package demos;

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

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
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;

public class SimpleWordFreqHistogram {
	public static void run(String input, String output){
		JobConf conf = new JobConf(SimpleWordFreqHistogram.class);
		conf.setJobName("simple word freq histogram");

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

		conf.setMapperClass(WordFreqMapper.class);
		//conf.setCombinerClass(SumReducer.class);
		conf.setReducerClass(SumReducer.class);

		// specify input and output dirs
		FileInputFormat.addInputPath(conf, new Path(input));
		FileOutputFormat.setOutputPath(conf, new Path(output));

		JobClient client = new JobClient();

		client.setConf(conf);
		try {
			JobClient.runJob(conf);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void main(String[] args) {
		if( args.length != 2 ){
			System.err.println("SimpleWordFreqHistogram <input_dir> <output_dir>");
		}else{
			run(args[0], args[1]);
		}
	}
}