bundles/org.simantics.r.scl/src/org/simantics/r/scl/variable/RListItemNode.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2014, 2016 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.r.scl.variable;\r
  13 \r
  14 import org.rosuda.REngine.REXP;\r
  15 import org.rosuda.REngine.REXPMismatchException;\r
  16 import org.rosuda.REngine.RList;\r
  17 \r
  18 public class RListItemNode implements RVariableNode {\r
  19 \r
  20         private RVariableNode parent;\r
  21         private int index;\r
  22         \r
  23         public RListItemNode(RVariableNode parent, int index) {\r
  24                 this.index = index;\r
  25                 this.parent = parent;\r
  26         }\r
  27 \r
  28         @Override\r
  29         public REXP getValue() {\r
  30                 REXP parentValue = parent.getValue();\r
  31                 if (parentValue == null || ! parentValue.isList())\r
  32                         return null;\r
  33                 \r
  34                 RList list;\r
  35                 try {\r
  36                         list = parentValue.asList();\r
  37                 } catch (REXPMismatchException e) {\r
  38                         // Should never happen\r
  39                         return null;\r
  40                 }\r
  41                 \r
  42                 return list.at(index);\r
  43         }\r
  44 \r
  45         @Override\r
  46         public String getName() {\r
  47                 return RNodeManager.INDEXED_ITEM_NAME_PREFIX + Integer.toString(index);\r
  48         }\r
  49 \r
  50         @Override\r
  51         public RVariableNode getParent() {\r
  52                 return parent;\r
  53         }\r
  54 }\r