
1142 } else if (old != null) {
1143 old.value = v;
1144 afterNodeAccess(old);
1145 return v;
1146 }
1147 else if (t != null)
1148 t.putTreeVal(this, tab, hash, key, v);
1149 else {
1150 tab[i] = newNode(hash, key, v, first);
1151 if (binCount >= TREEIFY_THRESHOLD - 1)
1152 treeifyBin(tab, hash);
1153 }
1154 modCount = mc + 1;
1155 ++size;
1156 afterNodeInsertion(true);
1157 return v;
1158 }
1159
1160 /**
1161 * {@inheritDoc}
1162 *
1163 * <p>This method will, on a best-effort basis, throw a
1164 * {@link ConcurrentModificationException} if it is detected that the
1165 * remapping function modifies this map during computation.
1166 *
1167 * @throws ConcurrentModificationException if it is detected that the
1168 * remapping function modified this map
1169 */
1170 @Override
1171 public V computeIfPresent(K key,
1172 BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1173 if (remappingFunction == null)
1174 throw new NullPointerException();
1175 Node<K,V> e; V oldValue;
1176 int hash = hash(key);
1177 if ((e = getNode(hash, key)) != null &&
1178 (oldValue = e.value) != null) {
1179 int mc = modCount;
1180 V v = remappingFunction.apply(key, oldValue);
1181 if (mc != modCount) { throw new ConcurrentModificationException(); }
1182 if (v != null) {
1183 e.value = v;
1184 afterNodeAccess(e);
1185 return v;
1186 }
1187 else
1188 removeNode(hash, key, null, false, true);
1189 }
1190 return null;
1191 }
1192
1193 /**
1194 * {@inheritDoc}
1195 *
1196 * <p>This method will, on a best-effort basis, throw a
1197 * {@link ConcurrentModificationException} if it is detected that the
1198 * remapping function modifies this map during computation.
1199 *
1200 * @throws ConcurrentModificationException if it is detected that the
1201 * remapping function modified this map
1202 */
1203 @Override
1204 public V compute(K key,
1205 BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1206 if (remappingFunction == null)
1207 throw new NullPointerException();
1208 int hash = hash(key);
1209 Node<K,V>[] tab; Node<K,V> first; int n, i;
1210 int binCount = 0;
1211 TreeNode<K,V> t = null;
1212 Node<K,V> old = null;
1213 if (size > threshold || (tab = table) == null ||
1214 (n = tab.length) == 0)
1215 n = (tab = resize()).length;
1216 if ((first = tab[i = (n - 1) & hash]) != null) {
1217 if (first instanceof TreeNode)
1218 old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
1219 else {
1220 Node<K,V> e = first; K k;
1221 do {
1222 if (e.hash == hash &&
1223 ((k = e.key) == key || (key != null && key.equals(k)))) {
1224 old = e;
1225 break;
1226 }
1227 ++binCount;
1228 } while ((e = e.next) != null);
1229 }
1230 }
1231 V oldValue = (old == null) ? null : old.value;
1232 int mc = modCount;
1233 V v = remappingFunction.apply(key, oldValue);
1234 if (mc != modCount) { throw new ConcurrentModificationException(); }
1235 if (old != null) {
1236 if (v != null) {
1237 old.value = v;
1238 afterNodeAccess(old);
1239 }
1240 else
1241 removeNode(hash, key, null, false, true);
1242 }
1243 else if (v != null) {
1244 if (t != null)
1245 t.putTreeVal(this, tab, hash, key, v);
1246 else {
1247 tab[i] = newNode(hash, key, v, first);
1248 if (binCount >= TREEIFY_THRESHOLD - 1)
1249 treeifyBin(tab, hash);
1250 }
1251 modCount = mc + 1;
1252 ++size;
1253 afterNodeInsertion(true);
1254 }
1255 return v;
1256 }
1257
1258 /**
1259 * {@inheritDoc}
1260 *
1261 * <p>This method will, on a best-effort basis, throw a
1262 * {@link ConcurrentModificationException} if it is detected that the
1263 * remapping function modifies this map during computation.
