org.apache.jena.query.text.analyzer.ConfigurableAnalyzer.java Source code

Introduction

Here is the source code for org.apache.jena.query.text.analyzer.ConfigurableAnalyzer.java

Source

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.query.text.analyzer;

import java.util.List;

import org.apache.jena.query.text.TextIndexException;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.core.KeywordTokenizer;
import org.apache.lucene.analysis.core.LetterTokenizer;
import org.apache.lucene.analysis.core.LowerCaseFilter;
import org.apache.lucene.analysis.core.WhitespaceTokenizer;
import org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter;
import org.apache.lucene.analysis.standard.StandardFilter;
import org.apache.lucene.analysis.standard.StandardTokenizer;

/** 
 * Lucene Analyzer implementation that can be configured with different
 * Tokenizer and (optionally) TokenFilter implementations.
 */

public class ConfigurableAnalyzer extends Analyzer {
    private final String tokenizer;
    private final List<String> filters;

    private Tokenizer getTokenizer(String tokenizerName) {
        switch (tokenizerName) {
        case "KeywordTokenizer":
            return new KeywordTokenizer();
        case "LetterTokenizer":
            return new LetterTokenizer();
        case "StandardTokenizer":
            return new StandardTokenizer();
        case "WhitespaceTokenizer":
            return new WhitespaceTokenizer();
        default:
            throw new TextIndexException("Unknown tokenizer : " + tokenizerName);
        }
    }

    private TokenFilter getTokenFilter(String filterName, TokenStream source) {
        switch (filterName) {
        case "ASCIIFoldingFilter":
            return new ASCIIFoldingFilter(source);
        case "LowerCaseFilter":
            return new LowerCaseFilter(source);
        case "StandardFilter":
            return new StandardFilter(source);
        default:
            throw new TextIndexException("Unknown filter : " + filterName);
        }
    }

    public ConfigurableAnalyzer(String tokenizer, List<String> filters) {
        this.tokenizer = tokenizer;
        this.filters = filters;
    }

    @Override
    protected TokenStreamComponents createComponents(String fieldName) {
        Tokenizer source = getTokenizer(this.tokenizer);
        TokenStream stream = source;
        for (String filter : this.filters) {
            stream = getTokenFilter(filter, stream);
        }
        return new TokenStreamComponents(source, stream);
    }

    @Override
    protected TokenStream normalize(String fieldName, TokenStream in) {
        TokenStream stream = in;
        for (String filter : this.filters) {
            stream = getTokenFilter(filter, stream);
        }
        return stream;
    }

}