Applied fixes from Julien Buret to improve MultiMap including
- values() backed by real map - clone works properly - ArrayLists can be added to a MultiMap Javadoc class git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@130874 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Stephen Colebourne
parent
7c12e16836
commit
c8de9e8066
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@ -1,7 +1,7 @@
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/*
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* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/MultiHashMap.java,v 1.7 2002/11/01 19:41:00 rwaldhoff Exp $
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* $Revision: 1.7 $
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* $Date: 2002/11/01 19:41:00 $
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* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/MultiHashMap.java,v 1.8 2002/11/24 19:36:48 scolebourne Exp $
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* $Revision: 1.8 $
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* $Date: 2002/11/24 19:36:48 $
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*
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* ====================================================================
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*
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@ -60,165 +60,333 @@
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*/
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package org.apache.commons.collections;
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import java.io.IOException;
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import java.io.ObjectInputStream;
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import java.util.AbstractCollection;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.HashMap;
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import java.util.Iterator;
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import java.util.Map;
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import java.util.NoSuchElementException;
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import java.util.Set;
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/**
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* <code>MultiHashMap</code> is the default implementation of the
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* {@link org.apache.commons.collections.MultiMap MultiMap} interface.
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* <p>
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* A <code>MultiMap</code> is a Map with slightly different semantics.
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* Instead of returning an Object, it returns a Collection.
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* So for example, you can put( key, new Integer(1) );
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* and then a Object get( key ); will return you a Collection
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* instead of an Integer.
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* Putting a value into the map will add the value to a Collection at that
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* key. Getting a value will always return a Collection, holding all the
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* values put to that key. This implementation uses an ArrayList as the
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* collection.
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* <p>
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* For example:
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* <pre>
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* MultiMap mhm = new MultiHashMap();
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* mhm.put(key, "A");
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* mhm.put(key, "B");
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* mhm.put(key, "C");
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* Collection coll = mhm.get(key);</pre>
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* <p>
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* <code>coll</code> will be a list containing "A", "B", "C".
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*
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* @since 2.0
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* @author Christopher Berry
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* @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
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* @author Steve Downey
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* @author Stephen Colebourne
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* @author <a href="mailto:jburet@yahoo.com">Julien Buret</a>
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*/
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public class MultiHashMap extends HashMap implements MultiMap
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{
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//----------------- Data
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public class MultiHashMap extends HashMap implements MultiMap {
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// deprecated name concept
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private static int sCount = 0;
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private String mName = null;
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public MultiHashMap()
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{
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//backed values collection
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private transient Collection values = null;
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// compatibility with commons-collection releases 2.0/2.1
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private static final long serialVersionUID = 1943563828307035349L;
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/**
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* Constructor.
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*/
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public MultiHashMap() {
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super();
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setName();
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}
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public MultiHashMap( int initialCapacity )
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{
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super( initialCapacity );
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/**
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* Constructor.
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*
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* @param initialCapacity the initial map capacity
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*/
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public MultiHashMap(int initialCapacity) {
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super(initialCapacity);
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setName();
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}
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public MultiHashMap(int initialCapacity, float loadFactor )
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{
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super( initialCapacity, loadFactor);
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/**
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* Constructor.
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*
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* @param initialCapacity the initial map capacity
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* @param loadFactor the amount 0.0-1.0 at which to resize the map
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*/
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public MultiHashMap(int initialCapacity, float loadFactor) {
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super(initialCapacity, loadFactor);
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setName();
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}
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public MultiHashMap( Map mapToCopy )
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{
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super( mapToCopy );
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/**
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* Constructor.
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*
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* @param mapToCopy a Map to copy
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*/
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public MultiHashMap(Map mapToCopy) {
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super(mapToCopy);
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}
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/**
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* Read the object during deserialization.
