MCSUtils/src/main/java/de/mcs/utils/threads/ThreadUtilities.java

/**
 * MCS Media Computer Software
 * Copyright 2012 by Wilfried Klaas
 * Project: MCSUtils
 * File: ThreadUtilities.java
 * EMail: W.Klaas@gmx.de
 * Created: 30.03.2012 Willie
 */

package de.mcs.utils.threads;

import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;

/**
 * @author Willie
 *
 */
public class ThreadUtilities {

  private static Thread consumerThread;
  private static Queue<Runnable> queue = new ConcurrentLinkedQueue<Runnable>();

  private static class ConsumerThread implements Runnable {
    private Thread activeThread;

    public void run() {
      while (true) {
        if ((activeThread == null) || (!activeThread.isAlive())) {
          Runnable poll = queue.poll();
          if (poll != null) {
            activeThread = invoke(poll);
          } else {
            try {
              Thread.sleep(100);
            } catch (InterruptedException e) {
              // e.printStackTrace();
            }
          }
        }
        // Thread.currentThread();
        Thread.yield();
      }
    }
  };

  public static Thread invoke(Runnable runnable) {
    Thread thread = new Thread(runnable);
    thread.start();
    return thread;
  }

  public static void invokeQueued(Runnable runnable) {
    if (consumerThread == null) {
      consumerThread = new Thread(new ConsumerThread());
      consumerThread.setDaemon(true);
      consumerThread.setName("background consumer thread");
      consumerThread.start();
    }
    queue.offer(runnable);
  }

  public static boolean invokeAndWait(int maxTimeSec, Runnable runnable) {
    Thread thread = invoke(runnable);
    long stop = System.currentTimeMillis() + (maxTimeSec * 1000);
    while (thread.isAlive() && (stop > System.currentTimeMillis())) {
      Thread.yield();
    }
    if (thread.isAlive()) {
      thread.interrupt();
      return false;
    }
    return true;
  }
}