1264 *
1265 * @throws ConcurrentModificationException if it is detected that the
1266 * remapping function modified this map
1267 */
1268 @Override
1269 public V merge(K key, V value,
1270 BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1271 if (value == null || remappingFunction == null)
1272 throw new NullPointerException();
1273 int hash = hash(key);
1274 Node<K,V>[] tab; Node<K,V> first; int n, i;
1275 int binCount = 0;
1276 TreeNode<K,V> t = null;
1277 Node<K,V> old = null;
1278 if (size > threshold || (tab = table) == null ||
1279 (n = tab.length) == 0)
1280 n = (tab = resize()).length;
1281 if ((first = tab[i = (n - 1) & hash]) != null) {
1282 if (first instanceof TreeNode)
1283 old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
1284 else {
1285 Node<K,V> e = first; K k;
1286 do {
1287 if (e.hash == hash &&
1288 ((k = e.key) == key || (key != null && key.equals(k)))) {
1289 old = e;
1290 break;
1291 }
1292 ++binCount;
1293 } while ((e = e.next) != null);
1294 }
1295 }
1296 if (old != null) {
1297 V v;
1298 if (old.value != null) {
1299 int mc = modCount;
1300 v = remappingFunction.apply(old.value, value);
1301 if (mc != modCount) {
1302 throw new ConcurrentModificationException();
1303 }
1304 } else {
1305 v = value;
1306 }
1307 if (v != null) {
1308 old.value = v;
1309 afterNodeAccess(old);
1310 }
1311 else
1312 removeNode(hash, key, null, false, true);
1313 return v;
1314 } else {
1315 if (t != null)
1316 t.putTreeVal(this, tab, hash, key, value);
1317 else {
1318 tab[i] = newNode(hash, key, value, first);
1319 if (binCount >= TREEIFY_THRESHOLD - 1)
1320 treeifyBin(tab, hash);
1321 }
1322 ++modCount;
1323 ++size;
1324 afterNodeInsertion(true);
1325 return value;
1326 }
1327 }
1328
1329 @Override
1330 public void forEach(BiConsumer<? super K, ? super V> action) {
1331 Node<K,V>[] tab;
1332 if (action == null)
1333 throw new NullPointerException();
1334 if (size > 0 && (tab = table) != null) {
1335 int mc = modCount;
1336 for (Node<K,V> e : tab) {
1337 for (; e != null; e = e.next)
1338 action.accept(e.key, e.value);
1339 }
1340 if (modCount != mc)
1341 throw new ConcurrentModificationException();
1342 }
1343 }
1344
1345 @Override
1346 public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1347 Node<K,V>[] tab;
1348 if (function == null)
1349 throw new NullPointerException();
1350 if (size > 0 && (tab = table) != null) {
1351 int mc = modCount;
1352 for (Node<K,V> e : tab) {
1353 for (; e != null; e = e.next) {
1354 e.value = function.apply(e.key, e.value);
1355 }
1356 }
1357 if (modCount != mc)
1358 throw new ConcurrentModificationException();
1359 }
1360 }
1361
1362 /* ------------------------------------------------------------ */
1363 // Cloning and serialization
1364
1365 /**
1366 * Returns a shallow copy of this {@code HashMap} instance: the keys and
1367 * values themselves are not cloned.
1368 *
1369 * @return a shallow copy of this map
1370 */
1371 @SuppressWarnings("unchecked")
1372 @Override
1373 public Object clone() {
1374 HashMap<K,V> result;
1375 try {
1376 result = (HashMap<K,V>)super.clone();
1377 } catch (CloneNotSupportedException e) {
1378 // this shouldn't happen, since we are Cloneable
1379 throw new InternalError(e);
1380 }
1381 result.reinitialize();
1382 result.putMapEntries(this, false);
1383 return result;
1384 }
1385
1386 // These methods are also used when serializing HashSets
1387 final float loadFactor() { return loadFactor; }
1388 final int capacity() {
1389 return (table != null) ? table.length :
1390 (threshold > 0) ? threshold :
1391 DEFAULT_INITIAL_CAPACITY;
1392 }
1393
1394 /**
1395 * Saves this map to a stream (that is, serializes it).
1396 *
1397 * @param s the stream
1398 * @throws IOException if an I/O error occurs
1399 * @serialData The <i>capacity</i> of the HashMap (the length of the
1400 * bucket array) is emitted (int), followed by the
1401 * <i>size</i> (an int, the number of key-value
1402 * mappings), followed by the key (Object) and value (Object)
1403 * for each key-value mapping. The key-value mappings are
1404 * emitted in no particular order.
1405 */
1406 private void writeObject(java.io.ObjectOutputStream s)
1407 throws IOException {
1408 int buckets = capacity();
1409 // Write out the threshold, loadfactor, and any hidden stuff
1410 s.defaultWriteObject();
1411 s.writeInt(buckets);
1412 s.writeInt(size);
1413 internalWriteEntries(s);
1414 }
1415
1416 /**
1417 * Reconstitutes this map from a stream (that is, deserializes it).
1418 * @param s the stream
1419 * @throws ClassNotFoundException if the class of a serialized object
1420 * could not be found
1421 * @throws IOException if an I/O error occurs
1422 */
1423 private void readObject(java.io.ObjectInputStream s)
1424 throws IOException, ClassNotFoundException {
1425 // Read in the threshold (ignored), loadfactor, and any hidden stuff
1426 s.defaultReadObject();
1427 reinitialize();
1428 if (loadFactor <= 0 || Float.isNaN(loadFactor))
1429 throw new InvalidObjectException("Illegal load factor: " +
1430 loadFactor);
1431 s.readInt(); // Read and ignore number of buckets
1432 int mappings = s.readInt(); // Read number of mappings (size)
1433 if (mappings < 0)
1434 throw new InvalidObjectException("Illegal mappings count: " +
1435 mappings);
1436 else if (mappings > 0) { // (if zero, use defaults)
1437 // Size the table using given load factor only if within
1438 // range of 0.25...4.0
1439 float lf = Math.min(Math.max(0.25f, loadFactor), 4.0f);
1440 float fc = (float)mappings / lf + 1.0f;
1441 int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ?
1442 DEFAULT_INITIAL_CAPACITY :
1443 (fc >= MAXIMUM_CAPACITY) ?
1444 MAXIMUM_CAPACITY :
1445 tableSizeFor((int)fc));
1446 float ft = (float)cap * lf;
1447 threshold = ((cap < MAXIMUM_CAPACITY && ft < MAXIMUM_CAPACITY) ?
1448 (int)ft : Integer.MAX_VALUE);
1449
1450 // Check Map.Entry[].class since it's the nearest public type to
1451 // what we're actually creating.
