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Java > Open Source Codes > org > apache > commons > jexl > parser > ASTIdentifier


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 JavaDoc 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 JavaDoc jjtAccept(ParserVisitor visitor, Object JavaDoc data) {
52         return visitor.visit(this, data);
53     }
54
55     /** {@inheritDoc} */
56     public Object JavaDoc value(JexlContext jc) throws Exception JavaDoc {
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 JavaDoc execute(Object JavaDoc obj, JexlContext jc) throws Exception JavaDoc {
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 JavaDoc getIdentifierString() {
81         return val;
82     }
83 }
84
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