org.apache.lucene.analysis.util

Class FilteringTokenFilter

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.TokenFilter

org.apache.lucene.analysis.util.FilteringTokenFilter

All Implemented Interfaces:

Closeable

Direct Known Subclasses:

KeepWordFilter, LengthFilter, StopFilter, TypeTokenFilter

public abstract class FilteringTokenFilter
extends TokenFilter

Abstract base class for TokenFilters that may remove tokens. You have to implement accept() and return a boolean if the current token should be preserved. incrementToken() uses this method to decide if a token should be passed to the caller.

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

Constructors

Constructor and Description
FilteringTokenFilter(boolean enablePositionIncrements, TokenStream input)

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract boolean	accept() Override this method and return if the current input token should be returned by incrementToken().
boolean	getEnablePositionIncrements()
boolean	incrementToken()
void	reset()
void	setEnablePositionIncrements(boolean enable) If true, this TokenFilter will preserve positions of the incoming tokens (ie, accumulate and set position increments of the removed tokens).

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

close, end

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

addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState

Methods inherited from class java.lang.Object

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

Constructor Detail

FilteringTokenFilter

public FilteringTokenFilter(boolean enablePositionIncrements,
                    TokenStream input)

Method Detail

accept

protected abstract boolean accept()
                           throws IOException

Override this method and return if the current input token should be returned by incrementToken().

Throws:

IOException

incrementToken

public final boolean incrementToken()
                             throws IOException

Specified by:

incrementToken in class TokenStream

Throws:

IOException

reset

public void reset()
           throws IOException

Overrides:

reset in class TokenFilter

Throws:

IOException

getEnablePositionIncrements

public boolean getEnablePositionIncrements()

See Also:

setEnablePositionIncrements(boolean)

setEnablePositionIncrements

public void setEnablePositionIncrements(boolean enable)

If true, this TokenFilter will preserve positions of the incoming tokens (ie, accumulate and set position increments of the removed tokens). Generally, true is best as it does not lose information (positions of the original tokens) during indexing.

When set, when a token is stopped (omitted), the position increment of the following token is incremented.

NOTE: be sure to also set org.apache.lucene.queryparser.classic.QueryParser#setEnablePositionIncrements if you use QueryParser to create queries.