/*
* ModeShape (http://www.modeshape.org)
*
* 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.modeshape.common.collection;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
/**
* A {@link Multimap} implementation that uses an {@link HashSet} to store the values associated with a key. This implementation
* does not allow duplicates and the values are not ordered.
*
* @param <K> the key type
* @param <V> the value type
*/
public class HashMultimap<K, V> extends AbstractMultimap<K, V> {
/**
* Creates a new, empty {@code LinkedHashMultimap} (that allows no duplicates) with the default initial capacity.
*
* @param <K> the key type
* @param <V> the value type
* @return the new linked-hash multimap; never null
*/
public static <K, V> HashMultimap<K, V> create() {
return new HashMultimap<K, V>();
}
protected HashMultimap() {
super(new HashMap<K, Collection<V>>());
}
@Override
protected Collection<V> createCollection() {
return new HashSet<V>();
}
@Override
protected Collection<V> createUnmodifiableEmptyCollection() {
return Collections.emptyList();
}
}