894286989e
2002-02-14 Mark Wielaard <mark@klomp.org> * java/math/BigInteger.java: import gnu.java.math.MPN not the whole package as a workaround for gcj 3.0.x 2002-02-14 Mark Wielaard <mark@klomp.org> * java/security/BasicPermission.java: extends with fully qualified classname as workaround for gcj 3.0.4. 2002-02-14 Eric Blake <ebb9@email.byu.edu> * java/net/DatagramSocketImpl.java (setOption, getOption): Work around gcj bug of wrong emitted qualifier for inherited method. * java/net/SocketImpl.java (setOption, getOption): Ditto. * java/util/WeakHashMap.java (WeakEntrySet): Add non-private constructor to reduce amount of emitted bytecode. While this happens to work around a jikes 1.15 bug, it is still a useful patch even for correct compilers. * java/rmi/server/RMIClassLoader.java (MyClassLoader): Ditto. * gnu/java/rmi/server/UnicastRemoteCall.java (DummyObjectOutputStream, DummyObjectInputStream): Ditto. 2002-02-14 Eric Blake <ebb9@email.byu.edu> * java/net/DatagramSocketImpl.java: Reformat (no code changes). * java/net/SocketImpl.java: Ditto. * java/rmi/server/RMIClassLoader.java: Ditto. * gnu/java/rmi/server/UnicastRemoteCall.java: Ditto. 2002-02-14 Mark Wielaard <mark@klomp.org> Thanks to Takashi Okamoto * java/util/Arrays.java (ArrayList.indexOf()): this.equals(). * java/util/Arrays.java (ArrayList.lastIndexOf()): Likewise. * java/util/WeakHashMap.java (WeakEntry.getEntry()): this.get(). From-SVN: r49778
874 lines
26 KiB
Java
874 lines
26 KiB
Java
/* java.util.WeakHashMap -- a hashtable that keeps only weak references
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to its keys, allowing the virtual machine to reclaim them
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Copyright (C) 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.util;
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import java.lang.ref.WeakReference;
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import java.lang.ref.ReferenceQueue;
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/**
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* A weak hash map has only weak references to the key. This means
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* that it allows the key to be garbage collected if they are not used
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* otherwise. If this happens, the weak hash map will eventually
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* remove the whole entry from this map. <br>
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*
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* A weak hash map makes most sense, if the keys doesn't override the
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* <code>equals</code>-method: If there is no other reference to the
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* key nobody can ever look up the key in this table and so the entry
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* can be removed. This table also works, if the <code>equals</code>
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* method is overloaded, e.g. with Strings as keys, but you should be
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* prepared that some entries disappear spontaneously. <br>
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*
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* You should also be prepared that this hash map behaves very
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* strange: The size of this map may spontaneously shrink (even if you
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* use a synchronized map and synchronize it); it behaves as if
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* another thread removes entries from this table without
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* synchronizations. The entry set returned by <code>entrySet</code>
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* has similar phenomenons: The size may spontaneously shrink, or an
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* entry, that was in the set before, suddenly disappears. <br>
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*
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* A weak hash map is not meant for caches; use a normal map, with
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* soft references as values instead, or try {@link LinkedHashMap}. <br>
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*
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* The weak hash map supports null values and null keys. The null key
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* is never deleted from the map (except explictly of course).
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* The performance of the methods are similar to that of a hash map. <br>
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*
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* The value objects are strongly referenced by this table. So if a
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* value object maintains a strong reference to the key (either direct
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* or indirect) the key will never be removed from this map. According
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* to Sun, this problem may be fixed in a future release. It is not
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* possible to do it with the jdk 1.2 reference model, though.
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*
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* @author Jochen Hoenicke
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* @author Eric Blake <ebb9@email.byu.edu>
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* @see HashMap
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* @see WeakReference
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* @see LinkedHashMap
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* @since 1.2
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* @status updated to 1.4
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*/
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public class WeakHashMap extends AbstractMap implements Map
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{
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/**
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* The default capacity for an instance of HashMap.
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* Sun's documentation mildly suggests that this (11) is the correct
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* value.
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*/
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private static final int DEFAULT_CAPACITY = 11;
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/**
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* The default load factor of a HashMap.
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*/
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private static final float DEFAULT_LOAD_FACTOR = 0.75F;
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/**
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* This is used instead of the key value <i>null</i>. It is needed
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* to distinguish between an null key and a removed key.