1452 SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Map.Entry[].class, cap);
1453 @SuppressWarnings({"rawtypes","unchecked"})
1454 Node<K,V>[] tab = (Node<K,V>[])new Node[cap];
1455 table = tab;
1456
1457 // Read the keys and values, and put the mappings in the HashMap
1458 for (int i = 0; i < mappings; i++) {
1459 @SuppressWarnings("unchecked")
1460 K key = (K) s.readObject();
1461 @SuppressWarnings("unchecked")
1462 V value = (V) s.readObject();
1463 putVal(hash(key), key, value, false, false);
1464 }
1465 }
1466 }
1467
1468 /* ------------------------------------------------------------ */
1469 // iterators
1470
1471 abstract class HashIterator {
1472 Node<K,V> next; // next entry to return
1473 Node<K,V> current; // current entry
1474 int expectedModCount; // for fast-fail
1475 int index; // current slot
1476
1477 HashIterator() {
1478 expectedModCount = modCount;
1479 Node<K,V>[] t = table;
1480 current = next = null;
1481 index = 0;
1482 if (t != null && size > 0) { // advance to first entry
1483 do {} while (index < t.length && (next = t[index++]) == null);
1484 }
1485 }
1486
1487 public final boolean hasNext() {
1488 return next != null;
1489 }
1490
1491 final Node<K,V> nextNode() {
1492 Node<K,V>[] t;
1493 Node<K,V> e = next;
1494 if (modCount != expectedModCount)
1495 throw new ConcurrentModificationException();
1496 if (e == null)
1497 throw new NoSuchElementException();
1498 if ((next = (current = e).next) == null && (t = table) != null) {
1499 do {} while (index < t.length && (next = t[index++]) == null);
1500 }
1501 return e;
1502 }
1503
1504 public final void remove() {
1505 Node<K,V> p = current;
1506 if (p == null)
1507 throw new IllegalStateException();
1508 if (modCount != expectedModCount)
1509 throw new ConcurrentModificationException();
1510 current = null;
1511 removeNode(p.hash, p.key, null, false, false);
1512 expectedModCount = modCount;
1513 }
1514 }
1515
1516 final class KeyIterator extends HashIterator
1517 implements Iterator<K> {
1518 public final K next() { return nextNode().key; }
1519 }
1520
1521 final class ValueIterator extends HashIterator
1522 implements Iterator<V> {
1523 public final V next() { return nextNode().value; }
1524 }
1525
1526 final class EntryIterator extends HashIterator
1527 implements Iterator<Map.Entry<K,V>> {
1528 public final Map.Entry<K,V> next() { return nextNode(); }
1529 }
1530
1531 /* ------------------------------------------------------------ */
1532 // spliterators
1533
1534 static class HashMapSpliterator<K,V> {
1535 final HashMap<K,V> map;
1536 Node<K,V> current; // current node
1537 int index; // current index, modified on advance/split
1538 int fence; // one past last index
1539 int est; // size estimate
1540 int expectedModCount; // for comodification checks
1541
1542 HashMapSpliterator(HashMap<K,V> m, int origin,
1543 int fence, int est,
1544 int expectedModCount) {
1545 this.map = m;
1546 this.index = origin;
1547 this.fence = fence;
1548 this.est = est;
1549 this.expectedModCount = expectedModCount;
1550 }
1551
1552 final int getFence() { // initialize fence and size on first use
1553 int hi;
1554 if ((hi = fence) < 0) {
1555 HashMap<K,V> m = map;
1556 est = m.size;
1557 expectedModCount = m.modCount;
1558 Node<K,V>[] tab = m.table;
1559 hi = fence = (tab == null) ? 0 : tab.length;
1560 }
1561 return hi;
1562 }
1563
1564 public final long estimateSize() {
1565 getFence(); // force init
1566 return (long) est;
1567 }
1568 }
1569
1570 static final class KeySpliterator<K,V>
1571 extends HashMapSpliterator<K,V>
1572 implements Spliterator<K> {
1573 KeySpliterator(HashMap<K,V> m, int origin, int fence, int est,
1574 int expectedModCount) {
1575 super(m, origin, fence, est, expectedModCount);
1576 }
1577
1578 public KeySpliterator<K,V> trySplit() {
1579 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1580 return (lo >= mid || current != null) ? null :
1581 new KeySpliterator<>(map, lo, index = mid, est >>>= 1,
1582 expectedModCount);
1583 }
1584
1585 public void forEachRemaining(Consumer<? super K> action) {
1586 int i, hi, mc;
1587 if (action == null)
1588 throw new NullPointerException();
1589 HashMap<K,V> m = map;
1590 Node<K,V>[] tab = m.table;
1591 if ((hi = fence) < 0) {
1592 mc = expectedModCount = m.modCount;
1593 hi = fence = (tab == null) ? 0 : tab.length;
1594 }
1595 else
1596 mc = expectedModCount;
1597 if (tab != null && tab.length >= hi &&
1598 (i = index) >= 0 && (i < (index = hi) || current != null)) {
1599 Node<K,V> p = current;
1600 current = null;
1601 do {
1602 if (p == null)
1603 p = tab[i++];
1604 else {
1605 action.accept(p.key);
1606 p = p.next;
1607 }
1608 } while (p != null || i < hi);
1609 if (m.modCount != mc)
1610 throw new ConcurrentModificationException();
1611 }
1612 }
1613
1614 public boolean tryAdvance(Consumer<? super K> action) {
1615 int hi;
1616 if (action == null)
1617 throw new NullPointerException();
1618 Node<K,V>[] tab = map.table;
1619 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
