org.apache.lucene.analysis

Class PerFieldAnalyzerWrapper

java.lang.Object

org.apache.lucene.analysis.Analyzer

org.apache.lucene.analysis.PerFieldAnalyzerWrapper

All Implemented Interfaces:

Closeable

public final class PerFieldAnalyzerWrapper
extends Analyzer

This analyzer is used to facilitate scenarios where different fields require different analysis techniques. Use the Map argument in PerFieldAnalyzerWrapper(Analyzer, java.util.Map) to add non-default analyzers for fields.

Example usage:

   Map analyzerPerField = new HashMap();
   analyzerPerField.put("firstname", new KeywordAnalyzer());
   analyzerPerField.put("lastname", new KeywordAnalyzer());

   PerFieldAnalyzerWrapper aWrapper =
      new PerFieldAnalyzerWrapper(new StandardAnalyzer(), analyzerPerField);
 

In this example, StandardAnalyzer will be used for all fields except "firstname" and "lastname", for which KeywordAnalyzer will be used.

A PerFieldAnalyzerWrapper can be used like any other analyzer, for both indexing and query parsing.

Constructor Summary

Constructors

Constructor and Description
PerFieldAnalyzerWrapper(Analyzer defaultAnalyzer) Constructs with default analyzer.
PerFieldAnalyzerWrapper(Analyzer defaultAnalyzer, Map<String,Analyzer> fieldAnalyzers) Constructs with default analyzer and a map of analyzers to use for specific fields.

Method Summary

Methods

Modifier and Type	Method and Description
void	addAnalyzer(String fieldName, Analyzer analyzer) Deprecated. Changing the Analyzer for a field after instantiation prevents reusability. Analyzers for fields should be set during construction.
int	getOffsetGap(Fieldable field) Return the offsetGap from the analyzer assigned to field
int	getPositionIncrementGap(String fieldName) Return the positionIncrementGap from the analyzer assigned to fieldName
TokenStream	reusableTokenStream(String fieldName, Reader reader) Creates a TokenStream that is allowed to be re-used from the previous time that the same thread called this method.
TokenStream	tokenStream(String fieldName, Reader reader) Creates a TokenStream which tokenizes all the text in the provided Reader.
String	toString()

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

close, getPreviousTokenStream, setPreviousTokenStream

Methods inherited from class java.lang.Object

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

Constructor Detail

PerFieldAnalyzerWrapper

public PerFieldAnalyzerWrapper(Analyzer defaultAnalyzer)

Constructs with default analyzer.

Parameters:

defaultAnalyzer - Any fields not specifically defined to use a different analyzer will use the one provided here.

PerFieldAnalyzerWrapper

public PerFieldAnalyzerWrapper(Analyzer defaultAnalyzer,
                       Map<String,Analyzer> fieldAnalyzers)

Constructs with default analyzer and a map of analyzers to use for specific fields.

Parameters:

defaultAnalyzer - Any fields not specifically defined to use a different analyzer will use the one provided here.

fieldAnalyzers - a Map (String field name to the Analyzer) to be used for those fields

Method Detail

addAnalyzer

@Deprecated
public void addAnalyzer(String fieldName,
                          Analyzer analyzer)

Deprecated. Changing the Analyzer for a field after instantiation prevents reusability. Analyzers for fields should be set during construction.

Defines an analyzer to use for the specified field.

Parameters:

fieldName - field name requiring a non-default analyzer

analyzer - non-default analyzer to use for field

tokenStream

public TokenStream tokenStream(String fieldName,
                      Reader reader)

Description copied from class: Analyzer

Creates a TokenStream which tokenizes all the text in the provided Reader. Must be able to handle null field name for backward compatibility.

Specified by:

tokenStream in class Analyzer

reusableTokenStream

public TokenStream reusableTokenStream(String fieldName,
                              Reader reader)
                                throws IOException

Description copied from class: Analyzer

Creates a TokenStream that is allowed to be re-used from the previous time that the same thread called this method. Callers that do not need to use more than one TokenStream at the same time from this analyzer should use this method for better performance.

Overrides:

reusableTokenStream in class Analyzer

Throws:

IOException

getPositionIncrementGap

public int getPositionIncrementGap(String fieldName)

Return the positionIncrementGap from the analyzer assigned to fieldName

Overrides:

getPositionIncrementGap in class Analyzer

Parameters:

fieldName - Fieldable name being indexed.

Returns:

position increment gap, added to the next token emitted from Analyzer.tokenStream(String,Reader)

getOffsetGap

public int getOffsetGap(Fieldable field)

Return the offsetGap from the analyzer assigned to field

Overrides:

getOffsetGap in class Analyzer

Parameters:

field - the field just indexed

Returns:

offset gap, added to the next token emitted from Analyzer.tokenStream(String,Reader)

toString

public String toString()

Overrides:

toString in class Object