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Java > Open Source Codes > com > sun > facelets > el > VariableMapperWrapper


1 /**
2  * Licensed under the Common Development and Distribution License,
3  * you may not use this file except in compliance with the License.
4  * You may obtain a copy of the License at
5  *
6  * http://www.sun.com/cddl/
7  *
8  * Unless required by applicable law or agreed to in writing, software
9  * distributed under the License is distributed on an "AS IS" BASIS,
10  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
11  * implied. See the License for the specific language governing
12  * permissions and limitations under the License.
13  */
14
15 package com.sun.facelets.el;
16
17 import java.util.HashMap JavaDoc;
18 import java.util.Map JavaDoc;
19
20 import javax.el.ValueExpression;
21 import javax.el.VariableMapper;
22
23 /**
24  * Utility class for wrapping another VariableMapper with a new context,
25  * represented by a {@link java.util.Map Map}. Modifications occur to the
26  * Map instance, but resolve against the wrapped
27  * VariableMapper if the Map doesn't contain the ValueExpression requested.
28  *
29  * @author Jacob Hookom
30  * @version $Id: VariableMapperWrapper.java,v 1.2 2005/08/24 04:38:57 jhook Exp $
31  */
32 public final class VariableMapperWrapper extends VariableMapper {
33
34     private final VariableMapper target;
35
36     private Map JavaDoc vars;
37
38     /**
39      *
40      */
41     public VariableMapperWrapper(VariableMapper orig) {
42         super();
43         this.target = orig;
44     }
45
46     /**
47      * First tries to resolve agains the inner Map, then the wrapped
48      * ValueExpression.
49      *
50      * @see javax.el.VariableMapper#resolveVariable(java.lang.String)
51      */
52     public ValueExpression resolveVariable(String JavaDoc variable) {
53         ValueExpression ve = null;
54         if (this.vars != null) {
55             ve = (ValueExpression) this.vars.get(variable);
56         }
57         if (ve == null) {
58             return this.target.resolveVariable(variable);
59         }
60         return ve;
61     }
62
63     /**
64      * Set the ValueExpression on the inner Map instance.
65      *
66      * @see javax.el.VariableMapper#setVariable(java.lang.String,
67      * javax.el.ValueExpression)
68      */
69     public ValueExpression setVariable(String JavaDoc variable,
70             ValueExpression expression) {
71         if (this.vars == null) {
72             this.vars = new HashMap JavaDoc();
73         }
74         return (ValueExpression) this.vars.put(variable, expression);
75     }
76 }
77
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