bundles/org.simantics.db.common/src/org/simantics/db/common/processor/MergingDelayedWriteProcessor.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.processor;\r
  13 \r
  14 import java.util.concurrent.ConcurrentLinkedQueue;\r
  15 \r
  16 import org.simantics.db.AsyncRequestProcessor;\r
  17 import org.simantics.db.WriteGraph;\r
  18 import org.simantics.db.common.request.DelayedWriteRequest;\r
  19 import org.simantics.db.common.utils.Logger;\r
  20 import org.simantics.db.exception.DatabaseException;\r
  21 import org.simantics.db.request.DelayedWrite;\r
  22 \r
  23 final public class MergingDelayedWriteProcessor extends ProcessorBase {\r
  24 \r
  25     final long transactionKeepalivePeriod;\r
  26     final ConcurrentLinkedQueue<DelayedWrite> queue = new ConcurrentLinkedQueue<DelayedWrite>(); \r
  27     final private AsyncRequestProcessor processor;\r
  28 \r
  29     boolean hasAlreadyRequest = false;\r
  30 \r
  31     public MergingDelayedWriteProcessor(AsyncRequestProcessor processor, long transactionKeepalivePeriod) {\r
  32         this.processor = processor;\r
  33         this.transactionKeepalivePeriod = transactionKeepalivePeriod;\r
  34     }\r
  35 \r
  36     class MergedWrite extends DelayedWriteRequest {\r
  37 \r
  38         @Override\r
  39         public void perform(WriteGraph graph) throws DatabaseException {\r
  40 \r
  41 //            System.out.println("MergedWrite begins");\r
  42 \r
  43             while (true) {\r
  44                 \r
  45                 DelayedWrite next = queue.poll();\r
  46                 if(next == null) {\r
  47                     synchronized (MergingDelayedWriteProcessor.this) {\r
  48                         if (transactionKeepalivePeriod > 0) {\r
  49                             try {\r
  50                                 MergingDelayedWriteProcessor.this.wait(transactionKeepalivePeriod);\r
  51                             } catch (InterruptedException e) {\r
  52                                         Logger.defaultLogError(e);\r
  53                             }\r
  54                             next = queue.poll();\r
  55                         }\r
  56                         if(next == null) {\r
  57                             hasAlreadyRequest = false;\r
  58 //                            System.out.println("MergedWrite ends");\r
  59                             return;\r
  60                         }\r
  61                     }\r
  62                 }\r
  63 \r
  64 //                System.out.println("MergedWrite executes " + next);\r
  65                 try {\r
  66                     next.perform(graph);\r
  67                 } catch(Throwable t) {\r
  68                         Logger.defaultLogError(t);\r
  69                 }\r
  70 \r
  71             }\r
  72 \r
  73         }\r
  74 \r
  75     }\r
  76 \r
  77     @Override\r
  78     public void asyncRequest(DelayedWrite request) {\r
  79         \r
  80         queue.add(request);\r
  81 \r
  82         synchronized (this) {\r
  83         \r
  84           if (!hasAlreadyRequest) {\r
  85               processor.asyncRequest(new MergedWrite());\r
  86               hasAlreadyRequest = true;\r
  87           } else {\r
  88               notify();\r
  89           }\r
  90           \r
  91         }\r
  92 \r
  93     }\r
  94 \r
  95     @Override\r
  96     public String toString() {\r
  97         return "MergingDelayedWriteProcessor@" + System.identityHashCode(this) + " (based on " + processor + ")";\r
  98     }\r
  99 \r
 100 }\r