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*/
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private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {
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// This method is needed because the 1.2/1.3 Java deserialisation called
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// put and thus messed up that method
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// default read object
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s.defaultReadObject();
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// problem only with jvm <1.4
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String version = "1.2";
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try {
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version = System.getProperty("java.version");
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} catch (SecurityException ex) {
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// ignore and treat as 1.2/1.3
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}
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if (version.startsWith("1.2") || version.startsWith("1.3")) {
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for (Iterator iterator = entrySet().iterator(); iterator.hasNext();) {
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Map.Entry entry = (Map.Entry) iterator.next();
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// put has created a extra collection level, remove it
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super.put(entry.getKey(), ((Collection) entry.getValue()).iterator().next());
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}
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}
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}
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private void setName()
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{
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/**
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* Create a name for the map.
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*/
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private void setName() {
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sCount++;
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mName = "MultiMap-" + sCount;
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}
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public String getName()
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{ return mName; }
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public Object put( Object key, Object value )
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{
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// NOTE:: put might be called during deserialization !!!!!!
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// so we must provide a hook to handle this case
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// This means that we cannot make MultiMaps of ArrayLists !!!
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if ( value instanceof ArrayList ) {
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return ( super.put( key, value ) );
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/**
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* Gets the name of the map.
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*
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* @deprecated no replacement. There is no good reason for a MultiMap to have a name
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* @return the name
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*/
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public String getName() {
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return mName;
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}
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/**
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* Put a key and value into the map.
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* <p>
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* The value is added to a collection mapped to the key instead of
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* replacing the previous value.
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*
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* @param key the key to set
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* @param value the value to set the key to
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* @return the value added if the add is successful, <code>null</code> otherwise
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*/
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public Object put(Object key, Object value) {
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// NOTE:: put is called during deserialization in JDK < 1.4 !!!!!!
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// so we must have a readObject()
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Collection coll = (Collection) super.get(key);
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if (coll == null) {
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coll = createCollection(null);
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super.put(key, coll);
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}
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ArrayList keyList = (ArrayList)(super.get( key ));
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if ( keyList == null ) {
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keyList = new ArrayList(10);
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super.put( key, keyList );
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}
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boolean results = keyList.add( value );
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return ( results ? value : null );
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boolean results = coll.add(value);
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return (results ? value : null);
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}
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public boolean containsValue( Object value )
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{
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/**
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* Does the map contain a specific value.
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* <p>
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* This searches the collection mapped to each key, and thus could be slow.
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*
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* @param value the value to search for
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* @return true if the list contains the value
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*/
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public boolean containsValue(Object value) {
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Set pairs = super.entrySet();
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if ( pairs == null )
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if (pairs == null) {
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return false;
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}
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Iterator pairsIterator = pairs.iterator();
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while ( pairsIterator.hasNext() ) {
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Map.Entry keyValuePair = (Map.Entry)(pairsIterator.next());
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ArrayList list = (ArrayList)(keyValuePair.getValue());
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if( list.contains( value ) )
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while (pairsIterator.hasNext()) {
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Map.Entry keyValuePair = (Map.Entry) pairsIterator.next();
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Collection coll = (Collection) keyValuePair.getValue();
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if (coll.contains(value)) {
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return true;
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}
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}
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return false;
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}
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public Object remove( Object key, Object item )
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{
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ArrayList valuesForKey = (ArrayList) super.get( key );
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if ( valuesForKey == null )
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/**
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* Removes a specific value from map.
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* <p>
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* The item is removed from the collection mapped to the specified key.
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*
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* @param key the key to remove from
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* @param value the value to remove
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* @return the value removed (which was passed in)
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*/
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public Object remove(Object key, Object item) {
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Collection valuesForKey = (Collection) super.get(key);
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if (valuesForKey == null) {
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return null;
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valuesForKey.remove( item );
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}
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valuesForKey.remove(item);
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return item;
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}
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public void clear()
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{
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/**
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* Clear the map.
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* <p>
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* This clears each collection in the map, and so may be slow.
