gr.ntua.h2rdf.concurrent.Executor.java Source code

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Here is the source code for gr.ntua.h2rdf.concurrent.Executor.java

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/*******************************************************************************
 * Copyright (c) 2012 Nikos Papailiou. 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/gpl.html
 * 
 * Contributors:
 *     Nikos Papailiou - initial API and implementation
 ******************************************************************************/
package gr.ntua.h2rdf.concurrent;

/**
 * A simple example program to use DataMonitor to start and
 * stop executables based on a znode. The program watches the
 * specified znode and saves the data that corresponds to the
 * znode in the filesystem. It also starts the specified program
 * with the specified arguments when the znode exists and kills
 * the program if the znode goes away.
 */
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Date;

import org.apache.hadoop.hbase.util.Bytes;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.ZooDefs.Ids;

public class Executor implements Watcher {

    String root;
    int deleted;

    boolean dead;
    ZooKeeper zk;
    String filename;
    Process child;
    static Integer mutex;
    public long startTimeReal;
    public static long startTime;
    private static String separator = "$query$";

    public Executor(String address, String root, String query) throws KeeperException, IOException {
        this.root = root;
        dead = false;
        filename = "";
        zk = new ZooKeeper(address, 3000, this);
        startTimeReal = new Date().getTime();
        byte[] value;
        value = Bytes.toBytes(query);
        byte[] v = new byte[value.length + 1];
        v[0] = (byte) 0;
        for (int i = 1; i < v.length; i++) {
            v[i] = value[i - 1];
        }
        try {
            String f = zk.create(root + "/element", v, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT_SEQUENTIAL);
            filename = "/out/" + f.split("/")[2];
            System.out.println(filename);
            zk.exists(filename, this);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        startTime = new Date().getTime();
        if (args.length < 3) {
            System.err.println("USAGE: Executor address root query");
            System.exit(2);
        }
        String NL = System.getProperty("line.separator");
        String address = args[0];
        String root = args[1];
        String table = args[2];
        String query = args[3];
        String prolog = "PREFIX dc: <http://dbpedia.org/resource/>" + "PREFIX p: <http://dbpedia.org/ontology/>"
                + "PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>"
                + "PREFIX ub: <http://www.lehigh.edu/~zhp2/2004/0401/univ-bench.owl#>"
                + "PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>";

        String q = table + separator + prolog + NL + query;

        try {
            new Executor(address, root, q).run();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void run() {

        try {
            synchronized (this) {
                while (!dead) {
                    wait();
                }
            }
        } catch (InterruptedException e) {
            long stopTime = new Date().getTime();
            System.out.println("Total time in ms: " + (stopTime - startTime));
            System.out.println("Real time in ms: " + (stopTime - startTimeReal));
        }
        long stopTime = new Date().getTime();
        System.out.println("Total time in ms: " + (stopTime - startTime));
        System.out.println("Real time in ms: " + (stopTime - startTimeReal));
    }

    public void process(WatchedEvent event) {
        String path = event.getPath();
        if (event.getType() == Event.EventType.None) {
            // We are are being told that the state of the
            // connection has changed
        } else {
            if (path.equals(filename) && (event.getType() == Event.EventType.NodeCreated)) {
                // It's all over
                System.out.println("Finished ");
                try {
                    dead = true;
                    synchronized (this) {
                        notifyAll();
                    }
                    zk.delete(filename, 0);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (KeeperException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }

        /*if (event.getType() == Event.EventType.None) {
        // We are are being told that the state of the
        // connection has changed
        switch (event.getState()) {
        case SyncConnected:
            // In this particular example we don't need to do anything
            // here - watches are automatically re-registered with 
            // server and any watches triggered while the client was 
            // disconnected will be delivered (in order of course)
            break;
        case Expired:
            // It's all over
           dead=true;
            synchronized (this) {
                notifyAll();
            }
            break;
        }
        } else {
        if (path != null && path.equals(filename)) {
            // Something has changed on the node, let's find out
            zk.exists(filename, true, this, null);
        }
        }*/
    }

    /* public void processResult(int rc, String path, Object ctx, Stat stat) {
    boolean exists;
        
    if(rc==Code.NoNode){
       dead=true;
        synchronized (this) {
            notifyAll();
        }
       return;
    }
    zk.exists(filename, true, this, null);
    return;
        
     }*/
}