| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.collections4; |
| |
| import java.util.List; |
| |
| /** |
| * Defines a map that holds a list of values against each key. |
| * <p> |
| * A {@code ListValuedMap} is a Map with slightly different semantics: |
| * <ul> |
| * <li>Putting a value into the map will add the value to a {@link List} at that key.</li> |
| * <li>Getting a value will return a {@link List}, holding all the values put to that key.</li> |
| * </ul> |
| * |
| * @since 4.1 |
| * @version $Id$ |
| */ |
| public interface ListValuedMap<K, V> extends MultiValuedMap<K, V> { |
| |
| /** |
| * Gets the list of values associated with the specified key. |
| * <p> |
| * This method will return an <b>empty</b> list if |
| * {@link #containsKey(Object)} returns {@code false}. Changes to the |
| * returned list will update the underlying {@code ListValuedMap} and |
| * vice-versa. |
| * |
| * @param key the key to retrieve |
| * @return the {@code List} of values, implementations should return an |
| * empty {@code List} for no mapping |
| * @throws NullPointerException if the key is null and null keys are invalid |
| */ |
| @Override |
| List<V> get(K key); |
| |
| /** |
| * Removes all values associated with the specified key. |
| * <p> |
| * The returned list <i>may</i> be modifiable, but updates will not be |
| * propagated to this list-valued map. In case no mapping was stored for the |
| * specified key, an empty, unmodifiable list will be returned. |
| * |
| * @param key the key to remove values from |
| * @return the {@code List} of values removed, implementations |
| * typically return an empty, unmodifiable {@code List} for no mapping found |
| * @throws UnsupportedOperationException if the map is unmodifiable |
| * @throws NullPointerException if the key is null and null keys are invalid |
| */ |
| @Override |
| List<V> remove(Object key); |
| |
| } |