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/EnumMap.java (1 of 18352 files). Show all

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	1	+/*
	2	+ * Copyright (c) 2003, 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	+
	28	+import java.util.Map.Entry;
	29	+import sun.misc.SharedSecrets;
	30	+
	31	+/**
	32	+ * A specialized {@link Map} implementation for use with enum type keys. All
	33	+ * of the keys in an enum map must come from a single enum type that is
	34	+ * specified, explicitly or implicitly, when the map is created. Enum maps
	35	+ * are represented internally as arrays. This representation is extremely
	36	+ * compact and efficient.
	37	+ *
	38	+ * <p>Enum maps are maintained in the <i>natural order</i> of their keys
	39	+ * (the order in which the enum constants are declared). This is reflected
	40	+ * in the iterators returned by the collections views ({@link #keySet()},
	41	+ * {@link #entrySet()}, and {@link #values()}).
	42	+ *
	43	+ * <p>Iterators returned by the collection views are <i>weakly consistent</i>:
	44	+ * they will never throw {@link ConcurrentModificationException} and they may
	45	+ * or may not show the effects of any modifications to the map that occur while
	46	+ * the iteration is in progress.
	47	+ *
	48	+ * <p>Null keys are not permitted. Attempts to insert a null key will
	49	+ * throw {@link NullPointerException}. Attempts to test for the
	50	+ * presence of a null key or to remove one will, however, function properly.
	51	+ * Null values are permitted.
	52	+
	53	+ * <P>Like most collection implementations <tt>EnumMap</tt> is not
	54	+ * synchronized. If multiple threads access an enum map concurrently, and at
	55	+ * least one of the threads modifies the map, it should be synchronized
	56	+ * externally. This is typically accomplished by synchronizing on some
	57	+ * object that naturally encapsulates the enum map. If no such object exists,
	58	+ * the map should be "wrapped" using the {@link Collections#synchronizedMap}
	59	+ * method. This is best done at creation time, to prevent accidental
	60	+ * unsynchronized access:
	61	+ *
	62	+ * <pre>
	63	+ * Map<EnumKey, V> m
	64	+ * = Collections.synchronizedMap(new EnumMap<EnumKey, V>(...));
	65	+ * </pre>
	66	+ *
	67	+ * <p>Implementation note: All basic operations execute in constant time.
	68	+ * They are likely (though not guaranteed) to be faster than their
	69	+ * {@link HashMap} counterparts.
	70	+ *
	71	+ * <p>This class is a member of the
	72	+ * <a href="{@docRoot}/../technotes/guides/collections/index.html">
	73	+ * Java Collections Framework</a>.
	74	+ *
	75	+ * @author Josh Bloch
	76	+ * @see EnumSet
	77	+ * @since 1.5
	78	+ */
	79	+public class EnumMap<K extends Enum<K>, V> extends AbstractMap<K, V>
	80	+ implements java.io.Serializable, Cloneable
	81	+{
	82	+ /**
	83	+ * The <tt>Class</tt> object for the enum type of all the keys of this map.
	84	+ *
	85	+ * @serial
	86	+ */
	87	+ private final Class<K> keyType;
	88	+
	89	+ /**
	90	+ * All of the values comprising K. (Cached for performance.)
	91	+ */
	92	+ private transient K[] keyUniverse;
	93	+
	94	+ /**
	95	+ * Array representation of this map. The ith element is the value
	96	+ * to which universe[i] is currently mapped, or null if it isn't
	97	+ * mapped to anything, or NULL if it's mapped to null.
	98	+ */
	99	+ private transient Object[] vals;
	100	+
	101	+ /**
	102	+ * The number of mappings in this map.
	103	+ */
	104	+ private transient int size = 0;
	105	+
	106	+ /**
	107	+ * Distinguished non-null value for representing null values.
	108	+ */
	109	+ private static final Object NULL = new Integer(0);
	110	+
	111	+ private Object maskNull(Object value) {
	112	+ return (value == null ? NULL : value);
	113	+ }
	114	+
	115	+ private V unmaskNull(Object value) {
	116	+ return (V) (value == NULL ? null : value);
	117	+ }
	118	+
	119	+ private static final Enum[] ZERO_LENGTH_ENUM_ARRAY = new Enum[0];
	120	+
	121	+ /**
	122	+ * Creates an empty enum map with the specified key type.