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*/
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// Package visible for use by nested classes.
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static final Object NULL_KEY = new Object()
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{
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/**
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* Sets the hashCode to 0, since that's what null would map to.
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* @return the hash code 0
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*/
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public int hashCode()
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{
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return 0;
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}
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/**
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* Compares this key to the given object. Normally, an object should
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* NEVER compare equal to null, but since we don't publicize NULL_VALUE,
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* it saves bytecode to do so here.
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* @return true iff o is this or null
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*/
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public boolean equals(Object o)
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{
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return null == o || this == o;
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}
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};
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/**
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* The reference queue where our buckets (which are WeakReferences) are
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* registered to.
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*/
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private final ReferenceQueue queue;
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/**
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* The number of entries in this hash map.
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*/
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// Package visible for use by nested classes.
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int size;
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/**
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* The load factor of this WeakHashMap. This is the maximum ratio of
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* size versus number of buckets. If size grows the number of buckets
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* must grow, too.
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*/
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private float loadFactor;
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/**
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* The rounded product of the capacity (i.e. number of buckets) and
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* the load factor. When the number of elements exceeds the
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* threshold, the HashMap calls <pre>rehash()</pre>.
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*/
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private int threshold;
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/**
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* The number of structural modifications. This is used by
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* iterators, to see if they should fail. This doesn't count
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* the silent key removals, when a weak reference is cleared
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* by the garbage collection. Instead the iterators must make
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* sure to have strong references to the entries they rely on.
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*/
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// Package visible for use by nested classes.
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int modCount;
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/**
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* The entry set. There is only one instance per hashmap, namely
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* theEntrySet. Note that the entry set may silently shrink, just
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* like the WeakHashMap.
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*/
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private final class WeakEntrySet extends AbstractSet
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{
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/**
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* Non-private constructor to reduce bytecode emitted.
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*/
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WeakEntrySet()
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{
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}
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/**
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* Returns the size of this set.
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*
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* @return the set size
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*/
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public int size()
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{
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return size;
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}
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/**
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* Returns an iterator for all entries.
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*
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* @return an Entry iterator
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*/
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public Iterator iterator()
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{
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return new Iterator()
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{
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/**
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* The entry that was returned by the last
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* <code>next()</code> call. This is also the entry whose
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* bucket should be removed by the <code>remove</code> call. <br>
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*
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* It is null, if the <code>next</code> method wasn't
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* called yet, or if the entry was already removed. <br>
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*
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* Remembering this entry here will also prevent it from
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* being removed under us, since the entry strongly refers
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* to the key.
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*/
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WeakBucket.WeakEntry lastEntry;
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/**
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* The entry that will be returned by the next
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* <code>next()</code> call. It is <code>null</code> if there
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* is no further entry. <br>
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*
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* Remembering this entry here will also prevent it from
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* being removed under us, since the entry strongly refers
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* to the key.
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*/
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WeakBucket.WeakEntry nextEntry = findNext(null);
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/**
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* The known number of modification to the list, if it differs
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* from the real number, we throw an exception.
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*/
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int knownMod = modCount;
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/**
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* Check the known number of modification to the number of
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* modifications of the table. If it differs from the real
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* number, we throw an exception.
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* @throws ConcurrentModificationException if the number
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* of modifications doesn't match.
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*/
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private void checkMod()
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{
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// This method will get inlined.
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cleanQueue();
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if (knownMod != modCount)
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throw new ConcurrentModificationException();
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}
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/**
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* Get a strong reference to the next entry after
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* lastBucket.
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* @param lastEntry the previous bucket, or null if we should
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* get the first entry.
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* @return the next entry.
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*/
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private WeakBucket.WeakEntry findNext(WeakBucket.WeakEntry lastEntry)
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{
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int slot;
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WeakBucket nextBucket;
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if (lastEntry != null)
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{
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nextBucket = lastEntry.getBucket().next;
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slot = lastEntry.getBucket().slot;
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}
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else
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{
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nextBucket = buckets[0];
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slot = 0;
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}
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while (true)
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{
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while (nextBucket != null)
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{
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WeakBucket.WeakEntry entry = nextBucket.getEntry();
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if (entry != null)
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// This is the next entry.
