org.apache.lucene.analysis.en.EnglishMinimalStemmer Maven / Gradle / Ivy
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* 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,
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* See the License for the specific language governing permissions and
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*/
package org.apache.lucene.analysis.en;
/**
* Minimal plural stemmer for English.
*
* This stemmer implements the "S-Stemmer" from
* How Effective Is Suffixing?
* Donna Harman.
*/
public class EnglishMinimalStemmer {
@SuppressWarnings("fallthrough")
public int stem(char s[], int len) {
if (len < 3 || s[len-1] != 's')
return len;
switch(s[len-2]) {
case 'u':
case 's': return len;
case 'e':
if (len > 3 && s[len-3] == 'i' && s[len-4] != 'a' && s[len-4] != 'e') {
s[len - 3] = 'y';
return len - 2;
}
if (s[len-3] == 'i' || s[len-3] == 'a' || s[len-3] == 'o' || s[len-3] == 'e')
return len; /* intentional fallthrough */
default: return len - 1;
}
}
}