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Fix put methods, optimize clear method, fix formatting

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bug 29440

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@171009 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Stephen Colebourne 2005-05-19 23:25:46 +00:00
parent 92cee86ea2
commit 9072508ad0
2 changed files with 139 additions and 93 deletions
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184
src/java/org/apache/commons/collections/map/MultiValueMap.java
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@ -15,31 +15,51 @@
*/
package org.apache.commons.collections.map;
import java.util.AbstractCollection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.apache.commons.collections.Factory;
import org.apache.commons.collections.MultiMap;
import org.apache.commons.collections.iterators.EmptyIterator;
import org.apache.commons.collections.iterators.IteratorChain;
import java.util.AbstractCollection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
/**
* A MultiValueMap decorates another map, allowing it to have
* more than one value for a key. The values of the map will be
* Collection objects. The types of which can be specified using
* either a Class object or a Factory which creates Collection
* objects.
* more than one value for a key.
* <p>
* A <code>MultiMap</code> is a Map with slightly different semantics.
* Putting a value into the map will add the value to a Collection at that key.
* Getting a value will return a Collection, holding all the values put to that key.
* <p>
* This implementation is a decorator, allowing any Map implementation
* to be used as the base.
* <p>
* In addition, this implementation allows the type of collection used
* for the values to be controlled. By default, an <code>ArrayList</code>
* is used, however a <code>Class</code> to instantiate may be specified,
* or a factory that returns a <code>Collection</code> instance.
*
* @author <a href="mailto:jcarman@apache.org">James Carman</a>
* @author James Carman
* @author Christopher Berry
* @author James Strachan
* @author Steve Downey
* @author Stephen Colebourne
* @author Julien Buret
* @author Serhiy Yevtushenko
* @version $Revision: $ $Date: $
* @since Commons Collections 3.2
*/
public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
/** The factory for creating value collections. */
private final Factory collectionFactory;
private Collection values;
/** The cached values. */
private transient Collection values;
/**
* Creates a map which wraps the given map and
@ -47,8 +67,8 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
*
* @param map the map to wrap
*/
public static Map decorate(Map map) {
return new MultiValueMap(map);
public static MultiValueMap decorate(Map map) {
return new MultiValueMap(map, new ReflectionFactory(ArrayList.class));
}
/**
@ -58,8 +78,8 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
* @param map the map to wrap
* @param collectionClass the type of the collection class
*/
public static Map decorate(Map map, Class collectionClass) {
return new MultiValueMap(map, collectionClass);
public static MultiValueMap decorate(Map map, Class collectionClass) {
return new MultiValueMap(map, new ReflectionFactory(collectionClass));
}
/**
@ -69,29 +89,17 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
* @param map the map to decorate
* @param collectionFactory the collection factory (must return a Collection object).
*/
public static Map decorate(Map map, Factory collectionFactory) {
public static MultiValueMap decorate(Map map, Factory collectionFactory) {
return new MultiValueMap(map, collectionFactory);
}
//-----------------------------------------------------------------------
/**
* Creates a MultiValueMap which wraps the given map and
* maps keys to ArrayLists.
*
* @param map the map to wrap
* Creates a MultiValueMap based on a <code>HashMap</code> and
* storing the multiple values in an <code>ArrayList</code>.
*/
protected MultiValueMap(Map map) {
this(map, ArrayList.class);
}
/**
* Creates a MultiValueMap which decorates the given <code>map</code> and
* maps keys to collections of type <code>collectionClass</code>.
*
* @param map the map to wrap
* @param collectionClass the type of the collection class
*/
protected MultiValueMap(Map map, Class collectionClass) {
this(map, new ReflectionFactory(collectionClass));
public MultiValueMap() {
this(new HashMap(), new ReflectionFactory(ArrayList.class));
}
/**
@ -99,26 +107,29 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
* creates the value collections using the supplied <code>collectionFactory</code>.
*
* @param map the map to decorate
* @param collectionFactory the collection factory (must return a Collection object).
* @param collectionFactory the collection factory which must return a Collection instance
*/
protected MultiValueMap(Map map, Factory collectionFactory) {
super(map);
if (collectionFactory == null) {
throw new IllegalArgumentException("The factory must not be null");
}
this.collectionFactory = collectionFactory;
}
//-----------------------------------------------------------------------
/**
* Clear the map.
* <p>
* This clears each collection in the map, and so may be slow.
*/
public void clear() {
Set pairs = getMap().entrySet();
Iterator pairsIterator = pairs.iterator();
while(pairsIterator.hasNext()) {
Map.Entry keyValuePair = (Map.Entry) pairsIterator.next();
Collection coll = (Collection) keyValuePair.getValue();
coll.clear();
}