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return entry;
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// Entry was cleared, try next.
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nextBucket = nextBucket.next;
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}
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slot++;
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if (slot == buckets.length)
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// No more buckets, we are through.
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return null;
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nextBucket = buckets[slot];
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}
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}
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/**
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* Checks if there are more entries.
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* @return true, iff there are more elements.
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* @throws ConcurrentModificationException if the hash map was
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* modified.
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*/
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public boolean hasNext()
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{
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checkMod();
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return nextEntry != null;
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}
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/**
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* Returns the next entry.
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* @return the next entry.
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* @throws ConcurrentModificationException if the hash map was
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* modified.
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* @throws NoSuchElementException if there is no entry.
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*/
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public Object next()
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{
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checkMod();
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if (nextEntry == null)
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throw new NoSuchElementException();
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lastEntry = nextEntry;
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nextEntry = findNext(lastEntry);
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return lastEntry;
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}
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/**
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* Removes the last returned entry from this set. This will
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* also remove the bucket of the underlying weak hash map.
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* @throws ConcurrentModificationException if the hash map was
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* modified.
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* @throws IllegalStateException if <code>next()</code> was
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* never called or the element was already removed.
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*/
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public void remove()
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{
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checkMod();
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if (lastEntry == null)
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throw new IllegalStateException();
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modCount++;
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internalRemove(lastEntry.getBucket());
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lastEntry = null;
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knownMod++;
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}
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};
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}
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}
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/**
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* A bucket is a weak reference to the key, that contains a strong
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* reference to the value, a pointer to the next bucket and its slot
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* number. <br>
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*
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* It would be cleaner to have a WeakReference as field, instead of
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* extending it, but if a weak reference gets cleared, we only get
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* the weak reference (by queue.poll) and wouldn't know where to
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* look for this reference in the hashtable, to remove that entry.
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*
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* @author Jochen Hoenicke
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*/
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private static class WeakBucket extends WeakReference
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{
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/**
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* The value of this entry. The key is stored in the weak
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* reference that we extend.
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*/
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Object value;
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/**
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* The next bucket describing another entry that uses the same
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* slot.
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*/
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WeakBucket next;
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/**
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* The slot of this entry. This should be
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* <pre>
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* Math.abs(key.hashCode() % buckets.length)
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* </pre>
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* But since the key may be silently removed we have to remember
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* the slot number.
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* If this bucket was removed the slot is -1. This marker will
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* prevent the bucket from being removed twice.
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*/
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int slot;
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/**
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* Creates a new bucket for the given key/value pair and the specified
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* slot.
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* @param key the key
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* @param queue the queue the weak reference belongs to
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* @param value the value
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* @param slot the slot. This must match the slot where this bucket
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* will be enqueued.
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*/
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public WeakBucket(Object key, ReferenceQueue queue, Object value,
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int slot)
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{
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super(key, queue);
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this.value = value;
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this.slot = slot;
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}
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/**
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* This class gives the <code>Entry</code> representation of the
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* current bucket. It also keeps a strong reference to the
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* key; bad things may happen otherwise.
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*/
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class WeakEntry implements Map.Entry
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{
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/**
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* The strong ref to the key.
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*/
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Object key;
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/**
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* Creates a new entry for the key.
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* @param key the key
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*/
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public WeakEntry(Object key)
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{
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this.key = key;
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}
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/**
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* Returns the underlying bucket.
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* @return the owning bucket
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*/
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public WeakBucket getBucket()
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{
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return WeakBucket.this;
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}
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/**
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* Returns the key.
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* @return the key
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*/
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public Object getKey()
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{
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return key == NULL_KEY ? null : key;
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}
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/**
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* Returns the value.
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* @return the value
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*/
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public Object getValue()
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{
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return value;
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}
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/**
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* This changes the value. This change takes place in
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* the underlying hash map.
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* @param newVal the new value
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* @return the old value
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*/
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public Object setValue(Object newVal)
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{
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Object oldVal = value;
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value = newVal;
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return oldVal;
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}
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/**
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* The hashCode as specified in the Entry interface.
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* @return the hash code
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*/
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public int hashCode()
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{
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return key.hashCode() ^ WeakHashMap.hashCode(value);
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}
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/**
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* The equals method as specified in the Entry interface.
