My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

Showing the changes to java/pkg/java/util/HashMap.java (1 of 18352 files). Show all

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	1	+/*
	2	+ * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
	3	+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	4	+ *
	5	+ * This code is free software; you can redistribute it and/or modify it
	6	+ * under the terms of the GNU General Public License version 2 only, as
	7	+ * published by the Free Software Foundation. Oracle designates this
	8	+ * particular file as subject to the "Classpath" exception as provided
	9	+ * by Oracle in the LICENSE file that accompanied this code.
	10	+ *
	11	+ * This code is distributed in the hope that it will be useful, but WITHOUT
	12	+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	13	+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	14	+ * version 2 for more details (a copy is included in the LICENSE file that
	15	+ * accompanied this code).
	16	+ *
	17	+ * You should have received a copy of the GNU General Public License version
	18	+ * 2 along with this work; if not, write to the Free Software Foundation,
	19	+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	20	+ *
	21	+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	22	+ * or visit www.oracle.com if you need additional information or have any
	23	+ * questions.
	24	+ */
	25	+
	26	+package java.util;
	27	+import java.io.*;
	28	+
	29	+/**
	30	+ * Hash table based implementation of the <tt>Map</tt> interface. This
	31	+ * implementation provides all of the optional map operations, and permits
	32	+ * <tt>null</tt> values and the <tt>null</tt> key. (The <tt>HashMap</tt>
	33	+ * class is roughly equivalent to <tt>Hashtable</tt>, except that it is
	34	+ * unsynchronized and permits nulls.) This class makes no guarantees as to
	35	+ * the order of the map; in particular, it does not guarantee that the order
	36	+ * will remain constant over time.
	37	+ *
	38	+ * <p>This implementation provides constant-time performance for the basic
	39	+ * operations (<tt>get</tt> and <tt>put</tt>), assuming the hash function
	40	+ * disperses the elements properly among the buckets. Iteration over
	41	+ * collection views requires time proportional to the "capacity" of the
	42	+ * <tt>HashMap</tt> instance (the number of buckets) plus its size (the number
	43	+ * of key-value mappings). Thus, it's very important not to set the initial
	44	+ * capacity too high (or the load factor too low) if iteration performance is
	45	+ * important.
	46	+ *
	47	+ * <p>An instance of <tt>HashMap</tt> has two parameters that affect its
	48	+ * performance: <i>initial capacity</i> and <i>load factor</i>. The
	49	+ * <i>capacity</i> is the number of buckets in the hash table, and the initial
	50	+ * capacity is simply the capacity at the time the hash table is created. The
	51	+ * <i>load factor</i> is a measure of how full the hash table is allowed to
	52	+ * get before its capacity is automatically increased. When the number of
	53	+ * entries in the hash table exceeds the product of the load factor and the
	54	+ * current capacity, the hash table is <i>rehashed</i> (that is, internal data
	55	+ * structures are rebuilt) so that the hash table has approximately twice the
	56	+ * number of buckets.
	57	+ *
	58	+ * <p>As a general rule, the default load factor (.75) offers a good tradeoff
	59	+ * between time and space costs. Higher values decrease the space overhead
	60	+ * but increase the lookup cost (reflected in most of the operations of the
	61	+ * <tt>HashMap</tt> class, including <tt>get</tt> and <tt>put</tt>). The
	62	+ * expected number of entries in the map and its load factor should be taken
	63	+ * into account when setting its initial capacity, so as to minimize the
	64	+ * number of rehash operations. If the initial capacity is greater
	65	+ * than the maximum number of entries divided by the load factor, no
	66	+ * rehash operations will ever occur.
	67	+ *
	68	+ * <p>If many mappings are to be stored in a <tt>HashMap</tt> instance,
	69	+ * creating it with a sufficiently large capacity will allow the mappings to
	70	+ * be stored more efficiently than letting it perform automatic rehashing as
	71	+ * needed to grow the table.
	72	+ *
	73	+ * <p><strong>Note that this implementation is not synchronized.</strong>
	74	+ * If multiple threads access a hash map concurrently, and at least one of
	75	+ * the threads modifies the map structurally, it <i>must</i> be
	76	+ * synchronized externally. (A structural modification is any operation
	77	+ * that adds or deletes one or more mappings; merely changing the value
	78	+ * associated with a key that an instance already contains is not a
	79	+ * structural modification.) This is typically accomplished by
	80	+ * synchronizing on some object that naturally encapsulates the map.
	81	+ *
	82	+ * If no such object exists, the map should be "wrapped" using the
	83	+ * {@link Collections#synchronizedMap Collections.synchronizedMap}
	84	+ * method. This is best done at creation time, to prevent accidental
	85	+ * unsynchronized access to the map:<pre>
	86	+ * Map m = Collections.synchronizedMap(new HashMap(...));</pre>
	87	+ *
	88	+ * <p>The iterators returned by all of this class's "collection view methods"
	89	+ * are <i>fail-fast</i>: if the map is structurally modified at any time after
	90	+ * the iterator is created, in any way except through the iterator's own
	91	+ * <tt>remove</tt> method, the iterator will throw a
	92	+ * {@link ConcurrentModificationException}. Thus, in the face of concurrent
	93	+ * modification, the iterator fails quickly and cleanly, rather than risking
	94	+ * arbitrary, non-deterministic behavior at an undetermined time in the
	95	+ * future.
