org.apache.lucene.analysis.fr
Class FrenchStemFilter

java.lang.Object
  org.apache.lucene.util.AttributeSource
      org.apache.lucene.analysis.TokenStream
          org.apache.lucene.analysis.TokenFilter
              org.apache.lucene.analysis.fr.FrenchStemFilter

All Implemented Interfaces:

Closeable

public final class FrenchStemFilter
extends TokenFilter

A TokenFilter that stems french words.

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

NOTE: This stemmer does not implement the Snowball algorithm correctly, especially involving case problems. It is recommended that you consider using the "French" stemmer in the snowball package instead. This stemmer will likely be deprecated in a future release.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

AttributeSource.AttributeFactory, AttributeSource.State

Field Summary

Fields inherited from class org.apache.lucene.analysis.TokenFilter

input

Constructor Summary

FrenchStemFilter(TokenStream in)

FrenchStemFilter(TokenStream in, Set exclusiontable)

Method Summary

boolean	incrementToken() Consumers (i.e., IndexWriter) use this method to advance the stream to the next token.
void	setExclusionTable(Map exclusiontable) Set an alternative exclusion list for this filter.
void	setStemmer(FrenchStemmer stemmer) Set a alternative/custom FrenchStemmer for this filter.

Methods inherited from class org.apache.lucene.analysis.TokenFilter

close, end, reset

Methods inherited from class org.apache.lucene.util.AttributeSource

addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, restoreState, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

FrenchStemFilter

public FrenchStemFilter(TokenStream in)

FrenchStemFilter

public FrenchStemFilter(TokenStream in,
                        Set exclusiontable)

Method Detail

incrementToken

public boolean incrementToken()
                       throws IOException

Description copied from class: TokenStream

Consumers (i.e., IndexWriter) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriate AttributeImpls with the attributes of the next token.

The producer must make no assumptions about the attributes after the method has been returned: the caller may arbitrarily change it. If the producer needs to preserve the state for subsequent calls, it can use AttributeSource.captureState() to create a copy of the current attribute state.

This method is called for every token of a document, so an efficient implementation is crucial for good performance. To avoid calls to AttributeSource.addAttribute(Class) and AttributeSource.getAttribute(Class), references to all AttributeImpls that this stream uses should be retrieved during instantiation.

To ensure that filters and consumers know which attributes are available, the attributes must be added during instantiation. Filters and consumers are not required to check for availability of attributes in TokenStream.incrementToken().

Specified by:

incrementToken in class TokenStream

Returns:

Returns true for the next token in the stream, or false at EOS

Throws:

IOException

setStemmer

public void setStemmer(FrenchStemmer stemmer)

Set a alternative/custom FrenchStemmer for this filter.

setExclusionTable

public void setExclusionTable(Map exclusiontable)

Set an alternative exclusion list for this filter.