ErrorsTag


1   /*
2    * $Id: ErrorsTag.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  import java.util.Locale  ;
23  
24  import javax.servlet.jsp.JspException  ;
25  import javax.servlet.jsp.tagext.TagSupport  ;
26  
27  import org.apache.struts.Globals;
28  import org.apache.struts.action.ActionMessage;
29  import org.apache.struts.action.ActionMessages;
30  import org.apache.struts.taglib.TagUtils;
31  import org.apache.struts.util.MessageResources;
32  
33  /**
34   * Custom tag that renders error messages if an appropriate request attribute
35   * has been created.  The tag looks for a request attribute with a reserved
36   * key, and assumes that it is either a String, a String array, containing
37   * message keys to be looked up in the module's MessageResources, or
38   * an object of type <code>org.apache.struts.action.ActionErrors</code>.
39   * <p>
40   * The following optional message keys will be utilized if corresponding
41   * messages exist for them in the application resources:
42   * <ul>
43   * <li><b>errors.header</b> - If present, the corresponding message will be
44   *     rendered prior to the individual list of error messages.</li>
45   * <li><b>errors.footer</b> - If present, the corresponding message will be
46   *     rendered following the individual list of error messages.</li>
47   * <li><b>errors.prefix</b> - If present, the corresponding message will be
48   *     rendered before each individual error message.</li>
49   * <li><b>errors.suffix</b> - If present, the corresponding message will be
50   *     rendered after each individual error message.</li>
51   * </ul>
52   *
53   * @version $Rev: 164530 $ $Date: 2005-04-25 04:11:07 +0100 (Mon, 25 Apr 2005) $
54   */
55  public class ErrorsTag extends TagSupport   {
56  
57      // ----------------------------------------------------------- Properties
58  
59      /**
60       * The servlet context attribute key for our resources.
61       */
62      protected String   bundle = null;
63  
64      public String   getBundle() {
65          return (this.bundle);
66      }
67  
68      public void setBundle(String   bundle) {
69          this.bundle = bundle;
70      }
71  
72      /**
73       * The default locale on our server.
74       * @deprecated Use Locale.getDefault() directly.
75       */
76      protected static Locale   defaultLocale = Locale.getDefault();
77  
78      /**
79       * The line ending string.
80       * @deprecated No longer used.
81       */
82      protected static String   lineEnd = System.getProperty("line.separator");
83  
84      /**
85       * The session attribute key for our locale.
86       */
87      protected String   locale = Globals.LOCALE_KEY;
88  
89      public String   getLocale() {
90          return (this.locale);
91      }
92  
93      public void setLocale(String   locale) {
94          this.locale = locale;
95      }
96  
97      /**
98       * The message resources for this package.
99       */
100     protected static MessageResources messages =
101         MessageResources.getMessageResources(Constants.Package + ".LocalStrings");
102 
103     /**
104      * The request attribute key for our error messages (if any).
105      */
106     protected String   name = Globals.ERROR_KEY;
107 
108     public String   getName() {
109         return (this.name);
110     }
111 
112     public void setName(String   name) {
113         this.name = name;
114     }
115 
116     /**
117      * The name of the property for which error messages should be returned,
118      * or <code>null</code> to return all errors.
119      */
120     protected String   property = null;
121 
122     public String   getProperty() {
123         return (this.property);
124     }
125 
126     public void setProperty(String   property) {
127         this.property = property;
128     }
129 
130     /**
131      * The message resource key for errors header.
132      */
133     protected String   header = null;
134 
135     public String   getHeader() {
136         return header == null ? "errors.header" : header;
137     }
138 
139     public void setHeader(String   header) {
140         this.header = header;
141     }
142 
143     /**
144      * The message resource key for errors footer.
145      */
146     protected String   footer = null;
147 
148     public String   getFooter() {
149         return footer == null ? "errors.footer" : footer;
150     }
151 
152     public void setFooter(String   footer) {
153         this.footer = footer;
154     }
155 
156     /**
157      * The message resource key for errors prefix.
