jtulach@1292: /*
jtulach@1292:  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
jtulach@1292:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
jtulach@1292:  *
jtulach@1292:  * This code is free software; you can redistribute it and/or modify it
jtulach@1292:  * under the terms of the GNU General Public License version 2 only, as
jtulach@1292:  * published by the Free Software Foundation.  Oracle designates this
jtulach@1292:  * particular file as subject to the "Classpath" exception as provided
jtulach@1292:  * by Oracle in the LICENSE file that accompanied this code.
jtulach@1292:  *
jtulach@1292:  * This code is distributed in the hope that it will be useful, but WITHOUT
jtulach@1292:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
jtulach@1292:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
jtulach@1292:  * version 2 for more details (a copy is included in the LICENSE file that
jtulach@1292:  * accompanied this code).
jtulach@1292:  *
jtulach@1292:  * You should have received a copy of the GNU General Public License version
jtulach@1292:  * 2 along with this work; if not, write to the Free Software Foundation,
jtulach@1292:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
jtulach@1292:  *
jtulach@1292:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
jtulach@1292:  * or visit www.oracle.com if you need additional information or have any
jtulach@1292:  * questions.
jtulach@1292:  */
jtulach@1292: 
jtulach@1292: package java.util;
jtulach@1292: 
jtulach@1292: import java.util.Map.Entry;
jtulach@1292: import sun.misc.SharedSecrets;
jtulach@1292: 
jtulach@1292: /**
jtulach@1292:  * A specialized {@link Map} implementation for use with enum type keys.  All
jtulach@1292:  * of the keys in an enum map must come from a single enum type that is
jtulach@1292:  * specified, explicitly or implicitly, when the map is created.  Enum maps
jtulach@1292:  * are represented internally as arrays.  This representation is extremely
jtulach@1292:  * compact and efficient.
jtulach@1292:  *
jtulach@1292:  * <p>Enum maps are maintained in the <i>natural order</i> of their keys
jtulach@1292:  * (the order in which the enum constants are declared).  This is reflected
jtulach@1292:  * in the iterators returned by the collections views ({@link #keySet()},
jtulach@1292:  * {@link #entrySet()}, and {@link #values()}).
jtulach@1292:  *
jtulach@1292:  * <p>Iterators returned by the collection views are <i>weakly consistent</i>:
jtulach@1292:  * they will never throw {@link ConcurrentModificationException} and they may
jtulach@1292:  * or may not show the effects of any modifications to the map that occur while
jtulach@1292:  * the iteration is in progress.
jtulach@1292:  *
jtulach@1292:  * <p>Null keys are not permitted.  Attempts to insert a null key will
jtulach@1292:  * throw {@link NullPointerException}.  Attempts to test for the
jtulach@1292:  * presence of a null key or to remove one will, however, function properly.
jtulach@1292:  * Null values are permitted.
jtulach@1292: 
jtulach@1292:  * <P>Like most collection implementations <tt>EnumMap</tt> is not
jtulach@1292:  * synchronized. If multiple threads access an enum map concurrently, and at
jtulach@1292:  * least one of the threads modifies the map, it should be synchronized
jtulach@1292:  * externally.  This is typically accomplished by synchronizing on some
jtulach@1292:  * object that naturally encapsulates the enum map.  If no such object exists,
jtulach@1292:  * the map should be "wrapped" using the {@link Collections#synchronizedMap}
jtulach@1292:  * method.  This is best done at creation time, to prevent accidental
jtulach@1292:  * unsynchronized access:
jtulach@1292:  *
jtulach@1292:  * <pre>
jtulach@1292:  *     Map&lt;EnumKey, V&gt; m
jtulach@1292:  *         = Collections.synchronizedMap(new EnumMap&lt;EnumKey, V&gt;(...));
jtulach@1292:  * </pre>
jtulach@1292:  *
jtulach@1292:  * <p>Implementation note: All basic operations execute in constant time.
jtulach@1292:  * They are likely (though not guaranteed) to be faster than their
jtulach@1292:  * {@link HashMap} counterparts.
jtulach@1292:  *
jtulach@1292:  * <p>This class is a member of the
jtulach@1292:  * <a href="{@docRoot}/../technotes/guides/collections/index.html">
jtulach@1292:  * Java Collections Framework</a>.
