View Javadoc

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   * Simple identifier - $foo or $foo.bar (both parts are identifiers).
23   * 
24   * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
25   * @version $Id: ASTIdentifier.java 398199 2006-04-29 16:30:05Z dion $
26   */
27  public class ASTIdentifier extends SimpleNode {
28      /*** the name of the variable. */
29      protected String val;
30  
31      /***
32       * Create the node given an id.
33       * 
34       * @param id node id.
35       */
36      public ASTIdentifier(int id) {
37          super(id);
38      }
39  
40      /***
41       * Create a node with the given parser and id.
42       * 
43       * @param p a parser.
44       * @param id node id.
45       */
46      public ASTIdentifier(Parser p, int id) {
47          super(p, id);
48      }
49  
50      /*** {@inheritDoc} */
51      public Object jjtAccept(ParserVisitor visitor, Object data) {
52          return visitor.visit(this, data);
53      }
54  
55      /*** {@inheritDoc} */
56      public Object value(JexlContext jc) throws Exception {
57          return jc.getVars().get(val);
58      }
59  
60      /***
61       * returns the value of itself applied to the object. We assume that an
62       * identifier can be gotten via a get(String).
63       * e.g. if we have bean.property, 'property' has been parsed as an identifier,
64       * and we need to resolve the expression by calling the property getter.
65       * 
66       * @param obj the object to evaluate against.
67       * @param jc the {@link JexlContext}.
68       * @throws Exception on any error.
69       * @return the resulting value.
70       * @see ASTArrayAccess#evaluateExpr(Object, Object)
71       */
72      public Object execute(Object obj, JexlContext jc) throws Exception {
73          return ASTArrayAccess.evaluateExpr(obj, val);
74      }
75  
76      /*** 
77       * Gets the name of the variable.
78       * @return the variable name.
79       */
80      public String getIdentifierString() {
81          return val;
82      }
83  }