158      */
159     protected String   prefix= null;
160 
161     public String   getPrefix() {
162         return prefix == null ? "errors.prefix" : prefix;
163     }
164 
165     public void setPrefix(String   prefix) {
166         this.prefix= prefix;
167     }
168 
169     /**
170      * The message resource key for errors suffix.
171      */
172     protected String   suffix= null;
173 
174     public String   getSuffix() {
175         return suffix == null ? "errors.suffix" : suffix;
176     }
177 
178     public void setSuffix(String   suffix) {
179         this.suffix= suffix;
180     }
181 
182     // ------------------------------------------------------- Public Methods
183 
184     /**
185      * Render the specified error messages if there are any.
186      *
187      * @exception JspException if a JSP exception has occurred
188      */
189     public int doStartTag() throws JspException   {
190 
191         // Were any error messages specified?
192         ActionMessages errors = null;
193         try {
194             errors = TagUtils.getInstance().getActionMessages(pageContext, name);
195         } catch (JspException   e) {
196             TagUtils.getInstance().saveException(pageContext, e);
197             throw e;
198         }
199 
200         if ((errors == null) || errors.isEmpty()) {
201             return (EVAL_BODY_INCLUDE);
202         }
203 
204         boolean headerPresent =
205             TagUtils.getInstance().present(pageContext, bundle, locale, getHeader());
206 
207         boolean footerPresent =
208             TagUtils.getInstance().present(pageContext, bundle, locale, getFooter());
209 
210         boolean prefixPresent =
211             TagUtils.getInstance().present(pageContext, bundle, locale, getPrefix());
212 
213         boolean suffixPresent =
214             TagUtils.getInstance().present(pageContext, bundle, locale, getSuffix());
215 
216         // Render the error messages appropriately
217         StringBuffer   results = new StringBuffer  ();
218         boolean headerDone = false;
219         String   message = null;
220         Iterator   reports = (property == null) ? errors.get() : errors.get(property);
221 
222         while (reports.hasNext()) {
223             ActionMessage report = (ActionMessage) reports.next();
224             if (!headerDone) {
225                 if (headerPresent) {
226                     message =
227                         TagUtils.getInstance().message(
228                             pageContext,
229                             bundle,
230                             locale,
231                             getHeader());
232                             
233                     results.append(message);
234                 }
235                 headerDone = true;
236             }
237             
238             if (prefixPresent) {
239                 message =
240                     TagUtils.getInstance().message(
241                         pageContext,
242                         bundle,
243                         locale,
244                         getPrefix());
245                 results.append(message);
246             }
247             
248             if (report.isResource()) {
249                 message =
250                     TagUtils.getInstance().message(
251                         pageContext,
252                         bundle,
253                         locale,
254                         report.getKey(),
255                         report.getValues());
256             } else {
257                 message = report.getKey();
258             }
259                     
260             if (message != null) {
261                 results.append(message);
262             }
263             
264             if (suffixPresent) {
265                 message =
266                     TagUtils.getInstance().message(
267                         pageContext,
268                         bundle,
269                         locale,
270                         getSuffix());
271                 results.append(message);
272             }
273         }
274         
275         if (headerDone && footerPresent) {
276             message =
277                 TagUtils.getInstance().message(pageContext, bundle, locale, getFooter());
278             results.append(message);
279         }
280 
281         TagUtils.getInstance().write(pageContext, results.toString());
282 
283         return (EVAL_BODY_INCLUDE);
284 
285     }
286 
287     /**
288      * Release any acquired resources.
289      */
290     public void release() {
291         super.release();
292         bundle = Globals.MESSAGES_KEY;
293         locale = Globals.LOCALE_KEY;
294         name = Globals.ERROR_KEY;
295         property = null;
296         header = null;
297         footer = null;
298         prefix = null;
299         suffix = null;
300     }
301 
302 }
303
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