jtulach@1292:  *
jtulach@1292:  * @author Josh Bloch
jtulach@1292:  * @see EnumSet
jtulach@1292:  * @since 1.5
jtulach@1292:  */
jtulach@1292: public class EnumMap<K extends Enum<K>, V> extends AbstractMap<K, V>
jtulach@1292:     implements java.io.Serializable, Cloneable
jtulach@1292: {
jtulach@1292:     /**
jtulach@1292:      * The <tt>Class</tt> object for the enum type of all the keys of this map.
jtulach@1292:      *
jtulach@1292:      * @serial
jtulach@1292:      */
jtulach@1292:     private final Class<K> keyType;
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * All of the values comprising K.  (Cached for performance.)
jtulach@1292:      */
jtulach@1292:     private transient K[] keyUniverse;
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Array representation of this map.  The ith element is the value
jtulach@1292:      * to which universe[i] is currently mapped, or null if it isn't
jtulach@1292:      * mapped to anything, or NULL if it's mapped to null.
jtulach@1292:      */
jtulach@1292:     private transient Object[] vals;
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * The number of mappings in this map.
jtulach@1292:      */
jtulach@1292:     private transient int size = 0;
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Distinguished non-null value for representing null values.
jtulach@1292:      */
jtulach@1292:     private static final Object NULL = new Integer(0);
jtulach@1292: 
jtulach@1292:     private Object maskNull(Object value) {
jtulach@1292:         return (value == null ? NULL : value);
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private V unmaskNull(Object value) {
jtulach@1292:         return (V) (value == NULL ? null : value);
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private static final Enum[] ZERO_LENGTH_ENUM_ARRAY = new Enum[0];
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Creates an empty enum map with the specified key type.
jtulach@1292:      *
jtulach@1292:      * @param keyType the class object of the key type for this enum map
jtulach@1292:      * @throws NullPointerException if <tt>keyType</tt> is null
jtulach@1292:      */
jtulach@1292:     public EnumMap(Class<K> keyType) {
jtulach@1292:         this.keyType = keyType;
jtulach@1292:         keyUniverse = getKeyUniverse(keyType);
jtulach@1292:         vals = new Object[keyUniverse.length];
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Creates an enum map with the same key type as the specified enum
jtulach@1292:      * map, initially containing the same mappings (if any).
jtulach@1292:      *
jtulach@1292:      * @param m the enum map from which to initialize this enum map
jtulach@1292:      * @throws NullPointerException if <tt>m</tt> is null
jtulach@1292:      */
jtulach@1292:     public EnumMap(EnumMap<K, ? extends V> m) {
jtulach@1292:         keyType = m.keyType;
jtulach@1292:         keyUniverse = m.keyUniverse;
jtulach@1292:         vals = m.vals.clone();
jtulach@1292:         size = m.size;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Creates an enum map initialized from the specified map.  If the
jtulach@1292:      * specified map is an <tt>EnumMap</tt> instance, this constructor behaves
jtulach@1292:      * identically to {@link #EnumMap(EnumMap)}.  Otherwise, the specified map
jtulach@1292:      * must contain at least one mapping (in order to determine the new
jtulach@1292:      * enum map's key type).
jtulach@1292:      *
jtulach@1292:      * @param m the map from which to initialize this enum map
jtulach@1292:      * @throws IllegalArgumentException if <tt>m</tt> is not an
jtulach@1292:      *     <tt>EnumMap</tt> instance and contains no mappings
jtulach@1292:      * @throws NullPointerException if <tt>m</tt> is null
jtulach@1292:      */
jtulach@1292:     public EnumMap(Map<K, ? extends V> m) {
jtulach@1292:         if (m instanceof EnumMap) {
jtulach@1292:             EnumMap<K, ? extends V> em = (EnumMap<K, ? extends V>) m;
jtulach@1292:             keyType = em.keyType;
jtulach@1292:             keyUniverse = em.keyUniverse;
jtulach@1292:             vals = em.vals.clone();
jtulach@1292:             size = em.size;
jtulach@1292:         } else {
jtulach@1292:             if (m.isEmpty())
jtulach@1292:                 throw new IllegalArgumentException("Specified map is empty");
jtulach@1292:             keyType = m.keySet().iterator().next().getDeclaringClass();
jtulach@1292:             keyUniverse = getKeyUniverse(keyType);
jtulach@1292:             vals = new Object[keyUniverse.length];
jtulach@1292:             putAll(m);
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     // Query Operations
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns the number of key-value mappings in this map.
