edu.uci.ics.fuzzyjoin.hadoop.tokens.array.Map.java Source code

Introduction

Here is the source code for edu.uci.ics.fuzzyjoin.hadoop.tokens.array.Map.java

Source

/**
 * Copyright 2010-2011 The Regents of the University of California
 *
 * Licensed 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.
 * 
 * Author: Rares Vernica <rares (at) ics.uci.edu>
 */

package edu.uci.ics.fuzzyjoin.hadoop.tokens.array;

import java.io.IOException;
import java.util.List;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;

import edu.uci.ics.fuzzyjoin.FuzzyJoinConfig;
import edu.uci.ics.fuzzyjoin.FuzzyJoinUtil;
import edu.uci.ics.fuzzyjoin.hadoop.IntArrayWritable;
import edu.uci.ics.fuzzyjoin.tokenizer.Tokenizer;
import edu.uci.ics.fuzzyjoin.tokenizer.TokenizerFactory;

/**
 * @author rares
 * 
 *         KEY1: not used
 * 
 *         VALUE1: record (e.g.,
 *         "unused_attribute:RID:unused_attribute:join_attribute:unused_attribute"
 *         )
 * 
 *         KEY2: token
 * 
 *         VALUE2: 1st: count (i.e., 1) and length, others: count (i.e., 1)
 * 
 */
public class Map extends MapReduceBase implements Mapper<Object, Text, Text, IntArrayWritable> {

    private final IntArrayWritable countArray = new IntArrayWritable();
    private final IntArrayWritable countLengthArray = new IntArrayWritable();
    private int[] dataColumns;
    private final Text token = new Text();
    private Tokenizer tokenizer;

    @Override
    public void configure(JobConf job) {
        tokenizer = TokenizerFactory.getTokenizer(
                job.get(FuzzyJoinConfig.TOKENIZER_PROPERTY, FuzzyJoinConfig.TOKENIZER_VALUE),
                FuzzyJoinConfig.WORD_SEPARATOR_REGEX, FuzzyJoinConfig.TOKEN_SEPARATOR);
        IntWritable one = new IntWritable(1);
        countArray.set(new IntWritable[] { one });
        countLengthArray.set(new IntWritable[] { one, new IntWritable() });
        //
        // set dataColumn
        //
        dataColumns = FuzzyJoinUtil
                .getDataColumns(job.get(FuzzyJoinConfig.RECORD_DATA_PROPERTY, FuzzyJoinConfig.RECORD_DATA_VALUE));
    }

    public void map(Object unused, Text record, OutputCollector<Text, IntArrayWritable> output, Reporter reporter)
            throws IOException {
        List<String> tokens = tokenizer
                .tokenize(FuzzyJoinUtil.getData(record.toString().split(FuzzyJoinConfig.RECORD_SEPARATOR_REGEX),
                        dataColumns, FuzzyJoinConfig.TOKEN_SEPARATOR));

        ((IntWritable) countLengthArray.get()[1]).set(tokens.size());

        //
        // 1st
        //
        token.set(tokens.get(0));
        // token.set(tokens.get(tokens.size() - 1));
        output.collect(token, countLengthArray);
        // output.collect(token, countArray); // no length statistics
        //
        // others
        //
        for (int i = 1; i < tokens.size(); ++i) {
            // for (int i = 0; i < tokens.size() - 1; ++i) {
            token.set(tokens.get(i));
            output.collect(token, countArray);
        }
    }
}