	96	+ *
	97	+ * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
	98	+ * as it is, generally speaking, impossible to make any hard guarantees in the
	99	+ * presence of unsynchronized concurrent modification. Fail-fast iterators
	100	+ * throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
	101	+ * Therefore, it would be wrong to write a program that depended on this
	102	+ * exception for its correctness: <i>the fail-fast behavior of iterators
	103	+ * should be used only to detect bugs.</i>
	104	+ *
	105	+ * <p>This class is a member of the
	106	+ * <a href="{@docRoot}/../technotes/guides/collections/index.html">
	107	+ * Java Collections Framework</a>.
	108	+ *
	109	+ * @param <K> the type of keys maintained by this map
	110	+ * @param <V> the type of mapped values
	111	+ *
	112	+ * @author Doug Lea
	113	+ * @author Josh Bloch
	114	+ * @author Arthur van Hoff
	115	+ * @author Neal Gafter
	116	+ * @see Object#hashCode()
	117	+ * @see Collection
	118	+ * @see Map
	119	+ * @see TreeMap
	120	+ * @see Hashtable
	121	+ * @since 1.2
	122	+ */
	123	+
	124	+public class HashMap<K,V>
	125	+ extends AbstractMap<K,V>
	126	+ implements Map<K,V>, Cloneable, Serializable
	127	+{
	128	+
	129	+ /**
	130	+ * The default initial capacity - MUST be a power of two.
	131	+ */
	132	+ static final int DEFAULT_INITIAL_CAPACITY = 16;
	133	+
	134	+ /**
	135	+ * The maximum capacity, used if a higher value is implicitly specified
	136	+ * by either of the constructors with arguments.
	137	+ * MUST be a power of two <= 1<<30.
	138	+ */
	139	+ static final int MAXIMUM_CAPACITY = 1 << 30;
	140	+
	141	+ /**
	142	+ * The load factor used when none specified in constructor.
	143	+ */
	144	+ static final float DEFAULT_LOAD_FACTOR = 0.75f;
	145	+
	146	+ /**
	147	+ * The table, resized as necessary. Length MUST Always be a power of two.
	148	+ */
	149	+ transient Entry[] table;
	150	+
	151	+ /**
	152	+ * The number of key-value mappings contained in this map.
	153	+ */
	154	+ transient int size;
	155	+
	156	+ /**
	157	+ * The next size value at which to resize (capacity * load factor).
	158	+ * @serial
	159	+ */
	160	+ int threshold;
	161	+
	162	+ /**
	163	+ * The load factor for the hash table.
	164	+ *
	165	+ * @serial
	166	+ */
	167	+ final float loadFactor;
	168	+
	169	+ /**
	170	+ * The number of times this HashMap has been structurally modified
	171	+ * Structural modifications are those that change the number of mappings in
	172	+ * the HashMap or otherwise modify its internal structure (e.g.,
	173	+ * rehash). This field is used to make iterators on Collection-views of
	174	+ * the HashMap fail-fast. (See ConcurrentModificationException).
	175	+ */
	176	+ transient int modCount;
	177	+
	178	+ /**
	179	+ * Constructs an empty <tt>HashMap</tt> with the specified initial
	180	+ * capacity and load factor.
	181	+ *
	182	+ * @param initialCapacity the initial capacity
	183	+ * @param loadFactor the load factor
	184	+ * @throws IllegalArgumentException if the initial capacity is negative
	185	+ * or the load factor is nonpositive
	186	+ */
	187	+ public HashMap(int initialCapacity, float loadFactor) {
	188	+ if (initialCapacity < 0)
	189	+ throw new IllegalArgumentException("Illegal initial capacity: " +
	190	+ initialCapacity);
	191	+ if (initialCapacity > MAXIMUM_CAPACITY)
	192	+ initialCapacity = MAXIMUM_CAPACITY;
	193	+ if (loadFactor <= 0 \|\| Float.isNaN(loadFactor))
	194	+ throw new IllegalArgumentException("Illegal load factor: " +
	195	+ loadFactor);
	196	+
	197	+ // Find a power of 2 >= initialCapacity
	198	+ int capacity = 1;
	199	+ while (capacity < initialCapacity)
	200	+ capacity <<= 1;
	201	+
	202	+ this.loadFactor = loadFactor;
	203	+ threshold = (int)(capacity * loadFactor);
	204	+ table = new Entry[capacity];
	205	+ init();
	206	+ }
	207	+
	208	+ /**
	209	+ * Constructs an empty <tt>HashMap</tt> with the specified initial
	210	+ * capacity and the default load factor (0.75).
	211	+ *
	212	+ * @param initialCapacity the initial capacity.
	213	+ * @throws IllegalArgumentException if the initial capacity is negative.
	214	+ */
	215	+ public HashMap(int initialCapacity) {
	216	+ this(initialCapacity, DEFAULT_LOAD_FACTOR);
	217	+ }
	218	+
	219	+ /**
	220	+ * Constructs an empty <tt>HashMap</tt> with the default initial capacity
	221	+ * (16) and the default load factor (0.75).
