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

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2013 Association for Decentralized Information Management\r
   3  * in Industry THTH ry.\r
   4  * All rights reserved. This program and the accompanying materials\r
   5  * are made available under the terms of the Eclipse Public License v1.0\r
   6  * which accompanies this distribution, and is available at\r
   7  * http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  * Contributors:\r
  10  *     VTT Technical Research Centre of Finland - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics.objmap.graph.rules.domain;\r
  13 \r
  14 import org.apache.log4j.Logger;\r
  15 import org.simantics.db.ReadGraph;\r
  16 import org.simantics.db.Resource;\r
  17 import org.simantics.db.WriteGraph;\r
  18 import org.simantics.db.exception.DatabaseException;\r
  19 import org.simantics.objmap.exceptions.MappingException;\r
  20 \r
  21 /**\r
  22  * Accesses a resource attached to the element by given functional relation.\r
  23  * @author Hannu Niemistö\r
  24  */\r
  25 public class RelatedObjectAccessor implements IDomainAccessor<Resource,Resource> {\r
  26 \r
  27     static Logger LOGGER = Logger.getLogger("org.simantics.objmap");\r
  28     \r
  29         Resource relation;\r
  30         \r
  31         public RelatedObjectAccessor(Resource relation) {\r
  32                 this.relation = relation;\r
  33         }\r
  34 \r
  35         @Override\r
  36         public Resource get(ReadGraph g, Resource element) throws MappingException {\r
  37                 try {\r
  38                     LOGGER.info("        RelatedObjectAccessor.get");\r
  39                         return g.getPossibleObject(element, relation);\r
  40                 } catch (DatabaseException e) {\r
  41                         throw new MappingException(e);\r
  42                 }\r
  43         }\r
  44         \r
  45         @Override\r
  46         public boolean set(WriteGraph g, Resource element, Resource value)\r
  47                         throws MappingException {\r
  48                 try {\r
  49                     LOGGER.info("        RelatedObjectAccessor.set");\r
  50                     Resource resource = g.getPossibleObject(element, relation);\r
  51                         if(resource == null) {\r
  52                             if(value == null)\r
  53                                 return false;\r
  54                             g.claim(element, relation, value);\r
  55                             return true;\r
  56                         }\r
  57                         else if(resource.equals(value))\r
  58                             return false;\r
  59                         else {\r
  60                             g.deny(element, relation);\r
  61                             if(value != null)\r
  62                                 g.claim(element, relation, value);\r
  63                             return true;\r
  64                         }\r
  65                 } catch (DatabaseException e) {\r
  66                         throw new MappingException(e);\r
  67                 }\r
  68                 \r
  69         }\r
  70 \r
  71 }\r