1620 while (current != null || index < hi) {
1621 if (current == null)
1622 current = tab[index++];
1623 else {
1624 K k = current.key;
1625 current = current.next;
1626 action.accept(k);
1627 if (map.modCount != expectedModCount)
1628 throw new ConcurrentModificationException();
1629 return true;
1630 }
1631 }
1632 }
1633 return false;
1634 }
1635
1636 public int characteristics() {
1637 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
1638 Spliterator.DISTINCT;
1639 }
1640 }
1641
1642 static final class ValueSpliterator<K,V>
1643 extends HashMapSpliterator<K,V>
1644 implements Spliterator<V> {
1645 ValueSpliterator(HashMap<K,V> m, int origin, int fence, int est,
1646 int expectedModCount) {
1647 super(m, origin, fence, est, expectedModCount);
1648 }
1649
1650 public ValueSpliterator<K,V> trySplit() {
1651 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1652 return (lo >= mid || current != null) ? null :
1653 new ValueSpliterator<>(map, lo, index = mid, est >>>= 1,
1654 expectedModCount);
1655 }
1656
1657 public void forEachRemaining(Consumer<? super V> action) {
1658 int i, hi, mc;
1659 if (action == null)
1660 throw new NullPointerException();
1661 HashMap<K,V> m = map;
1662 Node<K,V>[] tab = m.table;
1663 if ((hi = fence) < 0) {
1664 mc = expectedModCount = m.modCount;
1665 hi = fence = (tab == null) ? 0 : tab.length;
1666 }
1667 else
1668 mc = expectedModCount;
1669 if (tab != null && tab.length >= hi &&
1670 (i = index) >= 0 && (i < (index = hi) || current != null)) {
1671 Node<K,V> p = current;
1672 current = null;
1673 do {
1674 if (p == null)
1675 p = tab[i++];
1676 else {
1677 action.accept(p.value);
1678 p = p.next;
1679 }
1680 } while (p != null || i < hi);
1681 if (m.modCount != mc)
1682 throw new ConcurrentModificationException();
1683 }
1684 }
1685
1686 public boolean tryAdvance(Consumer<? super V> action) {
1687 int hi;
1688 if (action == null)
1689 throw new NullPointerException();
1690 Node<K,V>[] tab = map.table;
1691 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
1692 while (current != null || index < hi) {
1693 if (current == null)
1694 current = tab[index++];
1695 else {
1696 V v = current.value;
1697 current = current.next;
1698 action.accept(v);
1699 if (map.modCount != expectedModCount)
1700 throw new ConcurrentModificationException();
1701 return true;
1702 }
1703 }
1704 }
1705 return false;
1706 }
1707
1708 public int characteristics() {
1709 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0);
1710 }
1711 }
1712
1713 static final class EntrySpliterator<K,V>
1714 extends HashMapSpliterator<K,V>
1715 implements Spliterator<Map.Entry<K,V>> {
1716 EntrySpliterator(HashMap<K,V> m, int origin, int fence, int est,
1717 int expectedModCount) {
1718 super(m, origin, fence, est, expectedModCount);
1719 }
1720
1721 public EntrySpliterator<K,V> trySplit() {
1722 int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1723 return (lo >= mid || current != null) ? null :
1724 new EntrySpliterator<>(map, lo, index = mid, est >>>= 1,
1725 expectedModCount);
1726 }
1727
1728 public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
1729 int i, hi, mc;
1730 if (action == null)
1731 throw new NullPointerException();
1732 HashMap<K,V> m = map;
1733 Node<K,V>[] tab = m.table;
1734 if ((hi = fence) < 0) {
1735 mc = expectedModCount = m.modCount;
1736 hi = fence = (tab == null) ? 0 : tab.length;
1737 }
1738 else
1739 mc = expectedModCount;
1740 if (tab != null && tab.length >= hi &&
1741 (i = index) >= 0 && (i < (index = hi) || current != null)) {
1742 Node<K,V> p = current;
1743 current = null;
1744 do {
1745 if (p == null)
1746 p = tab[i++];
1747 else {
1748 action.accept(p);
1749 p = p.next;
1750 }
1751 } while (p != null || i < hi);
1752 if (m.modCount != mc)
1753 throw new ConcurrentModificationException();
1754 }
1755 }
1756
1757 public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
1758 int hi;
1759 if (action == null)
1760 throw new NullPointerException();
1761 Node<K,V>[] tab = map.table;
1762 if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
1763 while (current != null || index < hi) {
1764 if (current == null)
1765 current = tab[index++];
1766 else {
1767 Node<K,V> e = current;
1768 current = current.next;
1769 action.accept(e);
1770 if (map.modCount != expectedModCount)
1771 throw new ConcurrentModificationException();
1772 return true;
1773 }
1774 }
1775 }
1776 return false;
1777 }
1778
1779 public int characteristics() {
1780 return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
1781 Spliterator.DISTINCT;
1782 }
1783 }
1784
1785 /* ------------------------------------------------------------ */
1786 // LinkedHashMap support
1787
1788
1789 /*
1790 * The following package-protected methods are designed to be
1791 * overridden by LinkedHashMap, but not by any other subclass.
1792 * Nearly all other internal methods are also package-protected
1793 * but are declared final, so can be used by LinkedHashMap, view
1794 * classes, and HashSet.