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* @param o the object to compare to
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* @return true iff o represents the same key/value pair
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*/
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public boolean equals(Object o)
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{
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if (o instanceof Map.Entry)
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{
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Map.Entry e = (Map.Entry) o;
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return key.equals(e.getKey())
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&& WeakHashMap.equals(value, e.getValue());
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}
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return false;
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}
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public String toString()
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{
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return key + "=" + value;
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}
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}
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/**
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* This returns the entry stored in this bucket, or null, if the
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* bucket got cleared in the mean time.
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* @return the Entry for this bucket, if it exists
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*/
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WeakEntry getEntry()
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{
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final Object key = this.get();
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if (key == null)
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return null;
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return new WeakEntry(key);
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}
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}
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/**
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* The entry set returned by <code>entrySet()</code>.
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*/
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private final WeakEntrySet theEntrySet;
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/**
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* The hash buckets. These are linked lists.
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*/
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private WeakBucket[] buckets;
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/**
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* Creates a new weak hash map with default load factor and default
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* capacity.
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*/
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public WeakHashMap()
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{
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this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR);
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}
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/**
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* Creates a new weak hash map with default load factor and the given
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* capacity.
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* @param initialCapacity the initial capacity
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* @throws IllegalArgumentException if initialCapacity is negative
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*/
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public WeakHashMap(int initialCapacity)
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{
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this(initialCapacity, DEFAULT_LOAD_FACTOR);
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}
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/**
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* Creates a new weak hash map with the given initial capacity and
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* load factor.
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* @param initialCapacity the initial capacity.
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* @param loadFactor the load factor (see class description of HashMap).
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* @throws IllegalArgumentException if initialCapacity is negative, or
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* loadFactor is non-positive
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*/
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public WeakHashMap(int initialCapacity, float loadFactor)
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{
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// Check loadFactor for NaN as well.
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if (initialCapacity < 0 || ! (loadFactor > 0))
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throw new IllegalArgumentException();
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this.loadFactor = loadFactor;
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threshold = (int) (initialCapacity * loadFactor);
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theEntrySet = new WeakEntrySet();
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queue = new ReferenceQueue();
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buckets = new WeakBucket[initialCapacity];
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}
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/**
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* Construct a new WeakHashMap with the same mappings as the given map.
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* The WeakHashMap has a default load factor of 0.75.
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*
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* @param m the map to copy
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* @throws NullPointerException if m is null
|
|
* @since 1.3
|
|
*/
|
|
public WeakHashMap(Map m)
|
|
{
|
|
this(m.size(), DEFAULT_LOAD_FACTOR);
|
|
putAll(m);
|
|
}
|
|
|
|
/**
|
|
* Simply hashes a non-null Object to its array index.
|
|
* @param key the key to hash
|
|
* @return its slot number
|
|
*/
|
|
private int hash(Object key)
|
|
{
|
|
return Math.abs(key.hashCode() % buckets.length);
|
|
}
|
|
|
|
/**
|
|
* Cleans the reference queue. This will poll all references (which
|
|
* are WeakBuckets) from the queue and remove them from this map.
|
|
* This will not change modCount, even if it modifies the map. The
|
|
* iterators have to make sure that nothing bad happens. <br>
|
|
*
|
|
* Currently the iterator maintains a strong reference to the key, so
|
|
* that is no problem.
|
|
*/
|
|
// Package visible for use by nested classes.
|
|
void cleanQueue()
|
|
{
|
|
Object bucket = queue.poll();
|
|
while (bucket != null)
|
|
{
|
|
internalRemove((WeakBucket) bucket);
|
|
bucket = queue.poll();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Rehashes this hashtable. This will be called by the
|
|
* <code>add()</code> method if the size grows beyond the threshold.
|
|
* It will grow the bucket size at least by factor two and allocates
|
|
* new buckets.
|
|
*/
|
|
private void rehash()
|
|
{
|
|
WeakBucket[] oldBuckets = buckets;
|
|
int newsize = buckets.length * 2 + 1; // XXX should be prime.
|
|
threshold = (int) (newsize * loadFactor);
|
|
buckets = new WeakBucket[newsize];
|
|
|
|
// Now we have to insert the buckets again.
