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1 : jsr166 1.1 /*
2 : jsr166 1.4 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 : jsr166 1.1 * 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 : jsr166 1.3 import jdk.internal.misc.SharedSecrets;
38 : jsr166 1.1
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/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 : jsr166 1.5 int n = -1 >>> Integer.numberOfLeadingZeros(cap - 1);
380 : jsr166 1.1 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 :     }
505 :     else if (s > threshold)
506 :     resize();
507 :     for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
508 :     K key = e.getKey();
509 :     V value = e.getValue();
510 :     putVal(hash(key), key, value, false, evict);
511 :     }
512 :     }
513 :     }
514 :    
515 :     /**
516 :     * Returns the number of key-value mappings in this map.
517 :     *
518 :     * @return the number of key-value mappings in this map
519 :     */
520 :     public int size() {
521 :     return size;
522 :     }
523 :    
524 :     /**
525 :     * Returns {@code true} if this map contains no key-value mappings.
526 :     *
527 :     * @return {@code true} if this map contains no key-value mappings
528 :     */
529 :     public boolean isEmpty() {
530 :     return size == 0;
531 :     }
532 :    
533 :     /**
534 :     * Returns the value to which the specified key is mapped,
535 :     * or {@code null} if this map contains no mapping for the key.
536 :     *
537 :     * <p>More formally, if this map contains a mapping from a key
538 :     * {@code k} to a value {@code v} such that {@code (key==null ? k==null :
539 :     * key.equals(k))}, then this method returns {@code v}; otherwise
540 :     * it returns {@code null}. (There can be at most one such mapping.)
541 :     *
542 :     * <p>A return value of {@code null} does not <i>necessarily</i>
543 :     * indicate that the map contains no mapping for the key; it's also
544 :     * possible that the map explicitly maps the key to {@code null}.
545 :     * The {@link #containsKey containsKey} operation may be used to
546 :     * distinguish these two cases.
547 :     *
548 :     * @see #put(Object, Object)
549 :     */
550 :     public V get(Object key) {
551 :     Node<K,V> e;
552 :     return (e = getNode(hash(key), key)) == null ? null : e.value;
553 :     }
554 :    
555 :     /**
556 :     * Implements Map.get and related methods.
557 :     *
558 :     * @param hash hash for key
559 :     * @param key the key
560 :     * @return the node, or null if none
561 :     */
562 :     final Node<K,V> getNode(int hash, Object key) {
563 :     Node<K,V>[] tab; Node<K,V> first, e; int n; K k;
564 :     if ((tab = table) != null && (n = tab.length) > 0 &&
565 :     (first = tab[(n - 1) & hash]) != null) {
566 :     if (first.hash == hash && // always check first node
567 :     ((k = first.key) == key || (key != null && key.equals(k))))
568 :     return first;
569 :     if ((e = first.next) != null) {
570 :     if (first instanceof TreeNode)
571 :     return ((TreeNode<K,V>)first).getTreeNode(hash, key);
572 :     do {
573 :     if (e.hash == hash &&
574 :     ((k = e.key) == key || (key != null && key.equals(k))))
575 :     return e;
576 :     } while ((e = e.next) != null);
577 :     }
578 :     }
579 :     return null;
580 :     }
581 :    
582 :     /**
583 :     * Returns {@code true} if this map contains a mapping for the
584 :     * specified key.
585 :     *
586 :     * @param key The key whose presence in this map is to be tested
587 :     * @return {@code true} if this map contains a mapping for the specified
588 :     * key.
589 :     */
590 :     public boolean containsKey(Object key) {
591 :     return getNode(hash(key), key) != null;
592 :     }
593 :    
594 :     /**
595 :     * Associates the specified value with the specified key in this map.
596 :     * If the map previously contained a mapping for the key, the old
597 :     * value is replaced.
598 :     *
599 :     * @param key key with which the specified value is to be associated
600 :     * @param value value to be associated with the specified key
601 :     * @return the previous value associated with {@code key}, or
602 :     * {@code null} if there was no mapping for {@code key}.
603 :     * (A {@code null} return can also indicate that the map
604 :     * previously associated {@code null} with {@code key}.)
605 :     */
606 :     public V put(K key, V value) {
607 :     return putVal(hash(key), key, value, false, true);
608 :     }
609 :    
610 :     /**
611 :     * Implements Map.put and related methods.
612 :     *
613 :     * @param hash hash for key
614 :     * @param key the key
615 :     * @param value the value to put
616 :     * @param onlyIfAbsent if true, don't change existing value
617 :     * @param evict if false, the table is in creation mode.
618 :     * @return previous value, or null if none
619 :     */
620 :     final V putVal(int hash, K key, V value, boolean onlyIfAbsent,
621 :     boolean evict) {
622 :     Node<K,V>[] tab; Node<K,V> p; int n, i;
623 :     if ((tab = table) == null || (n = tab.length) == 0)
624 :     n = (tab = resize()).length;
625 :     if ((p = tab[i = (n - 1) & hash]) == null)
626 :     tab[i] = newNode(hash, key, value, null);
627 :     else {
628 :     Node<K,V> e; K k;
629 :     if (p.hash == hash &&
630 :     ((k = p.key) == key || (key != null && key.equals(k))))
631 :     e = p;
632 :     else if (p instanceof TreeNode)
633 :     e = ((TreeNode<K,V>)p).putTreeVal(this, tab, hash, key, value);
634 :     else {
635 :     for (int binCount = 0; ; ++binCount) {
636 :     if ((e = p.next) == null) {
637 :     p.next = newNode(hash, key, value, null);
638 :     if (binCount >= TREEIFY_THRESHOLD - 1) // -1 for 1st
639 :     treeifyBin(tab, hash);
640 :     break;
641 :     }
642 :     if (e.hash == hash &&
643 :     ((k = e.key) == key || (key != null && key.equals(k))))
644 :     break;
645 :     p = e;
646 :     }
647 :     }
648 :     if (e != null) { // existing mapping for key
649 :     V oldValue = e.value;
650 :     if (!onlyIfAbsent || oldValue == null)
651 :     e.value = value;
652 :     afterNodeAccess(e);
653 :     return oldValue;
654 :     }
655 :     }
656 :     ++modCount;
657 :     if (++size > threshold)
658 :     resize();
659 :     afterNodeInsertion(evict);
660 :     return null;
661 :     }
662 :    
663 :     /**
664 :     * Initializes or doubles table size. If null, allocates in
665 :     * accord with initial capacity target held in field threshold.
666 :     * Otherwise, because we are using power-of-two expansion, the
667 :     * elements from each bin must either stay at same index, or move
668 :     * with a power of two offset in the new table.
669 :     *
670 :     * @return the table
671 :     */
672 :     final Node<K,V>[] resize() {
673 :     Node<K,V>[] oldTab = table;
674 :     int oldCap = (oldTab == null) ? 0 : oldTab.length;
675 :     int oldThr = threshold;
676 :     int newCap, newThr = 0;
677 :     if (oldCap > 0) {
678 :     if (oldCap >= MAXIMUM_CAPACITY) {
679 :     threshold = Integer.MAX_VALUE;
680 :     return oldTab;
681 :     }
682 :     else if ((newCap = oldCap << 1) < MAXIMUM_CAPACITY &&
683 :     oldCap >= DEFAULT_INITIAL_CAPACITY)
684 :     newThr = oldThr << 1; // double threshold
685 :     }
686 :     else if (oldThr > 0) // initial capacity was placed in threshold
687 :     newCap = oldThr;
688 :     else { // zero initial threshold signifies using defaults
689 :     newCap = DEFAULT_INITIAL_CAPACITY;
690 :     newThr = (int)(DEFAULT_LOAD_FACTOR * DEFAULT_INITIAL_CAPACITY);
691 :     }
692 :     if (newThr == 0) {
693 :     float ft = (float)newCap * loadFactor;
694 :     newThr = (newCap < MAXIMUM_CAPACITY && ft < (float)MAXIMUM_CAPACITY ?
695 :     (int)ft : Integer.MAX_VALUE);
696 :     }
697 :     threshold = newThr;
698 :     @SuppressWarnings({"rawtypes","unchecked"})
699 :     Node<K,V>[] newTab = (Node<K,V>[])new Node[newCap];
700 :     table = newTab;
701 :     if (oldTab != null) {
702 :     for (int j = 0; j < oldCap; ++j) {
703 :     Node<K,V> e;
704 :     if ((e = oldTab[j]) != null) {
705 :     oldTab[j] = null;
706 :     if (e.next == null)
707 :     newTab[e.hash & (newCap - 1)] = e;
708 :     else if (e instanceof TreeNode)
709 :     ((TreeNode<K,V>)e).split(this, newTab, j, oldCap);
710 :     else { // preserve order
711 :     Node<K,V> loHead = null, loTail = null;
712 :     Node<K,V> hiHead = null, hiTail = null;
713 :     Node<K,V> next;
714 :     do {
715 :     next = e.next;
716 :     if ((e.hash & oldCap) == 0) {
717 :     if (loTail == null)
718 :     loHead = e;
719 :     else
720 :     loTail.next = e;
721 :     loTail = e;
722 :     }
723 :     else {
724 :     if (hiTail == null)
725 :     hiHead = e;
726 :     else
727 :     hiTail.next = e;
728 :     hiTail = e;
729 :     }
730 :     } while ((e = next) != null);
731 :     if (loTail != null) {
732 :     loTail.next = null;
733 :     newTab[j] = loHead;
734 :     }
735 :     if (hiTail != null) {
736 :     hiTail.next = null;
737 :     newTab[j + oldCap] = hiHead;
738 :     }
739 :     }
740 :     }
741 :     }
742 :     }
743 :     return newTab;
744 :     }
745 :    
746 :     /**
747 :     * Replaces all linked nodes in bin at index for given hash unless
748 :     * table is too small, in which case resizes instead.
