com.digitalpebble.behemoth.mahout.LuceneTokenizerMapper.java Source code

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Here is the source code for com.digitalpebble.behemoth.mahout.LuceneTokenizerMapper.java

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/**
 * 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 com.digitalpebble.behemoth.mahout;

import java.io.IOException;
import java.io.StringReader;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.mahout.common.ClassUtils;
import org.apache.mahout.common.StringTuple;
import org.apache.mahout.vectorizer.DefaultAnalyzer;
import org.apache.mahout.vectorizer.DocumentProcessor;

import com.digitalpebble.behemoth.BehemothDocument;

/**
 * Tokenizes a text document and outputs tokens in a StringTuple
 */
public class LuceneTokenizerMapper extends Mapper<Text, BehemothDocument, Text, StringTuple> {

    private Analyzer analyzer;

    @Override
    protected void map(Text key, BehemothDocument value, Context context) throws IOException, InterruptedException {
        String sContent = value.getText();
        if (sContent == null) {
            // no text available? skip
            context.getCounter("LuceneTokenizer", "BehemothDocWithoutText").increment(1);
            return;
        }
        TokenStream stream = analyzer.reusableTokenStream(key.toString(), new StringReader(sContent.toString()));
        CharTermAttribute termAtt = stream.addAttribute(CharTermAttribute.class);
        StringTuple document = new StringTuple();
        stream.reset();
        while (stream.incrementToken()) {
            if (termAtt.length() > 0) {
                document.add(new String(termAtt.buffer(), 0, termAtt.length()));
            }
        }
        context.write(key, document);
    }

    @Override
    protected void setup(Context context) throws IOException, InterruptedException {
        super.setup(context);
        analyzer = ClassUtils.instantiateAs(
                context.getConfiguration().get(DocumentProcessor.ANALYZER_CLASS, DefaultAnalyzer.class.getName()),
                Analyzer.class);
    }
}