jtulach@1292:      *
jtulach@1292:      * @return the number of key-value mappings in this map
jtulach@1292:      */
jtulach@1292:     public int size() {
jtulach@1292:         return size;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns <tt>true</tt> if this map maps one or more keys to the
jtulach@1292:      * specified value.
jtulach@1292:      *
jtulach@1292:      * @param value the value whose presence in this map is to be tested
jtulach@1292:      * @return <tt>true</tt> if this map maps one or more keys to this value
jtulach@1292:      */
jtulach@1292:     public boolean containsValue(Object value) {
jtulach@1292:         value = maskNull(value);
jtulach@1292: 
jtulach@1292:         for (Object val : vals)
jtulach@1292:             if (value.equals(val))
jtulach@1292:                 return true;
jtulach@1292: 
jtulach@1292:         return false;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns <tt>true</tt> if this map contains a mapping for the specified
jtulach@1292:      * key.
jtulach@1292:      *
jtulach@1292:      * @param key the key whose presence in this map is to be tested
jtulach@1292:      * @return <tt>true</tt> if this map contains a mapping for the specified
jtulach@1292:      *            key
jtulach@1292:      */
jtulach@1292:     public boolean containsKey(Object key) {
jtulach@1292:         return isValidKey(key) && vals[((Enum)key).ordinal()] != null;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private boolean containsMapping(Object key, Object value) {
jtulach@1292:         return isValidKey(key) &&
jtulach@1292:             maskNull(value).equals(vals[((Enum)key).ordinal()]);
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns the value to which the specified key is mapped,
jtulach@1292:      * or {@code null} if this map contains no mapping for the key.
jtulach@1292:      *
jtulach@1292:      * <p>More formally, if this map contains a mapping from a key
jtulach@1292:      * {@code k} to a value {@code v} such that {@code (key == k)},
jtulach@1292:      * then this method returns {@code v}; otherwise it returns
jtulach@1292:      * {@code null}.  (There can be at most one such mapping.)
jtulach@1292:      *
jtulach@1292:      * <p>A return value of {@code null} does not <i>necessarily</i>
jtulach@1292:      * indicate that the map contains no mapping for the key; it's also
jtulach@1292:      * possible that the map explicitly maps the key to {@code null}.
jtulach@1292:      * The {@link #containsKey containsKey} operation may be used to
jtulach@1292:      * distinguish these two cases.
jtulach@1292:      */
jtulach@1292:     public V get(Object key) {
jtulach@1292:         return (isValidKey(key) ?
jtulach@1292:                 unmaskNull(vals[((Enum)key).ordinal()]) : null);
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     // Modification Operations
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Associates the specified value with the specified key in this map.
jtulach@1292:      * If the map previously contained a mapping for this key, the old
jtulach@1292:      * value is replaced.
jtulach@1292:      *
jtulach@1292:      * @param key the key with which the specified value is to be associated
jtulach@1292:      * @param value the value to be associated with the specified key
jtulach@1292:      *
jtulach@1292:      * @return the previous value associated with specified key, or
jtulach@1292:      *     <tt>null</tt> if there was no mapping for key.  (A <tt>null</tt>
jtulach@1292:      *     return can also indicate that the map previously associated
jtulach@1292:      *     <tt>null</tt> with the specified key.)
jtulach@1292:      * @throws NullPointerException if the specified key is null
jtulach@1292:      */
jtulach@1292:     public V put(K key, V value) {
jtulach@1292:         typeCheck(key);
jtulach@1292: 
jtulach@1292:         int index = key.ordinal();
jtulach@1292:         Object oldValue = vals[index];
jtulach@1292:         vals[index] = maskNull(value);
jtulach@1292:         if (oldValue == null)
jtulach@1292:             size++;
jtulach@1292:         return unmaskNull(oldValue);
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Removes the mapping for this key from this map if present.
jtulach@1292:      *
jtulach@1292:      * @param key the key whose mapping is to be removed from the map
jtulach@1292:      * @return the previous value associated with specified key, or
jtulach@1292:      *     <tt>null</tt> if there was no entry for key.  (A <tt>null</tt>
jtulach@1292:      *     return can also indicate that the map previously associated
jtulach@1292:      *     <tt>null</tt> with the specified key.)
