bundles/org.simantics.objmap2/src/org/simantics/objmap/graph/rules/domain/RelatedObjectAccessor.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2013 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.objmap.graph.rules.domain;
  13
  14 import org.apache.log4j.Logger;
  15 import org.simantics.db.ReadGraph;
  16 import org.simantics.db.Resource;
  17 import org.simantics.db.WriteGraph;
  18 import org.simantics.db.exception.DatabaseException;
  19 import org.simantics.objmap.exceptions.MappingException;
  20
  21 /**
  22  * Accesses a resource attached to the element by given functional relation.
  23  * @author Hannu Niemistö
  24  */
  25 public class RelatedObjectAccessor implements IDomainAccessor<Resource,Resource> {
  26
  27     static Logger LOGGER = Logger.getLogger("org.simantics.objmap");
  28
  29         Resource relation;
  30
  31         public RelatedObjectAccessor(Resource relation) {
  32                 this.relation = relation;
  33         }
  34
  35         @Override
  36         public Resource get(ReadGraph g, Resource element) throws MappingException {
  37                 try {
  38                     LOGGER.info("        RelatedObjectAccessor.get");
  39                         return g.getPossibleObject(element, relation);
  40                 } catch (DatabaseException e) {
  41                         throw new MappingException(e);
  42                 }
  43         }
  44
  45         @Override
  46         public boolean set(WriteGraph g, Resource element, Resource value)
  47                         throws MappingException {
  48                 try {
  49                     LOGGER.info("        RelatedObjectAccessor.set");
  50                     Resource resource = g.getPossibleObject(element, relation);
  51                         if(resource == null) {
  52                             if(value == null)
  53                                 return false;
  54                             g.claim(element, relation, value);
  55                             return true;
  56                         }
  57                         else if(resource.equals(value))
  58                             return false;
  59                         else {
  60                             g.deny(element, relation);
  61                             if(value != null)
  62                                 g.claim(element, relation, value);
  63                             return true;
  64                         }
  65                 } catch (DatabaseException e) {
  66                         throw new MappingException(e);
  67                 }
  68
  69         }
  70
  71 }