bundles/org.simantics.browsing.ui.swt/src/org/simantics/browsing/ui/swt/internal/Threads.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2012 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  *******************************************************************************/
  12 package org.simantics.browsing.ui.swt.internal;
  13
  14 import java.util.concurrent.ExecutorService;
  15 import java.util.concurrent.Executors;
  16 import java.util.concurrent.LinkedBlockingQueue;
  17 import java.util.concurrent.ThreadFactory;
  18 import java.util.concurrent.ThreadPoolExecutor;
  19 import java.util.concurrent.TimeUnit;
  20 import java.util.concurrent.atomic.AtomicInteger;
  21
  22 import org.simantics.browsing.ui.swt.Activator;
  23
  24 /**
  25  * Pooled thread work executor for GraphExplorerImpl internal use only.
  26  *
  27  * Started by {@link Activator}.
  28  *
  29  * @author Tuukka Lehtonen
  30  */
  31 public final class Threads {
  32
  33     private static ExecutorService     executor;
  34
  35     public static synchronized void initialize() {
  36         if (executor == null) {
  37             initializeExecutor();
  38         }
  39     }
  40
  41     public static synchronized void shutdown() {
  42         if (executor != null) {
  43             executor.shutdown();
  44             executor = null;
  45         }
  46     }
  47
  48     private static ExecutorService initializeExecutor() {
  49         if (executor == null) {
  50             final ThreadGroup tg = new ThreadGroup("GraphExplorer-Worker-Group");
  51             final AtomicInteger counter = new AtomicInteger(0);
  52             ThreadFactory tf = new ThreadFactory() {
  53                 @Override
  54                 public Thread newThread(Runnable r) {
  55                     Thread t = new Thread(tg, r, "GraphExplorer-Worker-"+(counter.incrementAndGet()));
  56                     if (!t.isDaemon())
  57                         t.setDaemon(true);
  58                     if (t.getPriority() != Thread.NORM_PRIORITY)
  59                         t.setPriority(Thread.NORM_PRIORITY);
  60                     return t;
  61                 }
  62             };
  63
  64 //            int maxPoolSize = Math.min(Math.max(2, ThreadUtils.CORES), 8);
  65             int maxPoolSize = 1;
  66
  67             if(maxPoolSize == 1) {
  68
  69                 executor = Executors.newSingleThreadExecutor(tf);
  70
  71             } else {
  72
  73                 executor =
  74                         new ThreadPoolExecutor(maxPoolSize / 2, maxPoolSize,
  75                                         // Don't let the threads die too soon
  76                                         30L, TimeUnit.SECONDS,
  77                                         // LinkedBlockingQueue to allow queueing of tasks
  78                                         // even when all workers are busy.
  79                                         new LinkedBlockingQueue<Runnable>(),
  80                                         tf);
  81
  82             }
  83
  84         }
  85         return executor;
  86     }
  87
  88     public static ExecutorService getExecutor() {
  89         ExecutorService service = executor;
  90         if (service == null)
  91             throw new IllegalStateException("executor not initialized");
  92         return service;
  93     }
  94
  95 }