001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.collections4; 018 019import java.util.SortedMap; 020 021/** 022 * Defines the interface for a prefix tree, an ordered tree data structure. For 023 * more information, see <a href="https://en.wikipedia.org/wiki/Trie">Tries</a>. 024 * 025 * @param <K> the type of the keys in this map 026 * @param <V> the type of the values in this map 027 * @since 4.0 028 */ 029public interface Trie<K, V> extends IterableSortedMap<K, V> { 030 031 /** 032 * Returns a view of this {@link Trie} of all elements that are prefixed 033 * by the given key. 034 * <p> 035 * In a {@link Trie} with fixed size keys, this is essentially a 036 * {@link #get(Object)} operation. 037 * <p> 038 * For example, if the {@link Trie} contains 'Anna', 'Anael', 039 * 'Analu', 'Andreas', 'Andrea', 'Andres', and 'Anatole', then 040 * a lookup of 'And' would return 'Andreas', 'Andrea', and 'Andres'. 041 * 042 * @param key the key used in the search 043 * @return a {@link SortedMap} view of this {@link Trie} with all elements whose 044 * key is prefixed by the search key 045 */ 046 SortedMap<K, V> prefixMap(K key); 047 048}