Package org.apache.lucene.analysis.pattern

Class PatternReplaceFilter

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.TokenFilter

org.apache.lucene.analysis.pattern.PatternReplaceFilter

All Implemented Interfaces:

Closeable, AutoCloseable

public final class PatternReplaceFilter
extends TokenFilter

A TokenFilter which applies a Pattern to each token in the stream, replacing match occurances with the specified replacement string.

Note: Depending on the input and the pattern used and the input TokenStream, this TokenFilter may produce Tokens whose text is the empty string.

See Also:

• Pattern

Nested Class Summary

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

AttributeSource.AttributeFactory, AttributeSource.State

Constructor Summary

Constructors

Constructor	Description
PatternReplaceFilter(TokenStream in, Pattern p, String replacement, boolean all)	Constructs an instance to replace either the first, or all occurances

Method Summary

Modifier and Type	Method	Description
boolean	incrementToken()	Consumers (i.e., IndexWriter) use this method to advance the stream to the next token.

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, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Details

PatternReplaceFilter

public PatternReplaceFilter(TokenStream in,
 Pattern p,
 String replacement,
 boolean all)

Constructs an instance to replace either the first, or all occurances

Parameters:

in - the TokenStream to process

p - the patterm to apply to each Token

replacement - the "replacement string" to substitute, if null a blank string will be used. Note that this is not the literal string that will be used, '$' and '\' have special meaning.

all - if true, all matches will be replaced otherwise just the first match.

See Also:

• Matcher.quoteReplacement(java.lang.String)

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