src/test/testjar/UserNamePermission.java

package testjar;

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;

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

public  class UserNamePermission      
{

  private static final Log LOG = LogFactory.getLog(UserNamePermission.class);
  //This mapper will read the user name and pass in to the reducer
  public static class UserNameMapper extends Mapper<LongWritable,Text,Text,Text>
  {
    Text key1 = new Text("UserName");
    public void map(LongWritable key, Text value, Context context)
      throws IOException,InterruptedException {
      Text val = new Text(System.getProperty("user.name").toString());
      context.write(key1, val);
    }
  }

  //The reducer is responsible for writing the user name to the file
  //which will be validated by the testcase
  public static class UserNameReducer extends Reducer<Text,Text,Text,Text>
  {
    public void reduce(Text key, Iterator<Text> values,
      Context context) throws IOException,InterruptedException {
	  			
      LOG.info("The key "+key);
      if(values.hasNext())
      {
        Text val = values.next();
        LOG.info("The value  "+val);
	  				 
        context.write(key,new Text(System.getProperty("user.name")));
	  }
	  				  			 
	}
  }
		
  public static void main(String [] args) throws Exception
  {
    Path outDir = new Path("output");
    Configuration conf = new Configuration();
    Job job = new Job(conf, "user name check"); 
			
			
    job.setJarByClass(UserNamePermission.class);
    job.setMapperClass(UserNamePermission.UserNameMapper.class);
    job.setCombinerClass(UserNamePermission.UserNameReducer.class);
    job.setMapOutputKeyClass(Text.class);
    job.setMapOutputValueClass(Text.class);
    job.setReducerClass(UserNamePermission.UserNameReducer.class);
    job.setNumReduceTasks(1);
		    
    job.setInputFormatClass(TextInputFormat.class);
    TextInputFormat.addInputPath(job, new Path("input"));
    FileOutputFormat.setOutputPath(job, outDir);
		    
    System.exit(job.waitForCompletion(true) ? 0 : 1);
  }

}