package com.bigdata.hadoop.hdfs;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Job;

import org.apache.hadoop.mapreduce.Mapper;

import org.apache.hadoop.mapreduce.Reducer;

import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;

import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

public class WordCountTest {

	//step 1 Mapper Class

	public static class WordCountMapper extends Mapper<LongWritable, Text, Text, IntWritable>{

		private Text mapOutPutKey = new Text();

		private final static IntWritable mapOutPutValue = new IntWritable(1);

		@Override

		public void map(LongWritable key, Text value, Context context)

				throws IOException, InterruptedException {

			//get lines value

			String lineValue = value.toString();

			String[] strs = lineValue.split(" ");

			for(String str : strs){

				mapOutPutKey.set(str);

				context.write(mapOutPutKey, mapOutPutValue);

			}

		}

	}

	//step 2 Reducer Class

	public static class WordCountReducer extends Reducer<Text, IntWritable, Text, IntWritable>{

		private IntWritable outPutVlaue = new IntWritable();

		@Override

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

				throws IOException, InterruptedException {

			//temp : sum

			int sum = 0;

			for(IntWritable value : values){

				sum += value.get();

			}

			outPutVlaue.set(sum);

			context.write(key, outPutVlaue);

		}

	}

	//step 3 Driver

	public int run(String[] args) throws Exception, InterruptedException{

		//get configuration

		Configuration configuration = new Configuration();

		//get a job

		Job job = Job.getInstance(configuration,this.getClass().getName());

		job.setJarByClass(getClass());

		//get a input path

		Path inPath = new Path(args[0]);

		FileInputFormat.addInputPath(job, inPath);

		//get a output path

		Path outPath = new Path(args[1]);

		FileOutputFormat.setOutputPath(job, outPath);

		//Mapper

		job.setMapperClass(WordCountMapper.class);

		job.setMapOutputKeyClass(Text.class);

		job.setOutputValueClass(IntWritable.class);

		//Reducer

		job.setReducerClass(WordCountReducer.class);

		job.setOutputKeyClass(Text.class);

		job.setOutputValueClass(IntWritable.class);

		//submit job

		boolean isSUccess = job.waitForCompletion(true);

		return isSUccess ? 0 : 1;

	}

	public static void main(String[] args) throws Exception {

		args = new String[]{

			"hdfs://linux-66-64.liuwl.com:8020/user/liuwl/tmp/input",

			"hdfs://linux-66-64.liuwl.com:8020/user/liuwl/tmp/output"

		};

		int status = new WordCountTest().run(args);

		System.exit(status);

	}

}