749 :     */
750 :     final void treeifyBin(Node<K,V>[] tab, int hash) {
751 :     int n, index; Node<K,V> e;
752 :     if (tab == null || (n = tab.length) < MIN_TREEIFY_CAPACITY)
753 :     resize();
754 :     else if ((e = tab[index = (n - 1) & hash]) != null) {
755 :     TreeNode<K,V> hd = null, tl = null;
756 :     do {
757 :     TreeNode<K,V> p = replacementTreeNode(e, null);
758 :     if (tl == null)
759 :     hd = p;
760 :     else {
761 :     p.prev = tl;
762 :     tl.next = p;
763 :     }
764 :     tl = p;
765 :     } while ((e = e.next) != null);
766 :     if ((tab[index] = hd) != null)
767 :     hd.treeify(tab);
768 :     }
769 :     }
770 :    
771 :     /**
772 :     * Copies all of the mappings from the specified map to this map.
773 :     * These mappings will replace any mappings that this map had for
774 :     * any of the keys currently in the specified map.
775 :     *
776 :     * @param m mappings to be stored in this map
777 :     * @throws NullPointerException if the specified map is null
778 :     */
779 :     public void putAll(Map<? extends K, ? extends V> m) {
780 :     putMapEntries(m, true);
781 :     }
782 :    
783 :     /**
784 :     * Removes the mapping for the specified key from this map if present.
785 :     *
786 :     * @param key key whose mapping is to be removed from the map
787 :     * @return the previous value associated with {@code key}, or
788 :     * {@code null} if there was no mapping for {@code key}.
789 :     * (A {@code null} return can also indicate that the map
790 :     * previously associated {@code null} with {@code key}.)
791 :     */
792 :     public V remove(Object key) {
793 :     Node<K,V> e;
794 :     return (e = removeNode(hash(key), key, null, false, true)) == null ?
795 :     null : e.value;
796 :     }
797 :    
798 :     /**
799 :     * Implements Map.remove and related methods.
800 :     *
801 :     * @param hash hash for key
802 :     * @param key the key
803 :     * @param value the value to match if matchValue, else ignored
804 :     * @param matchValue if true only remove if value is equal
805 :     * @param movable if false do not move other nodes while removing
806 :     * @return the node, or null if none
807 :     */
808 :     final Node<K,V> removeNode(int hash, Object key, Object value,
809 :     boolean matchValue, boolean movable) {
810 :     Node<K,V>[] tab; Node<K,V> p; int n, index;
811 :     if ((tab = table) != null && (n = tab.length) > 0 &&
812 :     (p = tab[index = (n - 1) & hash]) != null) {
813 :     Node<K,V> node = null, e; K k; V v;
814 :     if (p.hash == hash &&
815 :     ((k = p.key) == key || (key != null && key.equals(k))))
816 :     node = p;
817 :     else if ((e = p.next) != null) {
818 :     if (p instanceof TreeNode)
819 :     node = ((TreeNode<K,V>)p).getTreeNode(hash, key);
820 :     else {
821 :     do {
822 :     if (e.hash == hash &&
823 :     ((k = e.key) == key ||
824 :     (key != null && key.equals(k)))) {
825 :     node = e;
826 :     break;
827 :     }
828 :     p = e;
829 :     } while ((e = e.next) != null);
830 :     }
831 :     }
832 :     if (node != null && (!matchValue || (v = node.value) == value ||
833 :     (value != null && value.equals(v)))) {
834 :     if (node instanceof TreeNode)
835 :     ((TreeNode<K,V>)node).removeTreeNode(this, tab, movable);
836 :     else if (node == p)
837 :     tab[index] = node.next;
838 :     else
839 :     p.next = node.next;
840 :     ++modCount;
841 :     --size;
842 :     afterNodeRemoval(node);
843 :     return node;
844 :     }
845 :     }
846 :     return null;
847 :     }
848 :    
849 :     /**
850 :     * Removes all of the mappings from this map.
851 :     * The map will be empty after this call returns.
852 :     */
853 :     public void clear() {
854 :     Node<K,V>[] tab;
855 :     modCount++;
856 :     if ((tab = table) != null && size > 0) {
857 :     size = 0;
858 :     for (int i = 0; i < tab.length; ++i)
859 :     tab[i] = null;
860 :     }
861 :     }
862 :    
863 :     /**
864 :     * Returns {@code true} if this map maps one or more keys to the
865 :     * specified value.
866 :     *
867 :     * @param value value whose presence in this map is to be tested
868 :     * @return {@code true} if this map maps one or more keys to the
869 :     * specified value
870 :     */
871 :     public boolean containsValue(Object value) {
872 :     Node<K,V>[] tab; V v;
873 :     if ((tab = table) != null && size > 0) {
874 :     for (Node<K,V> e : tab) {
875 :     for (; e != null; e = e.next) {
876 :     if ((v = e.value) == value ||
877 :     (value != null && value.equals(v)))
878 :     return true;
879 :     }
880 :     }
881 :     }
882 :     return false;
883 :     }
884 :    
885 :     /**
886 :     * Returns a {@link Set} view of the keys contained in this map.
887 :     * The set is backed by the map, so changes to the map are
888 :     * reflected in the set, and vice-versa. If the map is modified
889 :     * while an iteration over the set is in progress (except through
890 :     * the iterator's own {@code remove} operation), the results of
891 :     * the iteration are undefined. The set supports element removal,
892 :     * which removes the corresponding mapping from the map, via the
893 :     * {@code Iterator.remove}, {@code Set.remove},
894 :     * {@code removeAll}, {@code retainAll}, and {@code clear}
895 :     * operations. It does not support the {@code add} or {@code addAll}
896 :     * operations.
897 :     *
898 :     * @return a set view of the keys contained in this map
899 :     */
900 :     public Set<K> keySet() {
901 :     Set<K> ks = keySet;
902 :     if (ks == null) {
903 :     ks = new KeySet();
904 :     keySet = ks;
905 :     }
906 :     return 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 {@code remove} 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 {@code Iterator.remove},
945 :     * {@code Collection.remove}, {@code removeAll},
946 :     * {@code retainAll} and {@code clear} operations. It does not
947 :     * support the {@code add} or {@code addAll} operations.
948 :     *
949 :     * @return a view of the values contained in this map
950 :     */
951 :     public Collection<V> values() {
952 :     Collection<V> vs = values;
953 :     if (vs == null) {
954 :     vs = new Values();
955 :     values = vs;
956 :     }
957 :     return vs;
958 :     }
959 :    
960 :     final class Values extends AbstractCollection<V> {
961 :     public final int size() { return size; }
962 :     public final void clear() { HashMap.this.clear(); }
963 :     public final Iterator<V> iterator() { return new ValueIterator(); }
964 :     public final boolean contains(Object o) { return containsValue(o); }
965 :     public final Spliterator<V> spliterator() {
966 :     return new ValueSpliterator<>(HashMap.this, 0, -1, 0, 0);
967 :     }
968 :     public final void forEach(Consumer<? super V> action) {
969 :     Node<K,V>[] tab;
970 :     if (action == null)
971 :     throw new NullPointerException();
972 :     if (size > 0 && (tab = table) != null) {
973 :     int mc = modCount;
974 :     for (Node<K,V> e : tab) {
975 :     for (; e != null; e = e.next)
976 :     action.accept(e.value);
977 :     }
978 :     if (modCount != mc)
979 :     throw new ConcurrentModificationException();
980 :     }
981 :     }
982 :     }
983 :    
984 :     /**
985 :     * Returns a {@link Set} view of the mappings contained in this map.
986 :     * The set is backed by the map, so changes to the map are
987 :     * reflected in the set, and vice-versa. If the map is modified
988 :     * while an iteration over the set is in progress (except through
989 :     * the iterator's own {@code remove} operation, or through the
990 :     * {@code setValue} operation on a map entry returned by the
991 :     * iterator) the results of the iteration are undefined. The set
992 :     * supports element removal, which removes the corresponding
993 :     * mapping from the map, via the {@code Iterator.remove},
994 :     * {@code Set.remove}, {@code removeAll}, {@code retainAll} and
995 :     * {@code clear} operations. It does not support the
996 :     * {@code add} or {@code addAll} operations.
