bundles/org.simantics.mapping/src/org/simantics/mapping/constraint/instructions/TripletPredicateObjectQuery.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.Statement;
  22 import org.simantics.db.exception.DatabaseException;
  23 import org.simantics.layer0.Layer0;
  24
  25 public class TripletPredicateObjectQuery extends TripletInstruction {
  26
  27         Resource predicate;
  28
  29         public TripletPredicateObjectQuery(int variable0, int variable1, int variable2,
  30                         Resource predicate) {
  31                 super(variable0, variable1, variable2);
  32                 this.predicate = predicate;
  33         }
  34
  35         public TripletPredicateObjectQuery(int variable0, int variable1, int variable2) {
  36                 this(variable0, variable1, variable2, null);
  37         }
  38
  39         @Override
  40         public Object query(ReadGraph g, Object[] bindings) throws DatabaseException {
  41                 Resource r0 = (Resource)bindings[variable0];
  42 //              ITask task = ThreadLogger.getInstance().begin("g");
  43                 Collection<Statement> result =
  44                         predicate == null
  45                         ? g.getStatements(r0, Layer0.getInstance(g).IsWeaklyRelatedTo)
  46                                 : g.getStatements(r0, predicate);
  47 //              task.finish();
  48                 if(result.isEmpty())
  49                         return IInstruction.FAILURE;
  50                 Iterator<Statement> it = result.iterator();
  51                 Statement stat = it.next();
  52                 bindings[variable1] = stat.getPredicate();
  53                 bindings[variable2] = stat.getObject();
  54                 if(it.hasNext())
  55                         return it;
  56                 else
  57                         return null;
  58         }
  59
  60         @SuppressWarnings("unchecked")
  61         @Override
  62         public Object next(ReadGraph g, Object[] bindings, Object continuation) {
  63                 Iterator<Statement> it = (Iterator<Statement>)continuation;
  64                 if(it.hasNext()) {
  65                         Statement stat = it.next();
  66                         bindings[variable1] = stat.getPredicate();
  67                         bindings[variable2] = stat.getObject();
  68                         if(it.hasNext())
  69                                 return it;
  70                         else
  71                                 return null;
  72                 }
  73                 else
  74                         return IInstruction.FAILURE;
  75         }
  76
  77         @Override
  78         public void collectVariables(TIntHashSet reads, TIntHashSet writes) {
  79                 super.collectVariables(reads, writes);
  80                 writes.add(variable1);
  81                 writes.add(variable2);
  82         }
  83
  84 }