	222	+ */
	223	+ public HashMap() {
	224	+ this.loadFactor = DEFAULT_LOAD_FACTOR;
	225	+ threshold = (int)(DEFAULT_INITIAL_CAPACITY * DEFAULT_LOAD_FACTOR);
	226	+ table = new Entry[DEFAULT_INITIAL_CAPACITY];
	227	+ init();
	228	+ }
	229	+
	230	+ /**
	231	+ * Constructs a new <tt>HashMap</tt> with the same mappings as the
	232	+ * specified <tt>Map</tt>. The <tt>HashMap</tt> is created with
	233	+ * default load factor (0.75) and an initial capacity sufficient to
	234	+ * hold the mappings in the specified <tt>Map</tt>.
	235	+ *
	236	+ * @param m the map whose mappings are to be placed in this map
	237	+ * @throws NullPointerException if the specified map is null
	238	+ */
	239	+ public HashMap(Map<? extends K, ? extends V> m) {
	240	+ this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1,
	241	+ DEFAULT_INITIAL_CAPACITY), DEFAULT_LOAD_FACTOR);
	242	+ putAllForCreate(m);
	243	+ }
	244	+
	245	+ // internal utilities
	246	+
	247	+ /**
	248	+ * Initialization hook for subclasses. This method is called
	249	+ * in all constructors and pseudo-constructors (clone, readObject)
	250	+ * after HashMap has been initialized but before any entries have
	251	+ * been inserted. (In the absence of this method, readObject would
	252	+ * require explicit knowledge of subclasses.)
	253	+ */
	254	+ void init() {
	255	+ }
	256	+
	257	+ /**
	258	+ * Applies a supplemental hash function to a given hashCode, which
	259	+ * defends against poor quality hash functions. This is critical
	260	+ * because HashMap uses power-of-two length hash tables, that
	261	+ * otherwise encounter collisions for hashCodes that do not differ
	262	+ * in lower bits. Note: Null keys always map to hash 0, thus index 0.
	263	+ */
	264	+ static int hash(int h) {
	265	+ // This function ensures that hashCodes that differ only by
	266	+ // constant multiples at each bit position have a bounded
	267	+ // number of collisions (approximately 8 at default load factor).
	268	+ h ^= (h >>> 20) ^ (h >>> 12);
	269	+ return h ^ (h >>> 7) ^ (h >>> 4);
	270	+ }
	271	+
	272	+ /**
	273	+ * Returns index for hash code h.
	274	+ */
	275	+ static int indexFor(int h, int length) {
	276	+ return h & (length-1);
	277	+ }
	278	+
	279	+ /**
	280	+ * Returns the number of key-value mappings in this map.
	281	+ *
	282	+ * @return the number of key-value mappings in this map
	283	+ */
	284	+ public int size() {
	285	+ return size;
	286	+ }
	287	+
	288	+ /**
	289	+ * Returns <tt>true</tt> if this map contains no key-value mappings.
	290	+ *
	291	+ * @return <tt>true</tt> if this map contains no key-value mappings
	292	+ */
	293	+ public boolean isEmpty() {
	294	+ return size == 0;
	295	+ }
	296	+
	297	+ /**
	298	+ * Returns the value to which the specified key is mapped,
	299	+ * or {@code null} if this map contains no mapping for the key.
	300	+ *
	301	+ * <p>More formally, if this map contains a mapping from a key
	302	+ * {@code k} to a value {@code v} such that {@code (key==null ? k==null :
	303	+ * key.equals(k))}, then this method returns {@code v}; otherwise
	304	+ * it returns {@code null}. (There can be at most one such mapping.)
	305	+ *
	306	+ * <p>A return value of {@code null} does not <i>necessarily</i>
	307	+ * indicate that the map contains no mapping for the key; it's also
	308	+ * possible that the map explicitly maps the key to {@code null}.
	309	+ * The {@link #containsKey containsKey} operation may be used to
	310	+ * distinguish these two cases.
	311	+ *
	312	+ * @see #put(Object, Object)
	313	+ */
	314	+ public V get(Object key) {
	315	+ if (key == null)
	316	+ return getForNullKey();
	317	+ int hash = hash(key.hashCode());
	318	+ for (Entry<K,V> e = table[indexFor(hash, table.length)];
	319	+ e != null;
	320	+ e = e.next) {
	321	+ Object k;
	322	+ if (e.hash == hash && ((k = e.key) == key \|\| key.equals(k)))
	323	+ return e.value;
	324	+ }
	325	+ return null;
	326	+ }
	327	+
	328	+ /**
	329	+ * Offloaded version of get() to look up null keys. Null keys map
	330	+ * to index 0. This null case is split out into separate methods
	331	+ * for the sake of performance in the two most commonly used
	332	+ * operations (get and put), but incorporated with conditionals in
	333	+ * others.
	334	+ */
	335	+ private V getForNullKey() {
	336	+ for (Entry<K,V> e = table[0]; e != null; e = e.next) {
	337	+ if (e.key == null)
	338	+ return e.value;
	339	+ }
	340	+ return null;
	341	+ }
	342	+
	343	+ /**
	344	+ * Returns <tt>true</tt> if this map contains a mapping for the
	345	+ * specified key.
	346	+ *
	347	+ * @param key The key whose presence in this map is to be tested
	348	+ * @return <tt>true</tt> if this map contains a mapping for the specified
	349	+ * key.
	350	+ */
	351	+ public boolean containsKey(Object key) {
	352	+ return getEntry(key) != null;
	353	+ }
	354	+
	355	+ /**
	356	+ * Returns the entry associated with the specified key in the
	357	+ * HashMap. Returns null if the HashMap contains no mapping
	358	+ * for the key.
