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Java > Open Source Codes > org > apache > strutsel > taglib > bean > ELResourceTag


1 /*
2  * $Id: ELResourceTag.java 54933 2004-10-16 17:04:52Z germuska $
3  *
4  * Copyright 1999-2004 The Apache Software Foundation.
5  *
6  * Licensed under the Apache License, Version 2.0 (the "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18
19 package org.apache.strutsel.taglib.bean;
20
21 import org.apache.struts.taglib.bean.ResourceTag;
22 import javax.servlet.jsp.JspException JavaDoc;
23 import org.apache.strutsel.taglib.utils.EvalHelper;
24
25 /**
26  * Define a scripting variable based on the contents of the specified
27  * web application resource.
28  *<p>
29  * This class is a subclass of the class
30  * <code>org.apache.struts.taglib.bean.ResourceTag</code> which provides most of
31  * the described functionality. This subclass allows all attribute values to
32  * be specified as expressions utilizing the JavaServer Pages Standard Library
33  * expression language.
34  *
35  * @version $Rev: 54933 $
36  */
37 public class ELResourceTag extends ResourceTag {
38
39     /**
40      * Instance variable mapped to "id" tag attribute.
41      * (Mapping set in associated BeanInfo class.)
42      */
43     private String JavaDoc idExpr;
44     /**
45      * Instance variable mapped to "input" tag attribute.
46      * (Mapping set in associated BeanInfo class.)
47      */
48     private String JavaDoc inputExpr;
49     /**
50      * Instance variable mapped to "name" tag attribute.
51      * (Mapping set in associated BeanInfo class.)
52      */
53     private String JavaDoc nameExpr;
54
55     /**
56      * Getter method for "id" tag attribute.
57      * (Mapping set in associated BeanInfo class.)
58      */
59     public String JavaDoc getIdExpr() { return (idExpr); }
60     /**
61      * Getter method for "input" tag attribute.
62      * (Mapping set in associated BeanInfo class.)
63      */
64     public String JavaDoc getInputExpr() { return (inputExpr); }
65     /**
66      * Getter method for "name" tag attribute.
67      * (Mapping set in associated BeanInfo class.)
68      */
69     public String JavaDoc getNameExpr() { return (nameExpr); }
70
71     /**
72      * Setter method for "id" tag attribute.
73      * (Mapping set in associated BeanInfo class.)
74      */
75     public void setIdExpr(String JavaDoc idExpr) { this.idExpr = idExpr; }
76     /**
77      * Setter method for "input" tag attribute.
78      * (Mapping set in associated BeanInfo class.)
79      */
80     public void setInputExpr(String JavaDoc inputExpr) { this.inputExpr = inputExpr; }
81     /**
82      * Setter method for "name" tag attribute.
83      * (Mapping set in associated BeanInfo class.)
84      */
85     public void setNameExpr(String JavaDoc nameExpr) { this.nameExpr = nameExpr; }
86
87     /**
88      * Resets attribute values for tag reuse.
89      */
90     public void release()
91     {
92         super.release();
93         setIdExpr(null);
94         setInputExpr(null);
95         setNameExpr(null);
96     }
97     
98     /**
99      * Process the start tag.
100      *
101      * @exception JspException if a JSP exception has occurred
102      */
103     public int doStartTag() throws JspException JavaDoc {
104         evaluateExpressions();
105         return (super.doStartTag());
106     }
107
108     /**
109      * Processes all attribute values which use the JSTL expression evaluation
110      * engine to determine their values.
111      *
112      * @exception JspException if a JSP exception has occurred
113      */
114     private void evaluateExpressions() throws JspException JavaDoc {
115         String JavaDoc string = null;
116
117         if ((string = EvalHelper.evalString("id", getIdExpr(),
118                                             this, pageContext)) != null)
119             setId(string);
120
121         if ((string = EvalHelper.evalString("input", getInputExpr(),
122                                             this, pageContext)) != null)
123             setInput(string);
124
125         if ((string = EvalHelper.evalString("name", getNameExpr(),
126                                             this, pageContext)) != null)
127             setName(string);
128     }
129 }
130
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