bundles/org.simantics.mapping/src/org/simantics/mapping/constraint/instructions/BinaryPredicateObjectQuery.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.common.utils.NameUtils;\r
  22 import org.simantics.db.exception.DatabaseException;\r
  23 import org.simantics.layer0.utils.binaryPredicates.IBinaryPredicate;\r
  24 \r
  25 public class BinaryPredicateObjectQuery extends BinaryPredicateInstruction {\r
  26         \r
  27         public BinaryPredicateObjectQuery(int variable0, int variable1,\r
  28                         IBinaryPredicate predicate) {\r
  29                 super(variable0, variable1, predicate);\r
  30         }\r
  31 \r
  32         @Override\r
  33         public Object query(ReadGraph g, Object[] bindings) throws DatabaseException {          \r
  34                 Resource r0 = (Resource)bindings[variable0];\r
  35 //              ITask task = ThreadLogger.getInstance().begin("g");\r
  36                 Collection<Resource> result = predicate.getObjects(g, r0);\r
  37                 if(DEBUG) {\r
  38                 System.out.println("getObjects(" +\r
  39                         NameUtils.getSafeName(g, r0) + ", " +\r
  40                         predicate.toString(g) + ") returned " + result.size() + " objects"                      \r
  41                         );\r
  42                 }\r
  43 //              task.finish();\r
  44                 if(result.isEmpty())\r
  45                         return IInstruction.FAILURE;\r
  46                 Iterator<Resource> it = result.iterator();\r
  47                 bindings[variable1] = it.next();\r
  48                 if(it.hasNext())\r
  49                         return it;\r
  50                 else\r
  51                         return null;\r
  52         }\r
  53         \r
  54         @SuppressWarnings("unchecked")\r
  55         @Override\r
  56         public Object next(ReadGraph g, Object[] bindings, Object continuation) {\r
  57                 Iterator<Resource> it = (Iterator<Resource>)continuation;\r
  58                 if(it.hasNext()) {\r
  59                         bindings[variable1] = it.next();\r
  60                         if(it.hasNext())\r
  61                                 return it;\r
  62                         else\r
  63                                 return null;\r
  64                 }\r
  65                 else\r
  66                         return IInstruction.FAILURE;\r
  67         }       \r
  68         \r
  69         @Override\r
  70         public void collectVariables(TIntHashSet reads, TIntHashSet writes) {\r
  71                 super.collectVariables(reads, writes);\r
  72                 writes.add(variable1);\r
  73         }\r
  74 \r
  75 }\r