org.apache.lucene.analysis.util.StemmerUtil Maven / Gradle / Ivy
package org.apache.lucene.analysis.util;
/*
* 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.
*/
/**
* Some commonly-used stemming functions
*
* @lucene.internal
*/
public class StemmerUtil {
/** no instance */
private StemmerUtil() {}
/**
* Returns true if the character array starts with the suffix.
*
* @param s Input Buffer
* @param len length of input buffer
* @param prefix Prefix string to test
* @return true if s starts with prefix
*/
public static boolean startsWith(char s[], int len, String prefix) {
final int prefixLen = prefix.length();
if (prefixLen > len)
return false;
for (int i = 0; i < prefixLen; i++)
if (s[i] != prefix.charAt(i))
return false;
return true;
}
/**
* Returns true if the character array ends with the suffix.
*
* @param s Input Buffer
* @param len length of input buffer
* @param suffix Suffix string to test
* @return true if s ends with suffix
*/
public static boolean endsWith(char s[], int len, String suffix) {
final int suffixLen = suffix.length();
if (suffixLen > len)
return false;
for (int i = suffixLen - 1; i >= 0; i--)
if (s[len -(suffixLen - i)] != suffix.charAt(i))
return false;
return true;
}
/**
* Returns true if the character array ends with the suffix.
*
* @param s Input Buffer
* @param len length of input buffer
* @param suffix Suffix string to test
* @return true if s ends with suffix
*/
public static boolean endsWith(char s[], int len, char suffix[]) {
final int suffixLen = suffix.length;
if (suffixLen > len)
return false;
for (int i = suffixLen - 1; i >= 0; i--)
if (s[len -(suffixLen - i)] != suffix[i])
return false;
return true;
}
/**
* Delete a character in-place
*
* @param s Input Buffer
* @param pos Position of character to delete
* @param len length of input buffer
* @return length of input buffer after deletion
*/
public static int delete(char s[], int pos, int len) {
assert pos < len;
if (pos < len - 1) { // don't arraycopy if asked to delete last character
System.arraycopy(s, pos + 1, s, pos, len - pos - 1);
}
return len - 1;
}
/**
* Delete n characters in-place
*
* @param s Input Buffer
* @param pos Position of character to delete
* @param len Length of input buffer
* @param nChars number of characters to delete
* @return length of input buffer after deletion
*/
public static int deleteN(char s[], int pos, int len, int nChars) {
assert pos + nChars <= len;
if (pos + nChars < len) { // don't arraycopy if asked to delete the last characters
System.arraycopy(s, pos + nChars, s, pos, len - pos - nChars);
}
return len - nChars;
}
}