	359	+ */
	360	+ final Entry<K,V> getEntry(Object key) {
	361	+ int hash = (key == null) ? 0 : hash(key.hashCode());
	362	+ for (Entry<K,V> e = table[indexFor(hash, table.length)];
	363	+ e != null;
	364	+ e = e.next) {
	365	+ Object k;
	366	+ if (e.hash == hash &&
	367	+ ((k = e.key) == key \|\| (key != null && key.equals(k))))
	368	+ return e;
	369	+ }
	370	+ return null;
	371	+ }
	372	+
	373	+
	374	+ /**
	375	+ * Associates the specified value with the specified key in this map.
	376	+ * If the map previously contained a mapping for the key, the old
	377	+ * value is replaced.
	378	+ *
	379	+ * @param key key with which the specified value is to be associated
	380	+ * @param value value to be associated with the specified key
	381	+ * @return the previous value associated with <tt>key</tt>, or
	382	+ * <tt>null</tt> if there was no mapping for <tt>key</tt>.
	383	+ * (A <tt>null</tt> return can also indicate that the map
	384	+ * previously associated <tt>null</tt> with <tt>key</tt>.)
	385	+ */
	386	+ public V put(K key, V value) {
	387	+ if (key == null)
	388	+ return putForNullKey(value);
	389	+ int hash = hash(key.hashCode());
	390	+ int i = indexFor(hash, table.length);
	391	+ for (Entry<K,V> e = table[i]; e != null; e = e.next) {
	392	+ Object k;
	393	+ if (e.hash == hash && ((k = e.key) == key \|\| key.equals(k))) {
	394	+ V oldValue = e.value;
	395	+ e.value = value;
	396	+ e.recordAccess(this);
	397	+ return oldValue;
	398	+ }
	399	+ }
	400	+
	401	+ modCount++;
	402	+ addEntry(hash, key, value, i);
	403	+ return null;
	404	+ }
	405	+
	406	+ /**
	407	+ * Offloaded version of put for null keys
	408	+ */
	409	+ private V putForNullKey(V value) {
	410	+ for (Entry<K,V> e = table[0]; e != null; e = e.next) {
	411	+ if (e.key == null) {
	412	+ V oldValue = e.value;
	413	+ e.value = value;
	414	+ e.recordAccess(this);
	415	+ return oldValue;
	416	+ }
	417	+ }
	418	+ modCount++;
	419	+ addEntry(0, null, value, 0);
	420	+ return null;
	421	+ }
	422	+
	423	+ /**
	424	+ * This method is used instead of put by constructors and
	425	+ * pseudoconstructors (clone, readObject). It does not resize the table,
	426	+ * check for comodification, etc. It calls createEntry rather than
	427	+ * addEntry.
	428	+ */
	429	+ private void putForCreate(K key, V value) {
	430	+ int hash = (key == null) ? 0 : hash(key.hashCode());
	431	+ int i = indexFor(hash, table.length);
	432	+
	433	+ /**
	434	+ * Look for preexisting entry for key. This will never happen for
	435	+ * clone or deserialize. It will only happen for construction if the
	436	+ * input Map is a sorted map whose ordering is inconsistent w/ equals.
	437	+ */
	438	+ for (Entry<K,V> e = table[i]; e != null; e = e.next) {
	439	+ Object k;
	440	+ if (e.hash == hash &&
	441	+ ((k = e.key) == key \|\| (key != null && key.equals(k)))) {
	442	+ e.value = value;
	443	+ return;
	444	+ }
	445	+ }
	446	+
	447	+ createEntry(hash, key, value, i);
	448	+ }
	449	+
	450	+ private void putAllForCreate(Map<? extends K, ? extends V> m) {
	451	+ for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
	452	+ putForCreate(e.getKey(), e.getValue());
	453	+ }
	454	+
	455	+ /**
	456	+ * Rehashes the contents of this map into a new array with a
	457	+ * larger capacity. This method is called automatically when the
	458	+ * number of keys in this map reaches its threshold.
	459	+ *
	460	+ * If current capacity is MAXIMUM_CAPACITY, this method does not
	461	+ * resize the map, but sets threshold to Integer.MAX_VALUE.
	462	+ * This has the effect of preventing future calls.
	463	+ *
	464	+ * @param newCapacity the new capacity, MUST be a power of two;
	465	+ * must be greater than current capacity unless current
	466	+ * capacity is MAXIMUM_CAPACITY (in which case value
	467	+ * is irrelevant).
	468	+ */
	469	+ void resize(int newCapacity) {
	470	+ Entry[] oldTable = table;
	471	+ int oldCapacity = oldTable.length;
	472	+ if (oldCapacity == MAXIMUM_CAPACITY) {
	473	+ threshold = Integer.MAX_VALUE;
	474	+ return;
	475	+ }
	476	+
	477	+ Entry[] newTable = new Entry[newCapacity];
	478	+ transfer(newTable);
	479	+ table = newTable;
	480	+ threshold = (int)(newCapacity * loadFactor);
	481	+ }
	482	+
	483	+ /**
	484	+ * Transfers all entries from current table to newTable.
