org.apache.commons.collections4.trie.PatriciaTrie Maven / Gradle / Ivy
/*
* 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).
*
* A PATRICIA {@link org.apache.commons.collections4.Trie} is a compressed
* {@link org.apache.commons.collections4.Trie}. Instead of storing
* all data at the edges of the {@link org.apache.commons.collections4.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.
*
* 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.
*
* The {@link org.apache.commons.collections4.Trie} can return operations in
* lexicographical order using the 'prefixMap', 'submap', or 'iterator' methods.
* The {@link org.apache.commons.collections4.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.
*
* This PATRICIA {@link org.apache.commons.collections4.Trie} supports both variable
* length & fixed length keys. Some methods, such as {@link #prefixMap(Object)}
* are suited only to variable length keys.
*
* @param the type of the values in this map
*
* @see Radix Tree
* @see PATRICIA
* @see Crit-Bit Tree
* @since 4.0
*/
public class PatriciaTrie extends AbstractPatriciaTrie {
private static final long serialVersionUID = 4446367780901817838L;
public PatriciaTrie() {
super(new StringKeyAnalyzer());
}
public PatriciaTrie(final Map m) {
super(new StringKeyAnalyzer(), m);
}
}