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.logging.log4j.util;
18
19 /**
20 * An extension of {@code ReadOnlyStringMap} that imposes a total ordering on its keys.
21 * The map is ordered according to the natural ordering of its keys. This order is reflected when
22 * {@link #forEach(BiConsumer) consuming} the key-value pairs with a {@link BiConsumer} or a {@link TriConsumer}.
23 * <p>
24 * This interface views all key-value pairs as a sequence ordered by key, and allows
25 * keys and values to be accessed by their index in the sequence.
26 * </p>
27 *
28 * @see ReadOnlyStringMap
29 * @since 2.8
30 */
31 public interface IndexedReadOnlyStringMap extends ReadOnlyStringMap {
32
33 /**
34 * Viewing all key-value pairs as a sequence sorted by key, this method returns the key at the specified index,
35 * or {@code null} if the specified index is less than zero or greater or equal to the size of this collection.
36 *
37 * @param index the index of the key to return
38 * @return the key at the specified index or {@code null}
39 */
40 String getKeyAt(final int index);
41
42 /**
43 * Viewing all key-value pairs as a sequence sorted by key, this method returns the value at the specified index,
44 * or {@code null} if the specified index is less than zero or greater or equal to the size of this collection.
45 *
46 * @param index the index of the value to return
47 * @return the value at the specified index or {@code null}
48 */
49 <V> V getValueAt(final int index);
50
51 /**
52 * Viewing all key-value pairs as a sequence sorted by key, this method returns the index of the specified key in
53 * that sequence. If the specified key is not found, this method returns {@code (-(insertion point) - 1)}.
54 *
55 * @param key the key whose index in the ordered sequence of keys to return
56 * @return the index of the specified key or {@code (-(insertion point) - 1)} if the key is not found.
57 * The insertion point is defined as the point at which the key would be inserted into the array:
58 * the index of the first element in the range greater than the key, or {@code size()} if all elements
59 * are less than the specified key. Note that this guarantees that the return value will be >= 0
60 * if and only if the key is found.
61 */
62 int indexOfKey(final String key);
63 }