	485	+ */
	486	+ void transfer(Entry[] newTable) {
	487	+ Entry[] src = table;
	488	+ int newCapacity = newTable.length;
	489	+ for (int j = 0; j < src.length; j++) {
	490	+ Entry<K,V> e = src[j];
	491	+ if (e != null) {
	492	+ src[j] = null;
	493	+ do {
	494	+ Entry<K,V> next = e.next;
	495	+ int i = indexFor(e.hash, newCapacity);
	496	+ e.next = newTable[i];
	497	+ newTable[i] = e;
	498	+ e = next;
	499	+ } while (e != null);
	500	+ }
	501	+ }
	502	+ }
	503	+
	504	+ /**
	505	+ * Copies all of the mappings from the specified map to this map.
	506	+ * These mappings will replace any mappings that this map had for
	507	+ * any of the keys currently in the specified map.
	508	+ *
	509	+ * @param m mappings to be stored in this map
	510	+ * @throws NullPointerException if the specified map is null
	511	+ */
	512	+ public void putAll(Map<? extends K, ? extends V> m) {
	513	+ int numKeysToBeAdded = m.size();
	514	+ if (numKeysToBeAdded == 0)
	515	+ return;
	516	+
	517	+ /*
	518	+ * Expand the map if the map if the number of mappings to be added
	519	+ * is greater than or equal to threshold. This is conservative; the
	520	+ * obvious condition is (m.size() + size) >= threshold, but this
	521	+ * condition could result in a map with twice the appropriate capacity,
	522	+ * if the keys to be added overlap with the keys already in this map.
	523	+ * By using the conservative calculation, we subject ourself
	524	+ * to at most one extra resize.
	525	+ */
	526	+ if (numKeysToBeAdded > threshold) {
	527	+ int targetCapacity = (int)(numKeysToBeAdded / loadFactor + 1);
	528	+ if (targetCapacity > MAXIMUM_CAPACITY)
	529	+ targetCapacity = MAXIMUM_CAPACITY;
	530	+ int newCapacity = table.length;
	531	+ while (newCapacity < targetCapacity)
	532	+ newCapacity <<= 1;
	533	+ if (newCapacity > table.length)
	534	+ resize(newCapacity);
	535	+ }
	536	+
	537	+ for (Map.Entry<? extends K, ? extends V> e : m.entrySet())
	538	+ put(e.getKey(), e.getValue());
	539	+ }
	540	+
	541	+ /**
	542	+ * Removes the mapping for the specified key from this map if present.
	543	+ *
	544	+ * @param key key whose mapping is to be removed from the map
	545	+ * @return the previous value associated with <tt>key</tt>, or
	546	+ * <tt>null</tt> if there was no mapping for <tt>key</tt>.
	547	+ * (A <tt>null</tt> return can also indicate that the map
	548	+ * previously associated <tt>null</tt> with <tt>key</tt>.)
	549	+ */
	550	+ public V remove(Object key) {
	551	+ Entry<K,V> e = removeEntryForKey(key);
	552	+ return (e == null ? null : e.value);
	553	+ }
	554	+
	555	+ /**
	556	+ * Removes and returns the entry associated with the specified key
	557	+ * in the HashMap. Returns null if the HashMap contains no mapping
	558	+ * for this key.
	559	+ */
	560	+ final Entry<K,V> removeEntryForKey(Object key) {
	561	+ int hash = (key == null) ? 0 : hash(key.hashCode());
	562	+ int i = indexFor(hash, table.length);
	563	+ Entry<K,V> prev = table[i];
	564	+ Entry<K,V> e = prev;
	565	+
	566	+ while (e != null) {
	567	+ Entry<K,V> next = e.next;
	568	+ Object k;
	569	+ if (e.hash == hash &&
	570	+ ((k = e.key) == key \|\| (key != null && key.equals(k)))) {
	571	+ modCount++;
	572	+ size--;
	573	+ if (prev == e)
	574	+ table[i] = next;
	575	+ else
	576	+ prev.next = next;
	577	+ e.recordRemoval(this);
	578	+ return e;
	579	+ }
	580	+ prev = e;
	581	+ e = next;
	582	+ }
	583	+
	584	+ return e;
	585	+ }
	586	+
	587	+ /**
	588	+ * Special version of remove for EntrySet.
	589	+ */
	590	+ final Entry<K,V> removeMapping(Object o) {
	591	+ if (!(o instanceof Map.Entry))
	592	+ return null;
	593	+
	594	+ Map.Entry<K,V> entry = (Map.Entry<K,V>) o;
	595	+ Object key = entry.getKey();
	596	+ int hash = (key == null) ? 0 : hash(key.hashCode());
	597	+ int i = indexFor(hash, table.length);
	598	+ Entry<K,V> prev = table[i];
	599	+ Entry<K,V> e = prev;
	600	+
	601	+ while (e != null) {
	602	+ Entry<K,V> next = e.next;
	603	+ if (e.hash == hash && e.equals(entry)) {
	604	+ modCount++;
	605	+ size--;
	606	+ if (prev == e)
	607	+ table[i] = next;
	608	+ else
	609	+ prev.next = next;
	610	+ e.recordRemoval(this);
	611	+ return e;
	612	+ }
	613	+ prev = e;
	614	+ e = next;
	615	+ }
	616	+
	617	+ return e;
	618	+ }
	619	+
	620	+ /**
	621	+ * Removes all of the mappings from this map.
	622	+ * The map will be empty after this call returns.
	623	+ */
	624	+ public void clear() {
	625	+ modCount++;
	626	+ Entry[] tab = table;
	627	+ for (int i = 0; i < tab.length; i++)
	628	+ tab[i] = null;
	629	+ size = 0;
	630	+ }
	631	+
	632	+ /**
	633	+ * Returns <tt>true</tt> if this map maps one or more keys to the
	634	+ * specified value.
