| /* |
| * 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.trie; |
| |
| import java.util.Map; |
| |
| import org.apache.commons.collections4.trie.analyzer.StringKeyAnalyzer; |
| |
| /** |
| * Implementation of a PATRICIA Trie (Practical Algorithm to Retrieve Information |
| * Coded in Alphanumeric). |
| * <p> |
| * A PATRICIA {@link Trie} is a compressed {@link Trie}. Instead of storing |
| * all data at the edges of the {@link Trie} (and having empty internal nodes), |
| * PATRICIA stores data in every node. This allows for very efficient traversal, |
| * insert, delete, predecessor, successor, prefix, range, and {@link #select(Object)} |
| * operations. All operations are performed at worst in O(K) time, where K |
| * is the number of bits in the largest item in the tree. In practice, |
| * operations actually take O(A(K)) time, where A(K) is the average number of |
| * bits of all items in the tree. |
| * <p> |
| * Most importantly, PATRICIA requires very few comparisons to keys while |
| * doing any operation. While performing a lookup, each comparison (at most |
| * K of them, described above) will perform a single bit comparison against |
| * the given key, instead of comparing the entire key to another key. |
| * <p> |
| * The {@link Trie} can return operations in lexicographical order using the |
| * 'prefixMap', 'submap', or 'iterator' methods. The {@link Trie} can also |
| * scan for items that are 'bitwise' (using an XOR metric) by the 'select' method. |
| * Bitwise closeness is determined by the {@link KeyAnalyzer} returning true or |
| * false for a bit being set or not in a given key. |
| * <p> |
| * This PATRICIA {@link Trie} supports both variable length & fixed length |
| * keys. Some methods, such as {@link #prefixMap(Object)} are suited only |
| * to variable length keys. |
| * |
| * @see <a href="http://en.wikipedia.org/wiki/Radix_tree">Radix Tree</a> |
| * @see <a href="http://www.csse.monash.edu.au/~lloyd/tildeAlgDS/Tree/PATRICIA">PATRICIA</a> |
| * @see <a href="http://www.imperialviolet.org/binary/critbit.pdf">Crit-Bit Tree</a> |
| * @since 4.0 |
| * @version $Id$ |
| */ |
| public class PatriciaTrie<E> extends AbstractPatriciaTrie<String, E> { |
| |
| private static final long serialVersionUID = 4446367780901817838L; |
| |
| public PatriciaTrie() { |
| super(new StringKeyAnalyzer()); |
| } |
| |
| public PatriciaTrie(final Map<? extends String, ? extends E> m) { |
| super(new StringKeyAnalyzer(), m); |
| } |
| |
| } |