1795 */
1796
1797 // Create a regular (non-tree) node
1798 Node<K,V> newNode(int hash, K key, V value, Node<K,V> next) {
1799 return new Node<>(hash, key, value, next);
1800 }
1801
1802 // For conversion from TreeNodes to plain nodes
1803 Node<K,V> replacementNode(Node<K,V> p, Node<K,V> next) {
1804 return new Node<>(p.hash, p.key, p.value, next);
1805 }
1806
1807 // Create a tree bin node
1808 TreeNode<K,V> newTreeNode(int hash, K key, V value, Node<K,V> next) {
1809 return new TreeNode<>(hash, key, value, next);
1810 }
1811
1812 // For treeifyBin
1813 TreeNode<K,V> replacementTreeNode(Node<K,V> p, Node<K,V> next) {
1814 return new TreeNode<>(p.hash, p.key, p.value, next);
1815 }
1816
1817 /**
1818 * Reset to initial default state. Called by clone and readObject.
1819 */
1820 void reinitialize() {
1821 table = null;
1822 entrySet = null;
1823 keySet = null;
1824 values = null;
1825 modCount = 0;
1826 threshold = 0;
1827 size = 0;
1828 }
1829
1830 // Callbacks to allow LinkedHashMap post-actions
1831 void afterNodeAccess(Node<K,V> p) { }
1832 void afterNodeInsertion(boolean evict) { }
1833 void afterNodeRemoval(Node<K,V> p) { }
1834
1835 // Called only from writeObject, to ensure compatible ordering.
1836 void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException {
1837 Node<K,V>[] tab;
1838 if (size > 0 && (tab = table) != null) {
1839 for (Node<K,V> e : tab) {
1840 for (; e != null; e = e.next) {
1841 s.writeObject(e.key);
1842 s.writeObject(e.value);
1843 }
1844 }
1845 }
1846 }
1847
1848 /* ------------------------------------------------------------ */
1849 // Tree bins
1850
1851 /**
1852 * Entry for Tree bins. Extends LinkedHashMap.Entry (which in turn
1853 * extends Node) so can be used as extension of either regular or
1854 * linked node.
1855 */
1856 static final class TreeNode<K,V> extends LinkedHashMap.Entry<K,V> {
1857 TreeNode<K,V> parent; // red-black tree links
1858 TreeNode<K,V> left;
1859 TreeNode<K,V> right;
1860 TreeNode<K,V> prev; // needed to unlink next upon deletion
1861 boolean red;
1862 TreeNode(int hash, K key, V val, Node<K,V> next) {
1863 super(hash, key, val, next);
1864 }
1865
1866 /**
1867 * Returns root of tree containing this node.
1868 */
1869 final TreeNode<K,V> root() {
1870 for (TreeNode<K,V> r = this, p;;) {
1871 if ((p = r.parent) == null)
1872 return r;
1873 r = p;
1874 }
1875 }
1876
1877 /**
1878 * Ensures that the given root is the first node of its bin.
1879 */
1880 static <K,V> void moveRootToFront(Node<K,V>[] tab, TreeNode<K,V> root) {
1881 int n;
1882 if (root != null && tab != null && (n = tab.length) > 0) {
1883 int index = (n - 1) & root.hash;
1884 TreeNode<K,V> first = (TreeNode<K,V>)tab[index];
1885 if (root != first) {
1886 Node<K,V> rn;
1887 tab[index] = root;
1888 TreeNode<K,V> rp = root.prev;
1889 if ((rn = root.next) != null)
1890 ((TreeNode<K,V>)rn).prev = rp;
1891 if (rp != null)
1892 rp.next = rn;
1893 if (first != null)
1894 first.prev = root;
1895 root.next = first;
1896 root.prev = null;
1897 }
1898 assert checkInvariants(root);
1899 }
1900 }
1901
1902 /**
1903 * Finds the node starting at root p with the given hash and key.
1904 * The kc argument caches comparableClassFor(key) upon first use
1905 * comparing keys.
1906 */
1907 final TreeNode<K,V> find(int h, Object k, Class<?> kc) {
1908 TreeNode<K,V> p = this;
1909 do {
1910 int ph, dir; K pk;
1911 TreeNode<K,V> pl = p.left, pr = p.right, q;
1912 if ((ph = p.hash) > h)
1913 p = pl;
1914 else if (ph < h)
1915 p = pr;
1916 else if ((pk = p.key) == k || (k != null && k.equals(pk)))
1917 return p;
1918 else if (pl == null)
1919 p = pr;
1920 else if (pr == null)
1921 p = pl;
1922 else if ((kc != null ||
1923 (kc = comparableClassFor(k)) != null) &&
1924 (dir = compareComparables(kc, k, pk)) != 0)
1925 p = (dir < 0) ? pl : pr;
1926 else if ((q = pr.find(h, k, kc)) != null)
1927 return q;
1928 else
1929 p = pl;
1930 } while (p != null);
1931 return null;
1932 }
1933
1934 /**
1935 * Calls find for root node.
1936 */
1937 final TreeNode<K,V> getTreeNode(int h, Object k) {
1938 return ((parent != null) ? root() : this).find(h, k, null);
1939 }
1940
1941 /**
1942 * Tie-breaking utility for ordering insertions when equal
1943 * hashCodes and non-comparable. We don't require a total
1944 * order, just a consistent insertion rule to maintain
1945 * equivalence across rebalancings. Tie-breaking further than
1946 * necessary simplifies testing a bit.
