MessagesTag


1   /*
2    * $Id: MessagesTag.java 164530 2005-04-25 03:11:07Z niallp $ 
3    *
4    * Copyright 1999-2005 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 java.util.Iterator  ;
22  
23  import javax.servlet.jsp.JspException  ;
24  import javax.servlet.jsp.tagext.BodyTagSupport  ;
25  
26  import org.apache.struts.Globals;
27  import org.apache.struts.action.ActionMessage;
28  import org.apache.struts.action.ActionMessages;
29  import org.apache.struts.taglib.TagUtils;
30  import org.apache.struts.util.MessageResources;
31  
32  /**
33   * Custom tag that iterates the elements of a message collection.
34   * It defaults to retrieving the messages from <code>Globals.ERROR_KEY</code>,
35   * but if the message attribute is set to true then the messages will be
36   * retrieved from <code>Globals.MESSAGE_KEY</code>. This is an alternative
37   * to the default <code>ErrorsTag</code>.
38   *
39   * @version $Rev: 164530 $ $Date: 2005-04-25 04:11:07 +0100 (Mon, 25 Apr 2005) $
40   * @since Struts 1.1
41   */
42  public class MessagesTag extends BodyTagSupport   {
43  
44      /**
45       * The message resources for this package.
46       */
47      protected static MessageResources messageResources =
48         MessageResources.getMessageResources(Constants.Package + ".LocalStrings");
49  
50      /**
51       * Iterator of the elements of this error collection, while we are actually
52       * running.
53       */
54      protected Iterator   iterator = null;
55  
56      /**
57       * Whether or not any error messages have been processed.
58       */
59      protected boolean processed = false;
60  
61      /**
62       * The name of the scripting variable to be exposed.
63       */
64      protected String   id = null;
65  
66      /**
67       * The servlet context attribute key for our resources.
68       */
69      protected String   bundle = null;
70  
71      /**
72       * The session attribute key for our locale.
73       */
74      protected String   locale = Globals.LOCALE_KEY;
75  
76      /**
77       * The request attribute key for our error messages (if any).
78       */
79      protected String   name = Globals.ERROR_KEY;
80  
81      /**
82       * The name of the property for which error messages should be returned,
83       * or <code>null</code> to return all errors.
84       */
85      protected String   property = null;
86  
87      /**
88       * The message resource key for errors header.
89       */
90      protected String   header = null;
91  
92      /**
93       * The message resource key for errors footer.
94       */
95      protected String   footer = null;
96  
97      /**
98       * If this is set to 'true', then the <code>Globals.MESSAGE_KEY</code> will
99       * be used to retrieve the messages from scope.
100      */
101     protected String   message = null;
102 
103     public String   getId() {
104         return (this.id);
105     }
106 
107     public void setId(String   id) {
108         this.id = id;
109     }
110 
111     public String   getBundle() {
112         return (this.bundle);
113     }
114 
115     public void setBundle(String   bundle) {
116         this.bundle = bundle;
117     }
118 
119     public String   getLocale() {
120         return (this.locale);
121     }
122 
123     public void setLocale(String   locale) {
124         this.locale = locale;
125     }
126 
127     public String   getName() {
128         return (this.name);
129     }
130 
131     public void setName(String   name) {
132         this.name = name;
133     }
134 
135     public String   getProperty() {
136         return (this.property);
137     }
138 
139     public void setProperty(String   property) {
140         this.property = property;
141     }
142 
143     public String   getHeader() {
144         return (this.header);
145     }
146 
147     public void setHeader(String   header) {
148         this.header = header;
149     }
150 
151     public String   getFooter() {
152         return (this.footer);
153     }
154 
155     public void setFooter(String   footer) {
156         this.footer = footer;
157     }
158 
159     public String   getMessage() {
160         return (this.message);
161     }
162 
163     public void setMessage(String   message) {
164         this.message = message;
165     }
166 
167     /**
168      * Construct an iterator for the specified collection, and begin
169      * looping through the body once per element.
