001/*
002 * ModeShape (http://www.modeshape.org)
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *       http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.modeshape.common.collection;
017
018import java.util.ArrayList;
019import java.util.Collection;
020import java.util.Collections;
021import java.util.HashMap;
022import java.util.List;
023
024/**
025 * A {@link Multimap} implementation that uses an {@link ArrayList} to store the values associated with a key. This implementation
026 * allows duplicates and the values are ordered.
027 * 
028 * @param <K> the key type
029 * @param <V> the value type
030 */
031public class ArrayListMultimap<K, V> extends AbstractMultimap<K, V> implements ListMultimap<K, V> {
032
033    /**
034     * Creates a new, empty {@code LinkedHashMultimap} (that allows no duplicates) with the default initial capacity.
035     * 
036     * @param <K> the key type
037     * @param <V> the value type
038     * @return the new linked-hash multimap; never null
039     */
040    public static <K, V> ArrayListMultimap<K, V> create() {
041        return new ArrayListMultimap<K, V>();
042    }
043
044    protected ArrayListMultimap() {
045        super(new HashMap<K, Collection<V>>());
046    }
047
048    @Override
049    protected Collection<V> createCollection() {
050        return new ArrayList<V>();
051    }
052
053    @Override
054    protected Collection<V> createUnmodifiableEmptyCollection() {
055        return Collections.emptyList();
056    }
057
058    @Override
059    public List<V> get( K key ) {
060        return (List<V>)super.get(key);
061    }
062}