	635	+ *
	636	+ * @param value value whose presence in this map is to be tested
	637	+ * @return <tt>true</tt> if this map maps one or more keys to the
	638	+ * specified value
	639	+ */
	640	+ public boolean containsValue(Object value) {
	641	+ if (value == null)
	642	+ return containsNullValue();
	643	+
	644	+ Entry[] tab = table;
	645	+ for (int i = 0; i < tab.length ; i++)
	646	+ for (Entry e = tab[i] ; e != null ; e = e.next)
	647	+ if (value.equals(e.value))
	648	+ return true;
	649	+ return false;
	650	+ }
	651	+
	652	+ /**
	653	+ * Special-case code for containsValue with null argument
	654	+ */
	655	+ private boolean containsNullValue() {
	656	+ Entry[] tab = table;
	657	+ for (int i = 0; i < tab.length ; i++)
	658	+ for (Entry e = tab[i] ; e != null ; e = e.next)
	659	+ if (e.value == null)
	660	+ return true;
	661	+ return false;
	662	+ }
	663	+
	664	+ /**
	665	+ * Returns a shallow copy of this <tt>HashMap</tt> instance: the keys and
	666	+ * values themselves are not cloned.
	667	+ *
	668	+ * @return a shallow copy of this map
	669	+ */
	670	+ public Object clone() {
	671	+ HashMap<K,V> result = null;
	672	+ try {
	673	+ result = (HashMap<K,V>)super.clone();
	674	+ } catch (CloneNotSupportedException e) {
	675	+ // assert false;
	676	+ }
	677	+ result.table = new Entry[table.length];
	678	+ result.entrySet = null;
	679	+ result.modCount = 0;
	680	+ result.size = 0;
	681	+ result.init();
	682	+ result.putAllForCreate(this);
	683	+
	684	+ return result;
	685	+ }
	686	+
	687	+ static class Entry<K,V> implements Map.Entry<K,V> {
	688	+ final K key;
	689	+ V value;
	690	+ Entry<K,V> next;
	691	+ final int hash;
	692	+
	693	+ /**
	694	+ * Creates new entry.
	695	+ */
	696	+ Entry(int h, K k, V v, Entry<K,V> n) {
	697	+ value = v;
	698	+ next = n;
	699	+ key = k;
	700	+ hash = h;
	701	+ }
	702	+
	703	+ public final K getKey() {
	704	+ return key;
	705	+ }
	706	+
	707	+ public final V getValue() {
	708	+ return value;
	709	+ }
	710	+
	711	+ public final V setValue(V newValue) {
	712	+ V oldValue = value;
	713	+ value = newValue;
	714	+ return oldValue;
	715	+ }
	716	+
	717	+ public final boolean equals(Object o) {
	718	+ if (!(o instanceof Map.Entry))
	719	+ return false;
	720	+ Map.Entry e = (Map.Entry)o;
	721	+ Object k1 = getKey();
	722	+ Object k2 = e.getKey();
	723	+ if (k1 == k2 \|\| (k1 != null && k1.equals(k2))) {
	724	+ Object v1 = getValue();
	725	+ Object v2 = e.getValue();
	726	+ if (v1 == v2 \|\| (v1 != null && v1.equals(v2)))
	727	+ return true;
	728	+ }
	729	+ return false;
	730	+ }
	731	+
	732	+ public final int hashCode() {
	733	+ return (key==null ? 0 : key.hashCode()) ^
	734	+ (value==null ? 0 : value.hashCode());
	735	+ }
	736	+
	737	+ public final String toString() {
	738	+ return getKey() + "=" + getValue();
	739	+ }
	740	+
	741	+ /**
	742	+ * This method is invoked whenever the value in an entry is
	743	+ * overwritten by an invocation of put(k,v) for a key k that's already
	744	+ * in the HashMap.
	745	+ */
	746	+ void recordAccess(HashMap<K,V> m) {
	747	+ }
	748	+
	749	+ /**
	750	+ * This method is invoked whenever the entry is
	751	+ * removed from the table.
	752	+ */
	753	+ void recordRemoval(HashMap<K,V> m) {
	754	+ }
	755	+ }
	756	+
	757	+ /**
	758	+ * Adds a new entry with the specified key, value and hash code to
	759	+ * the specified bucket. It is the responsibility of this
	760	+ * method to resize the table if appropriate.
	761	+ *
	762	+ * Subclass overrides this to alter the behavior of put method.
	763	+ */
	764	+ void addEntry(int hash, K key, V value, int bucketIndex) {
	765	+ Entry<K,V> e = table[bucketIndex];
	766	+ table[bucketIndex] = new Entry<>(hash, key, value, e);
	767	+ if (size++ >= threshold)
	768	+ resize(2 * table.length);
	769	+ }
	770	+
	771	+ /**
	772	+ * Like addEntry except that this version is used when creating entries
	773	+ * as part of Map construction or "pseudo-construction" (cloning,
	774	+ * deserialization). This version needn't worry about resizing the table.
	775	+ *
	776	+ * Subclass overrides this to alter the behavior of HashMap(Map),
	777	+ * clone, and readObject.