997 :     *
998 :     * @return a set view of the mappings contained in this map
999 :     */
1000 :     public Set<Map.Entry<K,V>> entrySet() {
1001 :     Set<Map.Entry<K,V>> es;
1002 :     return (es = entrySet) == null ? (entrySet = new EntrySet()) : es;
1003 :     }
1004 :    
1005 :     final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
1006 :     public final int size() { return size; }
1007 :     public final void clear() { HashMap.this.clear(); }
1008 :     public final Iterator<Map.Entry<K,V>> iterator() {
1009 :     return new EntryIterator();
1010 :     }
1011 :     public final boolean contains(Object o) {
1012 :     if (!(o instanceof Map.Entry))
1013 :     return false;
1014 :     Map.Entry<?,?> e = (Map.Entry<?,?>) o;
1015 :     Object key = e.getKey();
1016 :     Node<K,V> candidate = getNode(hash(key), key);
1017 :     return candidate != null && candidate.equals(e);
1018 :     }
1019 :     public final boolean remove(Object o) {
1020 :     if (o instanceof Map.Entry) {
1021 :     Map.Entry<?,?> e = (Map.Entry<?,?>) o;
1022 :     Object key = e.getKey();
1023 :     Object value = e.getValue();
1024 :     return removeNode(hash(key), key, value, true, true) != null;
1025 :     }
1026 :     return false;
1027 :     }
1028 :     public final Spliterator<Map.Entry<K,V>> spliterator() {
1029 :     return new EntrySpliterator<>(HashMap.this, 0, -1, 0, 0);
1030 :     }
1031 :     public final void forEach(Consumer<? super Map.Entry<K,V>> action) {
1032 :     Node<K,V>[] tab;
1033 :     if (action == null)
1034 :     throw new NullPointerException();
1035 :     if (size > 0 && (tab = table) != null) {
1036 :     int mc = modCount;
1037 :     for (Node<K,V> e : tab) {
1038 :     for (; e != null; e = e.next)
1039 :     action.accept(e);
1040 :     }
1041 :     if (modCount != mc)
1042 :     throw new ConcurrentModificationException();
1043 :     }
1044 :     }
1045 :     }
1046 :    
1047 :     // Overrides of JDK8 Map extension methods
1048 :    
1049 :     @Override
1050 :     public V getOrDefault(Object key, V defaultValue) {
1051 :     Node<K,V> e;
1052 :     return (e = getNode(hash(key), key)) == null ? defaultValue : e.value;
1053 :     }
1054 :    
1055 :     @Override
1056 :     public V putIfAbsent(K key, V value) {
1057 :     return putVal(hash(key), key, value, true, true);
1058 :     }
1059 :    
1060 :     @Override
1061 :     public boolean remove(Object key, Object value) {
1062 :     return removeNode(hash(key), key, value, true, true) != null;
1063 :     }
1064 :    
1065 :     @Override
1066 :     public boolean replace(K key, V oldValue, V newValue) {
1067 :     Node<K,V> e; V v;
1068 :     if ((e = getNode(hash(key), key)) != null &&
1069 :     ((v = e.value) == oldValue || (v != null && v.equals(oldValue)))) {
1070 :     e.value = newValue;
1071 :     afterNodeAccess(e);
1072 :     return true;
1073 :     }
1074 :     return false;
1075 :     }
1076 :    
1077 :     @Override
1078 :     public V replace(K key, V value) {
1079 :     Node<K,V> e;
1080 :     if ((e = getNode(hash(key), key)) != null) {
1081 :     V oldValue = e.value;
1082 :     e.value = value;
1083 :     afterNodeAccess(e);
1084 :     return oldValue;
1085 :     }
1086 :     return null;
1087 :     }
1088 :    
1089 :     /**
1090 :     * {@inheritDoc}
1091 :     *
1092 :     * <p>This method will, on a best-effort basis, throw a
1093 :     * {@link ConcurrentModificationException} if it is detected that the
1094 :     * mapping function modifies this map during computation.
1095 :     *
1096 :     * @throws ConcurrentModificationException if it is detected that the
1097 :     * mapping function modified this map
1098 :     */
1099 :     @Override
1100 :     public V computeIfAbsent(K key,
1101 :     Function<? super K, ? extends V> mappingFunction) {
1102 :     if (mappingFunction == null)
1103 :     throw new NullPointerException();
1104 :     int hash = hash(key);
1105 :     Node<K,V>[] tab; Node<K,V> first; int n, i;
1106 :     int binCount = 0;
1107 :     TreeNode<K,V> t = null;
1108 :     Node<K,V> old = null;
1109 :     if (size > threshold || (tab = table) == null ||
1110 :     (n = tab.length) == 0)
1111 :     n = (tab = resize()).length;
1112 :     if ((first = tab[i = (n - 1) & hash]) != null) {
1113 :     if (first instanceof TreeNode)
1114 :     old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
1115 :     else {
1116 :     Node<K,V> e = first; K k;
1117 :     do {
1118 :     if (e.hash == hash &&
1119 :     ((k = e.key) == key || (key != null && key.equals(k)))) {
1120 :     old = e;
1121 :     break;
1122 :     }
1123 :     ++binCount;
1124 :     } while ((e = e.next) != null);
1125 :     }
1126 :     V oldValue;
1127 :     if (old != null && (oldValue = old.value) != null) {
1128 :     afterNodeAccess(old);
1129 :     return oldValue;
1130 :     }
1131 :     }
1132 :     int mc = modCount;
1133 :     V v = mappingFunction.apply(key);
1134 :     if (mc != modCount) { throw new ConcurrentModificationException(); }
1135 :     if (v == null) {
1136 :     return null;
1137 :     } else if (old != null) {
1138 :     old.value = v;
1139 :     afterNodeAccess(old);
1140 :     return v;
1141 :     }
1142 :     else if (t != null)
1143 :     t.putTreeVal(this, tab, hash, key, v);
1144 :     else {
1145 :     tab[i] = newNode(hash, key, v, first);
1146 :     if (binCount >= TREEIFY_THRESHOLD - 1)
1147 :     treeifyBin(tab, hash);
1148 :     }
1149 :     modCount = mc + 1;
1150 :     ++size;
1151 :     afterNodeInsertion(true);
1152 :     return v;
1153 :     }
1154 :    
1155 :     /**
1156 :     * {@inheritDoc}
1157 :     *
1158 :     * <p>This method will, on a best-effort basis, throw a
1159 :     * {@link ConcurrentModificationException} if it is detected that the
1160 :     * remapping function modifies this map during computation.
1161 :     *
1162 :     * @throws ConcurrentModificationException if it is detected that the
1163 :     * remapping function modified this map
1164 :     */
1165 :     @Override
1166 :     public V computeIfPresent(K key,
1167 :     BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1168 :     if (remappingFunction == null)
1169 :     throw new NullPointerException();
1170 :     Node<K,V> e; V oldValue;
1171 :     int hash = hash(key);
1172 :     if ((e = getNode(hash, key)) != null &&
1173 :     (oldValue = e.value) != null) {
1174 :     int mc = modCount;
1175 :     V v = remappingFunction.apply(key, oldValue);
1176 :     if (mc != modCount) { throw new ConcurrentModificationException(); }
1177 :     if (v != null) {
1178 :     e.value = v;
1179 :     afterNodeAccess(e);
1180 :     return v;
1181 :     }
1182 :     else
1183 :     removeNode(hash, key, null, false, true);
1184 :     }
1185 :     return null;
1186 :     }
1187 :    
1188 :     /**
1189 :     * {@inheritDoc}
1190 :     *
1191 :     * <p>This method will, on a best-effort basis, throw a
1192 :     * {@link ConcurrentModificationException} if it is detected that the
1193 :     * remapping function modifies this map during computation.
1194 :     *
1195 :     * @throws ConcurrentModificationException if it is detected that the
1196 :     * remapping function modified this map
1197 :     */
1198 :     @Override
1199 :     public V compute(K key,
1200 :     BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
1201 :     if (remappingFunction == null)
1202 :     throw new NullPointerException();
1203 :     int hash = hash(key);
1204 :     Node<K,V>[] tab; Node<K,V> first; int n, i;
1205 :     int binCount = 0;
1206 :     TreeNode<K,V> t = null;
1207 :     Node<K,V> old = null;
1208 :     if (size > threshold || (tab = table) == null ||
1209 :     (n = tab.length) == 0)
1210 :     n = (tab = resize()).length;
1211 :     if ((first = tab[i = (n - 1) & hash]) != null) {
1212 :     if (first instanceof TreeNode)
1213 :     old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
1214 :     else {
1215 :     Node<K,V> e = first; K k;
1216 :     do {
1217 :     if (e.hash == hash &&
1218 :     ((k = e.key) == key || (key != null && key.equals(k)))) {
1219 :     old = e;
1220 :     break;
1221 :     }
1222 :     ++binCount;
1223 :     } while ((e = e.next) != null);
1224 :     }
1225 :     }
1226 :     V oldValue = (old == null) ? null : old.value;
1227 :     int mc = modCount;
1228 :     V v = remappingFunction.apply(key, oldValue);
1229 :     if (mc != modCount) { throw new ConcurrentModificationException(); }
1230 :     if (old != null) {
1231 :     if (v != null) {
1232 :     old.value = v;
1233 :     afterNodeAccess(old);
1234 :     }
1235 :     else
1236 :     removeNode(hash, key, null, false, true);
1237 :     }
1238 :     else if (v != null) {
1239 :     if (t != null)
1240 :     t.putTreeVal(this, tab, hash, key, v);
1241 :     else {
1242 :     tab[i] = newNode(hash, key, v, first);
1243 :     if (binCount >= TREEIFY_THRESHOLD - 1)
1244 :     treeifyBin(tab, hash);
1245 :     }
1246 :     modCount = mc + 1;
1247 :     ++size;
1248 :     afterNodeInsertion(true);
1249 :     }
1250 :     return v;
1251 :     }
1252 :    
1253 :     /**
1254 :     * {@inheritDoc}
1255 :     *
1256 :     * <p>This method will, on a best-effort basis, throw a
1257 :     * {@link ConcurrentModificationException} if it is detected that the
1258 :     * remapping function modifies this map during computation.