	123	+ *
	124	+ * @param keyType the class object of the key type for this enum map
	125	+ * @throws NullPointerException if <tt>keyType</tt> is null
	126	+ */
	127	+ public EnumMap(Class<K> keyType) {
	128	+ this.keyType = keyType;
	129	+ keyUniverse = getKeyUniverse(keyType);
	130	+ vals = new Object[keyUniverse.length];
	131	+ }
	132	+
	133	+ /**
	134	+ * Creates an enum map with the same key type as the specified enum
	135	+ * map, initially containing the same mappings (if any).
	136	+ *
	137	+ * @param m the enum map from which to initialize this enum map
	138	+ * @throws NullPointerException if <tt>m</tt> is null
	139	+ */
	140	+ public EnumMap(EnumMap<K, ? extends V> m) {
	141	+ keyType = m.keyType;
	142	+ keyUniverse = m.keyUniverse;
	143	+ vals = m.vals.clone();
	144	+ size = m.size;
	145	+ }
	146	+
	147	+ /**
	148	+ * Creates an enum map initialized from the specified map. If the
	149	+ * specified map is an <tt>EnumMap</tt> instance, this constructor behaves
	150	+ * identically to {@link #EnumMap(EnumMap)}. Otherwise, the specified map
	151	+ * must contain at least one mapping (in order to determine the new
	152	+ * enum map's key type).
	153	+ *
	154	+ * @param m the map from which to initialize this enum map
	155	+ * @throws IllegalArgumentException if <tt>m</tt> is not an
	156	+ * <tt>EnumMap</tt> instance and contains no mappings
	157	+ * @throws NullPointerException if <tt>m</tt> is null
	158	+ */
	159	+ public EnumMap(Map<K, ? extends V> m) {
	160	+ if (m instanceof EnumMap) {
	161	+ EnumMap<K, ? extends V> em = (EnumMap<K, ? extends V>) m;
	162	+ keyType = em.keyType;
	163	+ keyUniverse = em.keyUniverse;
	164	+ vals = em.vals.clone();
	165	+ size = em.size;
	166	+ } else {
	167	+ if (m.isEmpty())
	168	+ throw new IllegalArgumentException("Specified map is empty");
	169	+ keyType = m.keySet().iterator().next().getDeclaringClass();
	170	+ keyUniverse = getKeyUniverse(keyType);
	171	+ vals = new Object[keyUniverse.length];
	172	+ putAll(m);
	173	+ }
	174	+ }
	175	+
	176	+ // Query Operations
	177	+
	178	+ /**
	179	+ * Returns the number of key-value mappings in this map.
	180	+ *
	181	+ * @return the number of key-value mappings in this map
	182	+ */
	183	+ public int size() {
	184	+ return size;
	185	+ }
	186	+
	187	+ /**
	188	+ * Returns <tt>true</tt> if this map maps one or more keys to the
	189	+ * specified value.
	190	+ *
	191	+ * @param value the value whose presence in this map is to be tested
	192	+ * @return <tt>true</tt> if this map maps one or more keys to this value
	193	+ */
	194	+ public boolean containsValue(Object value) {
	195	+ value = maskNull(value);
	196	+
	197	+ for (Object val : vals)
	198	+ if (value.equals(val))
	199	+ return true;
	200	+
	201	+ return false;
	202	+ }
	203	+
	204	+ /**
	205	+ * Returns <tt>true</tt> if this map contains a mapping for the specified
	206	+ * key.
	207	+ *
	208	+ * @param key the key whose presence in this map is to be tested
	209	+ * @return <tt>true</tt> if this map contains a mapping for the specified
	210	+ * key
	211	+ */
	212	+ public boolean containsKey(Object key) {
	213	+ return isValidKey(key) && vals[((Enum)key).ordinal()] != null;
	214	+ }
	215	+
	216	+ private boolean containsMapping(Object key, Object value) {
	217	+ return isValidKey(key) &&
	218	+ maskNull(value).equals(vals[((Enum)key).ordinal()]);
	219	+ }
	220	+
	221	+ /**
	222	+ * Returns the value to which the specified key is mapped,
	223	+ * or {@code null} if this map contains no mapping for the key.
