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Java > Open Source Codes > org > apache > webapp > admin > ApplicationServlet


1 /*
2  * Copyright 2001,2004 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
17
18 package org.apache.webapp.admin;
19
20 import java.text.DateFormat JavaDoc;
21 import java.util.HashSet JavaDoc;
22 import java.util.Locale JavaDoc;
23 import java.util.ResourceBundle JavaDoc;
24 import javax.management.MBeanServer JavaDoc;
25 import javax.servlet.ServletException JavaDoc;
26 import javax.servlet.UnavailableException JavaDoc;
27 import org.apache.commons.modeler.Registry;
28 import org.apache.struts.action.ActionServlet;
29 import org.apache.struts.util.MessageResources;
30
31
32 /**
33  * Subclass of ActionServlet that adds caching of the supported locales in the
34  * ApplicationLocales class.
35  *
36  * @author Patrick Luby
37  * @version $Revision: 1.5 $ $Date: 2004/02/27 14:59:01 $
38  */
39
40 public class ApplicationServlet extends ActionServlet {
41
42
43     // ----------------------------------------------------- Manifest Constants
44
45
46     /**
47      * The application scope key under which we store our
48      * <code>ApplicationLocales</code> instance.
49      */
50     public static final String JavaDoc LOCALES_KEY = "applicationLocales";
51
52
53     // ----------------------------------------------------- Instance Variables
54
55
56     /**
57      * The managed beans Registry used to look up metadata.
58      */
59     protected Registry registry = null;
60
61
62     /**
63      * The JMX MBeanServer we will use to look up management beans.
64      */
65     protected MBeanServer JavaDoc server = null;
66
67
68     // --------------------------------------------------------- Public Methods
69
70
71     /**
72      * Convenience method to make the managed beans Registry available.
73      *
74      * @exception ServletException if the Registry is not available
75      */
76     public Registry getRegistry() throws ServletException JavaDoc {
77
78         if (registry == null)
79             initRegistry();
80         return (this.registry);
81
82     }
83
84
85     /**
86      * Convenience method to make the JMX MBeanServer available.
87      *
88      * @exception ServletException if the MBeanServer is not available
89      */
90     public MBeanServer JavaDoc getServer() throws ServletException JavaDoc {
91
92         if (server == null)
93             initServer();
94         return (this.server);
95
96     }
97
98
99     /**
100      * Initialize this servlet.
101      *
102      * @exception ServletException if an initialization error occurs.
103      */
104     public void init() throws javax.servlet.ServletException JavaDoc {
105         super.init();
106         initApplicationLocales();
107     }
108
109
110     // ---------------------------------------------------- Protected Methods
111
112
113     /**
114      * Create and initialize the ApplicationLocales object, and make it
115      * available as a servlet context attribute.
116      */
117     protected void initApplicationLocales() {
118
119         ApplicationLocales locales = new ApplicationLocales(this);
120         getServletContext().setAttribute(LOCALES_KEY, locales);
121
122     }
123
124
125     /**
126      * Validate the existence of the Registry that should have been
127      * provided to us by an instance of
128      * <code>org.apache.catalina.mbean.ServerLifecycleListener</code>
129      * enabled at startup time.
130      *
131      * @exception ServletException if we cannot find the Registry
132      */
133     protected void initRegistry() throws ServletException JavaDoc {
134
135         registry = Registry.getRegistry();
136         //(Registry) getServletContext().getAttribute
137 // ("org.apache.catalina.Registry");
138 if (registry == null)
139             throw new UnavailableException JavaDoc("Registry is not available");
140
141     }
142
143
144     /**
145      * Validate the existence of the MBeanServer that should have been
146      * provided to us by an instance of
147      * <code>org.apache.catalina.mbean.ServerLifecycleListener</code>
148      * enabled at startup time.
149      *
150      * @exception ServletException if we cannot find the MBeanServer
151      */
152     protected void initServer() throws ServletException JavaDoc {
153
154         server = Registry.getRegistry().getMBeanServer();
155         //(MBeanServer) getServletContext().getAttribute
156 // ("org.apache.catalina.MBeanServer");
157 if (server == null)
158             throw new UnavailableException JavaDoc("MBeanServer is not available");
159
160     }
161
162
163 }
164
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