1259 :     *
1260 :     * @throws ConcurrentModificationException if it is detected that the
1261 :     * remapping function modified this map
1262 :     */
1263 :     @Override
1264 :     public V merge(K key, V value,
1265 :     BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
1266 : jsr166 1.6 if (value == null || remappingFunction == null)
1267 : jsr166 1.1 throw new NullPointerException();
1268 :     int hash = hash(key);
1269 :     Node<K,V>[] tab; Node<K,V> first; int n, i;
1270 :     int binCount = 0;
1271 :     TreeNode<K,V> t = null;
1272 :     Node<K,V> old = null;
1273 :     if (size > threshold || (tab = table) == null ||
1274 :     (n = tab.length) == 0)
1275 :     n = (tab = resize()).length;
1276 :     if ((first = tab[i = (n - 1) & hash]) != null) {
1277 :     if (first instanceof TreeNode)
1278 :     old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
1279 :     else {
1280 :     Node<K,V> e = first; K k;
1281 :     do {
1282 :     if (e.hash == hash &&
1283 :     ((k = e.key) == key || (key != null && key.equals(k)))) {
1284 :     old = e;
1285 :     break;
1286 :     }
1287 :     ++binCount;
1288 :     } while ((e = e.next) != null);
1289 :     }
1290 :     }
1291 :     if (old != null) {
1292 :     V v;
1293 :     if (old.value != null) {
1294 :     int mc = modCount;
1295 :     v = remappingFunction.apply(old.value, value);
1296 :     if (mc != modCount) {
1297 :     throw new ConcurrentModificationException();
1298 :     }
1299 :     } else {
1300 :     v = value;
1301 :     }
1302 :     if (v != null) {
1303 :     old.value = v;
1304 :     afterNodeAccess(old);
1305 :     }
1306 :     else
1307 :     removeNode(hash, key, null, false, true);
1308 :     return v;
1309 : jsr166 1.6 } else {
1310 : jsr166 1.1 if (t != null)
1311 :     t.putTreeVal(this, tab, hash, key, value);
1312 :     else {
1313 :     tab[i] = newNode(hash, key, value, first);
1314 :     if (binCount >= TREEIFY_THRESHOLD - 1)
1315 :     treeifyBin(tab, hash);
1316 :     }
1317 :     ++modCount;
1318 :     ++size;
1319 :     afterNodeInsertion(true);
1320 : jsr166 1.6 return value;
1321 : jsr166 1.1 }
1322 :     }
1323 :    
1324 :     @Override
1325 :     public void forEach(BiConsumer<? super K, ? super V> action) {
1326 :     Node<K,V>[] tab;
1327 :     if (action == null)
1328 :     throw new NullPointerException();
1329 :     if (size > 0 && (tab = table) != null) {
1330 :     int mc = modCount;
1331 :     for (Node<K,V> e : tab) {
1332 :     for (; e != null; e = e.next)
1333 :     action.accept(e.key, e.value);
1334 :     }
1335 :     if (modCount != mc)
1336 :     throw new ConcurrentModificationException();
1337 :     }
1338 :     }
1339 :    
1340 :     @Override
1341 :     public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
1342 :     Node<K,V>[] tab;
1343 :     if (function == null)
1344 :     throw new NullPointerException();
1345 :     if (size > 0 && (tab = table) != null) {
1346 :     int mc = modCount;
1347 :     for (Node<K,V> e : tab) {
1348 :     for (; e != null; e = e.next) {
1349 :     e.value = function.apply(e.key, e.value);
1350 :     }
1351 :     }
1352 :     if (modCount != mc)
1353 :     throw new ConcurrentModificationException();
1354 :     }
1355 :     }
1356 :    
1357 :     /* ------------------------------------------------------------ */
1358 :     // Cloning and serialization
1359 :    
1360 :     /**
1361 :     * Returns a shallow copy of this {@code HashMap} instance: the keys and
1362 :     * values themselves are not cloned.
1363 :     *
1364 :     * @return a shallow copy of this map
1365 :     */
1366 :     @SuppressWarnings("unchecked")
1367 :     @Override
1368 :     public Object clone() {
1369 :     HashMap<K,V> result;
1370 :     try {
1371 :     result = (HashMap<K,V>)super.clone();
1372 :     } catch (CloneNotSupportedException e) {
1373 :     // this shouldn't happen, since we are Cloneable
1374 :     throw new InternalError(e);
1375 :     }
1376 :     result.reinitialize();
1377 :     result.putMapEntries(this, false);
1378 :     return result;
1379 :     }
1380 :    
1381 :     // These methods are also used when serializing HashSets
1382 :     final float loadFactor() { return loadFactor; }
1383 :     final int capacity() {
1384 :     return (table != null) ? table.length :
1385 :     (threshold > 0) ? threshold :
1386 :     DEFAULT_INITIAL_CAPACITY;
1387 :     }
1388 :    
1389 :     /**
1390 : jsr166 1.2 * Saves this map to a stream (that is, serializes it).
1391 : jsr166 1.1 *
1392 : jsr166 1.2 * @param s the stream
1393 :     * @throws IOException if an I/O error occurs
1394 : jsr166 1.1 * @serialData The <i>capacity</i> of the HashMap (the length of the
1395 :     * bucket array) is emitted (int), followed by the
1396 :     * <i>size</i> (an int, the number of key-value
1397 :     * mappings), followed by the key (Object) and value (Object)
1398 :     * for each key-value mapping. The key-value mappings are
1399 :     * emitted in no particular order.
1400 :     */
1401 :     private void writeObject(java.io.ObjectOutputStream s)
1402 :     throws IOException {
1403 :     int buckets = capacity();
1404 :     // Write out the threshold, loadfactor, and any hidden stuff
1405 :     s.defaultWriteObject();
1406 :     s.writeInt(buckets);
1407 :     s.writeInt(size);
1408 :     internalWriteEntries(s);
1409 :     }
1410 :    
1411 :     /**
1412 : jsr166 1.2 * Reconstitutes this map from a stream (that is, deserializes it).
1413 :     * @param s the stream
1414 :     * @throws ClassNotFoundException if the class of a serialized object
1415 :     * could not be found
1416 :     * @throws IOException if an I/O error occurs
1417 : jsr166 1.1 */
1418 :     private void readObject(java.io.ObjectInputStream s)
1419 :     throws IOException, ClassNotFoundException {
1420 :     // Read in the threshold (ignored), loadfactor, and any hidden stuff
1421 :     s.defaultReadObject();
1422 :     reinitialize();
1423 :     if (loadFactor <= 0 || Float.isNaN(loadFactor))
1424 :     throw new InvalidObjectException("Illegal load factor: " +
1425 :     loadFactor);
1426 :     s.readInt(); // Read and ignore number of buckets
1427 :     int mappings = s.readInt(); // Read number of mappings (size)
1428 :     if (mappings < 0)
1429 :     throw new InvalidObjectException("Illegal mappings count: " +
1430 :     mappings);
1431 :     else if (mappings > 0) { // (if zero, use defaults)
1432 :     // Size the table using given load factor only if within
1433 :     // range of 0.25...4.0
1434 :     float lf = Math.min(Math.max(0.25f, loadFactor), 4.0f);
1435 :     float fc = (float)mappings / lf + 1.0f;
1436 :     int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ?
1437 :     DEFAULT_INITIAL_CAPACITY :
1438 :     (fc >= MAXIMUM_CAPACITY) ?
1439 :     MAXIMUM_CAPACITY :
1440 :     tableSizeFor((int)fc));
1441 :     float ft = (float)cap * lf;
1442 :     threshold = ((cap < MAXIMUM_CAPACITY && ft < MAXIMUM_CAPACITY) ?
1443 :     (int)ft : Integer.MAX_VALUE);
1444 : jsr166 1.3
1445 :     // Check Map.Entry[].class since it's the nearest public type to
1446 :     // what we're actually creating.
