Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.utils.thread / src / org / simantics / utils / threads / Throttler.java

diff --git a/bundles/org.simantics.utils.thread/src/org/simantics/utils/threads/Throttler.java b/bundles/org.simantics.utils.thread/src/org/simantics/utils/threads/Throttler.java
new file mode 100644 (file)
index 0000000..1f6068a
--- /dev/null
+++ b/bundles/org.simantics.utils.thread/src/org/simantics/utils/threads/Throttler.java
@@ -0,0 +1,95 @@
+/*******************************************************************************\r
+ * Copyright (c) 2012 Association for Decentralized Information Management in\r
+ * 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.utils.threads;\r
+\r
+import java.util.concurrent.TimeUnit;\r
+\r
+/**\r
+ * @author Antti Villberg\r
+ */\r
+public class Throttler implements Runnable {\r
+\r
+       final private IThreadWorkQueue thread;\r
+       final private int interval;\r
+\r
+       private boolean isScheduling = false;\r
+\r
+       private long[] dispatchTimes;\r
+       private long lastQueueTime;\r
+\r
+       private int dispatchTimePointer = 0;\r
+\r
+       private Runnable todo;\r
+\r
+       public Throttler(IThreadWorkQueue thread, int interval, int queueLength) {\r
+\r
+               this.thread = thread;\r
+               this.interval = interval;\r
+\r
+               long currentTime = System.currentTimeMillis();\r
+\r
+               dispatchTimes = new long[queueLength];\r
+               for(int i=0;i<dispatchTimes.length;i++)\r
+                       dispatchTimes[i] = currentTime - interval;\r
+\r
+               lastQueueTime = Long.MAX_VALUE;\r
+\r
+       }\r
+\r
+       public synchronized void run() {\r
+\r
+               if(todo != null) {\r
+                       thread.asyncExec(todo);\r
+                       todo = null;\r
+                       ThreadUtils.getTimer().schedule(this, interval, TimeUnit.MILLISECONDS);\r
+               } else {\r
+                       isScheduling = false;\r
+               }\r
+\r
+       }\r
+       \r
+       public synchronized void schedule(Runnable r) {\r
+\r
+               assert(thread.currentThreadAccess());\r
+               \r
+               dispatch(r);\r
+\r
+               if(getQueueTime() < interval) {\r
+\r
+                       isScheduling = true;\r
+                       ThreadUtils.getTimer().schedule(this, interval, TimeUnit.MILLISECONDS);\r
+\r
+               }\r
+\r
+       }\r
+\r
+       private long getQueueTime() {\r
+               return lastQueueTime;\r
+       }\r
+\r
+       private void dispatch(Runnable runnable) {\r
+\r
+               long time = System.currentTimeMillis();\r
+               lastQueueTime = time - dispatchTimes[dispatchTimePointer];\r
+               dispatchTimes[dispatchTimePointer] = time;\r
+               dispatchTimePointer = ((dispatchTimePointer+1) % dispatchTimes.length);\r
+\r
+               if(!isScheduling) {\r
+                       todo = null;\r
+                       runnable.run();\r
+               } else {\r
+                       todo = runnable;\r
+               }\r
+\r
+       }\r
+\r
+}\r