	224	+ *
	225	+ * <p>More formally, if this map contains a mapping from a key
	226	+ * {@code k} to a value {@code v} such that {@code (key == k)},
	227	+ * then this method returns {@code v}; otherwise it returns
	228	+ * {@code null}. (There can be at most one such mapping.)
	229	+ *
	230	+ * <p>A return value of {@code null} does not <i>necessarily</i>
	231	+ * indicate that the map contains no mapping for the key; it's also
	232	+ * possible that the map explicitly maps the key to {@code null}.
	233	+ * The {@link #containsKey containsKey} operation may be used to
	234	+ * distinguish these two cases.
	235	+ */
	236	+ public V get(Object key) {
	237	+ return (isValidKey(key) ?
	238	+ unmaskNull(vals[((Enum)key).ordinal()]) : null);
	239	+ }
	240	+
	241	+ // Modification Operations
	242	+
	243	+ /**
	244	+ * Associates the specified value with the specified key in this map.
	245	+ * If the map previously contained a mapping for this key, the old
	246	+ * value is replaced.
	247	+ *
	248	+ * @param key the key with which the specified value is to be associated
	249	+ * @param value the value to be associated with the specified key
	250	+ *
	251	+ * @return the previous value associated with specified key, or
	252	+ * <tt>null</tt> if there was no mapping for key. (A <tt>null</tt>
	253	+ * return can also indicate that the map previously associated
	254	+ * <tt>null</tt> with the specified key.)
	255	+ * @throws NullPointerException if the specified key is null
	256	+ */
	257	+ public V put(K key, V value) {
	258	+ typeCheck(key);
	259	+
	260	+ int index = key.ordinal();
	261	+ Object oldValue = vals[index];
	262	+ vals[index] = maskNull(value);
	263	+ if (oldValue == null)
	264	+ size++;
	265	+ return unmaskNull(oldValue);
	266	+ }
	267	+
	268	+ /**
	269	+ * Removes the mapping for this key from this map if present.
	270	+ *
	271	+ * @param key the key whose mapping is to be removed from the map
	272	+ * @return the previous value associated with specified key, or
	273	+ * <tt>null</tt> if there was no entry for key. (A <tt>null</tt>
	274	+ * return can also indicate that the map previously associated
	275	+ * <tt>null</tt> with the specified key.)
	276	+ */
	277	+ public V remove(Object key) {
	278	+ if (!isValidKey(key))
	279	+ return null;
	280	+ int index = ((Enum)key).ordinal();
	281	+ Object oldValue = vals[index];
	282	+ vals[index] = null;
	283	+ if (oldValue != null)
	284	+ size--;
	285	+ return unmaskNull(oldValue);
	286	+ }
	287	+
	288	+ private boolean removeMapping(Object key, Object value) {
	289	+ if (!isValidKey(key))
	290	+ return false;
	291	+ int index = ((Enum)key).ordinal();
	292	+ if (maskNull(value).equals(vals[index])) {
	293	+ vals[index] = null;
	294	+ size--;
	295	+ return true;
	296	+ }
	297	+ return false;
	298	+ }
	299	+
	300	+ /**
	301	+ * Returns true if key is of the proper type to be a key in this
	302	+ * enum map.
	303	+ */
	304	+ private boolean isValidKey(Object key) {
	305	+ if (key == null)
	306	+ return false;
	307	+
	308	+ // Cheaper than instanceof Enum followed by getDeclaringClass
	309	+ Class keyClass = key.getClass();
	310	+ return keyClass == keyType \|\| keyClass.getSuperclass() == keyType;
	311	+ }
	312	+
	313	+ // Bulk Operations
	314	+
	315	+ /**
	316	+ * Copies all of the mappings from the specified map to this map.
	317	+ * These mappings will replace any mappings that this map had for
	318	+ * any of the keys currently in the specified map.