jtulach@1292:      */
jtulach@1292:     public V remove(Object key) {
jtulach@1292:         if (!isValidKey(key))
jtulach@1292:             return null;
jtulach@1292:         int index = ((Enum)key).ordinal();
jtulach@1292:         Object oldValue = vals[index];
jtulach@1292:         vals[index] = null;
jtulach@1292:         if (oldValue != null)
jtulach@1292:             size--;
jtulach@1292:         return unmaskNull(oldValue);
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private boolean removeMapping(Object key, Object value) {
jtulach@1292:         if (!isValidKey(key))
jtulach@1292:             return false;
jtulach@1292:         int index = ((Enum)key).ordinal();
jtulach@1292:         if (maskNull(value).equals(vals[index])) {
jtulach@1292:             vals[index] = null;
jtulach@1292:             size--;
jtulach@1292:             return true;
jtulach@1292:         }
jtulach@1292:         return false;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns true if key is of the proper type to be a key in this
jtulach@1292:      * enum map.
jtulach@1292:      */
jtulach@1292:     private boolean isValidKey(Object key) {
jtulach@1292:         if (key == null)
jtulach@1292:             return false;
jtulach@1292: 
jtulach@1292:         // Cheaper than instanceof Enum followed by getDeclaringClass
jtulach@1292:         Class keyClass = key.getClass();
jtulach@1292:         return keyClass == keyType || keyClass.getSuperclass() == keyType;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     // Bulk Operations
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Copies all of the mappings from the specified map to this map.
jtulach@1292:      * These mappings will replace any mappings that this map had for
jtulach@1292:      * any of the keys currently in the specified map.
jtulach@1292:      *
jtulach@1292:      * @param m the mappings to be stored in this map
jtulach@1292:      * @throws NullPointerException the specified map is null, or if
jtulach@1292:      *     one or more keys in the specified map are null
jtulach@1292:      */
jtulach@1292:     public void putAll(Map<? extends K, ? extends V> m) {
jtulach@1292:         if (m instanceof EnumMap) {
jtulach@1292:             EnumMap<? extends K, ? extends V> em =
jtulach@1292:                 (EnumMap<? extends K, ? extends V>)m;
jtulach@1292:             if (em.keyType != keyType) {
jtulach@1292:                 if (em.isEmpty())
jtulach@1292:                     return;
jtulach@1292:                 throw new ClassCastException(em.keyType + " != " + keyType);
jtulach@1292:             }
jtulach@1292: 
jtulach@1292:             for (int i = 0; i < keyUniverse.length; i++) {
jtulach@1292:                 Object emValue = em.vals[i];
jtulach@1292:                 if (emValue != null) {
jtulach@1292:                     if (vals[i] == null)
jtulach@1292:                         size++;
jtulach@1292:                     vals[i] = emValue;
jtulach@1292:                 }
jtulach@1292:             }
jtulach@1292:         } else {
jtulach@1292:             super.putAll(m);
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Removes all mappings from this map.
jtulach@1292:      */
jtulach@1292:     public void clear() {
jtulach@1292:         Arrays.fill(vals, null);
jtulach@1292:         size = 0;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     // Views
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * This field is initialized to contain an instance of the entry set
jtulach@1292:      * view the first time this view is requested.  The view is stateless,
jtulach@1292:      * so there's no reason to create more than one.
jtulach@1292:      */
jtulach@1292:     private transient Set<Map.Entry<K,V>> entrySet = null;
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns a {@link Set} view of the keys contained in this map.
jtulach@1292:      * The returned set obeys the general contract outlined in
jtulach@1292:      * {@link Map#keySet()}.  The set's iterator will return the keys
jtulach@1292:      * in their natural order (the order in which the enum constants
jtulach@1292:      * are declared).
jtulach@1292:      *
jtulach@1292:      * @return a set view of the keys contained in this enum map
jtulach@1292:      */
jtulach@1292:     public Set<K> keySet() {
jtulach@1292:         Set<K> ks = keySet;
jtulach@1292:         if (ks != null)
jtulach@1292:             return ks;
jtulach@1292:         else
jtulach@1292:             return keySet = new KeySet();
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private class KeySet extends AbstractSet<K> {
jtulach@1292:         public Iterator<K> iterator() {
jtulach@1292:             return new KeyIterator();
jtulach@1292:         }
jtulach@1292:         public int size() {
jtulach@1292:             return size;
jtulach@1292:         }
jtulach@1292:         public boolean contains(Object o) {
jtulach@1292:             return containsKey(o);
jtulach@1292:         }
jtulach@1292:         public boolean remove(Object o) {
jtulach@1292:             int oldSize = size;
jtulach@1292:             EnumMap.this.remove(o);
jtulach@1292:             return size != oldSize;
jtulach@1292:         }
jtulach@1292:         public void clear() {
jtulach@1292:             EnumMap.this.clear();
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns a {@link Collection} view of the values contained in this map.
