bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/request/PossibleVariableIndexRoot.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.layer0.request;
  13
  14 import org.simantics.db.ReadGraph;
  15 import org.simantics.db.Resource;
  16 import org.simantics.db.exception.DatabaseException;
  17 import org.simantics.db.layer0.variable.Variable;
  18 import org.simantics.layer0.Layer0;
  19
  20 public class PossibleVariableIndexRoot extends VariableRead<Resource> {
  21
  22     public PossibleVariableIndexRoot(Variable variable) {
  23         super(variable);
  24     }
  25
  26     @Override
  27     public Resource perform(ReadGraph graph) throws DatabaseException {
  28
  29         Layer0 L0 = Layer0.getInstance(graph);
  30
  31         Resource represents = variable.getPossibleRepresents(graph);
  32         if(represents != null) {
  33                 if(graph.isInstanceOf(represents, L0.IndexRoot)) return represents;
  34                 if(graph.getRootLibrary().equals(represents)) return null;
  35         }
  36
  37         return graph.syncRequest(new PossibleVariableIndexRoot(variable.getParent(graph)));
  38
  39     }
  40
  41 }