Package org.apache.lucene.search.suggest.document

Class CompletionAnalyzer

java.lang.Object

org.apache.lucene.analysis.Analyzer

org.apache.lucene.analysis.AnalyzerWrapper

org.apache.lucene.search.suggest.document.CompletionAnalyzer

All Implemented Interfaces:

Closeable, AutoCloseable

public final class CompletionAnalyzer
extends AnalyzerWrapper

Wraps an Analyzer to provide additional completion-only tuning (e.g. preserving token separators, preserving position increments while converting a token stream to an automaton)

Can be used to index SuggestField and ContextSuggestField and as a query analyzer to PrefixCompletionQuery amd FuzzyCompletionQuery

NOTE: In most cases, index and query analyzer should have same values for preservePositionIncrements() and preserveSep()

Since:

5.1.0

Nested Class Summary

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

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

Constructor	Description
CompletionAnalyzer(Analyzer analyzer)	Calls CompletionAnalyzer(org.apache.lucene.analysis.Analyzer, boolean, boolean, int) preserving token separation, position increments and no limit on graph expansions
CompletionAnalyzer(Analyzer analyzer, boolean preserveSep, boolean preservePositionIncrements)	Calls CompletionAnalyzer(org.apache.lucene.analysis.Analyzer, boolean, boolean, int) with no limit on graph expansions
CompletionAnalyzer(Analyzer analyzer, boolean preserveSep, boolean preservePositionIncrements, int maxGraphExpansions)	Wraps an analyzer to convert its output token stream to an automaton
CompletionAnalyzer(Analyzer analyzer, int maxGraphExpansions)	Calls CompletionAnalyzer(org.apache.lucene.analysis.Analyzer, boolean, boolean, int) preserving token separation and position increments

Method Summary

Modifier and Type	Method	Description
protected Analyzer	getWrappedAnalyzer(String fieldName)	Retrieves the wrapped Analyzer appropriate for analyzing the field with the given name
boolean	preservePositionIncrements()	Returns true if position increments are preserved when converting the token stream to an automaton
boolean	preserveSep()	Returns true if separation between tokens are preserved when converting the token stream to an automaton
protected Analyzer.TokenStreamComponents	wrapComponents(String fieldName, Analyzer.TokenStreamComponents components)	Wraps / alters the given TokenStreamComponents, taken from the wrapped Analyzer, to form new components.

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

attributeFactory, createComponents, getOffsetGap, getPositionIncrementGap, initReader, initReaderForNormalization, normalize, wrapReader, wrapReaderForNormalization, wrapTokenStreamForNormalization

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

close, getReuseStrategy, getVersion, normalize, setVersion, tokenStream, tokenStream

Methods inherited from class java.lang.Object

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

Constructor Detail

CompletionAnalyzer

public CompletionAnalyzer(Analyzer analyzer,
                          boolean preserveSep,
                          boolean preservePositionIncrements,
                          int maxGraphExpansions)

Wraps an analyzer to convert its output token stream to an automaton

Parameters:

analyzer - token stream to be converted to an automaton

preserveSep - Preserve separation between tokens when converting to an automaton

preservePositionIncrements - Preserve position increments for tokens when converting to an automaton

maxGraphExpansions - Sets the maximum number of graph expansions of a completion automaton

CompletionAnalyzer

public CompletionAnalyzer(Analyzer analyzer)

Calls CompletionAnalyzer(org.apache.lucene.analysis.Analyzer, boolean, boolean, int) preserving token separation, position increments and no limit on graph expansions

CompletionAnalyzer

public CompletionAnalyzer(Analyzer analyzer,
                          boolean preserveSep,
                          boolean preservePositionIncrements)

Calls CompletionAnalyzer(org.apache.lucene.analysis.Analyzer, boolean, boolean, int) with no limit on graph expansions

CompletionAnalyzer

public CompletionAnalyzer(Analyzer analyzer,
                          int maxGraphExpansions)

Calls CompletionAnalyzer(org.apache.lucene.analysis.Analyzer, boolean, boolean, int) preserving token separation and position increments

Method Detail

preserveSep

public boolean preserveSep()

Returns true if separation between tokens are preserved when converting the token stream to an automaton

preservePositionIncrements

public boolean preservePositionIncrements()

Returns true if position increments are preserved when converting the token stream to an automaton

getWrappedAnalyzer

protected Analyzer getWrappedAnalyzer(String fieldName)

Description copied from class: AnalyzerWrapper

Retrieves the wrapped Analyzer appropriate for analyzing the field with the given name

Specified by:

getWrappedAnalyzer in class AnalyzerWrapper

Parameters:

fieldName - Name of the field which is to be analyzed

Returns:

Analyzer for the field with the given name. Assumed to be non-null

wrapComponents

protected 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.