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

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Here is the source code for com.intel.hadoop.graphbuilder.idnormalize.mapreduce.TransEdgeReducer.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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Scanner;
import java.util.StringTokenizer;

import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;
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.parser.FieldParser;
import com.intel.hadoop.graphbuilder.parser.GraphParser;

/**
 * This reducer class takes from mapper the input (h(v), [(D(u_i),v_i,
 * data)...]) and output (D(u_i), D(v_i), data). Because the key is based on
 * hash of the rawId, the loading of dictionary is minimized.
 * 
 * @param <VidType>
 */
public class TransEdgeReducer<VidType extends WritableComparable<VidType>> extends MapReduceBase
        implements Reducer<IntWritable, Text, Text, Text> {

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

    @Override
    public void configure(JobConf conf) {
        super.configure(conf);
        numChunks = conf.getInt("numChunks", 256);
        dictionaryPath = conf.get("dictionaryPath");
        dict = new HashMap<VidType, Long>();
        dictionaryId = -1;

        try {
            fs = FileSystem.get(conf);
        } catch (IOException e1) {
            e1.printStackTrace();
        }

        try {
            this.graphparser = (GraphParser) Class.forName(conf.get("GraphParser")).newInstance();
            this.vidparser = (FieldParser) Class.forName(conf.get("VidParser")).newInstance();
            this.edataparser = (FieldParser) Class.forName(conf.get("EdataParser")).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 {
        if (key.get() != dictionaryId) {
            dictionaryId = key.get();
            loadDictionary();
        }

        while (iter.hasNext()) {
            String line = iter.next().toString();
            StringTokenizer tk = new StringTokenizer(line);
            long sourceId = Long.valueOf(tk.nextToken());
            VidType target = vidparser.getValue(tk.nextToken());
            if (dict.containsKey(target)) {
                long targetId = dict.get(target);
                String edata = tk.hasMoreTokens() ? "\t" + tk.nextToken() : "";
                out.collect(null, new Text(sourceId + "\t" + targetId + edata));
            } else {
                LOG.error("Reducer: Cannot find key " + target.toString());
                LOG.error("Line: " + line);
            }
        }
    }

    /**
     * Load the dictionary partition with the current dictionaryId. Duplicate code
     * from {@code TransEdgeMapper#loadDictionary}.
     * 
     * @throws IOException
     */
    private void loadDictionary() throws IOException {
        dict.clear();
        String prefix = "vidhashmap" + dictionaryId;
        FileStatus[] stats = fs.listStatus(new Path(dictionaryPath));
        for (FileStatus stat : stats) {
            if (stat.getPath().getName().matches(".*" + prefix + "-r-.*")) {
                LOG.debug(("Mapper Load dictionary: " + stat.getPath().getName()));
                Scanner sc = new Scanner(new BufferedReader(new InputStreamReader(fs.open(stat.getPath()))));
                while (sc.hasNextLine()) {
                    String line = sc.nextLine();
                    StringTokenizer tokenizer = new StringTokenizer(line);
                    try {
                        long id = Long.valueOf(tokenizer.nextToken());
                        VidType rawid = vidparser.getValue(tokenizer.nextToken());
                        dict.put(rawid, Long.valueOf(id));
                    } catch (NoSuchElementException e) {
                        e.printStackTrace();
                        LOG.error("Error in loading vidmap entry:" + line);
                    }
                }
            }
        }
    }

    GraphParser<VidType, ?, ?> graphparser;
    FieldParser<VidType> vidparser;
    FieldParser edataparser;

    int dictionaryId;
    HashMap<VidType, Long> dict;
    int numChunks;
    String dictionaryPath;
    FileSystem fs;
}