1447 :     SharedSecrets.getJavaObjectInputStreamAccess().checkArray(s, Map.Entry[].class, cap);
1448 : jsr166 1.1 @SuppressWarnings({"rawtypes","unchecked"})
1449 :     Node<K,V>[] tab = (Node<K,V>[])new Node[cap];
1450 :     table = tab;
1451 :    
1452 :     // Read the keys and values, and put the mappings in the HashMap
1453 :     for (int i = 0; i < mappings; i++) {
1454 :     @SuppressWarnings("unchecked")
1455 :     K key = (K) s.readObject();
1456 :     @SuppressWarnings("unchecked")
1457 :     V value = (V) s.readObject();
1458 :     putVal(hash(key), key, value, false, false);
1459 :     }
1460 :     }
1461 :     }
1462 :    
1463 :     /* ------------------------------------------------------------ */
1464 :     // iterators
1465 :    
1466 :     abstract class HashIterator {
1467 :     Node<K,V> next; // next entry to return
1468 :     Node<K,V> current; // current entry
1469 :     int expectedModCount; // for fast-fail
1470 :     int index; // current slot
1471 :    
1472 :     HashIterator() {
1473 :     expectedModCount = modCount;
1474 :     Node<K,V>[] t = table;
1475 :     current = next = null;
1476 :     index = 0;
1477 :     if (t != null && size > 0) { // advance to first entry
1478 :     do {} while (index < t.length && (next = t[index++]) == null);
1479 :     }
1480 :     }
1481 :    
1482 :     public final boolean hasNext() {
1483 :     return next != null;
1484 :     }
1485 :    
1486 :     final Node<K,V> nextNode() {
1487 :     Node<K,V>[] t;
1488 :     Node<K,V> e = next;
1489 :     if (modCount != expectedModCount)
1490 :     throw new ConcurrentModificationException();
1491 :     if (e == null)
1492 :     throw new NoSuchElementException();
1493 :     if ((next = (current = e).next) == null && (t = table) != null) {
1494 :     do {} while (index < t.length && (next = t[index++]) == null);
1495 :     }
1496 :     return e;
1497 :     }
1498 :    
1499 :     public final void remove() {
1500 :     Node<K,V> p = current;
1501 :     if (p == null)
1502 :     throw new IllegalStateException();
1503 :     if (modCount != expectedModCount)
1504 :     throw new ConcurrentModificationException();
1505 :     current = null;
1506 :     removeNode(p.hash, p.key, null, false, false);
1507 :     expectedModCount = modCount;
1508 :     }
1509 :     }
1510 :    
1511 :     final class KeyIterator extends HashIterator
1512 :     implements Iterator<K> {
1513 :     public final K next() { return nextNode().key; }
1514 :     }
1515 :    
1516 :     final class ValueIterator extends HashIterator
1517 :     implements Iterator<V> {
1518 :     public final V next() { return nextNode().value; }
1519 :     }
1520 :    
1521 :     final class EntryIterator extends HashIterator
1522 :     implements Iterator<Map.Entry<K,V>> {
1523 :     public final Map.Entry<K,V> next() { return nextNode(); }
1524 :     }
1525 :    
1526 :     /* ------------------------------------------------------------ */
1527 :     // spliterators
1528 :    
1529 :     static class HashMapSpliterator<K,V> {
1530 :     final HashMap<K,V> map;
1531 :     Node<K,V> current; // current node
1532 :     int index; // current index, modified on advance/split
1533 :     int fence; // one past last index
1534 :     int est; // size estimate
1535 :     int expectedModCount; // for comodification checks
1536 :    
1537 :     HashMapSpliterator(HashMap<K,V> m, int origin,
1538 :     int fence, int est,
1539 :     int expectedModCount) {
1540 :     this.map = m;
1541 :     this.index = origin;
1542 :     this.fence = fence;
1543 :     this.est = est;
1544 :     this.expectedModCount = expectedModCount;
1545 :     }
1546 :    
1547 :     final int getFence() { // initialize fence and size on first use
1548 :     int hi;
1549 :     if ((hi = fence) < 0) {
1550 :     HashMap<K,V> m = map;
1551 :     est = m.size;
1552 :     expectedModCount = m.modCount;
1553 :     Node<K,V>[] tab = m.table;
1554 :     hi = fence = (tab == null) ? 0 : tab.length;
1555 :     }
1556 :     return hi;
1557 :     }
1558 :    
1559 :     public final long estimateSize() {
1560 :     getFence(); // force init
1561 :     return (long) est;
1562 :     }
1563 :     }
1564 :    
1565 :     static final class KeySpliterator<K,V>
1566 :     extends HashMapSpliterator<K,V>
1567 :     implements Spliterator<K> {
1568 :     KeySpliterator(HashMap<K,V> m, int origin, int fence, int est,
1569 :     int expectedModCount) {
1570 :     super(m, origin, fence, est, expectedModCount);
1571 :     }
1572 :    
1573 :     public KeySpliterator<K,V> trySplit() {
1574 :     int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1575 :     return (lo >= mid || current != null) ? null :
1576 :     new KeySpliterator<>(map, lo, index = mid, est >>>= 1,
1577 :     expectedModCount);
1578 :     }
1579 :    
1580 :     public void forEachRemaining(Consumer<? super K> action) {
1581 :     int i, hi, mc;
1582 :     if (action == null)
1583 :     throw new NullPointerException();
1584 :     HashMap<K,V> m = map;
1585 :     Node<K,V>[] tab = m.table;
1586 :     if ((hi = fence) < 0) {
1587 :     mc = expectedModCount = m.modCount;
1588 :     hi = fence = (tab == null) ? 0 : tab.length;
1589 :     }
1590 :     else
1591 :     mc = expectedModCount;
1592 :     if (tab != null && tab.length >= hi &&
1593 :     (i = index) >= 0 && (i < (index = hi) || current != null)) {
1594 :     Node<K,V> p = current;
1595 :     current = null;
1596 :     do {
1597 :     if (p == null)
1598 :     p = tab[i++];
1599 :     else {
1600 :     action.accept(p.key);
1601 :     p = p.next;
1602 :     }
1603 :     } while (p != null || i < hi);
1604 :     if (m.modCount != mc)
1605 :     throw new ConcurrentModificationException();
1606 :     }
1607 :     }
1608 :    
1609 :     public boolean tryAdvance(Consumer<? super K> action) {
1610 :     int hi;
1611 :     if (action == null)
1612 :     throw new NullPointerException();
1613 :     Node<K,V>[] tab = map.table;
1614 :     if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
1615 :     while (current != null || index < hi) {
1616 :     if (current == null)
1617 :     current = tab[index++];
1618 :     else {
1619 :     K k = current.key;
1620 :     current = current.next;
1621 :     action.accept(k);
1622 :     if (map.modCount != expectedModCount)
1623 :     throw new ConcurrentModificationException();
1624 :     return true;
1625 :     }
1626 :     }
1627 :     }
1628 :     return false;
1629 :     }
1630 :    
1631 :     public int characteristics() {
1632 :     return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
1633 :     Spliterator.DISTINCT;
1634 :     }
1635 :     }
1636 :    
1637 :     static final class ValueSpliterator<K,V>
1638 :     extends HashMapSpliterator<K,V>
1639 :     implements Spliterator<V> {
1640 :     ValueSpliterator(HashMap<K,V> m, int origin, int fence, int est,
1641 :     int expectedModCount) {
1642 :     super(m, origin, fence, est, expectedModCount);
1643 :     }
1644 :    
1645 :     public ValueSpliterator<K,V> trySplit() {
1646 :     int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1647 :     return (lo >= mid || current != null) ? null :
1648 :     new ValueSpliterator<>(map, lo, index = mid, est >>>= 1,
1649 :     expectedModCount);
1650 :     }
1651 :    
1652 :     public void forEachRemaining(Consumer<? super V> action) {
1653 :     int i, hi, mc;
1654 :     if (action == null)
1655 :     throw new NullPointerException();
1656 :     HashMap<K,V> m = map;
1657 :     Node<K,V>[] tab = m.table;
1658 :     if ((hi = fence) < 0) {
1659 :     mc = expectedModCount = m.modCount;
1660 :     hi = fence = (tab == null) ? 0 : tab.length;
1661 :     }
1662 :     else
1663 :     mc = expectedModCount;
1664 :     if (tab != null && tab.length >= hi &&
1665 :     (i = index) >= 0 && (i < (index = hi) || current != null)) {
1666 :     Node<K,V> p = current;
1667 :     current = null;
1668 :     do {
1669 :     if (p == null)
1670 :     p = tab[i++];
1671 :     else {
1672 :     action.accept(p.value);
1673 :     p = p.next;
1674 :     }
1675 :     } while (p != null || i < hi);
1676 :     if (m.modCount != mc)
1677 :     throw new ConcurrentModificationException();
1678 :     }
1679 :     }
1680 :    
1681 :     public boolean tryAdvance(Consumer<? super V> action) {
1682 :     int hi;
1683 :     if (action == null)
1684 :     throw new NullPointerException();
1685 :     Node<K,V>[] tab = map.table;
1686 :     if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
1687 :     while (current != null || index < hi) {
1688 :     if (current == null)
1689 :     current = tab[index++];
1690 :     else {
1691 :     V v = current.value;
1692 :     current = current.next;
1693 :     action.accept(v);
1694 :     if (map.modCount != expectedModCount)
1695 :     throw new ConcurrentModificationException();
1696 :     return true;
1697 :     }
1698 :     }
1699 :     }
1700 :     return false;
1701 :     }
1702 :    
1703 :     public int characteristics() {
1704 :     return (fence < 0 || est == map.size ? Spliterator.SIZED : 0);
1705 :     }
1706 :     }
1707 :    
1708 :     static final class EntrySpliterator<K,V>
1709 :     extends HashMapSpliterator<K,V>
1710 :     implements Spliterator<Map.Entry<K,V>> {
1711 :     EntrySpliterator(HashMap<K,V> m, int origin, int fence, int est,
1712 :     int expectedModCount) {
1713 :     super(m, origin, fence, est, expectedModCount);
1714 :     }
1715 :    
1716 :     public EntrySpliterator<K,V> trySplit() {
1717 :     int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1718 :     return (lo >= mid || current != null) ? null :
1719 :     new EntrySpliterator<>(map, lo, index = mid, est >>>= 1,
1720 :     expectedModCount);
1721 :     }
1722 :    
1723 :     public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
1724 :     int i, hi, mc;
1725 :     if (action == null)
1726 :     throw new NullPointerException();
1727 :     HashMap<K,V> m = map;
1728 :     Node<K,V>[] tab = m.table;
1729 :     if ((hi = fence) < 0) {
1730 :     mc = expectedModCount = m.modCount;
1731 :     hi = fence = (tab == null) ? 0 : tab.length;
1732 :     }
1733 :     else
1734 :     mc = expectedModCount;
1735 :     if (tab != null && tab.length >= hi &&
1736 :     (i = index) >= 0 && (i < (index = hi) || current != null)) {
1737 :     Node<K,V> p = current;
1738 :     current = null;
1739 :     do {
1740 :     if (p == null)
1741 :     p = tab[i++];
1742 :     else {
1743 :     action.accept(p);
1744 :     p = p.next;
1745 :     }
1746 :     } while (p != null || i < hi);
1747 :     if (m.modCount != mc)
1748 :     throw new ConcurrentModificationException();
1749 :     }
1750 :     }
1751 :    
1752 :     public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
1753 :     int hi;
1754 :     if (action == null)
1755 :     throw new NullPointerException();
1756 :     Node<K,V>[] tab = map.table;
1757 :     if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
1758 :     while (current != null || index < hi) {
1759 :     if (current == null)
1760 :     current = tab[index++];
1761 :     else {
1762 :     Node<K,V> e = current;
1763 :     current = current.next;
1764 :     action.accept(e);
1765 :     if (map.modCount != expectedModCount)
1766 :     throw new ConcurrentModificationException();
1767 :     return true;
1768 :     }
1769 :     }
1770 :     }
1771 :     return false;
1772 :     }
1773 :    
1774 :     public int characteristics() {
1775 :     return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
1776 :     Spliterator.DISTINCT;
1777 :     }
1778 :     }
1779 :    
1780 :     /* ------------------------------------------------------------ */
1781 :     // LinkedHashMap support
1782 :    
1783 :    
1784 :     /*
1785 :     * The following package-protected methods are designed to be
1786 :     * overridden by LinkedHashMap, but not by any other subclass.
