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1   /*
2    * Copyright 2002,2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.jexl.parser;
17  
18  import org.apache.commons.jexl.JexlContext;
19  
20  /***
21   *  reference - any variable expression
22   *
23   *  @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
24   *  @version $Id: ASTReference.java,v 1.3 2004/02/28 13:45:20 yoavs Exp $
25   */
26  public class ASTReference extends SimpleNode
27  {
28      SimpleNode root;
29  
30      public ASTReference(int id)
31      {
32          super(id);
33      }
34  
35      public ASTReference(Parser p, int id)
36      {
37          super(p, id);
38      }
39  
40  
41      /*** Accept the visitor. **/
42      public Object jjtAccept(ParserVisitor visitor, Object data)
43      {
44          return visitor.visit(this, data);
45      }
46  
47      public Object value(JexlContext jc)
48          throws Exception
49      {
50          return  execute(null,jc);
51      }
52  
53      public void jjtClose()
54      {
55          root = (SimpleNode) jjtGetChild(0);
56      }
57  
58      public Object execute(Object obj, JexlContext jc)
59               throws Exception
60       {
61           Object o = root.value(jc);
62  
63           /*
64            * ignore the first child - it's our identifier
65            */
66           for(int i=1; i<jjtGetNumChildren(); i++)
67           {
68               o = ( (SimpleNode) jjtGetChild(i)).execute(o,jc);
69  
70               if(o==null)
71                   return null;
72           }
73  
74           return o;
75       }
76  
77      public String getRootString()
78          throws Exception
79      {
80          if ( root instanceof ASTIdentifier)
81              return ((ASTIdentifier) root).getIdentifierString();
82  
83          if (root instanceof ASTArrayAccess)
84              return ((ASTArrayAccess) root).getIdentifierString();
85  
86          throw new Exception("programmer error : ASTReference : root not known"
87                      + root );
88      }
89  }