1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.myfaces.shared.view;
20
21 import javax.faces.application.Application;
22 import javax.faces.application.ViewHandler;
23 import javax.faces.component.UIViewRoot;
24 import javax.faces.context.FacesContext;
25 import javax.faces.view.ViewDeclarationLanguage;
26
27 import org.apache.myfaces.shared.application.InvalidViewIdException;
28
29 /**
30 * @author Simon Lessard (latest modification by $Author: bommel $)
31 * @version $Revision: 1187700 $ $Date: 2011-10-22 07:19:37 -0500 (Sat, 22 Oct 2011) $
32 *
33 * @since 2.0
34 */
35 public abstract class ViewDeclarationLanguageBase extends ViewDeclarationLanguage
36 {
37
38 /**
39 * Process the specification required algorithm that is generic to all PDL.
40 *
41 * @param context
42 * @param viewId
43 */
44 public UIViewRoot createView(FacesContext context, String viewId)
45 {
46 checkNull(context, "context");
47 //checkNull(viewId, "viewId");
48
49 try
50 {
51 viewId = calculateViewId(context, viewId);
52
53 Application application = context.getApplication();
54
55 // Create a new UIViewRoot object instance using Application.createComponent(UIViewRoot.COMPONENT_TYPE).
56 UIViewRoot newViewRoot = (UIViewRoot) application.createComponent(UIViewRoot.COMPONENT_TYPE);
57 UIViewRoot oldViewRoot = context.getViewRoot();
58 if (oldViewRoot == null)
59 {
60 // If not, this method must call calculateLocale() and calculateRenderKitId(), and store the results
61 // as the values of the locale and renderKitId, proeprties, respectively, of the newly created
62 // UIViewRoot.
63 ViewHandler handler = application.getViewHandler();
64 newViewRoot.setLocale(handler.calculateLocale(context));
65 newViewRoot.setRenderKitId(handler.calculateRenderKitId(context));
66 }
67 else
68 {
69 // If there is an existing UIViewRoot available on the FacesContext, this method must copy its locale
70 // and renderKitId to this new view root
71 newViewRoot.setLocale(oldViewRoot.getLocale());
72 newViewRoot.setRenderKitId(oldViewRoot.getRenderKitId());
73 }
74
75 // TODO: VALIDATE - The spec is silent on the following line, but I feel bad if I don't set it
76 newViewRoot.setViewId(viewId);
77
78 return newViewRoot;
79 }
80 catch (InvalidViewIdException e)
81 {
82 // If no viewId could be identified, or the viewId is exactly equal to the servlet mapping,
83 // send the response error code SC_NOT_FOUND with a suitable message to the client.
84 sendSourceNotFound(context, e.getMessage());
85
86 // TODO: VALIDATE - Spec is silent on the return value when an error was sent
87 return null;
88 }
89 }
90
91 /**
92 * {@inheritDoc}
93 */
94 @Override
95 public UIViewRoot restoreView(FacesContext context, String viewId)
96 {
97 checkNull(context, "context");
98 //checkNull(viewId, "viewId");
99
100 Application application = context.getApplication();
101
102 ViewHandler applicationViewHandler = application.getViewHandler();
103
104 String renderKitId = applicationViewHandler.calculateRenderKitId(context);
105
106 UIViewRoot viewRoot = application.getStateManager().restoreView(context, viewId, renderKitId);
107
108 return viewRoot;
109 }
110
111 /**
112 * Calculates the effective view identifier for the specified raw view identifier.
113 *
114 * @param context le current FacesContext
115 * @param viewId the raw view identifier
116 *
117 * @return the effective view identifier
118 */
119 protected abstract String calculateViewId(FacesContext context, String viewId);
120
121 /**
122 * Send a source not found to the client. Although it can be considered ok in JSP mode,
123 * I think it's pretty lame to have this kind of requirement at VDL level considering VDL
124 * represents the page --> JSF tree link, not the transport layer required to send a
125 * SC_NOT_FOUND.
126 *
127 * @param context le current FacesContext
128 * @param message the message associated with the error
129 */
130 protected abstract void sendSourceNotFound(FacesContext context, String message);
131
132 /**
133 * Check if the specified value of a param is <code>null</code>.
134 *
135 * @param o the parameter's value
136 * @param param the parameter's name
137 *
138 * @throws NullPointerException if the value is <code>null</code>
139 */
140 protected void checkNull(final Object o, final String param)
141 {
142 if (o == null)
143 {
144 throw new NullPointerException(param + " can not be null.");
145 }
146 }
147 }