1787 :     * Nearly all other internal methods are also package-protected
1788 :     * but are declared final, so can be used by LinkedHashMap, view
1789 :     * classes, and HashSet.
1790 :     */
1791 :    
1792 :     // Create a regular (non-tree) node
1793 :     Node<K,V> newNode(int hash, K key, V value, Node<K,V> next) {
1794 :     return new Node<>(hash, key, value, next);
1795 :     }
1796 :    
1797 :     // For conversion from TreeNodes to plain nodes
1798 :     Node<K,V> replacementNode(Node<K,V> p, Node<K,V> next) {
1799 :     return new Node<>(p.hash, p.key, p.value, next);
1800 :     }
1801 :    
1802 :     // Create a tree bin node
1803 :     TreeNode<K,V> newTreeNode(int hash, K key, V value, Node<K,V> next) {
1804 :     return new TreeNode<>(hash, key, value, next);
1805 :     }
1806 :    
1807 :     // For treeifyBin
1808 :     TreeNode<K,V> replacementTreeNode(Node<K,V> p, Node<K,V> next) {
1809 :     return new TreeNode<>(p.hash, p.key, p.value, next);
1810 :     }
1811 :    
1812 :     /**
1813 :     * Reset to initial default state. Called by clone and readObject.
1814 :     */
1815 :     void reinitialize() {
1816 :     table = null;
1817 :     entrySet = null;
1818 :     keySet = null;
1819 :     values = null;
1820 :     modCount = 0;
1821 :     threshold = 0;
1822 :     size = 0;
1823 :     }
1824 :    
1825 :     // Callbacks to allow LinkedHashMap post-actions
1826 :     void afterNodeAccess(Node<K,V> p) { }
1827 :     void afterNodeInsertion(boolean evict) { }
1828 :     void afterNodeRemoval(Node<K,V> p) { }
1829 :    
1830 :     // Called only from writeObject, to ensure compatible ordering.
1831 :     void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException {
1832 :     Node<K,V>[] tab;
1833 :     if (size > 0 && (tab = table) != null) {
1834 :     for (Node<K,V> e : tab) {
1835 :     for (; e != null; e = e.next) {
1836 :     s.writeObject(e.key);
1837 :     s.writeObject(e.value);
1838 :     }
1839 :     }
1840 :     }
1841 :     }
1842 :    
1843 :     /* ------------------------------------------------------------ */
1844 :     // Tree bins
1845 :    
1846 :     /**
1847 :     * Entry for Tree bins. Extends LinkedHashMap.Entry (which in turn
1848 :     * extends Node) so can be used as extension of either regular or
1849 :     * linked node.
1850 :     */
1851 :     static final class TreeNode<K,V> extends LinkedHashMap.Entry<K,V> {
1852 :     TreeNode<K,V> parent; // red-black tree links
1853 :     TreeNode<K,V> left;
1854 :     TreeNode<K,V> right;
1855 :     TreeNode<K,V> prev; // needed to unlink next upon deletion
1856 :     boolean red;
1857 :     TreeNode(int hash, K key, V val, Node<K,V> next) {
1858 :     super(hash, key, val, next);
1859 :     }
1860 :    
1861 :     /**
1862 :     * Returns root of tree containing this node.
1863 :     */
1864 :     final TreeNode<K,V> root() {
1865 :     for (TreeNode<K,V> r = this, p;;) {
1866 :     if ((p = r.parent) == null)
1867 :     return r;
1868 :     r = p;
1869 :     }
1870 :     }
1871 :    
1872 :     /**
1873 :     * Ensures that the given root is the first node of its bin.
1874 :     */
1875 :     static <K,V> void moveRootToFront(Node<K,V>[] tab, TreeNode<K,V> root) {
1876 :     int n;
1877 :     if (root != null && tab != null && (n = tab.length) > 0) {
1878 :     int index = (n - 1) & root.hash;
1879 :     TreeNode<K,V> first = (TreeNode<K,V>)tab[index];
1880 :     if (root != first) {
1881 :     Node<K,V> rn;
1882 :     tab[index] = root;
1883 :     TreeNode<K,V> rp = root.prev;
1884 :     if ((rn = root.next) != null)
1885 :     ((TreeNode<K,V>)rn).prev = rp;
1886 :     if (rp != null)
1887 :     rp.next = rn;
1888 :     if (first != null)
1889 :     first.prev = root;
1890 :     root.next = first;
1891 :     root.prev = null;
1892 :     }
1893 :     assert checkInvariants(root);
1894 :     }
1895 :     }
1896 :    
1897 :     /**
1898 :     * Finds the node starting at root p with the given hash and key.
1899 :     * The kc argument caches comparableClassFor(key) upon first use
1900 :     * comparing keys.
1901 :     */
1902 :     final TreeNode<K,V> find(int h, Object k, Class<?> kc) {
1903 :     TreeNode<K,V> p = this;
1904 :     do {
1905 :     int ph, dir; K pk;
1906 :     TreeNode<K,V> pl = p.left, pr = p.right, q;
1907 :     if ((ph = p.hash) > h)
1908 :     p = pl;
1909 :     else if (ph < h)
1910 :     p = pr;
1911 :     else if ((pk = p.key) == k || (k != null && k.equals(pk)))
1912 :     return p;
1913 :     else if (pl == null)
1914 :     p = pr;
1915 :     else if (pr == null)
1916 :     p = pl;
1917 :     else if ((kc != null ||
1918 :     (kc = comparableClassFor(k)) != null) &&
1919 :     (dir = compareComparables(kc, k, pk)) != 0)
1920 :     p = (dir < 0) ? pl : pr;
1921 :     else if ((q = pr.find(h, k, kc)) != null)
1922 :     return q;
1923 :     else
1924 :     p = pl;
1925 :     } while (p != null);
1926 :     return null;
1927 :     }
1928 :    
1929 :     /**
1930 :     * Calls find for root node.
1931 :     */
1932 :     final TreeNode<K,V> getTreeNode(int h, Object k) {
1933 :     return ((parent != null) ? root() : this).find(h, k, null);
1934 :     }
1935 :    
1936 :     /**
1937 :     * Tie-breaking utility for ordering insertions when equal
1938 :     * hashCodes and non-comparable. We don't require a total
1939 :     * order, just a consistent insertion rule to maintain
1940 :     * equivalence across rebalancings. Tie-breaking further than
1941 :     * necessary simplifies testing a bit.
1942 :     */
1943 :     static int tieBreakOrder(Object a, Object b) {
1944 :     int d;
1945 :     if (a == null || b == null ||
1946 :     (d = a.getClass().getName().
1947 :     compareTo(b.getClass().getName())) == 0)
1948 :     d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
1949 :     -1 : 1);
1950 :     return d;
1951 :     }
1952 :    
1953 :     /**
1954 :     * Forms tree of the nodes linked from this node.