	778	+ */
	779	+ void createEntry(int hash, K key, V value, int bucketIndex) {
	780	+ Entry<K,V> e = table[bucketIndex];
	781	+ table[bucketIndex] = new Entry<>(hash, key, value, e);
	782	+ size++;
	783	+ }
	784	+
	785	+ private abstract class HashIterator<E> implements Iterator<E> {
	786	+ Entry<K,V> next; // next entry to return
	787	+ int expectedModCount; // For fast-fail
	788	+ int index; // current slot
	789	+ Entry<K,V> current; // current entry
	790	+
	791	+ HashIterator() {
	792	+ expectedModCount = modCount;
	793	+ if (size > 0) { // advance to first entry
	794	+ Entry[] t = table;
	795	+ while (index < t.length && (next = t[index++]) == null)
	796	+ ;
	797	+ }
	798	+ }
	799	+
	800	+ public final boolean hasNext() {
	801	+ return next != null;
	802	+ }
	803	+
	804	+ final Entry<K,V> nextEntry() {
	805	+ if (modCount != expectedModCount)
	806	+ throw new ConcurrentModificationException();
	807	+ Entry<K,V> e = next;
	808	+ if (e == null)
	809	+ throw new NoSuchElementException();
	810	+
	811	+ if ((next = e.next) == null) {
	812	+ Entry[] t = table;
	813	+ while (index < t.length && (next = t[index++]) == null)
	814	+ ;
	815	+ }
	816	+ current = e;
	817	+ return e;
	818	+ }
	819	+
	820	+ public void remove() {
	821	+ if (current == null)
	822	+ throw new IllegalStateException();
	823	+ if (modCount != expectedModCount)
	824	+ throw new ConcurrentModificationException();
	825	+ Object k = current.key;
	826	+ current = null;
	827	+ HashMap.this.removeEntryForKey(k);
	828	+ expectedModCount = modCount;
	829	+ }
	830	+
	831	+ }
	832	+
	833	+ private final class ValueIterator extends HashIterator<V> {
	834	+ public V next() {
	835	+ return nextEntry().value;
	836	+ }
	837	+ }
	838	+
	839	+ private final class KeyIterator extends HashIterator<K> {
	840	+ public K next() {
	841	+ return nextEntry().getKey();
	842	+ }
	843	+ }
	844	+
	845	+ private final class EntryIterator extends HashIterator<Map.Entry<K,V>> {
	846	+ public Map.Entry<K,V> next() {
	847	+ return nextEntry();
	848	+ }
	849	+ }
	850	+
	851	+ // Subclass overrides these to alter behavior of views' iterator() method
	852	+ Iterator<K> newKeyIterator() {
	853	+ return new KeyIterator();
	854	+ }
	855	+ Iterator<V> newValueIterator() {
	856	+ return new ValueIterator();
	857	+ }
	858	+ Iterator<Map.Entry<K,V>> newEntryIterator() {
	859	+ return new EntryIterator();
	860	+ }
	861	+
	862	+
	863	+ // Views
	864	+
	865	+ private transient Set<Map.Entry<K,V>> entrySet = null;
	866	+
	867	+ /**
	868	+ * Returns a {@link Set} view of the keys contained in this map.
	869	+ * The set is backed by the map, so changes to the map are
	870	+ * reflected in the set, and vice-versa. If the map is modified
	871	+ * while an iteration over the set is in progress (except through
	872	+ * the iterator's own <tt>remove</tt> operation), the results of
	873	+ * the iteration are undefined. The set supports element removal,
	874	+ * which removes the corresponding mapping from the map, via the
	875	+ * <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
	876	+ * <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
	877	+ * operations. It does not support the <tt>add</tt> or <tt>addAll</tt>
	878	+ * operations.
	879	+ */
	880	+ public Set<K> keySet() {
	881	+ Set<K> ks = keySet;
	882	+ return (ks != null ? ks : (keySet = new KeySet()));
	883	+ }
	884	+
	885	+ private final class KeySet extends AbstractSet<K> {
	886	+ public Iterator<K> iterator() {
	887	+ return newKeyIterator();
	888	+ }
	889	+ public int size() {
	890	+ return size;
	891	+ }
	892	+ public boolean contains(Object o) {
	893	+ return containsKey(o);
	894	+ }
	895	+ public boolean remove(Object o) {
	896	+ return HashMap.this.removeEntryForKey(o) != null;
	897	+ }
	898	+ public void clear() {
	899	+ HashMap.this.clear();
	900	+ }
	901	+ }
	902	+
	903	+ /**
	904	+ * Returns a {@link Collection} view of the values contained in this map.
	905	+ * The collection is backed by the map, so changes to the map are
	906	+ * reflected in the collection, and vice-versa. If the map is
	907	+ * modified while an iteration over the collection is in progress
	908	+ * (except through the iterator's own <tt>remove</tt> operation),
	909	+ * the results of the iteration are undefined. The collection
	910	+ * supports element removal, which removes the corresponding
	911	+ * mapping from the map, via the <tt>Iterator.remove</tt>,
	912	+ * <tt>Collection.remove</tt>, <tt>removeAll</tt>,
	913	+ * <tt>retainAll</tt> and <tt>clear</tt> operations. It does not
	914	+ * support the <tt>add</tt> or <tt>addAll</tt> operations.
