KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > apache > tapestry > callback > DirectCallback


1 // Copyright 2004, 2005 The Apache Software Foundation
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 package org.apache.tapestry.callback;
16
17 import org.apache.hivemind.ApplicationRuntimeException;
18 import org.apache.hivemind.util.Defense;
19 import org.apache.tapestry.IComponent;
20 import org.apache.tapestry.IDirect;
21 import org.apache.tapestry.IPage;
22 import org.apache.tapestry.IRequestCycle;
23
24 /**
25  * Simple callback for re-invoking a {@link IDirect} trigger.
26  *
27  * @author Howard Lewis Ship
28  * @since 0.2.9
29  */
30
31 public class DirectCallback implements ICallback
32 {
33     /**
34      * @since 2.0.4
35      */
36
37     private static final long serialVersionUID = -8888847655917503471L;
38
39     private String JavaDoc _pageName;
40
41     private String JavaDoc _componentIdPath;
42
43     private Object JavaDoc[] _parameters;
44
45     public String JavaDoc toString()
46     {
47         StringBuffer JavaDoc buffer = new StringBuffer JavaDoc("DirectCallback[");
48
49         buffer.append(_pageName);
50         buffer.append('/');
51         buffer.append(_componentIdPath);
52
53         if (_parameters != null)
54         {
55             for (int i = 0; i < _parameters.length; i++)
56             {
57                 buffer.append(i == 0 ? " " : ", ");
58                 buffer.append(_parameters[i]);
59             }
60         }
61
62         buffer.append(']');
63
64         return buffer.toString();
65
66     }
67
68     /**
69      * Creates a new DirectCallback for the component. The parameters (which may be null) is
70      * retained, not copied.
71      */
72
73     public DirectCallback(IDirect component, Object JavaDoc[] parameters)
74     {
75         Defense.notNull(component, "component");
76
77         _pageName = component.getPage().getPageName();
78         _componentIdPath = component.getIdPath();
79         _parameters = parameters;
80     }
81
82     /**
83      * Locates the {@link IDirect}component that was previously identified (and whose page and id
84      * path were stored). Invokes {@link IRequestCycle#setListenerParameters(Object[])(Object[])}to
85      * restore the service parameters, then invokes {@link IDirect#trigger(IRequestCycle)}on the
86      * component.
87      */
88
89     public void performCallback(IRequestCycle cycle)
90     {
91         IPage page = cycle.getPage(_pageName);
92         IComponent component = page.getNestedComponent(_componentIdPath);
93         IDirect direct = null;
94
95         try
96         {
97             direct = (IDirect) component;
98         }
99         catch (ClassCastException JavaDoc ex)
100         {
101             throw new ApplicationRuntimeException(CallbackMessages.componentNotDirect(component),
102                     component, null, ex);
103         }
104
105         cycle.setListenerParameters(_parameters);
106         direct.trigger(cycle);
107     }
108 }
Popular Tags