	319	+ *
	320	+ * @param m the mappings to be stored in this map
	321	+ * @throws NullPointerException the specified map is null, or if
	322	+ * one or more keys in the specified map are null
	323	+ */
	324	+ public void putAll(Map<? extends K, ? extends V> m) {
	325	+ if (m instanceof EnumMap) {
	326	+ EnumMap<? extends K, ? extends V> em =
	327	+ (EnumMap<? extends K, ? extends V>)m;
	328	+ if (em.keyType != keyType) {
	329	+ if (em.isEmpty())
	330	+ return;
	331	+ throw new ClassCastException(em.keyType + " != " + keyType);
	332	+ }
	333	+
	334	+ for (int i = 0; i < keyUniverse.length; i++) {
	335	+ Object emValue = em.vals[i];
	336	+ if (emValue != null) {
	337	+ if (vals[i] == null)
	338	+ size++;
	339	+ vals[i] = emValue;
	340	+ }
	341	+ }
	342	+ } else {
	343	+ super.putAll(m);
	344	+ }
	345	+ }
	346	+
	347	+ /**
	348	+ * Removes all mappings from this map.
	349	+ */
	350	+ public void clear() {
	351	+ Arrays.fill(vals, null);
	352	+ size = 0;
	353	+ }
	354	+
	355	+ // Views
	356	+
	357	+ /**
	358	+ * This field is initialized to contain an instance of the entry set
	359	+ * view the first time this view is requested. The view is stateless,
	360	+ * so there's no reason to create more than one.
	361	+ */
	362	+ private transient Set<Map.Entry<K,V>> entrySet = null;
	363	+
	364	+ /**
	365	+ * Returns a {@link Set} view of the keys contained in this map.
	366	+ * The returned set obeys the general contract outlined in
	367	+ * {@link Map#keySet()}. The set's iterator will return the keys
	368	+ * in their natural order (the order in which the enum constants
	369	+ * are declared).
	370	+ *
	371	+ * @return a set view of the keys contained in this enum map
	372	+ */
	373	+ public Set<K> keySet() {
	374	+ Set<K> ks = keySet;
	375	+ if (ks != null)
	376	+ return ks;
	377	+ else
	378	+ return keySet = new KeySet();
	379	+ }
	380	+
	381	+ private class KeySet extends AbstractSet<K> {
	382	+ public Iterator<K> iterator() {
	383	+ return new KeyIterator();
	384	+ }
	385	+ public int size() {
	386	+ return size;
	387	+ }
	388	+ public boolean contains(Object o) {
	389	+ return containsKey(o);
	390	+ }
	391	+ public boolean remove(Object o) {
	392	+ int oldSize = size;
	393	+ EnumMap.this.remove(o);
	394	+ return size != oldSize;
	395	+ }
	396	+ public void clear() {
	397	+ EnumMap.this.clear();
	398	+ }
	399	+ }
	400	+
	401	+ /**
	402	+ * Returns a {@link Collection} view of the values contained in this map.
	403	+ * The returned collection obeys the general contract outlined in
	404	+ * {@link Map#values()}. The collection's iterator will return the
	405	+ * values in the order their corresponding keys appear in map,
	406	+ * which is their natural order (the order in which the enum constants
	407	+ * are declared).
	408	+ *
	409	+ * @return a collection view of the values contained in this map
	410	+ */
	411	+ public Collection<V> values() {
	412	+ Collection<V> vs = values;
	413	+ if (vs != null)
	414	+ return vs;
	415	+ else
	416	+ return values = new Values();
	417	+ }
	418	+
	419	+ private class Values extends AbstractCollection<V> {
	420	+ public Iterator<V> iterator() {
	421	+ return new ValueIterator();
	422	+ }
	423	+ public int size() {
	424	+ return size;
	425	+ }
	426	+ public boolean contains(Object o) {
	427	+ return containsValue(o);
	428	+ }
	429	+ public boolean remove(Object o) {
	430	+ o = maskNull(o);
	431	+
	432	+ for (int i = 0; i < vals.length; i++) {
	433	+ if (o.equals(vals[i])) {
	434	+ vals[i] = null;
	435	+ size--;
	436	+ return true;
	437	+ }
	438	+ }
	439	+ return false;
	440	+ }
	441	+ public void clear() {
	442	+ EnumMap.this.clear();
	443	+ }
	444	+ }
	445	+
	446	+ /**
	447	+ * Returns a {@link Set} view of the mappings contained in this map.
	448	+ * The returned set obeys the general contract outlined in
	449	+ * {@link Map#keySet()}. The set's iterator will return the
	450	+ * mappings in the order their keys appear in map, which is their
	451	+ * natural order (the order in which the enum constants are declared).
