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

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2012 Association for Decentralized Information Management\r
   3  * in Industry THTH ry.\r
   4  * All rights reserved. This program and the accompanying materials\r
   5  * are made available under the terms of the Eclipse Public License v1.0\r
   6  * which accompanies this distribution, and is available at\r
   7  * http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  * Contributors:\r
  10  *     VTT Technical Research Centre of Finland - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics.browsing.ui.swt.internal;\r
  13 \r
  14 import java.util.concurrent.ExecutorService;\r
  15 import java.util.concurrent.Executors;\r
  16 import java.util.concurrent.LinkedBlockingQueue;\r
  17 import java.util.concurrent.ThreadFactory;\r
  18 import java.util.concurrent.ThreadPoolExecutor;\r
  19 import java.util.concurrent.TimeUnit;\r
  20 import java.util.concurrent.atomic.AtomicInteger;\r
  21 \r
  22 import org.simantics.browsing.ui.swt.Activator;\r
  23 \r
  24 /**\r
  25  * Pooled thread work executor for GraphExplorerImpl internal use only.\r
  26  * \r
  27  * Started by {@link Activator}.\r
  28  * \r
  29  * @author Tuukka Lehtonen\r
  30  */\r
  31 public final class Threads {\r
  32 \r
  33     private static ExecutorService     executor;\r
  34 \r
  35     public static synchronized void initialize() {\r
  36         if (executor == null) {\r
  37             initializeExecutor();\r
  38         }\r
  39     }\r
  40 \r
  41     public static synchronized void shutdown() {\r
  42         if (executor != null) {\r
  43             executor.shutdown();\r
  44             executor = null;\r
  45         }\r
  46     }\r
  47 \r
  48     private static ExecutorService initializeExecutor() {\r
  49         if (executor == null) {\r
  50             final ThreadGroup tg = new ThreadGroup("GraphExplorer-Worker-Group");\r
  51             final AtomicInteger counter = new AtomicInteger(0);\r
  52             ThreadFactory tf = new ThreadFactory() {\r
  53                 @Override\r
  54                 public Thread newThread(Runnable r) {\r
  55                     Thread t = new Thread(tg, r, "GraphExplorer-Worker-"+(counter.incrementAndGet()));\r
  56                     if (!t.isDaemon())\r
  57                         t.setDaemon(true);\r
  58                     if (t.getPriority() != Thread.NORM_PRIORITY)\r
  59                         t.setPriority(Thread.NORM_PRIORITY);\r
  60                     return t;\r
  61                 }\r
  62             };\r
  63 \r
  64 //            int maxPoolSize = Math.min(Math.max(2, ThreadUtils.CORES), 8);\r
  65             int maxPoolSize = 1;\r
  66             \r
  67             if(maxPoolSize == 1) {\r
  68                 \r
  69                 executor = Executors.newSingleThreadExecutor(tf);\r
  70                 \r
  71             } else {\r
  72 \r
  73                 executor =\r
  74                         new ThreadPoolExecutor(maxPoolSize / 2, maxPoolSize,\r
  75                                         // Don't let the threads die too soon\r
  76                                         30L, TimeUnit.SECONDS,\r
  77                                         // LinkedBlockingQueue to allow queueing of tasks\r
  78                                         // even when all workers are busy.\r
  79                                         new LinkedBlockingQueue<Runnable>(),\r
  80                                         tf);\r
  81             \r
  82             }\r
  83             \r
  84         }\r
  85         return executor;\r
  86     }\r
  87 \r
  88     public static ExecutorService getExecutor() {\r
  89         ExecutorService service = executor;\r
  90         if (service == null)\r
  91             throw new IllegalStateException("executor not initialized");\r
  92         return service;\r
  93     }\r
  94 \r
  95 }\r