jtulach@1292:      * The returned collection obeys the general contract outlined in
jtulach@1292:      * {@link Map#values()}.  The collection's iterator will return the
jtulach@1292:      * values in the order their corresponding keys appear in map,
jtulach@1292:      * which is their natural order (the order in which the enum constants
jtulach@1292:      * are declared).
jtulach@1292:      *
jtulach@1292:      * @return a collection view of the values contained in this map
jtulach@1292:      */
jtulach@1292:     public Collection<V> values() {
jtulach@1292:         Collection<V> vs = values;
jtulach@1292:         if (vs != null)
jtulach@1292:             return vs;
jtulach@1292:         else
jtulach@1292:             return values = new Values();
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private class Values extends AbstractCollection<V> {
jtulach@1292:         public Iterator<V> iterator() {
jtulach@1292:             return new ValueIterator();
jtulach@1292:         }
jtulach@1292:         public int size() {
jtulach@1292:             return size;
jtulach@1292:         }
jtulach@1292:         public boolean contains(Object o) {
jtulach@1292:             return containsValue(o);
jtulach@1292:         }
jtulach@1292:         public boolean remove(Object o) {
jtulach@1292:             o = maskNull(o);
jtulach@1292: 
jtulach@1292:             for (int i = 0; i < vals.length; i++) {
jtulach@1292:                 if (o.equals(vals[i])) {
jtulach@1292:                     vals[i] = null;
jtulach@1292:                     size--;
jtulach@1292:                     return true;
jtulach@1292:                 }
jtulach@1292:             }
jtulach@1292:             return false;
jtulach@1292:         }
jtulach@1292:         public void clear() {
jtulach@1292:             EnumMap.this.clear();
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns a {@link Set} view of the mappings contained in this map.
jtulach@1292:      * The returned set obeys the general contract outlined in
jtulach@1292:      * {@link Map#keySet()}.  The set's iterator will return the
jtulach@1292:      * mappings in the order their keys appear in map, which is their
jtulach@1292:      * natural order (the order in which the enum constants are declared).
jtulach@1292:      *
jtulach@1292:      * @return a set view of the mappings contained in this enum map
jtulach@1292:      */
jtulach@1292:     public Set<Map.Entry<K,V>> entrySet() {
jtulach@1292:         Set<Map.Entry<K,V>> es = entrySet;
jtulach@1292:         if (es != null)
jtulach@1292:             return es;
jtulach@1292:         else
jtulach@1292:             return entrySet = new EntrySet();
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private class EntrySet extends AbstractSet<Map.Entry<K,V>> {
jtulach@1292:         public Iterator<Map.Entry<K,V>> iterator() {
jtulach@1292:             return new EntryIterator();
jtulach@1292:         }
jtulach@1292: 
jtulach@1292:         public boolean contains(Object o) {
jtulach@1292:             if (!(o instanceof Map.Entry))
jtulach@1292:                 return false;
jtulach@1292:             Map.Entry entry = (Map.Entry)o;
jtulach@1292:             return containsMapping(entry.getKey(), entry.getValue());
jtulach@1292:         }
jtulach@1292:         public boolean remove(Object o) {
jtulach@1292:             if (!(o instanceof Map.Entry))
jtulach@1292:                 return false;
jtulach@1292:             Map.Entry entry = (Map.Entry)o;
jtulach@1292:             return removeMapping(entry.getKey(), entry.getValue());
jtulach@1292:         }
jtulach@1292:         public int size() {
jtulach@1292:             return size;
jtulach@1292:         }
jtulach@1292:         public void clear() {
jtulach@1292:             EnumMap.this.clear();
jtulach@1292:         }
jtulach@1292:         public Object[] toArray() {
jtulach@1292:             return fillEntryArray(new Object[size]);
jtulach@1292:         }
jtulach@1292:         @SuppressWarnings("unchecked")
jtulach@1292:         public <T> T[] toArray(T[] a) {
jtulach@1292:             int size = size();
jtulach@1292:             if (a.length < size)
jtulach@1292:                 a = (T[])java.lang.reflect.Array
jtulach@1292:                     .newInstance(a.getClass().getComponentType(), size);
jtulach@1292:             if (a.length > size)