	452	+ *
	453	+ * @return a set view of the mappings contained in this enum map
	454	+ */
	455	+ public Set<Map.Entry<K,V>> entrySet() {
	456	+ Set<Map.Entry<K,V>> es = entrySet;
	457	+ if (es != null)
	458	+ return es;
	459	+ else
	460	+ return entrySet = new EntrySet();
	461	+ }
	462	+
	463	+ private class EntrySet extends AbstractSet<Map.Entry<K,V>> {
	464	+ public Iterator<Map.Entry<K,V>> iterator() {
	465	+ return new EntryIterator();
	466	+ }
	467	+
	468	+ public boolean contains(Object o) {
	469	+ if (!(o instanceof Map.Entry))
	470	+ return false;
	471	+ Map.Entry entry = (Map.Entry)o;
	472	+ return containsMapping(entry.getKey(), entry.getValue());
	473	+ }
	474	+ public boolean remove(Object o) {
	475	+ if (!(o instanceof Map.Entry))
	476	+ return false;
	477	+ Map.Entry entry = (Map.Entry)o;
	478	+ return removeMapping(entry.getKey(), entry.getValue());
	479	+ }
	480	+ public int size() {
	481	+ return size;
	482	+ }
	483	+ public void clear() {
	484	+ EnumMap.this.clear();
	485	+ }
	486	+ public Object[] toArray() {
	487	+ return fillEntryArray(new Object[size]);
	488	+ }
	489	+ @SuppressWarnings("unchecked")
	490	+ public <T> T[] toArray(T[] a) {
	491	+ int size = size();
	492	+ if (a.length < size)
	493	+ a = (T[])java.lang.reflect.Array
	494	+ .newInstance(a.getClass().getComponentType(), size);
	495	+ if (a.length > size)
	496	+ a[size] = null;
	497	+ return (T[]) fillEntryArray(a);
	498	+ }
	499	+ private Object[] fillEntryArray(Object[] a) {
	500	+ int j = 0;
	501	+ for (int i = 0; i < vals.length; i++)
	502	+ if (vals[i] != null)
	503	+ a[j++] = new AbstractMap.SimpleEntry<>(
	504	+ keyUniverse[i], unmaskNull(vals[i]));
	505	+ return a;
	506	+ }
	507	+ }
	508	+
	509	+ private abstract class EnumMapIterator<T> implements Iterator<T> {
	510	+ // Lower bound on index of next element to return
	511	+ int index = 0;
	512	+
	513	+ // Index of last returned element, or -1 if none
	514	+ int lastReturnedIndex = -1;
	515	+
	516	+ public boolean hasNext() {
	517	+ while (index < vals.length && vals[index] == null)
	518	+ index++;
	519	+ return index != vals.length;
	520	+ }
	521	+
	522	+ public void remove() {
	523	+ checkLastReturnedIndex();
	524	+
	525	+ if (vals[lastReturnedIndex] != null) {
	526	+ vals[lastReturnedIndex] = null;
	527	+ size--;
	528	+ }
	529	+ lastReturnedIndex = -1;
	530	+ }
	531	+
	532	+ private void checkLastReturnedIndex() {
	533	+ if (lastReturnedIndex < 0)
	534	+ throw new IllegalStateException();
	535	+ }
	536	+ }
	537	+
	538	+ private class KeyIterator extends EnumMapIterator<K> {
	539	+ public K next() {
	540	+ if (!hasNext())
	541	+ throw new NoSuchElementException();
	542	+ lastReturnedIndex = index++;
	543	+ return keyUniverse[lastReturnedIndex];
	544	+ }
	545	+ }
	546	+
	547	+ private class ValueIterator extends EnumMapIterator<V> {
	548	+ public V next() {
	549	+ if (!hasNext())
	550	+ throw new NoSuchElementException();
	551	+ lastReturnedIndex = index++;
	552	+ return unmaskNull(vals[lastReturnedIndex]);
	553	+ }
	554	+ }
	555	+
	556	+ private class EntryIterator extends EnumMapIterator<Map.Entry<K,V>> {
	557	+ private Entry lastReturnedEntry = null;
	558	+
	559	+ public Map.Entry<K,V> next() {
	560	+ if (!hasNext())
	561	+ throw new NoSuchElementException();
	562	+ lastReturnedEntry = new Entry(index++);
	563	+ return lastReturnedEntry;
	564	+ }
	565	+
	566	+ public void remove() {
	567	+ lastReturnedIndex =
	568	+ ((null == lastReturnedEntry) ? -1 : lastReturnedEntry.index);