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*/
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public void clear() {
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// For gc, clear each list in the map
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Set pairs = super.entrySet();
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Iterator pairsIterator = pairs.iterator();
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while ( pairsIterator.hasNext() ) {
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Map.Entry keyValuePair = (Map.Entry)(pairsIterator.next());
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ArrayList list = (ArrayList)(keyValuePair.getValue());
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list.clear();
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while (pairsIterator.hasNext()) {
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Map.Entry keyValuePair = (Map.Entry) pairsIterator.next();
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Collection coll = (Collection) keyValuePair.getValue();
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coll.clear();
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}
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super.clear();
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}
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public void putAll( Map mapToPut )
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{
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super.putAll( mapToPut );
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}
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/**
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* Note: Currently the returned {@link Collection} is <i>not</i>
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* backed by this map.
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* @see Map#values
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* @see http://issues.apache.org/bugzilla/show_bug.cgi?id=9573
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* Gets a view over all the values in the map.
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* <p>
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* The values view includes all the entries in the collections at each map key.
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*
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* @return the collection view of all the values in the map
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*/
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public Collection values()
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{
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ArrayList returnList = new ArrayList( super.size() );
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Set pairs = super.entrySet();
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Iterator pairsIterator = pairs.iterator();
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while ( pairsIterator.hasNext() ) {
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Map.Entry keyValuePair = (Map.Entry)(pairsIterator.next());
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ArrayList list = (ArrayList)(keyValuePair.getValue());
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Object[] values = list.toArray();
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for ( int ii=0; ii < values.length; ii++ ) {
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returnList.add( values[ii] );
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}
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}
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return returnList;
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public Collection values() {
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Collection vs = values;
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return (vs != null ? vs : (values = new Values()));
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}
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// FIXME:: do we need to implement this??
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// public boolean equals( Object obj ) {}
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// --------------- From Cloneable
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public Object clone()
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{
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MultiHashMap obj = (MultiHashMap)(super.clone());
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/**
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* Inner class to view the elements.
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*/
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private class Values extends AbstractCollection {
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public Iterator iterator() {
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return new ValueIterator();
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}
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public int size() {
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int compt = 0;
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Iterator it = iterator();
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while (it.hasNext()) {
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it.next();
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compt++;
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}
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return compt;
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}
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public void clear() {
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MultiHashMap.this.clear();
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}
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}
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/**
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* Inner iterator to view the elements.
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*/
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private class ValueIterator implements Iterator {
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private Iterator backedIterator;
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private Iterator tempIterator;
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private ValueIterator() {
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backedIterator = MultiHashMap.super.values().iterator();
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}
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private boolean searchNextIterator() {
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while (tempIterator == null || tempIterator.hasNext() == false) {
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if (backedIterator.hasNext() == false) {
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return false;
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}
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tempIterator = ((Collection) backedIterator.next()).iterator();
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}
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return true;
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}
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public boolean hasNext() {
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return searchNextIterator();
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}
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public Object next() {
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if (searchNextIterator() == false) {
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throw new NoSuchElementException();
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}
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return tempIterator.next();
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}
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public void remove() {
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if (tempIterator == null) {
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throw new IllegalStateException();
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}
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tempIterator.remove();
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}
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}
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/**
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* Clone the map.
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* <p>
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* The clone will shallow clone the collections as well as the map.
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*
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* @return the cloned map
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*/
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public Object clone() {
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MultiHashMap obj = (MultiHashMap) super.clone();
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obj.mName = mName;
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// clone each Collection container
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for (Iterator it = entrySet().iterator(); it.hasNext();) {
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Map.Entry entry = (Map.Entry) it.next();
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Collection coll = (Collection) entry.getValue();
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Collection newColl = createCollection(coll);
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entry.setValue(newColl);
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}
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return obj;
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}
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/**
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* Creates a new instance of the map value Collection container.
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* <p>
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* This method can be overridden to use your own collection type.
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*
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* @param coll the collection to copy, may be null
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* @return the new collection
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*/
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protected Collection createCollection(Collection coll) {
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if (coll == null) {
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return new ArrayList();
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} else {
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return new ArrayList(coll);
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}
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}
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}
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