com.groupbyinc.common.apache.commons.text.similarity.LongestCommonSubsequenceDistance 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.text.similarity;
/**
* An edit distance algorithm based on the length of the longest common subsequence between two strings.
*
*
* This code is directly based upon the implementation in {@link LongestCommonSubsequence}.
*
*
*
* For reference see:
* https://en.wikipedia.org/wiki/Longest_common_subsequence_problem.
*
*
* For further reading see:
*
* Lothaire, M. Applied combinatorics on words. New York: Cambridge U Press, 2005. 12-13
*
* @since 1.0
*/
public class LongestCommonSubsequenceDistance implements EditDistance {
/**
* Object for calculating the longest common subsequence that we can then normalize in apply.
*/
private final LongestCommonSubsequence longestCommonSubsequence = new LongestCommonSubsequence();
/**
* Calculates an edit distance between two CharSequence's left and
* right as: left.length() + right.length() - 2 * LCS(left, right), where
* LCS is given in {@link LongestCommonSubsequence#apply(CharSequence, CharSequence)}.
*
* @param left first character sequence
* @param right second character sequence
* @return distance
* @throws IllegalArgumentException
* if either String input {@code null}
*/
@Override
public Integer apply(final CharSequence left, final CharSequence right) {
// Quick return for invalid inputs
if (left == null || right == null) {
throw new IllegalArgumentException("Inputs must not be null");
}
return left.length() + right.length() - 2 * longestCommonSubsequence.apply(left, right);
}
}