bundles/org.simantics.mapping/src/org/simantics/mapping/constraint/instructions/TripletObjectQuery.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.mapping.constraint.instructions;\r
  13 \r
  14 import gnu.trove.set.hash.TIntHashSet;\r
  15 \r
  16 import java.util.Collection;\r
  17 import java.util.Iterator;\r
  18 \r
  19 import org.simantics.db.ReadGraph;\r
  20 import org.simantics.db.Resource;\r
  21 import org.simantics.db.exception.DatabaseException;\r
  22 \r
  23 public class TripletObjectQuery extends TripletInstruction {\r
  24 \r
  25         public TripletObjectQuery(int variable0, int variable1, int variable2) {\r
  26                 super(variable0, variable1, variable2); \r
  27         }\r
  28         \r
  29         @Override\r
  30         public Object query(ReadGraph g, Object[] bindings) throws DatabaseException {\r
  31                 Resource r0 = (Resource)bindings[variable0];\r
  32                 Resource r1 = (Resource)bindings[variable1];\r
  33                 Collection<Resource> result = g.getObjects(r0, r1);\r
  34                 if(result.isEmpty())\r
  35                         return IInstruction.FAILURE;\r
  36                 Iterator<Resource> it = result.iterator();\r
  37                 bindings[variable2] = it.next();\r
  38                 if(it.hasNext())\r
  39                         return it;\r
  40                 else\r
  41                         return null;\r
  42         }\r
  43         \r
  44         @SuppressWarnings("unchecked")\r
  45         @Override\r
  46         public Object next(ReadGraph g, Object[] bindings, Object continuation) {\r
  47                 Iterator<Resource> it = (Iterator<Resource>)continuation;\r
  48                 if(it.hasNext()) {\r
  49                         bindings[variable2] = it.next();\r
  50                         if(it.hasNext())\r
  51                                 return it;\r
  52                         else\r
  53                                 return null;\r
  54                 }\r
  55                 else\r
  56                         return IInstruction.FAILURE;\r
  57         }       \r
  58         \r
  59         @Override\r
  60         public void collectVariables(TIntHashSet reads, TIntHashSet writes) {           \r
  61                 super.collectVariables(reads, writes);\r
  62                 writes.add(variable2);\r
  63         }\r
  64 \r
  65 }\r