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