1955 :     */
1956 :     final void treeify(Node<K,V>[] tab) {
1957 :     TreeNode<K,V> root = null;
1958 :     for (TreeNode<K,V> x = this, next; x != null; x = next) {
1959 :     next = (TreeNode<K,V>)x.next;
1960 :     x.left = x.right = null;
1961 :     if (root == null) {
1962 :     x.parent = null;
1963 :     x.red = false;
1964 :     root = x;
1965 :     }
1966 :     else {
1967 :     K k = x.key;
1968 :     int h = x.hash;
1969 :     Class<?> kc = null;
1970 :     for (TreeNode<K,V> p = root;;) {
1971 :     int dir, ph;
1972 :     K pk = p.key;
1973 :     if ((ph = p.hash) > h)
1974 :     dir = -1;
1975 :     else if (ph < h)
1976 :     dir = 1;
1977 :     else if ((kc == null &&
1978 :     (kc = comparableClassFor(k)) == null) ||
1979 :     (dir = compareComparables(kc, k, pk)) == 0)
1980 :     dir = tieBreakOrder(k, pk);
1981 :    
1982 :     TreeNode<K,V> xp = p;
1983 :     if ((p = (dir <= 0) ? p.left : p.right) == null) {
1984 :     x.parent = xp;
1985 :     if (dir <= 0)
1986 :     xp.left = x;
1987 :     else
1988 :     xp.right = x;
1989 :     root = balanceInsertion(root, x);
1990 :     break;
1991 :     }
1992 :     }
1993 :     }
1994 :     }
1995 :     moveRootToFront(tab, root);
1996 :     }
1997 :    
1998 :     /**
1999 :     * Returns a list of non-TreeNodes replacing those linked from
2000 :     * this node.
2001 :     */
2002 :     final Node<K,V> untreeify(HashMap<K,V> map) {
2003 :     Node<K,V> hd = null, tl = null;
2004 :     for (Node<K,V> q = this; q != null; q = q.next) {
2005 :     Node<K,V> p = map.replacementNode(q, null);
2006 :     if (tl == null)
2007 :     hd = p;
2008 :     else
2009 :     tl.next = p;
2010 :     tl = p;
2011 :     }
2012 :     return hd;
2013 :     }
2014 :    
2015 :     /**
2016 :     * Tree version of putVal.
2017 :     */
2018 :     final TreeNode<K,V> putTreeVal(HashMap<K,V> map, Node<K,V>[] tab,
2019 :     int h, K k, V v) {
2020 :     Class<?> kc = null;
2021 :     boolean searched = false;
2022 :     TreeNode<K,V> root = (parent != null) ? root() : this;
2023 :     for (TreeNode<K,V> p = root;;) {
2024 :     int dir, ph; K pk;
2025 :     if ((ph = p.hash) > h)
2026 :     dir = -1;
2027 :     else if (ph < h)
2028 :     dir = 1;
2029 :     else if ((pk = p.key) == k || (k != null && k.equals(pk)))
2030 :     return p;
2031 :     else if ((kc == null &&
2032 :     (kc = comparableClassFor(k)) == null) ||
2033 :     (dir = compareComparables(kc, k, pk)) == 0) {
2034 :     if (!searched) {
2035 :     TreeNode<K,V> q, ch;
2036 :     searched = true;
2037 :     if (((ch = p.left) != null &&
2038 :     (q = ch.find(h, k, kc)) != null) ||
2039 :     ((ch = p.right) != null &&
2040 :     (q = ch.find(h, k, kc)) != null))
2041 :     return q;
2042 :     }
2043 :     dir = tieBreakOrder(k, pk);
2044 :     }
2045 :    
2046 :     TreeNode<K,V> xp = p;
2047 :     if ((p = (dir <= 0) ? p.left : p.right) == null) {
2048 :     Node<K,V> xpn = xp.next;
2049 :     TreeNode<K,V> x = map.newTreeNode(h, k, v, xpn);
2050 :     if (dir <= 0)
2051 :     xp.left = x;
2052 :     else
2053 :     xp.right = x;
2054 :     xp.next = x;
2055 :     x.parent = x.prev = xp;
2056 :     if (xpn != null)
2057 :     ((TreeNode<K,V>)xpn).prev = x;
2058 :     moveRootToFront(tab, balanceInsertion(root, x));
2059 :     return null;
2060 :     }
2061 :     }
2062 :     }
2063 :    
2064 :     /**
2065 :     * Removes the given node, that must be present before this call.
2066 :     * This is messier than typical red-black deletion code because we
2067 :     * cannot swap the contents of an interior node with a leaf
2068 :     * successor that is pinned by "next" pointers that are accessible
2069 :     * independently during traversal. So instead we swap the tree
2070 :     * linkages. If the current tree appears to have too few nodes,
2071 :     * the bin is converted back to a plain bin. (The test triggers
2072 :     * somewhere between 2 and 6 nodes, depending on tree structure).
2073 :     */
2074 :     final void removeTreeNode(HashMap<K,V> map, Node<K,V>[] tab,
2075 :     boolean movable) {
2076 :     int n;
2077 :     if (tab == null || (n = tab.length) == 0)
2078 :     return;
2079 :     int index = (n - 1) & hash;
2080 :     TreeNode<K,V> first = (TreeNode<K,V>)tab[index], root = first, rl;
2081 :     TreeNode<K,V> succ = (TreeNode<K,V>)next, pred = prev;
2082 :     if (pred == null)
2083 :     tab[index] = first = succ;
2084 :     else
2085 :     pred.next = succ;
2086 :     if (succ != null)
2087 :     succ.prev = pred;
2088 :     if (first == null)
2089 :     return;
2090 :     if (root.parent != null)
2091 :     root = root.root();
2092 :     if (root == null
2093 :     || (movable
2094 :     && (root.right == null
2095 :     || (rl = root.left) == null
2096 :     || rl.left == null))) {
2097 :     tab[index] = first.untreeify(map); // too small
2098 :     return;
2099 :     }
2100 :     TreeNode<K,V> p = this, pl = left, pr = right, replacement;
2101 :     if (pl != null && pr != null) {
2102 :     TreeNode<K,V> s = pr, sl;
2103 :     while ((sl = s.left) != null) // find successor
2104 :     s = sl;
2105 :     boolean c = s.red; s.red = p.red; p.red = c; // swap colors
2106 :     TreeNode<K,V> sr = s.right;
2107 :     TreeNode<K,V> pp = p.parent;
2108 :     if (s == pr) { // p was s's direct parent
2109 :     p.parent = s;
2110 :     s.right = p;
2111 :     }
2112 :     else {
2113 :     TreeNode<K,V> sp = s.parent;
2114 :     if ((p.parent = sp) != null) {
2115 :     if (s == sp.left)
2116 :     sp.left = p;
2117 :     else
2118 :     sp.right = p;
2119 :     }
2120 :     if ((s.right = pr) != null)
2121 :     pr.parent = s;
2122 :     }
2123 :     p.left = null;
2124 :     if ((p.right = sr) != null)
2125 :     sr.parent = p;
2126 :     if ((s.left = pl) != null)
2127 :     pl.parent = s;
2128 :     if ((s.parent = pp) == null)
2129 :     root = s;
2130 :     else if (p == pp.left)
2131 :     pp.left = s;
2132 :     else
2133 :     pp.right = s;
2134 :     if (sr != null)
2135 :     replacement = sr;
2136 :     else
2137 :     replacement = p;
2138 :     }
2139 :     else if (pl != null)
2140 :     replacement = pl;
2141 :     else if (pr != null)
2142 :     replacement = pr;
2143 :     else
2144 :     replacement = p;
2145 :     if (replacement != p) {
2146 :     TreeNode<K,V> pp = replacement.parent = p.parent;
2147 :     if (pp == null)
2148 : jsr166 1.7 (root = replacement).red = false;
2149 : jsr166 1.1 else if (p == pp.left)
2150 :     pp.left = replacement;
2151 :     else
2152 :     pp.right = replacement;
2153 :     p.left = p.right = p.parent = null;
2154 :     }
2155 :    
2156 :     TreeNode<K,V> r = p.red ? root : balanceDeletion(root, replacement);
2157 :    
2158 :     if (replacement == p) { // detach
2159 :     TreeNode<K,V> pp = p.parent;
2160 :     p.parent = null;
2161 :     if (pp != null) {
2162 :     if (p == pp.left)
2163 :     pp.left = null;
2164 :     else if (p == pp.right)
2165 :     pp.right = null;
2166 :     }
2167 :     }
2168 :     if (movable)
2169 :     moveRootToFront(tab, r);
2170 :     }
2171 :    
2172 :     /**
2173 :     * Splits nodes in a tree bin into lower and upper tree bins,
2174 :     * or untreeifies if now too small. Called only from resize;
2175 :     * see above discussion about split bits and indices.
