package org.myorg;

import java.io.IOException;
import java.util.*;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;

public class FindMax {

	public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable> {
		private IntWritable val = new IntWritable();
		private Text department = new Text();

		public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
			String line = value.toString();
			for (int i=0; i<line.length(); i=i+2){
				department.set(line[i]);
				val.set(line[i+1].parseInt());
			}
			output.collect(department, val);
		}
	}

	public static class Reduce extends MapReduceBase implements Reducer<Text, FloatWritable, Text, FloatWritable> {

		public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
			int maxx = 0;
			while (values.hasNext()) {
				int temp = values.next().get();
				if (maxx < temp){
					maxx = temp;
				}
			}
			output.collect(key, new IntWritable(maxx));
		}
	}

	public static void main(String[] args) throws Exception {
		JobConf conf = new JobConf(FindMax.class);
		conf.setJobName("findmax");

		conf.setOutputKeyClass(Text.class);
		conf.setOutputValueClass(IntWritable.class);

		conf.setMapperClass(Map.class);
		conf.setCombinerClass(Reduce.class);
		conf.setReducerClass(Reduce.class);

		conf.setInputFormat(TextInputFormat.class);
		conf.setOutputFormat(TextOutputFormat.class);

		FileInputFormat.setInputPaths(conf, new Path(args[0]));
		FileOutputFormat.setOutputPath(conf, new Path(args[1]));

		JobClient.runJob(conf);
	}
}