bundles/org.simantics.db.common/src/org/simantics/db/common/procedure/single/SingleSetSyncListener.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;\r
  13 \r
  14 import java.util.Collection;\r
  15 import java.util.HashSet;\r
  16 \r
  17 import org.simantics.db.AsyncReadGraph;\r
  18 import org.simantics.db.ReadGraph;\r
  19 import org.simantics.db.common.request.ReadRequest;\r
  20 import org.simantics.db.common.utils.Logger;\r
  21 import org.simantics.db.exception.DatabaseException;\r
  22 import org.simantics.db.procedure.AsyncListener;\r
  23 import org.simantics.db.procedure.AsyncProcedure;\r
  24 \r
  25 abstract public class SingleSetSyncListener<T> implements AsyncListener<Collection<T>>{\r
  26     \r
  27     private Collection<T> previous = null;\r
  28     \r
  29     /**\r
  30      * @param graph\r
  31      * @return <code>true</code> to continue, <code>false</code> to end processing here\r
  32      * @throws DatabaseException\r
  33      */\r
  34     public boolean start(ReadGraph graph) throws DatabaseException { return true; }\r
  35     public void add(ReadGraph graph, T item) throws DatabaseException {}\r
  36     public void remove(ReadGraph graph,T item) throws DatabaseException {}\r
  37     public void finished(ReadGraph graph) throws DatabaseException {}\r
  38 \r
  39     public void exception(ReadGraph graph, Throwable t) throws DatabaseException {\r
  40                 Logger.defaultLogError(t);\r
  41     }\r
  42     \r
  43     @Override\r
  44     final public void execute(AsyncReadGraph graph, final Collection<T> result) {\r
  45         \r
  46         if(result == null) {\r
  47                 Logger.defaultLogError("SingleSetSyncListener does not accept null result.");\r
  48                 return;\r
  49         }\r
  50         \r
  51         graph.asyncRequest(new ReadRequest() {\r
  52 \r
  53                         @Override\r
  54                         public void run(ReadGraph graph) throws DatabaseException {\r
  55 \r
  56                                 if (!start(graph))\r
  57                                         return;\r
  58 \r
  59                                 if(previous == null) {\r
  60 \r
  61                                         for(T t : result) add(graph, t);\r
  62 \r
  63                                 } else {\r
  64 \r
  65                                         HashSet<T> added = new HashSet<T>(result);\r
  66                                         added.removeAll(previous);\r
  67                                         HashSet<T> removed = new HashSet<T>(previous);\r
  68                                         removed.removeAll(result);\r
  69 \r
  70                                         for(T t : added) add(graph, t);\r
  71                                         for(T t : removed) remove(graph, t);\r
  72 \r
  73                                 }\r
  74 \r
  75                                 finished(graph);\r
  76 \r
  77                                 previous = result;\r
  78                                 \r
  79                         }\r
  80                 \r
  81         }, new AsyncProcedure<Object>() {\r
  82 \r
  83                         @Override\r
  84                         public void exception(AsyncReadGraph graph, Throwable t) {\r
  85                         Logger.defaultLogError(t);\r
  86                         }\r
  87 \r
  88             @Override\r
  89             public void execute(AsyncReadGraph graph, Object result) {\r
  90             }\r
  91                 \r
  92         });\r
  93         \r
  94     }\r
  95     \r
  96     @Override\r
  97     final public void exception(AsyncReadGraph graph, final Throwable throwable) {\r
  98         graph.asyncRequest(new ReadRequest() {\r
  99 \r
 100             @Override\r
 101             public void run(ReadGraph graph) throws DatabaseException {\r
 102                 exception((ReadGraph)graph, throwable);\r
 103             }\r
 104 \r
 105         });\r
 106     }\r
 107         \r
 108 }\r