org/objectweb/proactive/branchnbound/core/Task.java

/* 
 * ################################################################
 * 
 * ProActive: The Java(TM) library for Parallel, Distributed, 
 *            Concurrent computing with Security and Mobility
 * 
 * Copyright (C) 1997-2007 INRIA/University of Nice-Sophia Antipolis
 * Contact: proactive@objectweb.org
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or any later version.
 *  
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *  
 *  Initial developer(s):               The ProActive Team
 *                        http://www.inria.fr/oasis/ProActive/contacts.html
 *  Contributor(s): 
 * 
 * ################################################################
 */ 
package org.objectweb.proactive.branchnbound.core;

import java.io.IOException;
import java.io.Serializable;
import java.util.Vector;

import org.apache.log4j.Logger;
import org.objectweb.proactive.ProActive;
import org.objectweb.proactive.core.util.log.Loggers;
import org.objectweb.proactive.core.util.log.ProActiveLogger;


public abstract class Task implements Serializable, Comparable {
    protected static Logger logger = ProActiveLogger.getLogger(Loggers.P2P_SKELETONS_MANAGER);
    protected Result initLowerBound;
    protected Result initUpperBound;
    protected Worker worker = null;
    protected Object bestKnownSolution = null;

    public Task() {
        // nothing to do
    }

    public abstract Result execute();

    public abstract Vector split();

    public Result gather(Result[] results) {
        Result best = null;
        for (int i = 0; i < results.length; i++) {
            Result current = results[i];
            if (best == null) {
                if (current.isAnException()) {
                    continue;
                }
                best = current;
            } else {
                best = best.returnTheBest(current);
            }
        }
        return best;
    }

    public abstract void initLowerBound();

    public abstract void initUpperBound();

    public void setWorker(Worker worker) {
        this.worker = worker;
    }

    public int compareTo(Object arg) {
        Task t = (Task) arg;
        if (this.equals(t)) {
            return 0;
        } else if (this.hashCode() > t.hashCode()) {
            return -1;
        } else {
            return 1;
        }
    }

    public void setBestKnownSolution(Object newBestKnownResult) {
        if (this.bestKnownSolution != null) {
            synchronized (this.bestKnownSolution) {
                if (((Comparable) this.bestKnownSolution).compareTo(
                            newBestKnownResult) > 0) {
                    this.bestKnownSolution = newBestKnownResult;
                }
            }
        }
    }

    public void immediateTerminate() {
        try {
            ProActive.getBodyOnThis().terminate();
        } catch (IOException e) {
            logger.fatal("Couldn't terminate the task", e);
        }
    }
}

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