org.apache.lucene.analysis.miscellaneous

Class TrimFilter

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.TokenFilter

org.apache.lucene.analysis.miscellaneous.TrimFilter

All Implemented Interfaces:

Closeable, AutoCloseable

public final class TrimFilter
extends TokenFilter

Trims leading and trailing whitespace from Tokens in the stream.

As of Lucene 4.4, this filter does not support updateOffsets=true anymore as it can lead to broken token streams.

Nested Class Summary

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

AttributeSource.AttributeFactory, AttributeSource.State

Constructor Summary

Constructors

Constructor and Description
TrimFilter(Version version, TokenStream in) Create a new TrimFilter on top of in.
TrimFilter(Version version, TokenStream in, boolean updateOffsets) Deprecated. Offset updates are not supported anymore as of Lucene 4.4.

Method Summary

Modifier and Type	Method and 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 Detail

TrimFilter

@Deprecated
public TrimFilter(Version version,
                              TokenStream in,
                              boolean updateOffsets)

Deprecated. Offset updates are not supported anymore as of Lucene 4.4.

Create a new TrimFilter.

Parameters:

version - the Lucene match version

in - the stream to consume

updateOffsets - whether to update offsets

TrimFilter

public TrimFilter(Version version,
                  TokenStream in)

Create a new TrimFilter on top of in.

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:

false for end of stream; true otherwise

Throws:

IOException