AnagramMapper.java Source code

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Here is the source code for AnagramMapper.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.hadoop.examples.anagrams;

import java.io.IOException;
import java.util.Arrays;

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

/**
 * The Anagram mapper class gets a word as a line from the HDFS input and sorts the
 * letters in the word and writes its back to the output collector as 
 * Key : sorted word (letters in the word sorted)
 * Value: the word itself as the value.
 * When the reducer runs then we can group anagrams togather based on the sorted key.
 * 
 * @author subbu iyer
 *
 */
public class AnagramMapper extends MapReduceBase implements Mapper<LongWritable, Text, Text, Text> {

    private Text sortedText = new Text();
    private Text orginalText = new Text();

    public void map(LongWritable key, Text value, OutputCollector<Text, Text> outputCollector, Reporter reporter)
            throws IOException {

        String word = value.toString();
        char[] wordChars = word.toCharArray();
        Arrays.sort(wordChars);
        String sortedWord = new String(wordChars);
        sortedText.set(sortedWord);
        orginalText.set(word);
        outputCollector.collect(sortedText, orginalText);
    }

}