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Java > Open Source Codes > org > apache > pluto > portlet > admin > taglib > MessageTag


1 /*
2  * Copyright 2003,2004,2005 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.pluto.portlet.admin.taglib;
17
18 import java.io.IOException JavaDoc;
19 import java.io.PrintWriter JavaDoc;
20
21 import javax.portlet.PortletRequest;
22 import javax.portlet.PortletSession;
23 import javax.servlet.jsp.JspException JavaDoc;
24 import javax.servlet.jsp.JspTagException JavaDoc;
25 import javax.servlet.jsp.JspWriter JavaDoc;
26 import javax.servlet.jsp.tagext.TagSupport JavaDoc;
27
28 import org.apache.pluto.Constants;
29 import org.apache.pluto.portlet.admin.PlutoAdminConstants;
30 import org.apache.pluto.portlet.admin.bean.PortletMessage;
31 import org.apache.pluto.portlet.admin.bean.PortletMessageType;
32
33 /**
34  * Tag to print an error, info, alert, status or success message in a portlet
35  * as defined by Cascading Syle Sheet classes in Appendix PLT C of the
36  * Java Portlet Specification (JSR-168) version 1.0 (pg 116).
37  * <p>
38  * This class uses the PortletMessage and PortletMessageType classes to
39  * encapsulates message information. It also can handle a Throwable
40  * put in the session (see below), using the getMessage() for the message
41  * and printing out the stack trace in an HTML comment. All messages are
42  * wrapped in a &lt;p&gt; element containing a 'class' attribute with a
43  * spec-defined CSS value, which assumes these are defined in a CSS style
44  * sheet used by the JSP page. Right now this class can only handle one
45  * message per JSP page.
46  * </p>
47  * <p>
48  * There are three ways a message can be displayed using this tag:<br/>
49  * 1. Use the tag's message attribute on the JSP page to set the message
50  * as a String or expression that evaluates to a String. Optionally, you
51  * can use the messageType attribute. Valid messageType attributes
52  * are info, error, status, success and alert. The default message
53  * type is status.<br/>
54  * 2. Put a message in the portlet session encapsulated in a PortletMessage
55  * object with a PlutoAdminConstants.MESSAGE_ATTR session key. This class
56  * takes care of getting the attribute from the session, using its message and
57  * type data and removing the session attribute.<br/>
58  * 3. Put a Throwable in the portlet session with a PlutoAdminConstants.ERROR_ATTR
59  * key. This class takes care of getting the attribute from the session,
60  * using its data and removing the session attribute. Throwables are always
61  * given a messageType of error.<br/>
62  * </p>
63  *
64  * @author Craig Doremus
65  * @see org.apache.pluto.portlet.admin.bean.PortletMessage
66  * @see org.apache.pluto.portlet.admin.bean.PortletMessageType
67  * @see org.apache.pluto.portlet.admin.PlutoAdminConstants
68  */
69 public class MessageTag extends TagSupport JavaDoc {
70
71     private String JavaDoc message = null;
72     private String JavaDoc messageType = "status";
73     /* User-defined CSS class */
74     private String JavaDoc cssClass = "portlet-msg-info";
75
76     /************ JSR-168 defined CSS classes for messages ************/
77     /** CSS class for Error messages. Example: Portlet not available*/
78 public static final String JavaDoc MSG_ERROR_CSS_CLASS = "portlet-msg-error";
79     /** CSS class for Help messages, general additional information, etc. Example: Info about */
80     public static final String JavaDoc MSG_INFO_CSS_CLASS = "portlet-msg-info";
81     /** CSS class for Status of the current operation. Example: Progress: 80% */
82     public static final String JavaDoc MSG_STATUS_CSS_CLASS = "portlet-msg-status";
83     /** CSS class for Warning messages. Example: Timeout occurred, try again later */
84     public static final String JavaDoc MSG_ALERT_CSS_CLASS = "portlet-msg-alert";
85     /** CSS class for Verification of the successful completion of a task. Example: Operation completed successfully */
86     public static final String JavaDoc MSG_SUCCESS_CSS_CLASS = "portlet-msg-success";
87     /* ************************************************************* */
88
89     /**
90      * Does the work of the tag.
91      */
92     public int doStartTag() throws JspException JavaDoc {
93
94     PortletRequest request = (PortletRequest)pageContext.getRequest().getAttribute(Constants.PORTLET_REQUEST);
95     PortletSession session = request.getPortletSession();
96     Throwable JavaDoc error = (Throwable JavaDoc)session.getAttribute(PlutoAdminConstants.ERROR_ATTR);
97         session.removeAttribute(PlutoAdminConstants.ERROR_ATTR);
98     PortletMessage oMsg = (PortletMessage)session.getAttribute(PlutoAdminConstants.MESSAGE_ATTR);
99         session.removeAttribute(PlutoAdminConstants.MESSAGE_ATTR);
100
101     try {
102       JspWriter JavaDoc out = pageContext.getOut();
103       if (message != null ) {
104         if (cssClass == null) {
105             cssClass = PortletMessageType.getTypeByName(messageType).CssClass;
106         }
107           out.print(wrapHtml(message, cssClass));
108         } else if (oMsg != null ) {
109         out.print(wrapHtml(oMsg.getMessage(), oMsg.getType().CssClass));
110         } else if (error != null ) {
111             StringBuffer JavaDoc sb = new StringBuffer JavaDoc();
112             sb.append(error.getMessage());
113         if (error.getCause() != null) {
114             sb.append("<br>Underlying Exception cause: ");
115             sb.append(error.getCause().getMessage());
116         }
117         out.print(wrapHtml(sb.toString(), MSG_ERROR_CSS_CLASS));
118         //print out the stack trace in an HTML comment
119 out.println("<!-- " + PlutoAdminConstants.LS);
120         PrintWriter JavaDoc writer = new PrintWriter JavaDoc(out, true);
121         error.printStackTrace(writer);
122         out.print(PlutoAdminConstants.LS + "-->");
123         }
124     } catch (IOException JavaDoc e) {
125       throw new JspTagException JavaDoc("Error in tag MessageTag: " + e.toString());
126     }
127             return SKIP_BODY;
128       }
129
130     private String JavaDoc wrapHtml(String JavaDoc msg, String JavaDoc css){
131         StringBuffer JavaDoc sb = new StringBuffer JavaDoc();
132         sb.append("<p class=\"" + css + "\">");
133     sb.append(msg);
134     sb.append("</p>");
135     return sb.toString();
136     }
137
138     /**
139      * @param message The error message
140      */
141     public void setMessage(String JavaDoc message) {
142         this.message = message;
143     }
144
145     /**
146      * @param cssClass The cssClass to set.
147      */
148     public void setCssClass(String JavaDoc cssClass) {
149         this.cssClass = cssClass;
150     }
151     /**
152      * @param messageType The messageType to set.
153      */
154     public void setMessageType(String JavaDoc messageType) {
155         this.messageType = messageType;
156     }
157 }
158
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