Module org.apache.lucene.analysis.common

Package org.apache.lucene.analysis.miscellaneous

Class TypeAsSynonymFilter

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.TokenFilter

org.apache.lucene.analysis.miscellaneous.TypeAsSynonymFilter

All Implemented Interfaces:

Closeable, AutoCloseable, Unwrappable<TokenStream>

public final class TypeAsSynonymFilter
extends TokenFilter

Adds the TypeAttribute.type() as a synonym, i.e. another token at the same position, optionally with a specified prefix prepended, optionally transfering flags, and optionally ignoring some types. See TypeAsSynonymFilterFactory for full details.

Nested Class Summary

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

AttributeSource.State

Field Summary

Fields

Modifier and Type	Field	Description
private final FlagsAttribute	flagsAtt
private final Set<String>	ignore
private final PositionIncrementAttribute	posIncrAtt
private final String	prefix
private AttributeSource.State	savedToken
private final int	synFlagsMask
private final CharTermAttribute	termAtt
private final TypeAttribute	typeAtt

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

input

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

DEFAULT_TOKEN_ATTRIBUTE_FACTORY

Constructor Summary

Constructors

Constructor	Description
TypeAsSynonymFilter(TokenStream input)
TypeAsSynonymFilter(TokenStream input, String prefix)
TypeAsSynonymFilter(TokenStream input, String prefix, Set<String> ignore, int synFlagsMask)

Method Summary

Modifier and Type	Method	Description
boolean	incrementToken()	Consumers (i.e., IndexWriter) use this method to advance the stream to the next token.
void	reset()	This method is called by a consumer before it begins consumption using TokenStream.incrementToken().

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

close, end, unwrap

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

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

Methods inherited from class java.lang.Object

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

Field Details

termAtt

private final CharTermAttribute termAtt

typeAtt

private final TypeAttribute typeAtt

posIncrAtt

private final PositionIncrementAttribute posIncrAtt

flagsAtt

private final FlagsAttribute flagsAtt

prefix

private final String prefix

ignore

private final Set<String> ignore

synFlagsMask

private final int synFlagsMask

savedToken

private AttributeSource.State savedToken

Constructor Details

TypeAsSynonymFilter

public TypeAsSynonymFilter(TokenStream input)

TypeAsSynonymFilter

public TypeAsSynonymFilter(TokenStream input,
 String prefix)

Parameters:

input - input tokenstream

prefix - Prepend this string to every token type emitted as token text. If null, nothing will be prepended.

TypeAsSynonymFilter

public TypeAsSynonymFilter(TokenStream input,
 String prefix,
 Set<String> ignore,
 int synFlagsMask)

Parameters:

input - input tokenstream

prefix - Prepend this string to every token type emitted as token text. If null, nothing will be prepended.

ignore - types to ignore (and not convert to a synonym)

synFlagsMask - a mask to control what flags are propagated to the synonym.

Method Details

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:

false for end of stream; true otherwise

Throws:

IOException

reset

public void reset()
           throws IOException

Description copied from class: TokenFilter

This method is called by a consumer before it begins consumption using TokenStream.incrementToken().

Resets this stream to a clean state. Stateful implementations must implement this method so that they can be reused, just as if they had been created fresh.

If you override this method, always call super.reset(), otherwise some internal state will not be correctly reset (e.g., Tokenizer will throw IllegalStateException on further usage).

NOTE: The default implementation chains the call to the input TokenStream, so be sure to call super.reset() when overriding this method.

Overrides:

reset in class TokenFilter

Throws:

IOException