DescSorter.java Source code

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Here is the source code for DescSorter.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 org.apache.hadoop.examples;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;
import java.lang.Math;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Partitioner;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.MultipleInputs;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.partition.HashPartitioner;
import org.apache.hadoop.util.GenericOptionsParser;

public class DescSorter {

    public static class SortComparator extends WritableComparator {
        public SortComparator() {
            super(IntWritable.class, true);
        }

        public int compare(WritableComparable ck1, WritableComparable ck2) {
            return ((IntWritable) ck2).compareTo(((IntWritable) ck1));
        }
    }

    public static class AdjListMapper extends Mapper<Object, Text, IntWritable, IntWritable> {

        private IntWritable okey;
        private IntWritable oval;

        protected void setup(Context context) {
            okey = new IntWritable();
            oval = new IntWritable();
        }

        public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
            StringTokenizer st = new StringTokenizer(value.toString());
            String node, listElem;
            int count = 0;
            node = st.nextToken();
            while (st.hasMoreTokens()) {
                listElem = st.nextToken();
                count++;
            }
            okey.set(count);
            oval.set(Integer.parseInt(node));
            context.write(okey, oval);
        }
    }

    public static class Reducer extends Reducer<CompositeKey, IntWritable, IntWritable, Text> {
        HashMap<Integer, int[]> delays;

        protected void setup(Context context) {
            delays = new HashMap<Integer, int[]>();
        }

        protected void cleanup(Context context) throws IOException, InterruptedException {
            StringBuilder sb;
            IntWritable key = new IntWritable();
            Text val = new Text();
            int[] months;
            for (Map.Entry<Integer, int[]> entry : delays.entrySet()) {
                sb = new StringBuilder("");
                key.set((Integer) entry.getKey());
                months = (int[]) entry.getValue();
                for (int i = 0; i < months.length; i++) {
                    sb.append("(" + Integer.toString(i + 1) + "," + Integer.toString(months[i]) + ") ");
                }
                val.set(sb.toString());
                context.write(key, val);
            }
        }

        public void reduce(CompositeKey key, Iterable<IntWritable> values, Context context) {

            int sum = 0, count = 0;
            double avg;

            for (IntWritable iw : values) {
                sum += iw.get();
                count++;
            }
            avg = ((double) sum) / count;
            avg = Math.round(avg);

            if (delays.containsKey(key.getAirlineID())) {
                (delays.get(key.getAirlineID()))[key.getMonth() - 1] = (int) avg;
            } else {
                int[] months = new int[12];
                for (int i = 0; i < months.length; i++)
                    months[i] = 0;
                months[key.getMonth() - 1] = (int) avg;
                delays.put(key.getAirlineID(), months);
            }
        }
    }

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
        if (otherArgs.length < 2) {
            System.err.println("Usage: flights <in> <in> <out>");
            System.exit(2);
        }
        Job job = new Job(conf, "AvgDelays");
        job.setJarByClass(DescSorter.class);
        job.setMapperClass(FlightMapper.class);

        job.setMapOutputKeyClass(CompositeKey.class);
        job.setMapOutputValueClass(IntWritable.class);

        job.setPartitionerClass(CompositeKeyPartitioner.class);
        job.setSortComparatorClass(SortComparator.class);
        job.setGroupingComparatorClass(GroupingComparator.class);

        job.setReducerClass(AvgDelayReducer.class);
        job.setOutputKeyClass(IntWritable.class);
        job.setOutputValueClass(Text.class);

        for (int i = 0; i < otherArgs.length - 1; ++i) {
            FileInputFormat.addInputPath(job, new Path(otherArgs[i]));
        }
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[otherArgs.length - 1]));
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}