RadioTag


1   /*
2    * $Id: RadioTag.java 54929 2004-10-16 16:38:42Z 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.struts.taglib.html;
20  
21  import javax.servlet.jsp.JspException  ;
22  
23  import org.apache.struts.taglib.TagUtils;
24  import org.apache.struts.util.MessageResources;
25  
26  /**
27   * Tag for input fields of type "radio".
28   *
29   * @version $Rev: 54929 $ $Date: 2004-10-16 17:38:42 +0100 (Sat, 16 Oct 2004) $
30   */
31  public class RadioTag extends BaseHandlerTag {
32  
33  
34      // ----------------------------------------------------- Instance Variables
35  
36  
37      /**
38       * The message resources for this package.
39       */
40      protected static MessageResources messages =
41       MessageResources.getMessageResources(Constants.Package + ".LocalStrings");
42  
43  
44      /**
45       * The name of the bean containing our underlying property.
46       */
47      protected String   name = Constants.BEAN_KEY;
48  
49      public String   getName() {
50          return (this.name);
51      }
52  
53      public void setName(String   name) {
54          this.name = name;
55      }
56  
57  
58      /**
59       * The property name for this field.
60       */
61      protected String   property = null;
62  
63  
64      /**
65       * The body content of this tag (if any).
66       */
67      protected String   text = null;
68  
69  
70      /**
71       * The server value for this option.
72       */
73      protected String   value = null;
74  
75  
76      /**
77       * Name of the bean (in some scope) that will return the
78       * value of the radio tag.
79       * <p>
80       * If an iterator is used to render a series of radio tags,
81       * this field may be used to specify the name of the bean
82       * exposed by the iterator. In this case, the value attribute is
83       * used as the name of a property on the <code>idName</code> bean
84       * that returns the value of the radio tag in this iteration.
85       */
86      protected String   idName = null;
87  
88  
89      // ------------------------------------------------------------- Properties
90  
91  
92      /**
93       * Return the property name.
94       */
95      public String   getProperty() {
96  
97          return (this.property);
98  
99      }
100 
101     /**
102      * Set the property name.
103      *
104      * @param property The new property name
105      */
106     public void setProperty(String   property) {
107 
108         this.property = property;
109 
110     }
111 
112     /**
113      * Return the server value.
114      */
115     public String   getValue() {
116 
117         return (this.value);
118 
119     }
120 
121     /**
122      * Set the server value.
123      *
124      * @param value The new server value
125      */
126     public void setValue(String   value) {
127 
128         this.value = value;
129 
130     }
131 
132     /**
133      * Return the idName.
134      * @since Struts 1.1
135      */
136     public String   getIdName() {
137 
138         return (this.idName);
139 
140     }
141 
142     /**
143      * Set the idName.
144      * @since Struts 1.1
145      *
146      * @param idName The new idName
147      */
148     public void setIdName(String   idName) {
149 
150         this.idName=idName;
151 
152     }
153 
154 
155     // --------------------------------------------------------- Public Methods
156 
157 
158     /**
159      * Generate the required input tag.
160      * [Indexed property since Struts 1.1]
161      *
162      * @exception JspException if a JSP exception has occurred
163      */
164     public int doStartTag() throws JspException   {
165 
166         String   radioTag = renderRadioElement(serverValue(), currentValue());
167 
168         TagUtils.getInstance().write(pageContext, radioTag);
169 
170         this.text = null;
171         return (EVAL_BODY_TAG);
172     }
173 
174     /**
175      * Return the String to be used in the radio tag's <code>value</code> attribute 
176      * that gets sent to the server on form submission.
177      * @throws JspException
178      */
179     private String   serverValue() throws JspException   {
180 
181         // Not using indexed radio buttons
182         if (this.idName == null) {
183             return this.value;
184         }
185         
186         String   serverValue = this.lookupProperty(this.idName, this.value);
187         
188         return (serverValue == null) ? "" : serverValue;
189     }
190 
191     /**
192      * Acquire the current value of the bean specified by the <code>name</code> 
193      * attribute and the property specified by the <code>property</code> attribute.
194      * This radio button with this value will be checked.
195      * @throws JspException
196      */
197     private String   currentValue() throws JspException   {
198         String   current = this.lookupProperty(this.name, this.property);
199         
200         return (current == null) ? "" : current;
201     }
202     
203     /**
204      * Renders an HTML &lt;input type="radio"&gt; element.
205      * @param serverValue The data to be used in the tag's <code>value</code> 
206      * attribute and sent to the server when the form is submitted.
207      * @param checkedValue If the serverValue equals this value the radio button 
208      * will be checked.
209      * @return A radio input element.
210      * @throws JspException
211      * @since Struts 1.1
212      */
213     protected String   renderRadioElement(String   serverValue, String   checkedValue)
214         throws JspException   {
215             
216         StringBuffer   results = new StringBuffer  ("<input type=\"radio\"");
217 
218         prepareAttribute(results, "name", prepareName());
219         prepareAttribute(results, "accesskey", getAccesskey());
220         prepareAttribute(results, "tabindex", getTabindex());
221         prepareAttribute(results, "value", serverValue);
222         if (serverValue.equals(checkedValue)) {
223             results.append(" checked=\"checked\"");
224         }
225         results.append(prepareEventHandlers());
226         results.append(prepareStyles());
227         prepareOtherAttributes(results);
228         results.append(getElementClose());
229         return results.toString();
230     }
231 
232     /**
233      * Save the associated label from the body content.
234      *
235      * @exception JspException if a JSP exception has occurred
236      */
237     public int doAfterBody() throws JspException   {
238 
239         if (this.bodyContent != null) {
240             String   value = this.bodyContent.getString().trim();
241             if (value.length() > 0) {
242                 this.text = value;
243             }
244         }
245         
246         return (SKIP_BODY);
247     }
248 
249     /**
250      * Optionally render the associated label from the body content.
251      *
252      * @exception JspException if a JSP exception has occurred
253      */
254     public int doEndTag() throws JspException   {
255 
256         // Render any description for this radio button
257         if (this.text != null) {
258             TagUtils.getInstance().write(pageContext, text);
259         }
260         
261         return (EVAL_PAGE);
262 
263     }
264 
265 
266     /**
267      * Prepare the name element
268      * @return The element name.
269      */
270     protected String   prepareName() throws JspException   {
271 
272         if (property == null) {
273             return null;
274         }
275 
276         // * @since Struts 1.1
277         if(indexed) {
278             StringBuffer   results = new StringBuffer  ();
279             prepareIndex(results, name);
280             results.append(property);
281             return results.toString();
282         }
283 
284         return property;
285 
286     }
287 
288     /**
289      * Release any acquired resources.
290      */
291     public void release() {
292 
293         super.release();
294         idName = null;
295         name = Constants.BEAN_KEY;
296         property = null;
297         text = null;
298         value = null;
299 
300     }
301 
302 }
303
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