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1   /*
2    * Copyright 2002-2006 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  
17  package org.apache.commons.jexl.parser;
18  
19  import org.apache.commons.jexl.JexlContext;
20  
21  /***
22   * x = y, assigns a value to a variable in the context.
23   * 
24   * @author Dion Gillard
25   * 
26   */
27  public class ASTAssignment extends SimpleNode {
28      /***
29       * Create the node given an id.
30       * 
31       * @param id node id.
32       */
33      public ASTAssignment(int id) {
34          super(id);
35      }
36  
37      /***
38       * Create a node with the given parser and id.
39       * 
40       * @param p a parser.
41       * @param id node id.
42       */
43      public ASTAssignment(Parser p, int id) {
44          super(p, id);
45      }
46  
47      /*** {@inheritDoc} */
48      public Object jjtAccept(ParserVisitor visitor, Object data) {
49          return visitor.visit(this, data);
50      }
51  
52      /*** {@inheritDoc} */
53      public Object value(JexlContext context) throws Exception {
54          // left should be the variable (reference) to assign to
55          SimpleNode left = (SimpleNode) jjtGetChild(0);
56          // right should be the expression to evaluate
57          Object right = ((SimpleNode) jjtGetChild(1)).value(context);
58          if (left instanceof ASTReference) {
59              ASTReference reference = (ASTReference) left;
60              left = (SimpleNode) reference.jjtGetChild(0);
61              if (left instanceof ASTIdentifier) {
62                  String identifier = ((ASTIdentifier) left)
63                          .getIdentifierString();
64                  context.getVars().put(identifier, right);
65              }
66          }
67          return right;
68      }
69  }