bundles/org.simantics.db.common/src/org/simantics/db/common/procedure/single/wrapper/NullSingleOrNullProcedure.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2010 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.db.common.procedure.single.wrapper;\r
  13 \r
  14 import org.simantics.db.AsyncReadGraph;\r
  15 import org.simantics.db.common.utils.Logger;\r
  16 import org.simantics.db.procedure.AsyncProcedure;\r
  17 \r
  18 final public class NullSingleOrNullProcedure<Result> {\r
  19 \r
  20         private Result result = null;\r
  21         final AsyncProcedure<Result> procedure;\r
  22         \r
  23         boolean done = false;\r
  24         boolean found = false;\r
  25         int ready = 1;\r
  26         \r
  27 //      final AtomicBoolean done = new AtomicBoolean(false);\r
  28 //      final AtomicBoolean found = new AtomicBoolean(false);\r
  29 //      final AtomicInteger ready = new AtomicInteger(1);\r
  30 \r
  31         public NullSingleOrNullProcedure(AsyncProcedure<Result> procedure) {\r
  32 \r
  33                 this.procedure = procedure;\r
  34 \r
  35         }\r
  36 \r
  37         public void inc() {\r
  38                 ready++;\r
  39 //              ready.incrementAndGet();\r
  40         }\r
  41 \r
  42         public void dec(AsyncReadGraph graph) {\r
  43 \r
  44                 if((--ready) == 0) {\r
  45                         // Shall fire exactly once!\r
  46                         if(!done) {\r
  47                                 done = true;\r
  48                                 try {\r
  49                                         procedure.execute(graph, result);\r
  50                                 } catch (Throwable t) {\r
  51                                 Logger.defaultLogError(t);\r
  52                                 }\r
  53                         }\r
  54                 }\r
  55 \r
  56         }\r
  57 \r
  58         public void offer(AsyncReadGraph graph, Result result) {\r
  59 \r
  60                 if(!found) {\r
  61                         found = true;\r
  62                         this.result = result;\r
  63                 } else {\r
  64                         // Shall fire exactly once!\r
  65                         if(!done) {\r
  66                                 done = true;\r
  67                                 try {\r
  68                                         procedure.execute(graph, null);\r
  69                                 } catch (Throwable t) {\r
  70                                 Logger.defaultLogError(t);\r
  71                                 }\r
  72                         }\r
  73                 }\r
  74 \r
  75         }\r
  76 \r
  77         public void exception(AsyncReadGraph graph, Throwable t) {\r
  78                 // Shall fire exactly once!\r
  79                 if(!done) {\r
  80                         done = true;\r
  81                         try {\r
  82                                 procedure.exception(graph, t);\r
  83                         } catch (Throwable t2) {\r
  84                         Logger.defaultLogError(t2);\r
  85                         }\r
  86                 }\r
  87         }\r
  88 \r
  89 }\r