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

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

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package com.digitalpebble.behemoth.mahout;

/**
 * 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.
 */

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
import org.apache.mahout.common.HadoopUtil;
import org.apache.mahout.common.StringTuple;

import com.digitalpebble.behemoth.BehemothDocument;

/**
 * This class converts a set of input documents in the sequence file format of
 * {@link StringTuple}s.The {@link org.apache.hadoop.io.SequenceFile} input
 * should have a {@link Text} key containing the unique document identifier and
 * a {@link BehemothDocument} value containing the whole document.
 * 
 */
public final class DocumentProcessor {

    public static final String TOKENIZED_DOCUMENT_OUTPUT_FOLDER = "tokenized-documents";
    public static final String TOKEN_TYPE = "Token.type";
    public static final String FEATURE_NAME = "Feature.name";

    // public static final Charset CHARSET = Charset.forName("UTF-8");

    /**
     * Cannot be initialized. Use the static functions
     */
    private DocumentProcessor() {

    }

    /**
     * Convert the input documents into token array using the
     * {@link StringTuple} The input documents has to be in the
     * {@link org.apache.hadoop.io.SequenceFile} format
     * 
     * @param input
     *            input directory of the documents in
     *            {@link org.apache.hadoop.io.SequenceFile} format
     * @param output
     *            output directory were the {@link StringTuple} token array of
     *            each document has to be created
     * @param type
     *            The annotation type representing the tokens
     * @param feature
     *            The name of the features holding the token value
     * @throws IOException
     * @throws ClassNotFoundException
     * @throws InterruptedException
     */
    public static void tokenizeDocuments(Path input, String type, String feature, Path output)
            throws IOException, InterruptedException, ClassNotFoundException {
        Configuration conf = new Configuration();
        // this conf parameter needs to be set enable serialisation of conf
        // values
        conf.set("io.serializations", "org.apache.hadoop.io.serializer.JavaSerialization,"
                + "org.apache.hadoop.io.serializer.WritableSerialization");
        conf.set(TOKEN_TYPE, type);
        conf.set(FEATURE_NAME, feature);

        Job job = new Job(conf);
        job.setJobName("DocumentProcessor::DocumentTokenizer: input-folder: " + input);
        job.setJarByClass(DocumentProcessor.class);

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(StringTuple.class);
        FileInputFormat.setInputPaths(job, input);
        FileOutputFormat.setOutputPath(job, output);

        job.setMapperClass(SequenceFileTokenizerMapper.class);
        job.setInputFormatClass(SequenceFileInputFormat.class);
        job.setNumReduceTasks(0);
        job.setOutputFormatClass(SequenceFileOutputFormat.class);
        HadoopUtil.delete(conf, output);

        job.waitForCompletion(true);
    }
}