1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.collections4;
18
19 import java.util.Comparator;
20 import java.util.SortedMap;
21
22 /**
23 * Defines a map that allows bidirectional lookup between key and values
24 * and retains both keys and values in sorted order.
25 * <p>
26 * Implementations should allow a value to be looked up from a key and
27 * a key to be looked up from a value with equal performance.
28 * </p>
29 *
30 * @param <K> the type of the keys in the map
31 * @param <V> the type of the values in the map
32 * @since 3.0
33 */
34 public interface SortedBidiMap<K, V> extends OrderedBidiMap<K, V>, SortedMap<K, V> {
35
36 /**
37 * Gets a view of this map where the keys and values are reversed.
38 * <p>
39 * Changes to one map will be visible in the other and vice versa.
40 * This enables both directions of the map to be accessed equally.
41 * </p>
42 * <p>
43 * Implementations should seek to avoid creating a new object every time this
44 * method is called. See {@code AbstractMap.values()} etc. Calling this
45 * method on the inverse map should return the original.
46 * </p>
47 * <p>
48 * Implementations must return a {@code SortedBidiMap} instance,
49 * usually by forwarding to {@code inverseSortedBidiMap()}.
50 * </p>
51 *
52 * @return an inverted bidirectional map
53 */
54 @Override
55 SortedBidiMap<V, K> inverseBidiMap();
56
57 /**
58 * Gets the comparator used for the values in the value-to-key map aspect.
59 * @return Comparator<? super V>
60 */
61 Comparator<? super V> valueComparator();
62 }