December 14, 2010

Serialize Printing of "Hello BSP" with Apache Hama

Serialize Printing of "Hello BSP"

Each BSP task of the HAMA cluster, will print the string "Hello BSP" in serial order. This example will help you to understand the concepts of the BSP computing model.

  • Each task gets its own hostname (hostname:port pair) and a sorted list containing the hostnames of all the other peers.
  • Each task prints the LOG string "Hello BSP" only when its turn comes at intervals of 5 seconds.

BSP implementation of Serialize Printing of "Hello BSP"

public class SerializePrinting {
  
  public static class HelloBSP extends BSP {
    public static final Log LOG = LogFactory.getLog(HelloBSP.class);
    private Configuration conf;
    private final static int PRINT_INTERVAL = 5000;

    @Override
    public void bsp(BSPPeer bspPeer) throws IOException, KeeperException,
        InterruptedException {
      int num = Integer.parseInt(conf.get("bsp.peers.num"));

      int i = 0;
      for (String otherPeer : bspPeer.getAllPeerNames()) {
        if (bspPeer.getPeerName().equals(otherPeer)) {
          LOG.info("Hello BSP from " + i + " of " + num + ": "
              + bspPeer.getPeerName());
        }
        
        Thread.sleep(PRINT_INTERVAL);
        bspPeer.sync();
        i++;
      }
    }

    @Override
    public Configuration getConf() {
      return conf;
    }

    @Override
    public void setConf(Configuration conf) {
      this.conf = conf;
    }

  }

  public static void main(String[] args) throws InterruptedException,
      IOException {
    // BSP job configuration
    HamaConfiguration conf = new HamaConfiguration();
    // Execute locally
    // conf.set("bsp.master.address", "local");

    BSPJob bsp = new BSPJob(conf, SerializePrinting.class);
    // Set the job name
    bsp.setJobName("serialize printing");
    bsp.setBspClass(HelloBSP.class);

    BSPJobClient.runJob(bsp);
  }
}

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