|
|
for (int i = 0; i < oldBuckets.length; i++)
|
|
{
|
|
WeakBucket bucket = oldBuckets[i];
|
|
WeakBucket nextBucket;
|
|
while (bucket != null)
|
|
{
|
|
nextBucket = bucket.next;
|
|
|
|
Object key = bucket.get();
|
|
if (key == null)
|
|
{
|
|
// This bucket should be removed; it is probably
|
|
// already on the reference queue. We don't insert it
|
|
// at all, and mark it as cleared.
|
|
bucket.slot = -1;
|
|
size--;
|
|
}
|
|
else
|
|
{
|
|
// Add this bucket to its new slot.
|
|
int slot = hash(key);
|
|
bucket.slot = slot;
|
|
bucket.next = buckets[slot];
|
|
buckets[slot] = bucket;
|
|
}
|
|
bucket = nextBucket;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Finds the entry corresponding to key. Since it returns an Entry
|
|
* it will also prevent the key from being removed under us.
|
|
* @param key the key, may be null
|
|
* @return The WeakBucket.WeakEntry or null, if the key wasn't found.
|
|
*/
|
|
private WeakBucket.WeakEntry internalGet(Object key)
|
|
{
|
|
if (key == null)
|
|
key = NULL_KEY;
|
|
int slot = hash(key);
|
|
WeakBucket bucket = buckets[slot];
|
|
while (bucket != null)
|
|
{
|
|
WeakBucket.WeakEntry entry = bucket.getEntry();
|
|
if (entry != null && key.equals(entry.key))
|
|
return entry;
|
|
|
|
bucket = bucket.next;
|
|
}
|
|
return null;
|
|
}
|
|
|
|
/**
|
|
* Adds a new key/value pair to the hash map.
|
|
* @param key the key. This mustn't exists in the map. It may be null.
|
|
* @param value the value.
|
|
*/
|
|
private void internalAdd(Object key, Object value)
|
|
{
|
|
if (key == null)
|
|
key = NULL_KEY;
|
|
int slot = hash(key);
|
|
WeakBucket bucket = new WeakBucket(key, queue, value, slot);
|
|
bucket.next = buckets[slot];
|
|
buckets[slot] = bucket;
|
|
size++;
|
|
}
|
|
|
|
/**
|
|
* Removes a bucket from this hash map, if it wasn't removed before
|
|
* (e.g. one time through rehashing and one time through reference queue)
|
|
* @param bucket the bucket to remove.
|
|
*/
|
|
private void internalRemove(WeakBucket bucket)
|
|
{
|
|
int slot = bucket.slot;
|
|
if (slot == -1)
|
|
// This bucket was already removed.
|
|
return;
|
|
|
|
// Mark the bucket as removed. This is necessary, since the
|
|
// bucket may be enqueued later by the garbage collection, and
|
|
// internalRemove will be called a second time.
|
|
bucket.slot = -1;
|
|
if (buckets[slot] == bucket)
|
|
buckets[slot] = bucket.next;
|
|
else
|
|
{
|
|
WeakBucket prev = buckets[slot];
|
|
/* This may throw a NullPointerException. It shouldn't but if
|
|
* a race condition occurred (two threads removing the same
|
|
* bucket at the same time) it may happen. <br>
|
|
* But with race condition many much worse things may happen
|
|
* anyway.
|
|
*/
|
|
while (prev.next != bucket)
|
|
prev = prev.next;
|
|
prev.next = bucket.next;
|
|
}
|
|
size--;
|
|
}
|
|
|
|
/**
|
|
* Returns the size of this hash map. Note that the size() may shrink
|
|
* spontaneously, if the some of the keys were only weakly reachable.
|
|
* @return the number of entries in this hash map.
|
|
*/
|
|
public int size()
|
|
{
|
|
cleanQueue();
|
|
return size;
|
|
}
|
|
|
|
/**
|
|
* Tells if the map is empty. Note that the result may change
|
|
* spontanously, if all of the keys were only weakly reachable.
|
|
* @return true, iff the map is empty.
|
|
*/
|
|
public boolean isEmpty()
|
|
{
|
|
cleanQueue();
|
|
return size == 0;
|
|
}
|
|
|
|
/**
|
|
* Tells if the map contains the given key. Note that the result
|
|
* may change spontanously, if the key was only weakly
|
|
* reachable.
|
|
* @param key the key to look for
|
|
* @return true, iff the map contains an entry for the given key.
