bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/request/VariableIndexRoot.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.common.request.UnaryRead;
  17 import org.simantics.db.exception.DatabaseException;
  18 import org.simantics.db.layer0.variable.Variable;
  19 import org.simantics.layer0.Layer0;
  20
  21 public class VariableIndexRoot extends UnaryRead<Variable, Resource> {
  22
  23     public VariableIndexRoot(Variable variable) {
  24         super(variable);
  25     }
  26
  27     @Override
  28     public Resource perform(ReadGraph graph) throws DatabaseException {
  29
  30         Layer0 L0 = Layer0.getInstance(graph);
  31         Resource r = parameter.getPossibleRepresents(graph);
  32         if(r != null) {
  33                 if(graph.isInstanceOf(r, L0.IndexRoot)) return r;
  34         }
  35
  36         Variable parent = parameter.getParent(graph);
  37         if(parent != null) return graph.sync(new VariableIndexRoot(parent));
  38         else return null;
  39
  40     }
  41
  42 }