org.apache.lucene.analysis

Class DelegatingAnalyzerWrapper

java.lang.Object

org.apache.lucene.analysis.Analyzer

org.apache.lucene.analysis.AnalyzerWrapper

org.apache.lucene.analysis.DelegatingAnalyzerWrapper

All Implemented Interfaces:

Closeable, AutoCloseable

public abstract class DelegatingAnalyzerWrapper
extends AnalyzerWrapper

An analyzer wrapper, that doesn't allow to wrap components or readers. By disallowing it, it means that the thread local resources can be delegated to the delegate analyzer, and not also be allocated on this analyzer. This wrapper class is the base class of all analyzers that just delegate to another analyzer, e.g. per field name.

This solves the problem of per field analyzer wrapper, where it also maintains a thread local per field token stream components, while it can safely delegate those and not also hold these data structures, which can become expensive memory wise.

Please note: This analyzer uses a private Analyzer.ReuseStrategy, which is returned by Analyzer.getReuseStrategy(). This strategy is used when delegating. If you wrap this analyzer again and reuse this strategy, no delegation is done and the given fallback is used.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.analysis.Analyzer

Analyzer.GlobalReuseStrategy, Analyzer.PerFieldReuseStrategy, Analyzer.ReuseStrategy, Analyzer.TokenStreamComponents

Field Summary

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

GLOBAL_REUSE_STRATEGY, PER_FIELD_REUSE_STRATEGY

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DelegatingAnalyzerWrapper(Analyzer.ReuseStrategy fallbackStrategy) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
protected Analyzer.TokenStreamComponents	wrapComponents(String fieldName, Analyzer.TokenStreamComponents components) Wraps / alters the given TokenStreamComponents, taken from the wrapped Analyzer, to form new components.
protected Reader	wrapReader(String fieldName, Reader reader) Wraps / alters the given Reader.

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

createComponents, getOffsetGap, getPositionIncrementGap, getWrappedAnalyzer, initReader

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

close, getReuseStrategy, getVersion, setVersion, tokenStream, tokenStream

Methods inherited from class java.lang.Object

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

Constructor Detail

DelegatingAnalyzerWrapper

protected DelegatingAnalyzerWrapper(Analyzer.ReuseStrategy fallbackStrategy)

Constructor.

Parameters:

fallbackStrategy - is the strategy to use if delegation is not possible This is to support the common pattern: new OtherWrapper(thisWrapper.getReuseStrategy())

Method Detail

wrapComponents

protected final Analyzer.TokenStreamComponents wrapComponents(String fieldName,
                                            Analyzer.TokenStreamComponents components)

Description copied from class: AnalyzerWrapper

Wraps / alters the given TokenStreamComponents, taken from the wrapped Analyzer, to form new components. It is through this method that new TokenFilters can be added by AnalyzerWrappers. By default, the given components are returned.

Overrides:

wrapComponents in class AnalyzerWrapper

Parameters:

fieldName - Name of the field which is to be analyzed

components - TokenStreamComponents taken from the wrapped Analyzer

Returns:

Wrapped / altered TokenStreamComponents.

wrapReader

protected final Reader wrapReader(String fieldName,
                Reader reader)

Description copied from class: AnalyzerWrapper

Wraps / alters the given Reader. Through this method AnalyzerWrappers can implement AnalyzerWrapper.initReader(String, Reader). By default, the given reader is returned.

Overrides:

wrapReader in class AnalyzerWrapper

Parameters:

fieldName - name of the field which is to be analyzed

reader - the reader to wrap

Returns:

the wrapped reader