2176 :     *
2177 :     * @param map the map
2178 :     * @param tab the table for recording bin heads
2179 :     * @param index the index of the table being split
2180 :     * @param bit the bit of hash to split on
2181 :     */
2182 :     final void split(HashMap<K,V> map, Node<K,V>[] tab, int index, int bit) {
2183 :     TreeNode<K,V> b = this;
2184 :     // Relink into lo and hi lists, preserving order
2185 :     TreeNode<K,V> loHead = null, loTail = null;
2186 :     TreeNode<K,V> hiHead = null, hiTail = null;
2187 :     int lc = 0, hc = 0;
2188 :     for (TreeNode<K,V> e = b, next; e != null; e = next) {
2189 :     next = (TreeNode<K,V>)e.next;
2190 :     e.next = null;
2191 :     if ((e.hash & bit) == 0) {
2192 :     if ((e.prev = loTail) == null)
2193 :     loHead = e;
2194 :     else
2195 :     loTail.next = e;
2196 :     loTail = e;
2197 :     ++lc;
2198 :     }
2199 :     else {
2200 :     if ((e.prev = hiTail) == null)
2201 :     hiHead = e;
2202 :     else
2203 :     hiTail.next = e;
2204 :     hiTail = e;
2205 :     ++hc;
2206 :     }
2207 :     }
2208 :    
2209 :     if (loHead != null) {
2210 :     if (lc <= UNTREEIFY_THRESHOLD)
2211 :     tab[index] = loHead.untreeify(map);
2212 :     else {
2213 :     tab[index] = loHead;
2214 :     if (hiHead != null) // (else is already treeified)
2215 :     loHead.treeify(tab);
2216 :     }
2217 :     }
2218 :     if (hiHead != null) {
2219 :     if (hc <= UNTREEIFY_THRESHOLD)
2220 :     tab[index + bit] = hiHead.untreeify(map);
2221 :     else {
2222 :     tab[index + bit] = hiHead;
2223 :     if (loHead != null)
2224 :     hiHead.treeify(tab);
2225 :     }
2226 :     }
2227 :     }
2228 :    
2229 :     /* ------------------------------------------------------------ */
2230 :     // Red-black tree methods, all adapted from CLR
2231 :    
2232 :     static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root,
2233 :     TreeNode<K,V> p) {
2234 :     TreeNode<K,V> r, pp, rl;
2235 :     if (p != null && (r = p.right) != null) {
2236 :     if ((rl = p.right = r.left) != null)
2237 :     rl.parent = p;
2238 :     if ((pp = r.parent = p.parent) == null)
2239 :     (root = r).red = false;
2240 :     else if (pp.left == p)
2241 :     pp.left = r;
2242 :     else
2243 :     pp.right = r;
2244 :     r.left = p;
2245 :     p.parent = r;
2246 :     }
2247 :     return root;
2248 :     }
2249 :    
2250 :     static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root,
2251 :     TreeNode<K,V> p) {
2252 :     TreeNode<K,V> l, pp, lr;
2253 :     if (p != null && (l = p.left) != null) {
2254 :     if ((lr = p.left = l.right) != null)
2255 :     lr.parent = p;
2256 :     if ((pp = l.parent = p.parent) == null)
2257 :     (root = l).red = false;
2258 :     else if (pp.right == p)
2259 :     pp.right = l;
2260 :     else
2261 :     pp.left = l;
2262 :     l.right = p;
2263 :     p.parent = l;
2264 :     }
2265 :     return root;
2266 :     }
2267 :    
2268 :     static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root,
2269 :     TreeNode<K,V> x) {
2270 :     x.red = true;
2271 :     for (TreeNode<K,V> xp, xpp, xppl, xppr;;) {
2272 :     if ((xp = x.parent) == null) {
2273 :     x.red = false;
2274 :     return x;
2275 :     }
2276 :     else if (!xp.red || (xpp = xp.parent) == null)
2277 :     return root;
2278 :     if (xp == (xppl = xpp.left)) {
2279 :     if ((xppr = xpp.right) != null && xppr.red) {
2280 :     xppr.red = false;
2281 :     xp.red = false;
2282 :     xpp.red = true;
2283 :     x = xpp;
2284 :     }
2285 :     else {
2286 :     if (x == xp.right) {
2287 :     root = rotateLeft(root, x = xp);
2288 :     xpp = (xp = x.parent) == null ? null : xp.parent;
2289 :     }
2290 :     if (xp != null) {
2291 :     xp.red = false;
2292 :     if (xpp != null) {
2293 :     xpp.red = true;
2294 :     root = rotateRight(root, xpp);
2295 :     }
2296 :     }
2297 :     }
2298 :     }
2299 :     else {
2300 :     if (xppl != null && xppl.red) {
2301 :     xppl.red = false;
2302 :     xp.red = false;
2303 :     xpp.red = true;
2304 :     x = xpp;
2305 :     }
2306 :     else {
2307 :     if (x == xp.left) {
2308 :     root = rotateRight(root, x = xp);
2309 :     xpp = (xp = x.parent) == null ? null : xp.parent;
2310 :     }
2311 :     if (xp != null) {
2312 :     xp.red = false;
2313 :     if (xpp != null) {
2314 :     xpp.red = true;
2315 :     root = rotateLeft(root, xpp);
2316 :     }
2317 :     }
2318 :     }
2319 :     }
2320 :     }
2321 :     }
2322 :    
2323 :     static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root,
2324 :     TreeNode<K,V> x) {
2325 :     for (TreeNode<K,V> xp, xpl, xpr;;) {
2326 :     if (x == null || x == root)
2327 :     return root;
2328 :     else if ((xp = x.parent) == null) {
2329 :     x.red = false;
2330 :     return x;
2331 :     }
2332 :     else if (x.red) {
2333 :     x.red = false;
2334 :     return root;
2335 :     }
2336 :     else if ((xpl = xp.left) == x) {
2337 :     if ((xpr = xp.right) != null && xpr.red) {
2338 :     xpr.red = false;
2339 :     xp.red = true;
2340 :     root = rotateLeft(root, xp);
2341 :     xpr = (xp = x.parent) == null ? null : xp.right;
2342 :     }
2343 :     if (xpr == null)
2344 :     x = xp;
2345 :     else {
2346 :     TreeNode<K,V> sl = xpr.left, sr = xpr.right;
2347 :     if ((sr == null || !sr.red) &&
2348 :     (sl == null || !sl.red)) {
2349 :     xpr.red = true;
2350 :     x = xp;
2351 :     }
2352 :     else {
2353 :     if (sr == null || !sr.red) {
2354 :     if (sl != null)
2355 :     sl.red = false;
2356 :     xpr.red = true;
2357 :     root = rotateRight(root, xpr);
2358 :     xpr = (xp = x.parent) == null ?
2359 :     null : xp.right;
2360 :     }
2361 :     if (xpr != null) {
2362 :     xpr.red = (xp == null) ? false : xp.red;
2363 :     if ((sr = xpr.right) != null)
2364 :     sr.red = false;
2365 :     }
2366 :     if (xp != null) {
2367 :     xp.red = false;
2368 :     root = rotateLeft(root, xp);
2369 :     }
2370 :     x = root;
2371 :     }
2372 :     }
2373 :     }
2374 :     else { // symmetric
2375 :     if (xpl != null && xpl.red) {
2376 :     xpl.red = false;
2377 :     xp.red = true;
2378 :     root = rotateRight(root, xp);
2379 :     xpl = (xp = x.parent) == null ? null : xp.left;
2380 :     }
2381 :     if (xpl == null)
2382 :     x = xp;
2383 :     else {
2384 :     TreeNode<K,V> sl = xpl.left, sr = xpl.right;
2385 :     if ((sl == null || !sl.red) &&
2386 :     (sr == null || !sr.red)) {
2387 :     xpl.red = true;
2388 :     x = xp;
2389 :     }
2390 :     else {
2391 :     if (sl == null || !sl.red) {
2392 :     if (sr != null)
2393 :     sr.red = false;
2394 :     xpl.red = true;
2395 :     root = rotateLeft(root, xpl);
2396 :     xpl = (xp = x.parent) == null ?
2397 :     null : xp.left;
2398 :     }
2399 :     if (xpl != null) {
2400 :     xpl.red = (xp == null) ? false : xp.red;
2401 :     if ((sl = xpl.left) != null)
2402 :     sl.red = false;
2403 :     }
2404 :     if (xp != null) {
2405 :     xp.red = false;
2406 :     root = rotateRight(root, xp);
2407 :     }
2408 :     x = root;
2409 :     }
2410 :     }
2411 :     }
2412 :     }
2413 :     }
2414 :    
2415 :     /**
2416 :     * Recursive invariant check
2417 :     */
2418 :     static <K,V> boolean checkInvariants(TreeNode<K,V> t) {
2419 :     TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right,
2420 :     tb = t.prev, tn = (TreeNode<K,V>)t.next;
2421 :     if (tb != null && tb.next != t)
2422 :     return false;
2423 :     if (tn != null && tn.prev != t)
2424 :     return false;
2425 :     if (tp != null && t != tp.left && t != tp.right)
2426 :     return false;
2427 :     if (tl != null && (tl.parent != t || tl.hash > t.hash))
2428 :     return false;
2429 :     if (tr != null && (tr.parent != t || tr.hash < t.hash))
2430 :     return false;
2431 :     if (t.red && tl != null && tl.red && tr != null && tr.red)
2432 :     return false;
2433 :     if (tl != null && !checkInvariants(tl))
2434 :     return false;
2435 :     if (tr != null && !checkInvariants(tr))
2436 :     return false;
2437 :     return true;
2438 :     }
2439 :     }
2440 :    
2441 :     }

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