Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.browsing.ui.swt / src / org / simantics / browsing / ui / swt / internal / Threads.java

diff --git a/bundles/org.simantics.browsing.ui.swt/src/org/simantics/browsing/ui/swt/internal/Threads.java b/bundles/org.simantics.browsing.ui.swt/src/org/simantics/browsing/ui/swt/internal/Threads.java
new file mode 100644 (file)
index 0000000..be25de6
--- /dev/null
+++ b/bundles/org.simantics.browsing.ui.swt/src/org/simantics/browsing/ui/swt/internal/Threads.java
@@ -0,0 +1,95 @@
+/*******************************************************************************\r
+ * Copyright (c) 2007, 2012 Association for Decentralized Information Management\r
+ * in Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ *\r
+ * Contributors:\r
+ *     VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+package org.simantics.browsing.ui.swt.internal;\r
+\r
+import java.util.concurrent.ExecutorService;\r
+import java.util.concurrent.Executors;\r
+import java.util.concurrent.LinkedBlockingQueue;\r
+import java.util.concurrent.ThreadFactory;\r
+import java.util.concurrent.ThreadPoolExecutor;\r
+import java.util.concurrent.TimeUnit;\r
+import java.util.concurrent.atomic.AtomicInteger;\r
+\r
+import org.simantics.browsing.ui.swt.Activator;\r
+\r
+/**\r
+ * Pooled thread work executor for GraphExplorerImpl internal use only.\r
+ * \r
+ * Started by {@link Activator}.\r
+ * \r
+ * @author Tuukka Lehtonen\r
+ */\r
+public final class Threads {\r
+\r
+    private static ExecutorService     executor;\r
+\r
+    public static synchronized void initialize() {\r
+        if (executor == null) {\r
+            initializeExecutor();\r
+        }\r
+    }\r
+\r
+    public static synchronized void shutdown() {\r
+        if (executor != null) {\r
+            executor.shutdown();\r
+            executor = null;\r
+        }\r
+    }\r
+\r
+    private static ExecutorService initializeExecutor() {\r
+        if (executor == null) {\r
+            final ThreadGroup tg = new ThreadGroup("GraphExplorer-Worker-Group");\r
+            final AtomicInteger counter = new AtomicInteger(0);\r
+            ThreadFactory tf = new ThreadFactory() {\r
+                @Override\r
+                public Thread newThread(Runnable r) {\r
+                    Thread t = new Thread(tg, r, "GraphExplorer-Worker-"+(counter.incrementAndGet()));\r
+                    if (!t.isDaemon())\r
+                        t.setDaemon(true);\r
+                    if (t.getPriority() != Thread.NORM_PRIORITY)\r
+                        t.setPriority(Thread.NORM_PRIORITY);\r
+                    return t;\r
+                }\r
+            };\r
+\r
+//            int maxPoolSize = Math.min(Math.max(2, ThreadUtils.CORES), 8);\r
+            int maxPoolSize = 1;\r
+            \r
+            if(maxPoolSize == 1) {\r
+               \r
+               executor = Executors.newSingleThreadExecutor(tf);\r
+               \r
+            } else {\r
+\r
+               executor =\r
+                       new ThreadPoolExecutor(maxPoolSize / 2, maxPoolSize,\r
+                                       // Don't let the threads die too soon\r
+                                       30L, TimeUnit.SECONDS,\r
+                                       // LinkedBlockingQueue to allow queueing of tasks\r
+                                       // even when all workers are busy.\r
+                                       new LinkedBlockingQueue<Runnable>(),\r
+                                       tf);\r
+            \r
+            }\r
+            \r
+        }\r
+        return executor;\r
+    }\r
+\r
+    public static ExecutorService getExecutor() {\r
+        ExecutorService service = executor;\r
+        if (service == null)\r
+            throw new IllegalStateException("executor not initialized");\r
+        return service;\r
+    }\r
+\r
+}\r