Add keywords

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@209673 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Stephen Colebourne 2005-07-07 23:31:39 +00:00
parent 0fdd5982c3
commit c9a30909de
1 changed files with 407 additions and 407 deletions

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/*
* Copyright 2001-2005 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.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
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;
/**
* A MultiValueMap decorates another map, allowing it to have
* 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 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;
/** The cached values. */
private transient Collection values;
/**
* Creates a map which wraps the given map and
* maps keys to ArrayLists.
*
* @param map the map to wrap
*/
public static MultiValueMap decorate(Map map) {
return new MultiValueMap(map, new ReflectionFactory(ArrayList.class));
}
/**
* Creates a map 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
*/
public static MultiValueMap decorate(Map map, Class collectionClass) {
return new MultiValueMap(map, new ReflectionFactory(collectionClass));
}
/**
* Creates a map which decorates the given <code>map</code> and
* 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).
*/
public static MultiValueMap decorate(Map map, Factory collectionFactory) {
return new MultiValueMap(map, collectionFactory);
}
//-----------------------------------------------------------------------
/**
* Creates a MultiValueMap based on a <code>HashMap</code> and
* storing the multiple values in an <code>ArrayList</code>.
*/
public MultiValueMap() {
this(new HashMap(), new ReflectionFactory(ArrayList.class));
}
/**
* Creates a MultiValueMap which decorates the given <code>map</code> and
* creates the value collections using the supplied <code>collectionFactory</code>.
*
* @param map the map to decorate
* @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.
*/
public void 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();
}
/**
* Removes a specific value from map.
* <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>.
*
* @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
*/
public Object remove(Object key, Object value) {
Collection valuesForKey = getCollection(key);
if (valuesForKey == null) {
return null;
}
boolean removed = valuesForKey.remove(value);
if (removed == false) {
return null;
}
if (valuesForKey.isEmpty()) {
remove(key);
}
return value;
}
/**
* Checks whether the map contains the value specified.
* <p>
* This checks all collections against all keys for the value, and thus could be slow.
*
* @param value the value to search for
* @return true if the map contains the value
*/
public boolean containsValue(Object value) {
Set pairs = getMap().entrySet();
if (pairs == null) {
return false;
}
Iterator pairsIterator = pairs.iterator();
while (pairsIterator.hasNext()) {
Map.Entry keyValuePair = (Map.Entry) pairsIterator.next();
Collection coll = (Collection) keyValuePair.getValue();
if (coll.contains(value)) {
return true;
}
}
return false;
}
/**
* Adds the value to the collection associated with the specified key.
* <p>
* 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 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) {
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;
}
} else {
result = coll.add(value);
}
return (result ? value : null);
}
/**
* Gets a collection containing all the values in the map.
* <p>
* This returns a collection containing the combination of values from all keys.
*
* @return a collection view of the values contained in this map
*/
public Collection values() {
Collection vs = values;
return (vs != null ? vs : (values = new Values()));
}
/**
* Checks whether the collection at the specified key contains the value.
*
* @param value the value to search for
* @return true if the map contains the value
*/
public boolean containsValue(Object key, Object value) {
Collection coll = getCollection(key);
if (coll == null) {
return false;
}
return coll.contains(value);
}
/**
* Gets the collection mapped to the specified key.
* This method is a convenience method to typecast the result of <code>get(key)</code>.
*
* @param key the key to retrieve
* @return the collection mapped to the key, null if no mapping
*/
public Collection getCollection(Object key) {
return (Collection) getMap().get(key);
}
/**
* Gets the size of the collection mapped to the specified key.
*
* @param key the key to get size for
* @return the size of the collection at the key, zero if key not in map
*/
public int size(Object key) {
Collection coll = getCollection(key);
if (coll == null) {
return 0;
}
return coll.size();
}
/**
* 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
* @return true if this map changed
*/
public boolean putAll(Object key, Collection values) {
if (values == null || values.size() == 0) {
return false;
}
Collection coll = getCollection(key);
if (coll == null) {
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.
*
* @param key the key to get an iterator for
* @return the iterator of the collection at the key, empty iterator if key not in map
*/
public Iterator iterator(Object key) {
if (!containsKey(key)) {
return EmptyIterator.INSTANCE;
} else {
return new ValuesIterator(key);
}
}
/**
* Gets the total size of the map by counting all the values.
*
* @return the total size of the map counting all values
*/
public int totalSize() {
int total = 0;
Collection values = getMap().values();
for (Iterator it = values.iterator(); it.hasNext();) {
Collection coll = (Collection) it.next();
total += coll.size();
}
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 it = keySet().iterator(); it.hasNext();) {
chain.addIterator(new ValuesIterator(it.next()));
}
return chain;
}
public int size() {
return totalSize();
}
public void clear() {
MultiValueMap.this.clear();
}
}
/**
* Inner class that provides the values iterator.
*/
private class ValuesIterator implements Iterator {
private final Object key;
private final Collection values;
private final Iterator iterator;
public ValuesIterator(Object key) {
this.key = key;
this.values = getCollection(key);
this.iterator = values.iterator();
}
public void remove() {
iterator.remove();
if (values.isEmpty()) {
MultiValueMap.this.remove(key);
}
}
public boolean hasNext() {
return iterator.hasNext();
}
public Object next() {
return iterator.next();
}
}
/**
* Inner class that provides a simple reflection factory.
