+/*******************************************************************************\r
+ * Copyright (c) 2007, 2010 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.db.common.procedure.single.wrapper;\r
+\r
+import java.util.concurrent.atomic.AtomicBoolean;\r
+import java.util.concurrent.atomic.AtomicInteger;\r
+\r
+import org.simantics.db.AsyncReadGraph;\r
+import org.simantics.db.common.utils.Logger;\r
+import org.simantics.db.procedure.AsyncProcedure;\r
+\r
+final public class DeepSingleOrNullProcedure<Result> {\r
+ \r
+ private Result result = null;\r
+ final AsyncProcedure<Result> procedure;\r
+ final AtomicBoolean done = new AtomicBoolean(false);\r
+ final AtomicBoolean found = new AtomicBoolean(false);\r
+ final AtomicInteger ready = new AtomicInteger(1);\r
+ \r
+ public DeepSingleOrNullProcedure(AsyncProcedure<Result> procedure) {\r
+ \r
+ this.procedure = procedure;\r
+ \r
+ }\r
+ \r
+ public void inc() {\r
+ \r
+ ready.incrementAndGet();\r
+ \r
+ }\r
+ \r
+ public void dec(AsyncReadGraph graph) {\r
+\r
+ if(ready.decrementAndGet() == 0) {\r
+ // Shall fire exactly once!\r
+ if(done.compareAndSet(false, true)) {\r
+ try {\r
+ if(found.compareAndSet(false, true)) {\r
+ procedure.execute(graph, null);\r
+ } else {\r
+ procedure.execute(graph, result);\r
+ }\r
+ } catch (Throwable t) {\r
+ Logger.defaultLogError(t);\r
+ procedure.execute(graph, null);\r
+ }\r
+ }\r
+ }\r
+ \r
+ }\r
+\r
+ public void offer(AsyncReadGraph graph, Result result) {\r
+ \r
+ if(found.compareAndSet(false, true)) {\r
+ this.result = result;\r
+ } else {\r
+ // Shall fire exactly once!\r
+ if(done.compareAndSet(false, true)) {\r
+ try {\r
+ procedure.execute(graph, null);\r
+ } catch (Throwable t) {\r
+ Logger.defaultLogError(t);\r
+ procedure.execute(graph, null);\r
+ }\r
+ }\r
+ }\r
+ \r
+ }\r
+ \r
+ public void exception(AsyncReadGraph graph, Throwable t) {\r
+ // Shall fire exactly once!\r
+ if(done.compareAndSet(false, true)) {\r
+ try {\r
+ procedure.execute(graph, null);\r
+ } catch (Throwable t2) {\r
+ Logger.defaultLogError(t);\r
+ procedure.execute(graph, null);\r
+ }\r
+ }\r
+ }\r
+ \r
+}\r