source: sample/hadoop-0.16/tw/org/nchc/demo/DemoHBaseSink.java @ 142

/**

 * Program: DemoHBaseSink.java

 * Editor: Waue Chen 

 * From :  NCHC. Taiwn

 * Last Update Date: 07/02/2008

 * Re-code from : Cloud9: A MapReduce Library for Hadoop

 */

/*

 * Cloud9: A MapReduce Library for Hadoop

 */



package tw.org.nchc.demo;



import java.io.IOException;

import java.util.Iterator;



import org.apache.hadoop.fs.Path;

import org.apache.hadoop.hbase.io.ImmutableBytesWritable;

import org.apache.hadoop.hbase.mapred.TableReduce;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.MapWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapred.JobClient;

import org.apache.hadoop.mapred.JobConf;

import org.apache.hadoop.mapred.OutputCollector;

import org.apache.hadoop.mapred.Reporter;

import org.apache.hadoop.mapred.lib.IdentityMapper;

import org.apache.hadoop.mapred.lib.IdentityReducer;



/**

 * 

 */

public class DemoHBaseSink {



  private static class ReduceClass extends TableReduce<LongWritable, Text> {



    // this is the column we're going to be writing

    private static final Text col = new Text("default:text");



    // this map holds the columns per row

    private MapWritable map = new MapWritable();



    public void reduce(LongWritable key, Iterator<Text> values,

        OutputCollector<Text, MapWritable> output, Reporter reporter)

        throws IOException {



      // contents must be ImmutableBytesWritable

      ImmutableBytesWritable bytes = new ImmutableBytesWritable(values

          .next().getBytes());



      // populate the current row

      map.clear();

      map.put(col, bytes);



      // add the row with the key as the row id

      output.collect(new Text(key.toString()), map);

    }

  }



  private DemoHBaseSink() {

  }



  /**

   * Runs the demo.

   */

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

    String filename = "/shared/sample";



    int mapTasks = 1;

    int reduceTasks = 1;



    JobConf conf = new JobConf(DemoHBaseSink.class);

    conf.setJobName("wordcount");



    // must initialize the TableReduce before running job

    TableReduce.initJob("test", ReduceClass.class, conf);



    conf.setNumMapTasks(mapTasks);

    conf.setNumReduceTasks(reduceTasks);

    conf.setInputPath(new Path(filename));

    conf.setMapperClass(IdentityMapper.class);

    conf.setCombinerClass(IdentityReducer.class);

    conf.setReducerClass(ReduceClass.class);



    JobClient.runJob(conf);

  }

}