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.SortedMap; 20 21 /** 22 * Defines the interface for a prefix tree, an ordered tree data structure. For 23 * more information, see <a href="https://en.wikipedia.org/wiki/Trie">Tries</a>. 24 * 25 * @param <K> the type of the keys in this map 26 * @param <V> the type of the values in this map 27 * @since 4.0 28 */ 29 public interface Trie<K, V> extends IterableSortedMap<K, V> { 30 31 /** 32 * Returns a view of this {@link Trie} of all elements that are prefixed 33 * by the given key. 34 * <p> 35 * In a {@link Trie} with fixed size keys, this is essentially a 36 * {@link #get(Object)} operation. 37 * <p> 38 * For example, if the {@link Trie} contains 'Anna', 'Anael', 39 * 'Analu', 'Andreas', 'Andrea', 'Andres', and 'Anatole', then 40 * a lookup of 'And' would return 'Andreas', 'Andrea', and 'Andres'. 41 * 42 * @param key the key used in the search 43 * @return a {@link SortedMap} view of this {@link Trie} with all elements whose 44 * key is prefixed by the search key 45 */ 46 SortedMap<K, V> prefixMap(K key); 47 48 }