jtulach@1292:                 a[size] = null;
jtulach@1292:             return (T[]) fillEntryArray(a);
jtulach@1292:         }
jtulach@1292:         private Object[] fillEntryArray(Object[] a) {
jtulach@1292:             int j = 0;
jtulach@1292:             for (int i = 0; i < vals.length; i++)
jtulach@1292:                 if (vals[i] != null)
jtulach@1292:                     a[j++] = new AbstractMap.SimpleEntry<>(
jtulach@1292:                         keyUniverse[i], unmaskNull(vals[i]));
jtulach@1292:             return a;
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private abstract class EnumMapIterator<T> implements Iterator<T> {
jtulach@1292:         // Lower bound on index of next element to return
jtulach@1292:         int index = 0;
jtulach@1292: 
jtulach@1292:         // Index of last returned element, or -1 if none
jtulach@1292:         int lastReturnedIndex = -1;
jtulach@1292: 
jtulach@1292:         public boolean hasNext() {
jtulach@1292:             while (index < vals.length && vals[index] == null)
jtulach@1292:                 index++;
jtulach@1292:             return index != vals.length;
jtulach@1292:         }
jtulach@1292: 
jtulach@1292:         public void remove() {
jtulach@1292:             checkLastReturnedIndex();
jtulach@1292: 
jtulach@1292:             if (vals[lastReturnedIndex] != null) {
jtulach@1292:                 vals[lastReturnedIndex] = null;
jtulach@1292:                 size--;
jtulach@1292:             }
jtulach@1292:             lastReturnedIndex = -1;
jtulach@1292:         }
jtulach@1292: 
jtulach@1292:         private void checkLastReturnedIndex() {
jtulach@1292:             if (lastReturnedIndex < 0)
jtulach@1292:                 throw new IllegalStateException();
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private class KeyIterator extends EnumMapIterator<K> {
jtulach@1292:         public K next() {
jtulach@1292:             if (!hasNext())
jtulach@1292:                 throw new NoSuchElementException();
jtulach@1292:             lastReturnedIndex = index++;
jtulach@1292:             return keyUniverse[lastReturnedIndex];
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private class ValueIterator extends EnumMapIterator<V> {
jtulach@1292:         public V next() {
jtulach@1292:             if (!hasNext())
jtulach@1292:                 throw new NoSuchElementException();
jtulach@1292:             lastReturnedIndex = index++;
jtulach@1292:             return unmaskNull(vals[lastReturnedIndex]);
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private class EntryIterator extends EnumMapIterator<Map.Entry<K,V>> {
jtulach@1292:         private Entry lastReturnedEntry = null;
jtulach@1292: 
jtulach@1292:         public Map.Entry<K,V> next() {
jtulach@1292:             if (!hasNext())
jtulach@1292:                 throw new NoSuchElementException();
jtulach@1292:             lastReturnedEntry = new Entry(index++);
jtulach@1292:             return lastReturnedEntry;
jtulach@1292:         }
jtulach@1292: 
jtulach@1292:         public void remove() {
jtulach@1292:             lastReturnedIndex =
jtulach@1292:                 ((null == lastReturnedEntry) ? -1 : lastReturnedEntry.index);
jtulach@1292:             super.remove();
jtulach@1292:             lastReturnedEntry.index = lastReturnedIndex;
jtulach@1292:             lastReturnedEntry = null;
jtulach@1292:         }
jtulach@1292: 
jtulach@1292:         private class Entry implements Map.Entry<K,V> {
jtulach@1292:             private int index;
jtulach@1292: 
jtulach@1292:             private Entry(int index) {
jtulach@1292:                 this.index = index;
jtulach@1292:             }
jtulach@1292: 
jtulach@1292:             public K getKey() {
jtulach@1292:                 checkIndexForEntryUse();
jtulach@1292:                 return keyUniverse[index];
jtulach@1292:             }
jtulach@1292: 
jtulach@1292:             public V getValue() {
jtulach@1292:                 checkIndexForEntryUse();
jtulach@1292:                 return unmaskNull(vals[index]);
jtulach@1292:             }
jtulach@1292: 
jtulach@1292:             public V setValue(V value) {
jtulach@1292:                 checkIndexForEntryUse();
jtulach@1292:                 V oldValue = unmaskNull(vals[index]);
jtulach@1292:                 vals[index] = maskNull(value);
jtulach@1292:                 return oldValue;
