package mpi.fruitfly.general;

/**
 * <p>Title: MultiThreading </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2007</p>
 *
 * <p>Company: </p>
 *
 * <p>License: GPL
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License 2
 * as published by the Free Software Foundation.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * @author Stephan Preibisch
 * @version 1.0
 */

public class MultiThreading
{
    /*
    final int start = 0;
    final int end = 10;

    final AtomicInteger ai = new AtomicInteger(start);

    Thread[] threads = newThreads();
    for (int ithread = 0; ithread < threads.length; ++ithread)
    {
        threads[ithread] = new Thread(new Runnable()
        {
            public void run()
            {
                // do something....
                // for example:
                for (int i3 = ai.getAndIncrement(); i3 < end; i3 = ai.getAndIncrement())
                {
                }
            }
        });
    }
    startAndJoin(threads);
    */

    public static void startTask(Runnable run)
    {
        Thread[] threads = newThreads();

        for (int ithread = 0; ithread < threads.length; ++ithread)
            threads[ithread] = new Thread(run);

        startAndJoin(threads);
    }

    public static void startTask(Runnable run, int numThreads)
    {
        Thread[] threads = newThreads(numThreads);

        for (int ithread = 0; ithread < threads.length; ++ithread)
            threads[ithread] = new Thread(run);

        startAndJoin(threads);
    }


    public static Thread[] newThreads()
    {
      int nthread = Runtime.getRuntime().availableProcessors();
      return new Thread[nthread];
    }

    public static Thread[] newThreads(int numThreads)
    {
      return new Thread[numThreads];
    }

    public static void startAndJoin(Thread[] threads)
    {
        for (int ithread = 0; ithread < threads.length; ++ithread)
        {
            threads[ithread].setPriority(Thread.NORM_PRIORITY);
            threads[ithread].start();
        }

        try
        {
            for (int ithread = 0; ithread < threads.length; ++ithread)
                threads[ithread].join();
        } catch (InterruptedException ie)
        {
            throw new RuntimeException(ie);
        }
    }
}