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1   /*
2    * $Id: ELHtmlTag.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.html;
22  
23  import org.apache.struts.taglib.html.HtmlTag;
24  import org.apache.strutsel.taglib.utils.EvalHelper;
25  
26  import javax.servlet.jsp.JspException;
27  
28  /**
29   * Renders an HTML <html> element with appropriate language attributes if
30   * there is a current Locale available in the user's session. <p> This class
31   * is a subclass of the class <code>org.apache.struts.taglib.html.HtmlTag</code>
32   * which provides most of the described functionality.  This subclass allows
33   * all attribute values to be specified as expressions utilizing the
34   * JavaServer Pages Standard Library expression language.
35   *
36   * @version $Rev: 471754 $
37   */
38  public class ELHtmlTag extends HtmlTag {
39      /**
40       * Instance variable mapped to "lang" tag attribute. (Mapping set in
41       * associated BeanInfo class.)
42       */
43      private String langExpr;
44  
45      /**
46       * Instance variable mapped to "xhtml" tag attribute. (Mapping set in
47       * associated BeanInfo class.)
48       */
49      private String xhtmlExpr;
50  
51      /**
52       * Getter method for "lang" tag attribute. (Mapping set in associated
53       * BeanInfo class.)
54       */
55      public String getLangExpr() {
56          return (langExpr);
57      }
58  
59      /**
60       * Getter method for "xhtml" tag attribute. (Mapping set in associated
61       * BeanInfo class.)
62       */
63      public String getXhtmlExpr() {
64          return (xhtmlExpr);
65      }
66  
67      /**
68       * Setter method for "lang" tag attribute. (Mapping set in associated
69       * BeanInfo class.)
70       */
71      public void setLangExpr(String langExpr) {
72          this.langExpr = langExpr;
73      }
74  
75      /**
76       * Setter method for "xhtml" tag attribute. (Mapping set in associated
77       * BeanInfo class.)
78       */
79      public void setXhtmlExpr(String xhtmlExpr) {
80          this.xhtmlExpr = xhtmlExpr;
81      }
82  
83      /**
84       * Resets attribute values for tag reuse.
85       */
86      public void release() {
87          super.release();
88          setLangExpr(null);
89          setXhtmlExpr(null);
90      }
91  
92      /**
93       * Process the start tag.
94       *
95       * @throws JspException if a JSP exception has occurred
96       */
97      public int doStartTag() throws JspException {
98          evaluateExpressions();
99  
100         return (super.doStartTag());
101     }
102 
103     /**
104      * Processes all attribute values which use the JSTL expression evaluation
105      * engine to determine their values.
106      *
107      * @throws JspException if a JSP exception has occurred
108      */
109     private void evaluateExpressions()
110         throws JspException {
111         Boolean bool = null;
112         String string = null;
113 
114         if ((bool =
115                 EvalHelper.evalBoolean("lang", getLangExpr(), this, pageContext)) != null) {
116             setLang(bool.booleanValue());
117         }
118 
119         if ((bool =
120                 EvalHelper.evalBoolean("xhtml", getXhtmlExpr(), this,
121                     pageContext)) != null) {
122             setXhtml(bool.booleanValue());
123         }
124     }
125 }