bundles/org.simantics.db.common/src/org/simantics/db/common/request/PossibleIndexRoot.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.db.common.request;
  13
  14 import java.util.Collection;
  15 import java.util.HashSet;
  16
  17 import org.simantics.db.ReadGraph;
  18 import org.simantics.db.Resource;
  19 import org.simantics.db.exception.DatabaseException;
  20 import org.simantics.layer0.Layer0;
  21
  22 public class PossibleIndexRoot extends ResourceRead<Resource> {
  23
  24     public PossibleIndexRoot(Resource resource) {
  25         super(resource);
  26     }
  27
  28     @Override
  29     public Resource perform(ReadGraph graph) throws DatabaseException {
  30
  31         Layer0 L0 = Layer0.getInstance(graph);
  32
  33         if (graph.isInstanceOf(resource, L0.IndexRoot))
  34             return resource;
  35
  36         Collection<Resource> parents = new HashSet<Resource>(graph.getObjects(resource, L0.IsOwnedBy));
  37         Resource parent = parents.size() == 1 ? parents.iterator().next() : null;
  38
  39         // What is this?
  40         if(resource.equals(parent))
  41                 parent = null;
  42
  43         if (parent == null) {
  44
  45                 if(parents.size() > 1) {
  46                         // Maybe we have a case where there is ConsistsOf and HasProperty that is incorrectly classified as IsComposedOf
  47                         parent = graph.getPossibleObject(resource, L0.PartOf);
  48                 }
  49
  50                 // Assertion object?
  51                 if(parent == null)
  52                         parent = graph.getPossibleObject(resource, L0.HasObjectInverse);
  53
  54                 if(parent == null) return null;
  55
  56         }
  57
  58         return graph.syncRequest(new PossibleIndexRoot(parent));
  59
  60     }
  61
  62 }