	915	+ */
	916	+ public Collection<V> values() {
	917	+ Collection<V> vs = values;
	918	+ return (vs != null ? vs : (values = new Values()));
	919	+ }
	920	+
	921	+ private final class Values extends AbstractCollection<V> {
	922	+ public Iterator<V> iterator() {
	923	+ return newValueIterator();
	924	+ }
	925	+ public int size() {
	926	+ return size;
	927	+ }
	928	+ public boolean contains(Object o) {
	929	+ return containsValue(o);
	930	+ }
	931	+ public void clear() {
	932	+ HashMap.this.clear();
	933	+ }
	934	+ }
	935	+
	936	+ /**
	937	+ * Returns a {@link Set} view of the mappings contained in this map.
	938	+ * The set is backed by the map, so changes to the map are
	939	+ * reflected in the set, and vice-versa. If the map is modified
	940	+ * while an iteration over the set is in progress (except through
	941	+ * the iterator's own <tt>remove</tt> operation, or through the
	942	+ * <tt>setValue</tt> operation on a map entry returned by the
	943	+ * iterator) the results of the iteration are undefined. The set
	944	+ * supports element removal, which removes the corresponding
	945	+ * mapping from the map, via the <tt>Iterator.remove</tt>,
	946	+ * <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt> and
	947	+ * <tt>clear</tt> operations. It does not support the
	948	+ * <tt>add</tt> or <tt>addAll</tt> operations.
	949	+ *
	950	+ * @return a set view of the mappings contained in this map
	951	+ */
	952	+ public Set<Map.Entry<K,V>> entrySet() {
	953	+ return entrySet0();
	954	+ }
	955	+
	956	+ private Set<Map.Entry<K,V>> entrySet0() {
	957	+ Set<Map.Entry<K,V>> es = entrySet;
	958	+ return es != null ? es : (entrySet = new EntrySet());
	959	+ }
	960	+
	961	+ private final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
	962	+ public Iterator<Map.Entry<K,V>> iterator() {
	963	+ return newEntryIterator();
	964	+ }
	965	+ public boolean contains(Object o) {
	966	+ if (!(o instanceof Map.Entry))
	967	+ return false;
	968	+ Map.Entry<K,V> e = (Map.Entry<K,V>) o;
	969	+ Entry<K,V> candidate = getEntry(e.getKey());
	970	+ return candidate != null && candidate.equals(e);
	971	+ }
	972	+ public boolean remove(Object o) {
	973	+ return removeMapping(o) != null;
	974	+ }
	975	+ public int size() {
	976	+ return size;
	977	+ }
	978	+ public void clear() {
	979	+ HashMap.this.clear();
	980	+ }
	981	+ }
	982	+
	983	+ /**
	984	+ * Save the state of the <tt>HashMap</tt> instance to a stream (i.e.,
	985	+ * serialize it).
	986	+ *
	987	+ * @serialData The <i>capacity</i> of the HashMap (the length of the
	988	+ * bucket array) is emitted (int), followed by the
	989	+ * <i>size</i> (an int, the number of key-value
	990	+ * mappings), followed by the key (Object) and value (Object)
	991	+ * for each key-value mapping. The key-value mappings are
	992	+ * emitted in no particular order.
	993	+ */
	994	+ private void writeObject(java.io.ObjectOutputStream s)
	995	+ throws IOException
	996	+ {
	997	+ Iterator<Map.Entry<K,V>> i =
	998	+ (size > 0) ? entrySet0().iterator() : null;
	999	+
	1000	+ // Write out the threshold, loadfactor, and any hidden stuff
	1001	+ s.defaultWriteObject();
	1002	+
	1003	+ // Write out number of buckets
	1004	+ s.writeInt(table.length);
	1005	+
	1006	+ // Write out size (number of Mappings)
	1007	+ s.writeInt(size);
	1008	+
	1009	+ // Write out keys and values (alternating)
	1010	+ if (i != null) {
	1011	+ while (i.hasNext()) {
	1012	+ Map.Entry<K,V> e = i.next();
	1013	+ s.writeObject(e.getKey());
	1014	+ s.writeObject(e.getValue());
	1015	+ }
	1016	+ }
	1017	+ }
	1018	+
	1019	+ private static final long serialVersionUID = 362498820763181265L;
	1020	+
	1021	+ /**
	1022	+ * Reconstitute the <tt>HashMap</tt> instance from a stream (i.e.,
	1023	+ * deserialize it).
	1024	+ */
	1025	+ private void readObject(java.io.ObjectInputStream s)
	1026	+ throws IOException, ClassNotFoundException
	1027	+ {
	1028	+ // Read in the threshold, loadfactor, and any hidden stuff
	1029	+ s.defaultReadObject();
	1030	+
	1031	+ // Read in number of buckets and allocate the bucket array;
	1032	+ int numBuckets = s.readInt();
	1033	+ table = new Entry[numBuckets];
	1034	+
	1035	+ init(); // Give subclass a chance to do its thing.
	1036	+
	1037	+ // Read in size (number of Mappings)
	1038	+ int size = s.readInt();
	1039	+
	1040	+ // Read the keys and values, and put the mappings in the HashMap
	1041	+ for (int i=0; i<size; i++) {
	1042	+ K key = (K) s.readObject();
	1043	+ V value = (V) s.readObject();
	1044	+ putForCreate(key, value);
	1045	+ }
	1046	+ }
	1047	+
	1048	+ // These methods are used when serializing HashSets
	1049	+ int capacity() { return table.length; }
	1050	+ float loadFactor() { return loadFactor; }
	1051	+}