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Java > Open Source Codes > org > apache > jasper > runtime > VariableMapperImpl


1 /*
2  * The contents of this file are subject to the terms
3  * of the Common Development and Distribution License
4  * (the "License"). You may not use this file except
5  * in compliance with the License.
6  *
7  * You can obtain a copy of the license at
8  * glassfish/bootstrap/legal/CDDLv1.0.txt or
9  * https://glassfish.dev.java.net/public/CDDLv1.0.html.
10  * See the License for the specific language governing
11  * permissions and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL
14  * HEADER in each file and include the License file at
15  * glassfish/bootstrap/legal/CDDLv1.0.txt. If applicable,
16  * add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your
18  * own identifying information: Portions Copyright [yyyy]
19  * [name of copyright owner]
20  *
21  * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
22  *
23  * Portions Copyright Apache Software Foundation.
24  */
25
26 package org.apache.jasper.runtime;
27
28 import java.util.HashMap JavaDoc;
29 import javax.el.ELContext;
30 import javax.el.ELResolver;
31 import javax.el.VariableMapper;
32 import javax.el.ValueExpression;
33
34
35 /**
36  * <p>This is the implementation of VariableMapper.
37  * The compiler creates an empty variable mapper when an ELContext is created.
38  * The variable mapper will be updated by tag handlers, if necessary.
39  *
40  * @author Kin-man Chung
41  * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: kchung $
42  **/
43
44 public class VariableMapperImpl extends VariableMapper
45 {
46     //-------------------------------------
47 /**
48      * Constructor
49      **/
50     public VariableMapperImpl () {
51         map = new HashMap JavaDoc();
52     }
53   
54     //-------------------------------------
55 /**
56      * Resolves the specified variable within the given context.
57      * Returns null if the variable is not found.
58      **/
59     public ValueExpression resolveVariable (String JavaDoc variable) {
60         return (ValueExpression) map.get(variable);
61     }
62
63     public ValueExpression setVariable(String JavaDoc variable,
64                                        ValueExpression expression) {
65         ValueExpression prev = null;
66         if (expression == null) {
67             map.remove(variable);
68         } else {
69             prev = (ValueExpression) map.get(variable);
70             map.put(variable, expression);
71         }
72         return prev;
73     }
74
75     private HashMap JavaDoc map;
76 }
77
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