bundles/org.simantics.mapping/src/org/simantics/mapping/constraint/instructions/BinaryPredicateObjectQuery.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.mapping.constraint.instructions;
  13
  14 import gnu.trove.set.hash.TIntHashSet;
  15
  16 import java.util.Collection;
  17 import java.util.Iterator;
  18
  19 import org.simantics.db.ReadGraph;
  20 import org.simantics.db.Resource;
  21 import org.simantics.db.common.utils.NameUtils;
  22 import org.simantics.db.exception.DatabaseException;
  23 import org.simantics.layer0.utils.binaryPredicates.IBinaryPredicate;
  24
  25 public class BinaryPredicateObjectQuery extends BinaryPredicateInstruction {
  26
  27         public BinaryPredicateObjectQuery(int variable0, int variable1,
  28                         IBinaryPredicate predicate) {
  29                 super(variable0, variable1, predicate);
  30         }
  31
  32         @Override
  33         public Object query(ReadGraph g, Object[] bindings) throws DatabaseException {
  34                 Resource r0 = (Resource)bindings[variable0];
  35 //              ITask task = ThreadLogger.getInstance().begin("g");
  36                 Collection<Resource> result = predicate.getObjects(g, r0);
  37                 if(DEBUG) {
  38                 System.out.println("getObjects(" +
  39                         NameUtils.getSafeName(g, r0) + ", " +
  40                         predicate.toString(g) + ") returned " + result.size() + " objects"
  41                         );
  42                 }
  43 //              task.finish();
  44                 if(result.isEmpty())
  45                         return IInstruction.FAILURE;
  46                 Iterator<Resource> it = result.iterator();
  47                 bindings[variable1] = it.next();
  48                 if(it.hasNext())
  49                         return it;
  50                 else
  51                         return null;
  52         }
  53
  54         @SuppressWarnings("unchecked")
  55         @Override
  56         public Object next(ReadGraph g, Object[] bindings, Object continuation) {
  57                 Iterator<Resource> it = (Iterator<Resource>)continuation;
  58                 if(it.hasNext()) {
  59                         bindings[variable1] = it.next();
  60                         if(it.hasNext())
  61                                 return it;
  62                         else
  63                                 return null;
  64                 }
  65                 else
  66                         return IInstruction.FAILURE;
  67         }
  68
  69         @Override
  70         public void collectVariables(TIntHashSet reads, TIntHashSet writes) {
  71                 super.collectVariables(reads, writes);
  72                 writes.add(variable1);
  73         }
  74
  75 }