jtulach@1292:             }
jtulach@1292: 
jtulach@1292:             public boolean equals(Object o) {
jtulach@1292:                 if (index < 0)
jtulach@1292:                     return o == this;
jtulach@1292: 
jtulach@1292:                 if (!(o instanceof Map.Entry))
jtulach@1292:                     return false;
jtulach@1292: 
jtulach@1292:                 Map.Entry e = (Map.Entry)o;
jtulach@1292:                 V ourValue = unmaskNull(vals[index]);
jtulach@1292:                 Object hisValue = e.getValue();
jtulach@1292:                 return (e.getKey() == keyUniverse[index] &&
jtulach@1292:                         (ourValue == hisValue ||
jtulach@1292:                          (ourValue != null && ourValue.equals(hisValue))));
jtulach@1292:             }
jtulach@1292: 
jtulach@1292:             public int hashCode() {
jtulach@1292:                 if (index < 0)
jtulach@1292:                     return super.hashCode();
jtulach@1292: 
jtulach@1292:                 return entryHashCode(index);
jtulach@1292:             }
jtulach@1292: 
jtulach@1292:             public String toString() {
jtulach@1292:                 if (index < 0)
jtulach@1292:                     return super.toString();
jtulach@1292: 
jtulach@1292:                 return keyUniverse[index] + "="
jtulach@1292:                     + unmaskNull(vals[index]);
jtulach@1292:             }
jtulach@1292: 
jtulach@1292:             private void checkIndexForEntryUse() {
jtulach@1292:                 if (index < 0)
jtulach@1292:                     throw new IllegalStateException("Entry was removed");
jtulach@1292:             }
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     // Comparison and hashing
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Compares the specified object with this map for equality.  Returns
jtulach@1292:      * <tt>true</tt> if the given object is also a map and the two maps
jtulach@1292:      * represent the same mappings, as specified in the {@link
jtulach@1292:      * Map#equals(Object)} contract.
jtulach@1292:      *
jtulach@1292:      * @param o the object to be compared for equality with this map
jtulach@1292:      * @return <tt>true</tt> if the specified object is equal to this map
jtulach@1292:      */
jtulach@1292:     public boolean equals(Object o) {
jtulach@1292:         if (this == o)
jtulach@1292:             return true;
jtulach@1292:         if (o instanceof EnumMap)
jtulach@1292:             return equals((EnumMap)o);
jtulach@1292:         if (!(o instanceof Map))
jtulach@1292:             return false;
jtulach@1292: 
jtulach@1292:         Map<K,V> m = (Map<K,V>)o;
jtulach@1292:         if (size != m.size())
jtulach@1292:             return false;
jtulach@1292: 
jtulach@1292:         for (int i = 0; i < keyUniverse.length; i++) {
jtulach@1292:             if (null != vals[i]) {
jtulach@1292:                 K key = keyUniverse[i];
jtulach@1292:                 V value = unmaskNull(vals[i]);
jtulach@1292:                 if (null == value) {
jtulach@1292:                     if (!((null == m.get(key)) && m.containsKey(key)))
jtulach@1292:                        return false;
jtulach@1292:                 } else {
jtulach@1292:                    if (!value.equals(m.get(key)))
jtulach@1292:                       return false;
jtulach@1292:                 }
jtulach@1292:             }
jtulach@1292:         }
jtulach@1292: 
jtulach@1292:         return true;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private boolean equals(EnumMap em) {
jtulach@1292:         if (em.keyType != keyType)
jtulach@1292:             return size == 0 && em.size == 0;
jtulach@1292: 
jtulach@1292:         // Key types match, compare each value
jtulach@1292:         for (int i = 0; i < keyUniverse.length; i++) {
jtulach@1292:             Object ourValue =    vals[i];
jtulach@1292:             Object hisValue = em.vals[i];
jtulach@1292:             if (hisValue != ourValue &&
jtulach@1292:                 (hisValue == null || !hisValue.equals(ourValue)))
jtulach@1292:                 return false;
jtulach@1292:         }
jtulach@1292:         return true;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns the hash code value for this map.  The hash code of a map is
jtulach@1292:      * defined to be the sum of the hash codes of each entry in the map.
