com.groupbyinc.common.apache.commons.collections4.trie.PatriciaTrie Maven / Gradle / Ivy
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* 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,
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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 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.
*
* 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 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.
*
* 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 Radix Tree
* @see PATRICIA
* @see Crit-Bit Tree
* @since 4.0
* @version $Id: PatriciaTrie.java 1543928 2013-11-20 20:15:35Z tn $
*/
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);
}
}