org.apache.lucene.analysis.de: public final class: GermanStemFilter

org.apache.lucene.analysis.de
public final class: GermanStemFilter [javadoc | source]

java.lang.Object
   org.apache.lucene.analysis.TokenStream
      org.apache.lucene.analysis.TokenFilter
         org.apache.lucene.analysis.de.GermanStemFilter

A filter that stems German words. It supports a table of words that should not be stemmed at all. The stemmer used can be changed at runtime after the filter object is created (as long as it is a GermanStemmer).

version: $ - Id: GermanStemFilter.java 564236 2007-08-09 15:21:19Z gsingers $

Fields inherited from org.apache.lucene.analysis.TokenFilter:
input

Constructor:
public GermanStemFilter(TokenStream in) { super(in); stemmer = new GermanStemmer(); }
public GermanStemFilter(TokenStream in, Set exclusionSet) { this( in ); this.exclusionSet = exclusionSet; } Builds a GermanStemFilter that uses an exclusiontable.

Constructor:

 public GermanStemFilter(TokenStream in) {
        
      super(in);
      stemmer = new GermanStemmer();
}

 public GermanStemFilter(TokenStream in,
    Set exclusionSet) {
      this( in );
      this.exclusionSet = exclusionSet;
}

Builds a GermanStemFilter that uses an exclusiontable.

Method from org.apache.lucene.analysis.de.GermanStemFilter Summary:
next, setExclusionSet, setStemmer

Methods from org.apache.lucene.analysis.TokenFilter:
close

Methods from org.apache.lucene.analysis.TokenStream:
close, next, next, reset

Methods from java.lang.Object:
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method from org.apache.lucene.analysis.de.GermanStemFilter Detail:
public final Token next() throws IOException { if ( ( token = input.next() ) == null ) { return null; } // Check the exclusiontable else if ( exclusionSet != null && exclusionSet.contains( token.termText() ) ) { return token; } else { String s = stemmer.stem( token.termText() ); // If not stemmed, dont waste the time creating a new token if ( !s.equals( token.termText() ) ) { return new Token( s, token.startOffset(), token.endOffset(), token.type() ); } return token; } }
public void setExclusionSet(Set exclusionSet) { this.exclusionSet = exclusionSet; } Set an alternative exclusion list for this filter.
public void setStemmer(GermanStemmer stemmer) { if ( stemmer != null ) { this.stemmer = stemmer; } } Set a alternative/custom GermanStemmer for this filter.

Method from org.apache.lucene.analysis.de.GermanStemFilter Detail:

 public final Token next() throws IOException {
      if ( ( token = input.next() ) == null ) {
        return null;
      }
      // Check the exclusiontable
      else if ( exclusionSet != null && exclusionSet.contains( token.termText() ) ) {
        return token;
      }
      else {
        String s = stemmer.stem( token.termText() );
        // If not stemmed, dont waste the time creating a new token
        if ( !s.equals( token.termText() ) ) {
          return new Token( s, token.startOffset(),
            token.endOffset(), token.type() );
        }
        return token;
      }
}

 public  void setExclusionSet(Set exclusionSet) {
      this.exclusionSet = exclusionSet;
}

Set an alternative exclusion list for this filter.

 public  void setStemmer(GermanStemmer stemmer) {
      if ( stemmer != null ) {
        this.stemmer = stemmer;
      }
}

Set a alternative/custom GermanStemmer for this filter.