1947 */
1948 static int tieBreakOrder(Object a, Object b) {
1949 int d;
1950 if (a == null || b == null ||
1951 (d = a.getClass().getName().
1952 compareTo(b.getClass().getName())) == 0)
1953 d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
1954 -1 : 1);
1955 return d;
1956 }
1957
1958 /**
1959 * Forms tree of the nodes linked from this node.
1960 */
1961 final void treeify(Node<K,V>[] tab) {
1962 TreeNode<K,V> root = null;
1963 for (TreeNode<K,V> x = this, next; x != null; x = next) {
1964 next = (TreeNode<K,V>)x.next;
1965 x.left = x.right = null;
1966 if (root == null) {
1967 x.parent = null;
1968 x.red = false;
1969 root = x;
1970 }
1971 else {
1972 K k = x.key;
1973 int h = x.hash;
1974 Class<?> kc = null;
1975 for (TreeNode<K,V> p = root;;) {
1976 int dir, ph;
1977 K pk = p.key;
1978 if ((ph = p.hash) > h)
1979 dir = -1;
1980 else if (ph < h)
1981 dir = 1;
1982 else if ((kc == null &&
1983 (kc = comparableClassFor(k)) == null) ||
1984 (dir = compareComparables(kc, k, pk)) == 0)
1985 dir = tieBreakOrder(k, pk);
1986
1987 TreeNode<K,V> xp = p;
1988 if ((p = (dir <= 0) ? p.left : p.right) == null) {
1989 x.parent = xp;
1990 if (dir <= 0)
1991 xp.left = x;
1992 else
1993 xp.right = x;
1994 root = balanceInsertion(root, x);
1995 break;
1996 }
1997 }
1998 }
1999 }
2000 moveRootToFront(tab, root);
2001 }
2002
2003 /**
2004 * Returns a list of non-TreeNodes replacing those linked from
2005 * this node.
2006 */
2007 final Node<K,V> untreeify(HashMap<K,V> map) {
2008 Node<K,V> hd = null, tl = null;
2009 for (Node<K,V> q = this; q != null; q = q.next) {
2010 Node<K,V> p = map.replacementNode(q, null);
2011 if (tl == null)
2012 hd = p;
2013 else
2014 tl.next = p;
2015 tl = p;
2016 }
2017 return hd;
2018 }
2019
2020 /**
2021 * Tree version of putVal.
2022 */
2023 final TreeNode<K,V> putTreeVal(HashMap<K,V> map, Node<K,V>[] tab,
2024 int h, K k, V v) {
2025 Class<?> kc = null;
2026 boolean searched = false;
2027 TreeNode<K,V> root = (parent != null) ? root() : this;
2028 for (TreeNode<K,V> p = root;;) {
2029 int dir, ph; K pk;
2030 if ((ph = p.hash) > h)
2031 dir = -1;
2032 else if (ph < h)
2033 dir = 1;
2034 else if ((pk = p.key) == k || (k != null && k.equals(pk)))
2035 return p;
2036 else if ((kc == null &&
2037 (kc = comparableClassFor(k)) == null) ||
2038 (dir = compareComparables(kc, k, pk)) == 0) {
2039 if (!searched) {
2040 TreeNode<K,V> q, ch;
2041 searched = true;
2042 if (((ch = p.left) != null &&
2043 (q = ch.find(h, k, kc)) != null) ||
2044 ((ch = p.right) != null &&
2045 (q = ch.find(h, k, kc)) != null))
2046 return q;
2047 }
2048 dir = tieBreakOrder(k, pk);
2049 }
2050
2051 TreeNode<K,V> xp = p;
2052 if ((p = (dir <= 0) ? p.left : p.right) == null) {
2053 Node<K,V> xpn = xp.next;
2054 TreeNode<K,V> x = map.newTreeNode(h, k, v, xpn);
2055 if (dir <= 0)
2056 xp.left = x;
2057 else
2058 xp.right = x;
2059 xp.next = x;
2060 x.parent = x.prev = xp;
2061 if (xpn != null)
2062 ((TreeNode<K,V>)xpn).prev = x;
2063 moveRootToFront(tab, balanceInsertion(root, x));
2064 return null;
2065 }
2066 }
2067 }
2068
2069 /**
2070 * Removes the given node, that must be present before this call.
2071 * This is messier than typical red-black deletion code because we
2072 * cannot swap the contents of an interior node with a leaf
2073 * successor that is pinned by "next" pointers that are accessible
2074 * independently during traversal. So instead we swap the tree
2075 * linkages. If the current tree appears to have too few nodes,
2076 * the bin is converted back to a plain bin. (The test triggers
2077 * somewhere between 2 and 6 nodes, depending on tree structure).