	569	+ super.remove();
	570	+ lastReturnedEntry.index = lastReturnedIndex;
	571	+ lastReturnedEntry = null;
	572	+ }
	573	+
	574	+ private class Entry implements Map.Entry<K,V> {
	575	+ private int index;
	576	+
	577	+ private Entry(int index) {
	578	+ this.index = index;
	579	+ }
	580	+
	581	+ public K getKey() {
	582	+ checkIndexForEntryUse();
	583	+ return keyUniverse[index];
	584	+ }
	585	+
	586	+ public V getValue() {
	587	+ checkIndexForEntryUse();
	588	+ return unmaskNull(vals[index]);
	589	+ }
	590	+
	591	+ public V setValue(V value) {
	592	+ checkIndexForEntryUse();
	593	+ V oldValue = unmaskNull(vals[index]);
	594	+ vals[index] = maskNull(value);
	595	+ return oldValue;
	596	+ }
	597	+
	598	+ public boolean equals(Object o) {
	599	+ if (index < 0)
	600	+ return o == this;
	601	+
	602	+ if (!(o instanceof Map.Entry))
	603	+ return false;
	604	+
	605	+ Map.Entry e = (Map.Entry)o;
	606	+ V ourValue = unmaskNull(vals[index]);
	607	+ Object hisValue = e.getValue();
	608	+ return (e.getKey() == keyUniverse[index] &&
	609	+ (ourValue == hisValue \|\|
	610	+ (ourValue != null && ourValue.equals(hisValue))));
	611	+ }
	612	+
	613	+ public int hashCode() {
	614	+ if (index < 0)
	615	+ return super.hashCode();
	616	+
	617	+ return entryHashCode(index);
	618	+ }
	619	+
	620	+ public String toString() {
	621	+ if (index < 0)
	622	+ return super.toString();
	623	+
	624	+ return keyUniverse[index] + "="
	625	+ + unmaskNull(vals[index]);
	626	+ }
	627	+
	628	+ private void checkIndexForEntryUse() {
	629	+ if (index < 0)
	630	+ throw new IllegalStateException("Entry was removed");
	631	+ }
	632	+ }
	633	+ }
	634	+
	635	+ // Comparison and hashing
	636	+
	637	+ /**
	638	+ * Compares the specified object with this map for equality. Returns
	639	+ * <tt>true</tt> if the given object is also a map and the two maps
	640	+ * represent the same mappings, as specified in the {@link
	641	+ * Map#equals(Object)} contract.
	642	+ *
	643	+ * @param o the object to be compared for equality with this map
	644	+ * @return <tt>true</tt> if the specified object is equal to this map
	645	+ */
	646	+ public boolean equals(Object o) {
	647	+ if (this == o)
	648	+ return true;
	649	+ if (o instanceof EnumMap)
	650	+ return equals((EnumMap)o);
	651	+ if (!(o instanceof Map))
	652	+ return false;
	653	+
	654	+ Map<K,V> m = (Map<K,V>)o;
	655	+ if (size != m.size())
	656	+ return false;
	657	+
	658	+ for (int i = 0; i < keyUniverse.length; i++) {
	659	+ if (null != vals[i]) {
	660	+ K key = keyUniverse[i];
	661	+ V value = unmaskNull(vals[i]);
	662	+ if (null == value) {
	663	+ if (!((null == m.get(key)) && m.containsKey(key)))
	664	+ return false;
	665	+ } else {
	666	+ if (!value.equals(m.get(key)))
	667	+ return false;
	668	+ }
	669	+ }
	670	+ }
	671	+
	672	+ return true;
	673	+ }
	674	+
	675	+ private boolean equals(EnumMap em) {
	676	+ if (em.keyType != keyType)
	677	+ return size == 0 && em.size == 0;
	678	+
	679	+ // Key types match, compare each value
	680	+ for (int i = 0; i < keyUniverse.length; i++) {
	681	+ Object ourValue = vals[i];
	682	+ Object hisValue = em.vals[i];
	683	+ if (hisValue != ourValue &&
	684	+ (hisValue == null \|\| !hisValue.equals(ourValue)))
	685	+ return false;
	686	+ }
	687	+ return true;
	688	+ }
	689	+
	690	+ /**
	691	+ * Returns the hash code value for this map. The hash code of a map is
	692	+ * defined to be the sum of the hash codes of each entry in the map.
