Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.db.common / src / org / simantics / db / common / procedure / single / wrapper / SingleFunctionalOrNullProcedure.java

diff --git a/bundles/org.simantics.db.common/src/org/simantics/db/common/procedure/single/wrapper/SingleFunctionalOrNullProcedure.java b/bundles/org.simantics.db.common/src/org/simantics/db/common/procedure/single/wrapper/SingleFunctionalOrNullProcedure.java
new file mode 100644 (file)
index 0000000..e593daf
--- /dev/null
+++ b/bundles/org.simantics.db.common/src/org/simantics/db/common/procedure/single/wrapper/SingleFunctionalOrNullProcedure.java
@@ -0,0 +1,76 @@
+/*******************************************************************************\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
+\r
+import org.simantics.db.AsyncReadGraph;\r
+import org.simantics.db.common.procedure.adapter.AsyncMultiProcedureAdapter;\r
+import org.simantics.db.exception.ManyObjectsForFunctionalRelationException;\r
+import org.simantics.db.procedure.AsyncProcedure;\r
+\r
+final public class SingleFunctionalOrNullProcedure<Result> extends AsyncMultiProcedureAdapter<Result> {\r
+    \r
+       final String location;\r
+       final AsyncProcedure<Result> procedure;\r
+    final AtomicBoolean found = new AtomicBoolean(false);\r
+    final AtomicBoolean guard = new AtomicBoolean(false);\r
+    final AtomicBoolean exception = new AtomicBoolean(false);\r
+    \r
+    public SingleFunctionalOrNullProcedure(String location, AsyncProcedure<Result> procedure) {\r
+        \r
+       this.location = location;\r
+        this.procedure = procedure;\r
+        \r
+    }\r
+    \r
+    @Override\r
+    public void execute(AsyncReadGraph graph, Result result) {\r
+        \r
+        assert(!guard.get());\r
+\r
+        if(found.compareAndSet(false, true)) {\r
+            procedure.execute(graph, result);\r
+        } else {\r
+            if(exception.compareAndSet(false, true)) {\r
+                procedure.exception(graph, new ManyObjectsForFunctionalRelationException(location + " -> " + procedure));\r
+            }\r
+        }\r
+        \r
+    }\r
+       \r
+    @Override\r
+    public void finished(AsyncReadGraph graph) {\r
+\r
+        assert(!guard.get());\r
+        \r
+        guard.set(true);\r
+        \r
+        if(found.compareAndSet(false, true)) {\r
+            procedure.execute(graph, null);\r
+        }\r
+        \r
+    }\r
+    \r
+    @Override\r
+    public void exception(AsyncReadGraph graph, Throwable t) {\r
+        \r
+        procedure.exception(graph, t);\r
+        \r
+    }\r
+    \r
+    @Override\r
+    public String toString() {\r
+        return "SingleFunctionalOrNullProcedure -> " + procedure;\r
+    }\r
+\r
+}\r