http://lucene.apache.org/lucene-parent/lucene-analyzers-common: Additional Analyzers (The Apache Software Foundation) 
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TokenFilter and Analyzer implementations that use Snowball stemmers. 

This project provides pre-compiled version of the Snowball stemmers
based on revision 500 of the Tartarus Snowball repository,
together with classes integrating them with the Lucene search engine.




A few changes has been made to the static Snowball code and compiled stemmers:



    
  
  • Class SnowballProgram is made abstract and contains new abstract method stem() to avoid reflection in Lucene filter class SnowballFilter.
    • 
  
  • All use of StringBuffers has been refactored to StringBuilder for speed.
    • 
  
  • Snowball BSD license header has been added to the Java classes to avoid having RAT adding ASL headers.
    • 




See the Snowball home page for more information about the algorithms.




IMPORTANT NOTICE ON BACKWARDS COMPATIBILITY!




An index created using the Snowball module in Lucene 2.3.2 and below
might not be compatible with the Snowball module in Lucene 2.4 or greater.




For more information about this issue see:
https://issues.apache.org/jira/browse/LUCENE-1142



/**
 * {@link org.apache.lucene.analysis.TokenFilter} and {@link
 * org.apache.lucene.analysis.Analyzer} implementations that use Snowball
 * stemmers.
 * <p>
 * This project provides pre-compiled version of the Snowball stemmers
 * based on revision 500 of the Tartarus Snowball repository,
 * together with classes integrating them with the Lucene search engine.
 * </p>
 * <p>
 * A few changes has been made to the static Snowball code and compiled stemmers:
 * </p>
 * <ul>
 *   <li>Class SnowballProgram is made abstract and contains new abstract method stem() to avoid reflection in Lucene filter class SnowballFilter.</li>
 *   <li>All use of StringBuffers has been refactored to StringBuilder for speed.</li>
 *   <li>Snowball BSD license header has been added to the Java classes to avoid having RAT adding ASL headers.</li>
 * </ul>
 * <p>
 * See the Snowball <a href ="http://snowball.tartarus.org/">home page</a> for more information about the algorithms.
 * </p>
 * 
 * <p>
 * <b>IMPORTANT NOTICE ON BACKWARDS COMPATIBILITY!</b>
 * </p>
 * <p>
 * An index created using the Snowball module in Lucene 2.3.2 and below
 * might not be compatible with the Snowball module in Lucene 2.4 or greater.
 * </p>
 * <p>
 * For more information about this issue see:
 * https://issues.apache.org/jira/browse/LUCENE-1142
 * </p>
 */
package org.apache.lucene.analysis.snowball;