bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/request/PossibleVariableIndexRoot.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2010 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.db.layer0.request;\r
  13 \r
  14 import org.simantics.db.ReadGraph;\r
  15 import org.simantics.db.Resource;\r
  16 import org.simantics.db.exception.DatabaseException;\r
  17 import org.simantics.db.layer0.variable.Variable;\r
  18 import org.simantics.layer0.Layer0;\r
  19 \r
  20 public class PossibleVariableIndexRoot extends VariableRead<Resource> {\r
  21 \r
  22     public PossibleVariableIndexRoot(Variable variable) {\r
  23         super(variable);\r
  24     }\r
  25 \r
  26     @Override\r
  27     public Resource perform(ReadGraph graph) throws DatabaseException {\r
  28 \r
  29         Layer0 L0 = Layer0.getInstance(graph);\r
  30         \r
  31         Resource represents = variable.getPossibleRepresents(graph);\r
  32         if(represents != null) {\r
  33                 if(graph.isInstanceOf(represents, L0.IndexRoot)) return represents;\r
  34                 if(graph.getRootLibrary().equals(represents)) return null;\r
  35         }\r
  36         \r
  37         return graph.syncRequest(new PossibleVariableIndexRoot(variable.getParent(graph)));\r
  38 \r
  39     }\r
  40 \r
  41 }\r