2078 */
2079 final void removeTreeNode(HashMap<K,V> map, Node<K,V>[] tab,
2080 boolean movable) {
2081 int n;
2082 if (tab == null || (n = tab.length) == 0)
2083 return;
2084 int index = (n - 1) & hash;
2085 TreeNode<K,V> first = (TreeNode<K,V>)tab[index], root = first, rl;
2086 TreeNode<K,V> succ = (TreeNode<K,V>)next, pred = prev;
2087 if (pred == null)
2088 tab[index] = first = succ;
2089 else
2090 pred.next = succ;
2091 if (succ != null)
2092 succ.prev = pred;
2093 if (first == null)
2094 return;
2095 if (root.parent != null)
2096 root = root.root();
2097 if (root == null
2098 || (movable
2099 && (root.right == null
2100 || (rl = root.left) == null
2101 || rl.left == null))) {
2102 tab[index] = first.untreeify(map); // too small
2103 return;
2104 }
2105 TreeNode<K,V> p = this, pl = left, pr = right, replacement;
2106 if (pl != null && pr != null) {
2107 TreeNode<K,V> s = pr, sl;
2108 while ((sl = s.left) != null) // find successor
2109 s = sl;
2110 boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2111 TreeNode<K,V> sr = s.right;
2112 TreeNode<K,V> pp = p.parent;
2113 if (s == pr) { // p was s's direct parent
2114 p.parent = s;
2115 s.right = p;
2116 }
2117 else {
2118 TreeNode<K,V> sp = s.parent;
2119 if ((p.parent = sp) != null) {
2120 if (s == sp.left)
2121 sp.left = p;
2122 else
2123 sp.right = p;
2124 }
2125 if ((s.right = pr) != null)
2126 pr.parent = s;
2127 }
2128 p.left = null;
2129 if ((p.right = sr) != null)
2130 sr.parent = p;
2131 if ((s.left = pl) != null)
2132 pl.parent = s;
2133 if ((s.parent = pp) == null)
2134 root = s;
2135 else if (p == pp.left)
2136 pp.left = s;
2137 else
2138 pp.right = s;
2139 if (sr != null)
2140 replacement = sr;
2141 else
2142 replacement = p;
2143 }
2144 else if (pl != null)
2145 replacement = pl;
2146 else if (pr != null)
2147 replacement = pr;
2148 else
2149 replacement = p;
2150 if (replacement != p) {
2151 TreeNode<K,V> pp = replacement.parent = p.parent;
2152 if (pp == null)
2153 (root = replacement).red = false;
2154 else if (p == pp.left)
2155 pp.left = replacement;
2156 else
2157 pp.right = replacement;
2158 p.left = p.right = p.parent = null;
2159 }
2160
2161 TreeNode<K,V> r = p.red ? root : balanceDeletion(root, replacement);
2162
2163 if (replacement == p) { // detach
2164 TreeNode<K,V> pp = p.parent;
2165 p.parent = null;
2166 if (pp != null) {
2167 if (p == pp.left)
2168 pp.left = null;
2169 else if (p == pp.right)
2170 pp.right = null;
2171 }
2172 }
2173 if (movable)
2174 moveRootToFront(tab, r);
2175 }
2176
2177 /**
2178 * Splits nodes in a tree bin into lower and upper tree bins,
2179 * or untreeifies if now too small. Called only from resize;
2180 * see above discussion about split bits and indices.
2181 *
2182 * @param map the map
2183 * @param tab the table for recording bin heads
2184 * @param index the index of the table being split
2185 * @param bit the bit of hash to split on
2186 */
2187 final void split(HashMap<K,V> map, Node<K,V>[] tab, int index, int bit) {
2188 TreeNode<K,V> b = this;
2189 // Relink into lo and hi lists, preserving order
2190 TreeNode<K,V> loHead = null, loTail = null;
2191 TreeNode<K,V> hiHead = null, hiTail = null;
2192 int lc = 0, hc = 0;
2193 for (TreeNode<K,V> e = b, next; e != null; e = next) {
2194 next = (TreeNode<K,V>)e.next;
2195 e.next = null;
2196 if ((e.hash & bit) == 0) {
2197 if ((e.prev = loTail) == null)
2198 loHead = e;
2199 else
2200 loTail.next = e;
2201 loTail = e;
2202 ++lc;
2203 }
2204 else {
2205 if ((e.prev = hiTail) == null)
2206 hiHead = e;
2207 else
2208 hiTail.next = e;
2209 hiTail = e;
2210 ++hc;
2211 }
2212 }
2213
2214 if (loHead != null) {
2215 if (lc <= UNTREEIFY_THRESHOLD)
2216 tab[index] = loHead.untreeify(map);
2217 else {
2218 tab[index] = loHead;
2219 if (hiHead != null) // (else is already treeified)
2220 loHead.treeify(tab);
2221 }
2222 }
2223 if (hiHead != null) {
2224 if (hc <= UNTREEIFY_THRESHOLD)
2225 tab[index + bit] = hiHead.untreeify(map);
2226 else {
2227 tab[index + bit] = hiHead;
2228 if (loHead != null)
2229 hiHead.treeify(tab);
2230 }
2231 }
2232 }
2233
2234 /* ------------------------------------------------------------ */
2235 // Red-black tree methods, all adapted from CLR
2236
2237 static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
2238 TreeNode<K,V> p) {
2239 TreeNode<K,V> r, pp, rl;
2240 if (p != null && (r = p.right) != null) {
2241 if ((rl = p.right = r.left) != null)
2242 rl.parent = p;
2243 if ((pp = r.parent = p.parent) == null)
2244 (root = r).red = false;
2245 else if (pp.left == p)
2246 pp.left = r;
2247 else
2248 pp.right = r;
2249 r.left = p;
2250 p.parent = r;
2251 }
