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.slf4j.Logger;
  15 import org.slf4j.LoggerFactory;
  16 import org.simantics.db.ReadGraph;
  17 import org.simantics.db.Resource;
  18 import org.simantics.db.WriteGraph;
  19 import org.simantics.db.exception.DatabaseException;
  20 import org.simantics.objmap.exceptions.MappingException;
  21
  22 /**
  23  * Accesses a resource attached to the element by given functional relation.
  24  * @author Hannu Niemistö
  25  */
  26 public class RelatedObjectAccessor implements IDomainAccessor<Resource,Resource> {
  27
  28     static Logger LOGGER = LoggerFactory.getLogger(RelatedObjectAccessor.class);
  29
  30         Resource relation;
  31
  32         public RelatedObjectAccessor(Resource relation) {
  33                 this.relation = relation;
  34         }
  35
  36         @Override
  37         public Resource get(ReadGraph g, Resource element) throws MappingException {
  38                 try {
  39                     LOGGER.info("        RelatedObjectAccessor.get");
  40                         return g.getPossibleObject(element, relation);
  41                 } catch (DatabaseException e) {
  42                         throw new MappingException(e);
  43                 }
  44         }
  45
  46         @Override
  47         public boolean set(WriteGraph g, Resource element, Resource value)
  48                         throws MappingException {
  49                 try {
  50                     LOGGER.info("        RelatedObjectAccessor.set");
  51                     Resource resource = g.getPossibleObject(element, relation);
  52                         if(resource == null) {
  53                             if(value == null)
  54                                 return false;
  55                             g.claim(element, relation, value);
  56                             return true;
  57                         }
  58                         else if(resource.equals(value))
  59                             return false;
  60                         else {
  61                             g.deny(element, relation);
  62                             if(value != null)
  63                                 g.claim(element, relation, value);
  64                             return true;
  65                         }
  66                 } catch (DatabaseException e) {
  67                         throw new MappingException(e);
  68                 }
  69
  70         }
  71
  72 }