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Java > Open Source Codes > org > apache > jetspeed > modules > actions > portlets > PortletActionEvent


1 /*
2  * Copyright 2000-2001,2004 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  * PortletActionEvent.java
18  *
19  * Created on January 29, 2003, 4:20 PM
20  */
21 package org.apache.jetspeed.modules.actions.portlets;
22
23 import java.lang.reflect.Method JavaDoc;
24
25 import java.util.Enumeration JavaDoc;
26 import java.util.HashMap JavaDoc;
27
28 import org.apache.jetspeed.portal.Portlet;
29 import org.apache.jetspeed.portal.portlets.GenericMVCPortlet;
30 import org.apache.jetspeed.util.PortletSessionState;
31 import org.apache.turbine.modules.ActionEvent;
32 import org.apache.turbine.services.velocity.TurbineVelocity;
33 import org.apache.turbine.util.ParameterParser;
34 import org.apache.turbine.util.RunData;
35
36 import org.apache.velocity.context.Context;
37
38
39 /**
40  * Provides form based action handling via the eventSubmit_do[action] pattern.
41  * Works just like the mechanism described for the velocity portlet. Extends
42  * this convienent functionality to all GenericMVCPortlets
43  *
44  * @author tkuebler
45  * @author <a HREF="mailto:weaver@apache.org">Scott T. Weaver</a>
46  * @version $Id: PortletActionEvent.java,v 1.3.2.1 2003/02/24 18:45:42 tkuebler Exp $
47  * @stereotype moment-interval
48  */
49 public abstract class PortletActionEvent
50     extends ActionEvent
51   {
52     
53     /**
54      * Cache ActionEvent methods to avoid repeated replection
55      * method lookups.
56      */
57     private static final HashMap JavaDoc eventMethods = new HashMap JavaDoc();
58
59     /**
60      * You need to implement this in your classes that extend this
61      * class.
62      *
63      * @param data A Turbine RunData object.
64      * @exception Exception, a generic exception.
65      */
66     public abstract void doPerform(RunData data)
67                             throws Exception JavaDoc;
68
69     /**
70      * This overrides the default Action.perform() to execute the
71      * doEvent() method. If that fails, then it will execute the
72      * doPerform() method instead.
73      *
74      * @param data A Turbine RunData object.
75      * @exception Exception, a generic exception.
76      */
77     protected void perform(RunData data)
78                     throws Exception JavaDoc
79       {
80
81         try
82           {
83             executeEvents(data, TurbineVelocity.getContext(data));
84           }
85         catch (NoSuchMethodException JavaDoc e)
86           {
87             doPerform(data);
88           }
89       }
90
91     /**
92      * This method should be called to execute the event based system.
93      *
94      * @param data A Turbine RunData object.
95      * @param context context information.
96      * @exception Exception, a generic exception.
97      */
98     public void executeEvents(RunData data, Context context)
99                        throws Exception JavaDoc
100       {
101
102         // Name of the button.
103 String JavaDoc theButton = null;
104         
105         // Portlet whom this action is a target of
106 Portlet portlet = (Portlet) context.get(GenericMVCPortlet.PORTLET);
107
108         // ParameterParser.
109 ParameterParser pp = data.getParameters();
110         String JavaDoc button = pp.convert(BUTTON);
111
112         // Loop through and find the button.
113 for (Enumeration JavaDoc e = pp.keys(); e.hasMoreElements();)
114           {
115
116             String JavaDoc key = (String JavaDoc) e.nextElement();
117
118             if (key.startsWith(button))
119               {
120                 theButton = formatString(key);
121
122                 break;
123               }
124           }
125
126         if (theButton == null )
127           {
128             throw new NoSuchMethodException JavaDoc("ActionEvent: The button was null");
129           }
130
131  
132
133         if (!fireEvent(data, Context.class, context, theButton) && PortletSessionState.isMyRequest(data, portlet))
134         {
135             // Old JSP actions use Portlet instead of Context
136 // as their event method's 2nd parameter
137 if (!fireEvent(data, Portlet.class,
138                 portlet,
139                 theButton))
140             {
141                 // Attempt to execut things the old way..
142 super.executeEvents(data);
143             }
144         }
145
146       }
147       
148     /**
149      * Convenience method for firing portlet events.
150      * @author <a HREF="mailto:weaver@apache.org">Scott T. Weaver</a>
151      */
152     protected boolean fireEvent(RunData data, Class JavaDoc deltaClass, Object JavaDoc deltaValue, String JavaDoc theButton)
153     {
154         try
155         {
156             // The arguments to the method to find.
157 Class JavaDoc[] classes = new Class JavaDoc[2];
158             classes[0] = RunData.class;
159             classes[1] = deltaClass;
160             
161             // The arguments to pass to the method to execute.
162 Object JavaDoc[] args = new Object JavaDoc[2];
163             
164             String JavaDoc methodKey = getClass().getName()+":"
165                                +theButton+":"+classes[0].getName()
166                                +":"+classes[1].getName();
167             
168             Method JavaDoc method = (Method JavaDoc)eventMethods.get(methodKey);
169             if(method == null)
170             {
171                 method = getClass().getMethod(theButton, classes);
172                 eventMethods.put(methodKey, method);
173             }
174             args[0] = data;
175             args[1] = deltaValue;
176             method.invoke(this, args);
177             return true;
178         }
179         catch (Exception JavaDoc e)
180         {
181             return false;
182         }
183         
184     }
185       
186      
187   }
188
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