// If you believe that you have GC issues here, try uncommenting this code
// Set pairs = getMap().entrySet();
// Iterator pairsIterator = pairs.iterator();
// while (pairsIterator.hasNext()) {
// Map.Entry keyValuePair = (Map.Entry) pairsIterator.next();
// Collection coll = (Collection) keyValuePair.getValue();
// coll.clear();
// }
getMap().clear();
}
@ -175,26 +186,30 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
}
/**
* Removes a specific value from map.
* Adds the value to the collection associated with the specified key.
* <p>
* The item is removed from the collection mapped to the specified key.
* Other values attached to that key are unaffected.
* <p>
* If the last value for a key is removed, <code>null</code> will be returned
* from a subsequant <code>get(key)</code>.
* Unlike a normal <code>Map</code> the previous value is not replaced.
* Instead the new value is added to the collection stored against the key.
*
* @param key the key to remove from
* @param value the value to remove
* @return the value removed (which was passed in), null if nothing removed
* @param key the key to store against
* @param value the value to add to the collection at the key
* @return the value added if the map changed and null if the map did not change
*/
public Object put(Object key, Object value) {
Collection c = getCollection(key);
if(c == null) {
c = (Collection) collectionFactory.create();
getMap().put(key, c);
boolean result = false;
Collection coll = getCollection(key);
if (coll == null) {
coll = createCollection(1);
result = coll.add(value);
if (coll.size() > 0) {
// only add if non-zero size to maintain class state
getMap().put(key, coll);
result = false;
}
boolean results = c.add(value);
return (results ? value : null);
} else {
result = coll.add(value);
}
return (result ? value : null);
}
/**
@ -249,7 +264,8 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
}
/**
* Adds a collection of values to the collection associated with the specified key.
* Adds a collection of values to the collection associated with
* the specified key.
*
* @param key the key to store against
* @param values the values to add to the collection at the key, null ignored
@ -261,11 +277,18 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
}
Collection coll = getCollection(key);
if (coll == null) {
coll = (Collection) collectionFactory.create();
coll = createCollection(values.size());
boolean result = coll.addAll(values);
if (coll.size() > 0) {
// only add if non-zero size to maintain class state
getMap().put(key, coll);
result = false;
}
return result;
} else {
return coll.addAll(values);
}
}
/**
* Gets an iterator for the collection mapped to the specified key.
@ -276,8 +299,7 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
public Iterator iterator(Object key) {
if (!containsKey(key)) {
return EmptyIterator.INSTANCE;
}
else {
} else {
return new ValuesIterator(key);
}
}
@ -297,11 +319,29 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
return total;
}
/**
* Creates a new instance of the map value Collection container
* using the factory.
* <p>
* This method can be overridden to perform your own processing
* instead of using the factory.
*
* @param size the collection size that is about to be added
* @return the new collection
*/
protected Collection createCollection(int size) {
return (Collection) collectionFactory.create();
}
//-----------------------------------------------------------------------
/**
* Inner class that provides the values view.
*/
private class Values extends AbstractCollection {
public Iterator iterator() {
final IteratorChain chain = new IteratorChain();
for(Iterator i = keySet().iterator(); i.hasNext();) {
chain.addIterator(new ValuesIterator(i.next()));
for (Iterator it = keySet().iterator(); it.hasNext();) {
chain.addIterator(new ValuesIterator(it.next()));
}
return chain;
}
@ -315,6 +355,9 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
}
}
/**
* Inner class that provides the values iterator.
*/
private class ValuesIterator implements Iterator {
private final Object key;
private final Collection values;
@ -342,6 +385,9 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
}
}
/**
* Inner class that provides a simple reflection factory.
*/
private static class ReflectionFactory implements Factory {
private final Class clazz;
@ -352,10 +398,10 @@ public class MultiValueMap extends AbstractMapDecorator implements MultiMap {
public Object create() {
try {
return clazz.newInstance();
}
catch(Exception e) {
throw new RuntimeException("Cannot instantiate class " + clazz + ".", e);
} catch (Exception ex) {
throw new RuntimeException("Cannot instantiate class: " + clazz, ex);
}
}
}
}

6
src/test/org/apache/commons/collections/map/TestMultiValueMap.java
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@ -1,5 +1,5 @@
/*
* Copyright 2001-2005 The Apache Software Foundation
* Copyright 2005 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@ -28,7 +28,7 @@ import java.util.Collection;
import org.apache.commons.collections.IteratorUtils;
/**
* TestMultiValueMap
* TestMultiValueMap.
*
* @author <a href="mailto:jcarman@apache.org">James Carman</a>
* @since Commons Collections 3.2
@ -93,7 +93,7 @@ public class TestMultiValueMap extends TestCase {
}
private MultiValueMap createTestMap(Class collectionClass) {
final MultiValueMap map = new MultiValueMap(new HashMap(), collectionClass);
final MultiValueMap map = MultiValueMap.decorate(new HashMap(), collectionClass);
map.put("one", "uno");
map.put("one", "un");
map.put("two", "dos");