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1   /*
2    * $Id: ELResourceTag.java 471754 2006-11-06 14:55:09Z husted $
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  package org.apache.strutsel.taglib.bean;
22  
23  import org.apache.struts.taglib.bean.ResourceTag;
24  import org.apache.strutsel.taglib.utils.EvalHelper;
25  
26  import javax.servlet.jsp.JspException;
27  
28  /**
29   * Define a scripting variable based on the contents of the specified web
30   * application resource. <p> This class is a subclass of the class
31   * <code>org.apache.struts.taglib.bean.ResourceTag</code> which provides most
32   * of the described functionality.  This subclass allows all attribute values
33   * to be specified as expressions utilizing the JavaServer Pages Standard
34   * Library expression language.
35   *
36   * @version $Rev: 471754 $
37   */
38  public class ELResourceTag extends ResourceTag {
39      /**
40       * Instance variable mapped to "id" tag attribute. (Mapping set in
41       * associated BeanInfo class.)
42       */
43      private String idExpr;
44  
45      /**
46       * Instance variable mapped to "input" tag attribute. (Mapping set in
47       * associated BeanInfo class.)
48       */
49      private String inputExpr;
50  
51      /**
52       * Instance variable mapped to "name" tag attribute. (Mapping set in
53       * associated BeanInfo class.)
54       */
55      private String nameExpr;
56  
57      /**
58       * Getter method for "id" tag attribute. (Mapping set in associated
59       * BeanInfo class.)
60       */
61      public String getIdExpr() {
62          return (idExpr);
63      }
64  
65      /**
66       * Getter method for "input" tag attribute. (Mapping set in associated
67       * BeanInfo class.)
68       */
69      public String getInputExpr() {
70          return (inputExpr);
71      }
72  
73      /**
74       * Getter method for "name" tag attribute. (Mapping set in associated
75       * BeanInfo class.)
76       */
77      public String getNameExpr() {
78          return (nameExpr);
79      }
80  
81      /**
82       * Setter method for "id" tag attribute. (Mapping set in associated
83       * BeanInfo class.)
84       */
85      public void setIdExpr(String idExpr) {
86          this.idExpr = idExpr;
87      }
88  
89      /**
90       * Setter method for "input" tag attribute. (Mapping set in associated
91       * BeanInfo class.)
92       */
93      public void setInputExpr(String inputExpr) {
94          this.inputExpr = inputExpr;
95      }
96  
97      /**
98       * Setter method for "name" tag attribute. (Mapping set in associated
99       * BeanInfo class.)
100      */
101     public void setNameExpr(String nameExpr) {
102         this.nameExpr = nameExpr;
103     }
104 
105     /**
106      * Resets attribute values for tag reuse.
107      */
108     public void release() {
109         super.release();
110         setIdExpr(null);
111         setInputExpr(null);
112         setNameExpr(null);
113     }
114 
115     /**
116      * Process the start tag.
117      *
118      * @throws JspException if a JSP exception has occurred
119      */
120     public int doStartTag() throws JspException {
121         evaluateExpressions();
122 
123         return (super.doStartTag());
124     }
125 
126     /**
127      * Processes all attribute values which use the JSTL expression evaluation
128      * engine to determine their values.
129      *
130      * @throws JspException if a JSP exception has occurred
131      */
132     private void evaluateExpressions()
133         throws JspException {
134         String string = null;
135 
136         if ((string =
137                 EvalHelper.evalString("id", getIdExpr(), this, pageContext)) != null) {
138             setId(string);
139         }
140 
141         if ((string =
142                 EvalHelper.evalString("input", getInputExpr(), this, pageContext)) != null) {
143             setInput(string);
144         }
145 
146         if ((string =
147                 EvalHelper.evalString("name", getNameExpr(), this, pageContext)) != null) {
148             setName(string);
149         }
150     }
151 }