package khanolkar.mapreduce.join.samples.reducesidejoin;

import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.filecache.DistributedCache;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

//********************************************************************************
//Class:    DriverRSJ 
//Purpose:  Driver for Reduce Side Join of two datasets
//          with a 1..1 or 1..many cardinality on join key 
//Author:   Anagha Khanolkar
//*********************************************************************************

public class DriverRSJ extends Configured implements Tool {

	@Override
	public int run(String[] args) throws Exception {

		// {{
		// Exit job if required arguments have not been provided
		if (args.length != 3) {
			System.out
					.printf("Three parameters are required for DriverRSJ- <input dir1> <input dir2> <output dir>\n");
			return -1;
		}
		// }{

		// {{
		// Job instantiation
		Job job = new Job(getConf());
		Configuration conf = job.getConfiguration();
		job.setJarByClass(DriverRSJ.class);
		job.setJobName("ReduceSideJoin");
		// }}

		// {{
		// Add side data to distributed cache
		DistributedCache
				.addCacheArchive(
						new URI(
								"/user/akhanolk/joinProject/data/departments_map.tar.gz"),
						conf);

		// }}

		// {
		// Set sourceIndex for input files;
		// sourceIndex is an attribute of the compositeKey,
		// to drive order, and reference source
		// Can be done dynamically; Hard-coded file names for simplicity
		conf.setInt("part-e", 1);// Set Employee file to 1
		conf.setInt("part-sc", 2);// Set Current salary file to 2
		conf.setInt("part-sh", 3);// Set Historical salary file to 3

		// }

		// {
		// Build csv list of input files
		StringBuilder inputPaths = new StringBuilder();
		inputPaths.append(args[0].toString()).append(",")
				.append(args[1].toString());
		// }

		// {{
		// Configure remaining aspects of the job
		FileInputFormat.setInputPaths(job, inputPaths.toString());
		FileOutputFormat.setOutputPath(job, new Path(args[2]));

		job.setMapperClass(MapperRSJ.class);
		job.setMapOutputKeyClass(CompositeKeyWritableRSJ.class);
		job.setMapOutputValueClass(Text.class);

		job.setPartitionerClass(PartitionerRSJ.class);
		job.setSortComparatorClass(SortingComparatorRSJ.class);
		job.setGroupingComparatorClass(GroupingComparatorRSJ.class);

		job.setNumReduceTasks(4);
		job.setReducerClass(ReducerRSJ.class);
		job.setOutputKeyClass(NullWritable.class);
		job.setOutputValueClass(Text.class);
		// }}

		boolean success = job.waitForCompletion(true);
		return success ? 0 : 1;
	}

	public static void main(String[] args) throws Exception {
		int exitCode = ToolRunner.run(new Configuration(), new DriverRSJ(),
				args);
		System.exit(exitCode);
	}
}