com.intel.hadoop.graphbuilder.idnormalize.mapreduce.HashIdReducer.java Source code

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Here is the source code for com.intel.hadoop.graphbuilder.idnormalize.mapreduce.HashIdReducer.java

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/* Copyright (C) 2012 Intel Corporation.
 *     All rights reserved.
 *           
 *  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.
 *
 * For more about this software visit:
 *      http://www.01.org/GraphBuilder 
 */
package com.intel.hadoop.graphbuilder.idnormalize.mapreduce;

import java.io.IOException;
import java.util.Iterator;

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.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.log4j.Logger;

import com.intel.hadoop.graphbuilder.graph.Vertex;
import com.intel.hadoop.graphbuilder.parser.FieldParser;
import com.intel.hadoop.graphbuilder.parser.GraphParser;

/**
 * Reducer class reduce the (baseid, List<(vid, vdata)>) into a dictionary
 * (lvid, vid), and a new vertex data file (lvid, vdata), where lvid = baseid +
 * vid.index * splitsize; Because the splitsize is fixed for all mapper using
 * option {@code mapred.line.input.format.linespermap} in the {@code JobConf},
 * this guarantee all vids are mapped into [0, ..., |V|-1]. The assumption is
 * that the input should not contain any duplicate vertex ids.
 * 
 */
public class HashIdReducer extends MapReduceBase implements Reducer<IntWritable, Text, Text, Text> {

    private static final Logger LOG = Logger.getLogger(HashIdReducer.class);

    @Override
    public void configure(JobConf job) {
        super.configure(job);
        splitsize = job.getInt("mapred.line.input.format.linespermap", 600000);
        try {
            this.graphparser = (GraphParser) Class.forName(job.get("GraphParser")).newInstance();
            this.vidparser = (FieldParser) Class.forName(job.get("VidParser")).newInstance();
            this.vdataparser = (FieldParser) Class.forName(job.get("VdataParser")).newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void reduce(IntWritable key, Iterator<Text> iter, OutputCollector<Text, Text> out, Reporter reporter)
            throws IOException {
        long baseid = key.get();
        int split = 0;
        while (iter.hasNext()) {
            Vertex v = graphparser.parseVertex(iter.next().toString(), vidparser, vdataparser);
            long newId = baseid + splitsize * split;
            out.collect(new Text("vidmap"), new Text(newId + "\t" + v.vid()));
            out.collect(new Text("vdata"), new Text("!" + newId + "\t" + v.vdata().toString()));
            split++;
        }
    }

    private int splitsize;
    private GraphParser graphparser;
    private FieldParser vidparser;
    private FieldParser vdataparser;
}