|
|
*/
|
|
public boolean containsKey(Object key)
|
|
{
|
|
cleanQueue();
|
|
return internalGet(key) != null;
|
|
}
|
|
|
|
/**
|
|
* Gets the value the key is mapped to.
|
|
* @return the value the key was mapped to. It returns null if
|
|
* the key wasn't in this map, or if the mapped value was
|
|
* explicitly set to null.
|
|
*/
|
|
public Object get(Object key)
|
|
{
|
|
cleanQueue();
|
|
WeakBucket.WeakEntry entry = internalGet(key);
|
|
return entry == null ? null : entry.getValue();
|
|
}
|
|
|
|
/**
|
|
* Adds a new key/value mapping to this map.
|
|
* @param key the key, may be null
|
|
* @param value the value, may be null
|
|
* @return the value the key was mapped to previously. It returns
|
|
* null if the key wasn't in this map, or if the mapped value
|
|
* was explicitly set to null.
|
|
*/
|
|
public Object put(Object key, Object value)
|
|
{
|
|
cleanQueue();
|
|
WeakBucket.WeakEntry entry = internalGet(key);
|
|
if (entry != null)
|
|
return entry.setValue(value);
|
|
|
|
modCount++;
|
|
if (size >= threshold)
|
|
rehash();
|
|
|
|
internalAdd(key, value);
|
|
return null;
|
|
}
|
|
|
|
/**
|
|
* Removes the key and the corresponding value from this map.
|
|
* @param key the key. This may be null.
|
|
* @return the value the key was mapped to previously. It returns
|
|
* null if the key wasn't in this map, or if the mapped value was
|
|
* explicitly set to null.
|
|
*/
|
|
public Object remove(Object key)
|
|
{
|
|
cleanQueue();
|
|
WeakBucket.WeakEntry entry = internalGet(key);
|
|
if (entry == null)
|
|
return null;
|
|
|
|
modCount++;
|
|
internalRemove(entry.getBucket());
|
|
return entry.getValue();
|
|
}
|
|
|
|
/**
|
|
* Returns a set representation of the entries in this map. This
|
|
* set will not have strong references to the keys, so they can be
|
|
* silently removed. The returned set has therefore the same
|
|
* strange behaviour (shrinking size(), disappearing entries) as
|
|
* this weak hash map.
|
|
* @return a set representation of the entries.
|
|
*/
|
|
public Set entrySet()
|
|
{
|
|
cleanQueue();
|
|
return theEntrySet;
|
|
}
|
|
|
|
/**
|
|
* Clears all entries from this map.
|
|
*/
|
|
public void clear()
|
|
{
|
|
super.clear();
|
|
}
|
|
|
|
/**
|
|
* Returns true if the map contains at least one key which points to
|
|
* the specified object as a value. Note that the result
|
|
* may change spontanously, if its key was only weakly reachable.
|
|
* @param value the value to search for
|
|
* @return true if it is found in the set.
|
|
*/
|
|
public boolean containsValue(Object value)
|
|
{
|
|
cleanQueue();
|
|
return super.containsValue(value);
|
|
}
|
|
|
|
/**
|
|
* Returns a set representation of the keys in this map. This
|
|
* set will not have strong references to the keys, so they can be
|
|
* silently removed. The returned set has therefore the same
|
|
* strange behaviour (shrinking size(), disappearing entries) as
|
|
* this weak hash map.
|
|
* @return a set representation of the keys.
|
|
*/
|
|
public Set keySet()
|
|
{
|
|
cleanQueue();
|
|
return super.keySet();
|
|
}
|
|
|
|
/**
|
|
* Puts all of the mappings from the given map into this one. If the
|
|
* key already exists in this map, its value is replaced.
|
|
* @param m the map to copy in
|
|
*/
|
|
public void putAll(Map m)
|
|
{
|
|
super.putAll(m);
|
|
}
|
|
|
|
/**
|
|
* Returns a collection representation of the values in this map. This
|
|
* collection will not have strong references to the keys, so mappings
|
|
* can be silently removed. The returned collection has therefore the same
|
|
* strange behaviour (shrinking size(), disappearing entries) as
|
|
* this weak hash map.
|
|
* @return a collection representation of the values.
|
|
*/
|
|
public Collection values()
|
|
{
|
|
cleanQueue();
|
|
return super.values();
|
|
}
|
|
}
|