170      *
171      * @exception JspException if a JSP exception has occurred
172      */
173     public int doStartTag() throws JspException   {
174         // Initialize for a new request.
175         processed = false;
176 
177         // Were any messages specified?
178         ActionMessages messages = null;
179 
180         // Make a local copy of the name attribute that we can modify.
181         String   name = this.name;
182 
183         if (message != null && "true".equalsIgnoreCase(message)) {
184             name = Globals.MESSAGE_KEY;
185         }
186 
187         try {
188             messages = TagUtils.getInstance().getActionMessages(pageContext, name);
189 
190         } catch (JspException   e) {
191             TagUtils.getInstance().saveException(pageContext, e);
192             throw e;
193         }
194 
195         // Acquire the collection we are going to iterate over
196         this.iterator = (property == null) ? messages.get() : messages.get(property);
197 
198         // Store the first value and evaluate, or skip the body if none
199         if (!this.iterator.hasNext()) {
200             return SKIP_BODY;
201         }
202 
203         ActionMessage report = (ActionMessage) this.iterator.next();
204         String   msg = null;
205         if (report.isResource()) {
206             msg = TagUtils.getInstance().message(
207                      pageContext,
208                      bundle,
209                      locale,
210                      report.getKey(),
211                      report.getValues());
212         } else {
213             msg = report.getKey();
214         }
215 
216         if (msg == null) {
217             pageContext.removeAttribute(id);
218         } else {
219             pageContext.setAttribute(id, msg);
220         }
221 
222         if (header != null && header.length() > 0) {
223             String   headerMessage =
224                 TagUtils.getInstance().message(pageContext, bundle, locale, header);
225 
226             if (headerMessage != null) {
227                 TagUtils.getInstance().write(pageContext, headerMessage);
228             }
229         }
230 
231         // Set the processed variable to true so the
232         // doEndTag() knows processing took place
233         processed = true;
234 
235         return (EVAL_BODY_TAG);
236     }
237 
238     /**
239      * Make the next collection element available and loop, or
240      * finish the iterations if there are no more elements.
241      *
242      * @exception JspException if a JSP exception has occurred
243      */
244     public int doAfterBody() throws JspException   {
245         // Render the output from this iteration to the output stream
246         if (bodyContent != null) {
247             TagUtils.getInstance().writePrevious(pageContext, bodyContent.getString());
248             bodyContent.clearBody();
249         }
250 
251         // Decide whether to iterate or quit
252         if (iterator.hasNext()) {
253             ActionMessage report = (ActionMessage) iterator.next();
254             String   msg =
255                 TagUtils.getInstance().message(
256                     pageContext,
257                     bundle,
258                     locale,
259                     report.getKey(),
260                     report.getValues());
261 
262            if (msg == null) {
263                pageContext.removeAttribute(id);
264            } else {
265                pageContext.setAttribute(id, msg);
266            }
267 
268            return (EVAL_BODY_TAG);
269         } else {
270            return (SKIP_BODY);
271         }
272 
273     }
274 
275 
276     /**
277      * Clean up after processing this enumeration.
278      *
279      * @exception JspException if a JSP exception has occurred
280      */
281     public int doEndTag() throws JspException   {
282        if (processed && footer != null && footer.length() > 0) {
283 
284         String   footerMessage =
285             TagUtils.getInstance().message(pageContext, bundle, locale, footer);
286 
287           if (footerMessage != null) {
288              TagUtils.getInstance().write(pageContext, footerMessage);
289           }
290        }
291 
292        return EVAL_PAGE;
293     }
294 
295 
296     /**
297      * Release all allocated resources.
298      */
299     public void release() {
300        super.release();
301        iterator = null;
302        processed = false;
303        id = null;
304        bundle = null;
305        locale = Globals.LOCALE_KEY;
306        name = Globals.ERROR_KEY;
307        property = null;
308        header = null;
309        footer = null;
310        message = null;
311     }
312 
313 }
314
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