bundles/org.simantics.utils.thread/src/org/simantics/utils/threads/ExecutorWorker.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2018 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *     Semantum Oy - added shutdown facilities
  12  *******************************************************************************/
  13
  14 package org.simantics.utils.threads;
  15
  16 import java.util.concurrent.Callable;
  17 import java.util.concurrent.ScheduledFuture;
  18 import java.util.concurrent.ScheduledThreadPoolExecutor;
  19 import java.util.concurrent.TimeUnit;
  20 import java.util.concurrent.atomic.AtomicInteger;
  21
  22 /**
  23  * @author Toni Kalajainen
  24  * @author Tuukka Lehtonen
  25  */
  26 public class ExecutorWorker {
  27
  28         private static volatile ExecutorWorker instance;
  29
  30         public static ExecutorWorker getInstance() {
  31                 if (instance == null) {
  32                         synchronized (ExecutorWorker.class) {
  33                                 if (instance == null)
  34                                         instance = new ExecutorWorker();
  35                         }
  36                 }
  37                 return instance;
  38         }
  39
  40         private ExecutorWorker() {}
  41
  42         private final AtomicInteger counter = new AtomicInteger(0);
  43         private final ThreadGroup threadGroup = new ThreadGroup("ExecutorWorker-Group");
  44         private ScheduledThreadPoolExecutor pool = new ScheduledThreadPoolExecutor(1, r -> {
  45                 Thread t = new Thread(threadGroup, r, "ExecutorWorker-" + (counter.incrementAndGet()));
  46                 if (!t.isDaemon())
  47                         t.setDaemon(true);
  48                 if (t.getPriority() != Thread.NORM_PRIORITY)
  49                         t.setPriority(Thread.NORM_PRIORITY);
  50                 return t;
  51         });
  52
  53         public synchronized ScheduledFuture<Object> timerExec(final Executable executable, int delay)
  54         {
  55                 Callable<Object> c = () -> {
  56                         ThreadUtils.asyncExec(executable.threadAccess, executable.runnable);
  57                         return null;
  58                 };
  59                 return pool.schedule(c, delay, TimeUnit.MILLISECONDS);
  60         }
  61
  62         private void shutdownThis() {
  63                 ScheduledThreadPoolExecutor e = pool;
  64                 if (e != null) {
  65                         pool = null;
  66                         ThreadUtils.shutdownAndAwaitTermination(e, 1000);
  67                 }
  68         }
  69
  70         public static synchronized void shutdown() {
  71                 ExecutorWorker i = instance;
  72                 if (i != null) {
  73                         instance = null;
  74                         i.shutdownThis();
  75                 }
  76         }
  77
  78 }