*/
private static class ReflectionFactory implements Factory {
private final Class clazz;
public ReflectionFactory(Class clazz) {
this.clazz = clazz;
}
public Object create() {
try {
return clazz.newInstance();
} catch (Exception ex) {
throw new RuntimeException("Cannot instantiate class: " + clazz, ex);
}
}
}
}
/*
* Copyright 2001-2005 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.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
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;
/**
* A MultiValueMap decorates another map, allowing it to have
* 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 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;
/** The cached values. */
private transient Collection values;
/**
* Creates a map which wraps the given map and
* maps keys to ArrayLists.
*
* @param map the map to wrap
*/
public static MultiValueMap decorate(Map map) {
return new MultiValueMap(map, new ReflectionFactory(ArrayList.class));
}
/**
* Creates a map 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
*/
public static MultiValueMap decorate(Map map, Class collectionClass) {
return new MultiValueMap(map, new ReflectionFactory(collectionClass));
}
/**
* Creates a map which decorates the given <code>map</code> and
* 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).
*/
public static MultiValueMap decorate(Map map, Factory collectionFactory) {
return new MultiValueMap(map, collectionFactory);
}
//-----------------------------------------------------------------------
/**
* Creates a MultiValueMap based on a <code>HashMap</code> and
* storing the multiple values in an <code>ArrayList</code>.
*/
public MultiValueMap() {
this(new HashMap(), new ReflectionFactory(ArrayList.class));
}
/**
* Creates a MultiValueMap which decorates the given <code>map</code> and
* creates the value collections using the supplied <code>collectionFactory</code>.
*
* @param map the map to decorate
* @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.
*/
public void 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();
}
/**
* Removes a specific value from map.
* <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>.
*
* @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
*/
public Object remove(Object key, Object value) {
Collection valuesForKey = getCollection(key);
if (valuesForKey == null) {
return null;
}
boolean removed = valuesForKey.remove(value);
if (removed == false) {
return null;
}
if (valuesForKey.isEmpty()) {
remove(key);
}
return value;
}
/**
* Checks whether the map contains the value specified.
* <p>
* This checks all collections against all keys for the value, and thus could be slow.
*
* @param value the value to search for
* @return true if the map contains the value
*/
public boolean containsValue(Object value) {
Set pairs = getMap().entrySet();
if (pairs == null) {
return false;
}
Iterator pairsIterator = pairs.iterator();
while (pairsIterator.hasNext()) {
Map.Entry keyValuePair = (Map.Entry) pairsIterator.next();
Collection coll = (Collection) keyValuePair.getValue();
if (coll.contains(value)) {
return true;
}
}
return false;
}
/**
* Adds the value to the collection associated with the specified key.
* <p>
* 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 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) {
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;
}
} else {
result = coll.add(value);
}
return (result ? value : null);
}
/**
* Gets a collection containing all the values in the map.
* <p>
* This returns a collection containing the combination of values from all keys.
*
* @return a collection view of the values contained in this map
*/
public Collection values() {
Collection vs = values;
return (vs != null ? vs : (values = new Values()));
}
/**
* Checks whether the collection at the specified key contains the value.
*
* @param value the value to search for
* @return true if the map contains the value
*/
public boolean containsValue(Object key, Object value) {
Collection coll = getCollection(key);
if (coll == null) {
return false;
}
return coll.contains(value);
}
/**
* Gets the collection mapped to the specified key.
* This method is a convenience method to typecast the result of <code>get(key)</code>.
*
* @param key the key to retrieve
* @return the collection mapped to the key, null if no mapping
*/
public Collection getCollection(Object key) {
return (Collection) getMap().get(key);
}
/**
* Gets the size of the collection mapped to the specified key.
*
* @param key the key to get size for
* @return the size of the collection at the key, zero if key not in map
*/
public int size(Object key) {
Collection coll = getCollection(key);
if (coll == null) {
return 0;
}
return coll.size();
}
/**
* 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
* @return true if this map changed
*/
public boolean putAll(Object key, Collection values) {
if (values == null || values.size() == 0) {
return false;
}
Collection coll = getCollection(key);
if (coll == null) {
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.
*
* @param key the key to get an iterator for
* @return the iterator of the collection at the key, empty iterator if key not in map
*/
public Iterator iterator(Object key) {
if (!containsKey(key)) {
return EmptyIterator.INSTANCE;
} else {
return new ValuesIterator(key);
}
}
/**
* Gets the total size of the map by counting all the values.
*
* @return the total size of the map counting all values
*/
public int totalSize() {
int total = 0;
Collection values = getMap().values();
for (Iterator it = values.iterator(); it.hasNext();) {
Collection coll = (Collection) it.next();
total += coll.size();
}
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 it = keySet().iterator(); it.hasNext();) {
chain.addIterator(new ValuesIterator(it.next()));
}
return chain;
}
public int size() {
return totalSize();
}
public void clear() {
MultiValueMap.this.clear();
}
}
/**
* Inner class that provides the values iterator.
*/
private class ValuesIterator implements Iterator {
private final Object key;
private final Collection values;
private final Iterator iterator;
public ValuesIterator(Object key) {
this.key = key;
this.values = getCollection(key);
this.iterator = values.iterator();
}
public void remove() {
iterator.remove();
if (values.isEmpty()) {
MultiValueMap.this.remove(key);
}
}
public boolean hasNext() {
return iterator.hasNext();
}
public Object next() {
return iterator.next();
}
}
/**
* Inner class that provides a simple reflection factory.
*/
private static class ReflectionFactory implements Factory {
private final Class clazz;
public ReflectionFactory(Class clazz) {
this.clazz = clazz;
}
public Object create() {
try {
return clazz.newInstance();
} catch (Exception ex) {
throw new RuntimeException("Cannot instantiate class: " + clazz, ex);
}
}
}
}