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Lucene example source code file (StemmerUtil.java)

This example Lucene source code file (StemmerUtil.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

stemmerutil, stemmerutil, string, string

The Lucene StemmerUtil.java source code

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 */
public class 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 <code>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 <code>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 <code>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) {
    if (pos < len) 
      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) {
    // TODO: speed up, this is silly
    for (int i = 0; i < nChars; i++)
      len = delete(s, pos, len);
    return len;
  }
}

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