jtulach@1292:      */
jtulach@1292:     public int hashCode() {
jtulach@1292:         int h = 0;
jtulach@1292: 
jtulach@1292:         for (int i = 0; i < keyUniverse.length; i++) {
jtulach@1292:             if (null != vals[i]) {
jtulach@1292:                 h += entryHashCode(i);
jtulach@1292:             }
jtulach@1292:         }
jtulach@1292: 
jtulach@1292:         return h;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private int entryHashCode(int index) {
jtulach@1292:         return (keyUniverse[index].hashCode() ^ vals[index].hashCode());
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns a shallow copy of this enum map.  (The values themselves
jtulach@1292:      * are not cloned.
jtulach@1292:      *
jtulach@1292:      * @return a shallow copy of this enum map
jtulach@1292:      */
jtulach@1292:     public EnumMap<K, V> clone() {
jtulach@1292:         EnumMap<K, V> result = null;
jtulach@1292:         try {
jtulach@1292:             result = (EnumMap<K, V>) super.clone();
jtulach@1292:         } catch(CloneNotSupportedException e) {
jtulach@1292:             throw new AssertionError();
jtulach@1292:         }
jtulach@1292:         result.vals = result.vals.clone();
jtulach@1292:         return result;
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Throws an exception if e is not of the correct type for this enum set.
jtulach@1292:      */
jtulach@1292:     private void typeCheck(K key) {
jtulach@1292:         Class keyClass = key.getClass();
jtulach@1292:         if (keyClass != keyType && keyClass.getSuperclass() != keyType)
jtulach@1292:             throw new ClassCastException(keyClass + " != " + keyType);
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Returns all of the values comprising K.
jtulach@1292:      * The result is uncloned, cached, and shared by all callers.
jtulach@1292:      */
jtulach@1292:     private static <K extends Enum<K>> K[] getKeyUniverse(Class<K> keyType) {
jtulach@1292:         return SharedSecrets.getJavaLangAccess()
jtulach@1292:                                         .getEnumConstantsShared(keyType);
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     private static final long serialVersionUID = 458661240069192865L;
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Save the state of the <tt>EnumMap</tt> instance to a stream (i.e.,
jtulach@1292:      * serialize it).
jtulach@1292:      *
jtulach@1292:      * @serialData The <i>size</i> of the enum map (the number of key-value
jtulach@1292:      *             mappings) is emitted (int), followed by the key (Object)
jtulach@1292:      *             and value (Object) for each key-value mapping represented
jtulach@1292:      *             by the enum map.
jtulach@1292:      */
jtulach@1292:     private void writeObject(java.io.ObjectOutputStream s)
jtulach@1292:         throws java.io.IOException
jtulach@1292:     {
jtulach@1292:         // Write out the key type and any hidden stuff
jtulach@1292:         s.defaultWriteObject();
jtulach@1292: 
jtulach@1292:         // Write out size (number of Mappings)
jtulach@1292:         s.writeInt(size);
jtulach@1292: 
jtulach@1292:         // Write out keys and values (alternating)
jtulach@1292:         int entriesToBeWritten = size;
jtulach@1292:         for (int i = 0; entriesToBeWritten > 0; i++) {
jtulach@1292:             if (null != vals[i]) {
jtulach@1292:                 s.writeObject(keyUniverse[i]);
jtulach@1292:                 s.writeObject(unmaskNull(vals[i]));
jtulach@1292:                 entriesToBeWritten--;
jtulach@1292:             }
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: 
jtulach@1292:     /**
jtulach@1292:      * Reconstitute the <tt>EnumMap</tt> instance from a stream (i.e.,
jtulach@1292:      * deserialize it).
jtulach@1292:      */
jtulach@1292:     private void readObject(java.io.ObjectInputStream s)
jtulach@1292:         throws java.io.IOException, ClassNotFoundException
jtulach@1292:     {
jtulach@1292:         // Read in the key type and any hidden stuff
jtulach@1292:         s.defaultReadObject();
jtulach@1292: 
jtulach@1292:         keyUniverse = getKeyUniverse(keyType);
jtulach@1292:         vals = new Object[keyUniverse.length];
jtulach@1292: 
jtulach@1292:         // Read in size (number of Mappings)
jtulach@1292:         int size = s.readInt();
jtulach@1292: 
jtulach@1292:         // Read the keys and values, and put the mappings in the HashMap
jtulach@1292:         for (int i = 0; i < size; i++) {
jtulach@1292:             K key = (K) s.readObject();
jtulach@1292:             V value = (V) s.readObject();
jtulach@1292:             put(key, value);
jtulach@1292:         }
jtulach@1292:     }
jtulach@1292: }