Module org.apache.jena.text

Package org.apache.jena.query.text.assembler

Class GenericAnalyzerAssembler

java.lang.Object

org.apache.jena.assembler.assemblers.AssemblerBase

org.apache.jena.query.text.assembler.GenericAnalyzerAssembler

All Implemented Interfaces:

org.apache.jena.assembler.Assembler

public class GenericAnalyzerAssembler
extends org.apache.jena.assembler.assemblers.AssemblerBase

Creates generic analyzers given a fully qualified Class name and a list of parameters for a constructor of the Class.

The parameters may be of the following types:

     text:TypeString    String
     text:TypeSet       org.apache.lucene.analysis.util.CharArraySet
     text:TypeFile      java.io.FileReader
     text:TypeInt       int
     text:TypeBoolean   boolean
     text:TypeAnalyzer  org.apache.lucene.analysis.Analyzer
 

Although the list of types is not exhaustive it is a simple matter to create a wrapper Analyzer that reads a file with information that can be used to initialize any sort of parameters that may be needed for a given Analyzer. The provided types cover the vast majority of cases.

For example, org.apache.lucene.analysis.ja.JapaneseAnalyzer has a constructor with 4 parameters: a UserDict, a CharArraySet, a JapaneseTokenizer.Mode, and a Set<String>. So a simple wrapper can extract the values needed for the various parameters with types not available in this extension, construct the required instances, and instantiate the JapaneseAnalyzer.

Adding custom Analyzers such as the above wrapper analyzer is a simple matter of adding the Analyzer class and any associated filters and tokenizer and so on to the classpath for Jena - usually in a jar. Of course, all of the Analyzers that are included in the Lucene distribution bundled with Jena are available as generic Analyzers as well.

Each parameter object is specified with:

• an optional text:paramName that may be used to document which parameter is represented
• a text:paramType which is one of: text:TypeString, text:TypeSet, text:TypeFile, text:TypeInt, text:TypeBoolean, text:TypeAnalyzer.
• a text:paramValue which is an xsd:string, xsd:boolean or xsd:int or resource.

A parameter of type text:TypeSet must have a list of zero or more Strings.

A parameter of type text:TypeString, text:TypeFile, text:TypeBoolean, text:TypeInt or text:TypeAnalyzer must have a single text:paramValue of the appropriate type.

Examples:

    text:map (
         [ text:field "text" ; 
           text:predicate rdfs:label;
           text:analyzer [
               a text:GenericAnalyzer ;
               text:class "org.apache.lucene.analysis.en.EnglishAnalyzer" ;
               text:params (
                    [ text:paramName "stopwords" ;
                      text:paramType text:TypeSet ;
                      text:paramValue ("the" "a" "an") ]
                    [ text:paramName "stemExclusionSet" ;
                      text:paramType text:TypeSet ;
                      text:paramValue ("ing" "ed") ]
                    )
           ] .
 

    text:map (
         [ text:field "text" ; 
           text:predicate rdfs:label;
           text:analyzer [
               a text:GenericAnalyzer ;
               text:class "org.apache.lucene.analysis.shingle.ShingleAnalyzerWrapper" ;
               text:params (
                    [ text:paramName "defaultAnalyzer" ;
                      text:paramType text:TypeAnalyzer ;
                      text:paramValue [ a text:SimpleAnalyzer ] ]
                    [ text:paramName "maxShingleSize" ;
                      text:paramType text:TypeInt ;
                      text:paramValue 3 ]
                    )
           ] .
 

Field Summary

Fields inherited from interface org.apache.jena.assembler.Assembler

content, defaultModel, documentManager, general, infModel, memoryModel, ontModel, ontModelSpec, prefixMapping, reasonerFactory, ruleSet, unionModel

Constructor Summary

Constructors

Constructor	Description
GenericAnalyzerAssembler()

Method Summary

Modifier and Type	Method	Description
org.apache.lucene.analysis.Analyzer	open(org.apache.jena.assembler.Assembler a, org.apache.jena.rdf.model.Resource root, org.apache.jena.assembler.Mode mode)

Methods inherited from class org.apache.jena.assembler.assemblers.AssemblerBase

getOptionalClassName, getRequiredResource, open, open, openModel, openModel

Methods inherited from class java.lang.Object

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

Constructor Details

GenericAnalyzerAssembler

public GenericAnalyzerAssembler()

Method Details

open

public org.apache.lucene.analysis.Analyzer open(org.apache.jena.assembler.Assembler a,
 org.apache.jena.rdf.model.Resource root,
 org.apache.jena.assembler.Mode mode)

Specified by:

open in interface org.apache.jena.assembler.Assembler

Specified by:

open in class org.apache.jena.assembler.assemblers.AssemblerBase