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1   /*
2    * $Id: ErrorsTag.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.struts.taglib.html;
22  
23  import org.apache.struts.Globals;
24  import org.apache.struts.action.ActionMessage;
25  import org.apache.struts.action.ActionMessages;
26  import org.apache.struts.taglib.TagUtils;
27  import org.apache.struts.util.MessageResources;
28  
29  import javax.servlet.jsp.JspException;
30  import javax.servlet.jsp.tagext.TagSupport;
31  
32  import java.util.Iterator;
33  
34  /**
35   * Custom tag that renders error messages if an appropriate request attribute
36   * has been created.  The tag looks for a request attribute with a reserved
37   * key, and assumes that it is either a String, a String array, containing
38   * message keys to be looked up in the module's MessageResources, or an object
39   * of type <code>org.apache.struts.action.ActionErrors</code>. <p> The
40   * following optional message keys will be utilized if corresponding messages
41   * exist for them in the application resources:
42   *
43   * <ul>
44   *
45   * <li><b>errors.header</b> - If present, the corresponding message will be
46   * rendered prior to the individual list of error messages.</li>
47   *
48   * <li><b>errors.footer</b> - If present, the corresponding message will be
49   * rendered following the individual list of error messages.</li>
50   *
51   * <li><b>errors.prefix</b> - If present, the corresponding message will be
52   * rendered before each individual error message.</li>
53   *
54   * <li><b>errors.suffix</b> - If present, the corresponding message will be
55   * rendered after each individual error message.</li>
56   *
57   * </ul>
58   *
59   * @version $Rev: 471754 $ $Date: 2005-08-21 19:08:45 -0400 (Sun, 21 Aug 2005)
60   *          $
61   */
62  public class ErrorsTag extends TagSupport {
63      /**
64       * The message resources for this package.
65       */
66      protected static MessageResources messages =
67          MessageResources.getMessageResources(Constants.Package
68              + ".LocalStrings");
69  
70      // ----------------------------------------------------------- Properties
71  
72      /**
73       * The servlet context attribute key for our resources.
74       */
75      protected String bundle = null;
76  
77      /**
78       * The session attribute key for our locale.
79       */
80      protected String locale = Globals.LOCALE_KEY;
81  
82      /**
83       * The request attribute key for our error messages (if any).
84       */
85      protected String name = Globals.ERROR_KEY;
86  
87      /**
88       * The name of the property for which error messages should be returned,
89       * or <code>null</code> to return all errors.
90       */
91      protected String property = null;
92  
93      /**
94       * The message resource key for errors header.
95       */
96      protected String header = null;
97  
98      /**
99       * The message resource key for errors footer.
100      */
101     protected String footer = null;
102 
103     /**
104      * The message resource key for errors prefix.
105      */
106     protected String prefix = null;
107 
108     /**
109      * The message resource key for errors suffix.
110      */
111     protected String suffix = null;
112 
113     public String getBundle() {
114         return (this.bundle);
115     }
116 
117     public void setBundle(String bundle) {
118         this.bundle = bundle;
119     }
120 
121     public String getLocale() {
122         return (this.locale);
123     }
124 
125     public void setLocale(String locale) {
126         this.locale = locale;
127     }
128 
129     public String getName() {
130         return (this.name);
131     }
132 
133     public void setName(String name) {
134         this.name = name;
135     }
136 
137     public String getProperty() {
138         return (this.property);
139     }
140 
141     public void setProperty(String property) {
142         this.property = property;
143     }
144 
145     public String getHeader() {
146         return (header == null) ? "errors.header" : header;
147     }
148 
149     public void setHeader(String header) {
150         this.header = header;
151     }
152 
153     public String getFooter() {
154         return (footer == null) ? "errors.footer" : footer;
155     }
156 
157     public void setFooter(String footer) {
158         this.footer = footer;
159     }
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     public String getSuffix() {
170         return (suffix == null) ? "errors.suffix" : suffix;
171     }
172 
173     public void setSuffix(String suffix) {
174         this.suffix = suffix;
175     }
176 
177     // ------------------------------------------------------- Public Methods
178 
179     /**
180      * Render the specified error messages if there are any.
181      *
182      * @throws JspException if a JSP exception has occurred
183      */
184     public int doStartTag() throws JspException {
185         // Were any error messages specified?
186         ActionMessages errors = null;
187 
188         try {
189             errors =
190                 TagUtils.getInstance().getActionMessages(pageContext, name);
191         } catch (JspException e) {
192             TagUtils.getInstance().saveException(pageContext, e);
193             throw e;
194         }
195 
196         if ((errors == null) || errors.isEmpty()) {
197             return (EVAL_BODY_INCLUDE);
198         }
199 
200         boolean headerPresent =
201             TagUtils.getInstance().present(pageContext, bundle, locale,
202                 getHeader());
203 
204         boolean footerPresent =
205             TagUtils.getInstance().present(pageContext, bundle, locale,
206                 getFooter());
207 
208         boolean prefixPresent =
209             TagUtils.getInstance().present(pageContext, bundle, locale,
210                 getPrefix());
211 
212         boolean suffixPresent =
213             TagUtils.getInstance().present(pageContext, bundle, locale,
214                 getSuffix());
215 
216         // Render the error messages appropriately
217         StringBuffer results = new StringBuffer();
218         boolean headerDone = false;
219         String message = null;
220         Iterator reports =
221             (property == null) ? errors.get() : errors.get(property);
222 
223         while (reports.hasNext()) {
224             ActionMessage report = (ActionMessage) reports.next();
225 
226             if (!headerDone) {
227                 if (headerPresent) {
228                     message =
229                         TagUtils.getInstance().message(pageContext, bundle,
230                             locale, getHeader());
231 
232                     results.append(message);
233                 }
234 
235                 headerDone = true;
236             }
237 
238             if (prefixPresent) {
239                 message =
240                     TagUtils.getInstance().message(pageContext, bundle, locale,
241                         getPrefix());
242                 results.append(message);
243             }
244 
245             if (report.isResource()) {
246                 message =
247                     TagUtils.getInstance().message(pageContext, bundle, locale,
248                         report.getKey(), report.getValues());
249             } else {
250                 message = report.getKey();
251             }
252 
253             if (message != null) {
254                 results.append(message);
255             }
256 
257             if (suffixPresent) {
258                 message =
259                     TagUtils.getInstance().message(pageContext, bundle, locale,
260                         getSuffix());
261                 results.append(message);
262             }
263         }
264 
265         if (headerDone && footerPresent) {
266             message =
267                 TagUtils.getInstance().message(pageContext, bundle, locale,
268                     getFooter());
269             results.append(message);
270         }
271 
272         TagUtils.getInstance().write(pageContext, results.toString());
273 
274         return (EVAL_BODY_INCLUDE);
275     }
276 
277     /**
278      * Release any acquired resources.
279      */
280     public void release() {
281         super.release();
282         bundle = Globals.MESSAGES_KEY;
283         locale = Globals.LOCALE_KEY;
284         name = Globals.ERROR_KEY;
285         property = null;
286         header = null;
287         footer = null;
288         prefix = null;
289         suffix = null;
290     }
291 }