	693	+ */
	694	+ public int hashCode() {
	695	+ int h = 0;
	696	+
	697	+ for (int i = 0; i < keyUniverse.length; i++) {
	698	+ if (null != vals[i]) {
	699	+ h += entryHashCode(i);
	700	+ }
	701	+ }
	702	+
	703	+ return h;
	704	+ }
	705	+
	706	+ private int entryHashCode(int index) {
	707	+ return (keyUniverse[index].hashCode() ^ vals[index].hashCode());
	708	+ }
	709	+
	710	+ /**
	711	+ * Returns a shallow copy of this enum map. (The values themselves
	712	+ * are not cloned.
	713	+ *
	714	+ * @return a shallow copy of this enum map
	715	+ */
	716	+ public EnumMap<K, V> clone() {
	717	+ EnumMap<K, V> result = null;
	718	+ try {
	719	+ result = (EnumMap<K, V>) super.clone();
	720	+ } catch(CloneNotSupportedException e) {
	721	+ throw new AssertionError();
	722	+ }
	723	+ result.vals = result.vals.clone();
	724	+ return result;
	725	+ }
	726	+
	727	+ /**
	728	+ * Throws an exception if e is not of the correct type for this enum set.
	729	+ */
	730	+ private void typeCheck(K key) {
	731	+ Class keyClass = key.getClass();
	732	+ if (keyClass != keyType && keyClass.getSuperclass() != keyType)
	733	+ throw new ClassCastException(keyClass + " != " + keyType);
	734	+ }
	735	+
	736	+ /**
	737	+ * Returns all of the values comprising K.
	738	+ * The result is uncloned, cached, and shared by all callers.
	739	+ */
	740	+ private static <K extends Enum<K>> K[] getKeyUniverse(Class<K> keyType) {
	741	+ return SharedSecrets.getJavaLangAccess()
	742	+ .getEnumConstantsShared(keyType);
	743	+ }
	744	+
	745	+ private static final long serialVersionUID = 458661240069192865L;
	746	+
	747	+ /**
	748	+ * Save the state of the <tt>EnumMap</tt> instance to a stream (i.e.,
	749	+ * serialize it).
	750	+ *
	751	+ * @serialData The <i>size</i> of the enum map (the number of key-value
	752	+ * mappings) is emitted (int), followed by the key (Object)
	753	+ * and value (Object) for each key-value mapping represented
	754	+ * by the enum map.
	755	+ */
	756	+ private void writeObject(java.io.ObjectOutputStream s)
	757	+ throws java.io.IOException
	758	+ {
	759	+ // Write out the key type and any hidden stuff
	760	+ s.defaultWriteObject();
	761	+
	762	+ // Write out size (number of Mappings)
	763	+ s.writeInt(size);
	764	+
	765	+ // Write out keys and values (alternating)
	766	+ int entriesToBeWritten = size;
	767	+ for (int i = 0; entriesToBeWritten > 0; i++) {
	768	+ if (null != vals[i]) {
	769	+ s.writeObject(keyUniverse[i]);
	770	+ s.writeObject(unmaskNull(vals[i]));
	771	+ entriesToBeWritten--;
	772	+ }
	773	+ }
	774	+ }
	775	+
	776	+ /**
	777	+ * Reconstitute the <tt>EnumMap</tt> instance from a stream (i.e.,
	778	+ * deserialize it).
	779	+ */
	780	+ private void readObject(java.io.ObjectInputStream s)
	781	+ throws java.io.IOException, ClassNotFoundException
	782	+ {
	783	+ // Read in the key type and any hidden stuff
	784	+ s.defaultReadObject();
	785	+
	786	+ keyUniverse = getKeyUniverse(keyType);
	787	+ vals = new Object[keyUniverse.length];
	788	+
	789	+ // Read in size (number of Mappings)
	790	+ int size = s.readInt();
	791	+
	792	+ // Read the keys and values, and put the mappings in the HashMap
	793	+ for (int i = 0; i < size; i++) {
	794	+ K key = (K) s.readObject();
	795	+ V value = (V) s.readObject();
	796	+ put(key, value);
	797	+ }
	798	+ }
	799	+}