2252 return root;
2253 }
2254
2255 static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
2256 TreeNode<K,V> p) {
2257 TreeNode<K,V> l, pp, lr;
2258 if (p != null && (l = p.left) != null) {
2259 if ((lr = p.left = l.right) != null)
2260 lr.parent = p;
2261 if ((pp = l.parent = p.parent) == null)
2262 (root = l).red = false;
2263 else if (pp.right == p)
2264 pp.right = l;
2265 else
2266 pp.left = l;
2267 l.right = p;
2268 p.parent = l;
2269 }
2270 return root;
2271 }
2272
2273 static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
2274 TreeNode<K,V> x) {
2275 x.red = true;
2276 for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
2277 if ((xp = x.parent) == null) {
2278 x.red = false;
2279 return x;
2280 }
2281 else if (!xp.red || (xpp = xp.parent) == null)
2282 return root;
2283 if (xp == (xppl = xpp.left)) {
2284 if ((xppr = xpp.right) != null && xppr.red) {
2285 xppr.red = false;
2286 xp.red = false;
2287 xpp.red = true;
2288 x = xpp;
2289 }
2290 else {
2291 if (x == xp.right) {
2292 root = rotateLeft(root, x = xp);
2293 xpp = (xp = x.parent) == null ? null : xp.parent;
2294 }
2295 if (xp != null) {
2296 xp.red = false;
2297 if (xpp != null) {
2298 xpp.red = true;
2299 root = rotateRight(root, xpp);
2300 }
2301 }
2302 }
2303 }
2304 else {
2305 if (xppl != null && xppl.red) {
2306 xppl.red = false;
2307 xp.red = false;
2308 xpp.red = true;
2309 x = xpp;
2310 }
2311 else {
2312 if (x == xp.left) {
2313 root = rotateRight(root, x = xp);
2314 xpp = (xp = x.parent) == null ? null : xp.parent;
2315 }
2316 if (xp != null) {
2317 xp.red = false;
2318 if (xpp != null) {
2319 xpp.red = true;
2320 root = rotateLeft(root, xpp);
2321 }
2322 }
2323 }
2324 }
2325 }
2326 }
2327
2328 static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
2329 TreeNode<K,V> x) {
2330 for (TreeNode<K,V> xp, xpl, xpr;;) {
2331 if (x == null || x == root)
2332 return root;
2333 else if ((xp = x.parent) == null) {
2334 x.red = false;
2335 return x;
2336 }
2337 else if (x.red) {
2338 x.red = false;
2339 return root;
2340 }
2341 else if ((xpl = xp.left) == x) {
2342 if ((xpr = xp.right) != null && xpr.red) {
2343 xpr.red = false;
2344 xp.red = true;
2345 root = rotateLeft(root, xp);
2346 xpr = (xp = x.parent) == null ? null : xp.right;
2347 }
2348 if (xpr == null)
2349 x = xp;
2350 else {
2351 TreeNode<K,V> sl = xpr.left, sr = xpr.right;
2352 if ((sr == null || !sr.red) &&
2353 (sl == null || !sl.red)) {
2354 xpr.red = true;
2355 x = xp;
2356 }
2357 else {
2358 if (sr == null || !sr.red) {
2359 if (sl != null)
2360 sl.red = false;
2361 xpr.red = true;
2362 root = rotateRight(root, xpr);
2363 xpr = (xp = x.parent) == null ?
2364 null : xp.right;
2365 }
2366 if (xpr != null) {
2367 xpr.red = (xp == null) ? false : xp.red;
2368 if ((sr = xpr.right) != null)
2369 sr.red = false;
2370 }
2371 if (xp != null) {
2372 xp.red = false;
2373 root = rotateLeft(root, xp);
2374 }
2375 x = root;
2376 }
2377 }
2378 }
2379 else { // symmetric
2380 if (xpl != null && xpl.red) {
2381 xpl.red = false;
2382 xp.red = true;
2383 root = rotateRight(root, xp);
2384 xpl = (xp = x.parent) == null ? null : xp.left;
2385 }
2386 if (xpl == null)
2387 x = xp;
2388 else {
2389 TreeNode<K,V> sl = xpl.left, sr = xpl.right;
2390 if ((sl == null || !sl.red) &&
2391 (sr == null || !sr.red)) {
2392 xpl.red = true;
2393 x = xp;
2394 }
2395 else {
2396 if (sl == null || !sl.red) {
2397 if (sr != null)
2398 sr.red = false;
2399 xpl.red = true;
2400 root = rotateLeft(root, xpl);
2401 xpl = (xp = x.parent) == null ?
2402 null : xp.left;
2403 }
2404 if (xpl != null) {
2405 xpl.red = (xp == null) ? false : xp.red;
2406 if ((sl = xpl.left) != null)
2407 sl.red = false;
2408 }
2409 if (xp != null) {
2410 xp.red = false;
2411 root = rotateRight(root, xp);
2412 }
2413 x = root;
2414 }
2415 }
2416 }
2417 }
2418 }
2419
2420 /**
2421 * Recursive invariant check
2422 */
2423 static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
2424 TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
2425 tb = t.prev, tn = (TreeNode<K,V>)t.next;
2426 if (tb != null && tb.next != t)
2427 return false;
2428 if (tn != null && tn.prev != t)
2429 return false;
2430 if (tp != null && t != tp.left && t != tp.right)
2431 return false;
2432 if (tl != null && (tl.parent != t || tl.hash > t.hash))
2433 return false;
2434 if (tr != null && (tr.parent != t || tr.hash < t.hash))
2435 return false;
2436 if (t.red && tl != null && tl.red && tr != null && tr.red)
2437 return false;
2438 if (tl != null && !checkInvariants(tl))
2439 return false;
2440 if (tr != null && !checkInvariants(tr))
2441 return false;
2442 return true;
2443 }
2444 }
2445
2446 }