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 * @since 2.0
31 */
32 public abstract class ViewDeclarationLanguageBase extends ViewDeclarationLanguage
33 {
34
35 /**
36 * Process the specification required algorithm that is generic to all PDL.
37 *
38 * @param context
39 * @param viewId
40 */
41 public UIViewRoot createView(FacesContext context, String viewId)
42 {
43 checkNull(context, "context");
44 //checkNull(viewId, "viewId");
45
46 try
47 {
48 viewId = calculateViewId(context, viewId);
49
50 Application application = context.getApplication();
51
52 // Create a new UIViewRoot object instance using Application.createComponent(UIViewRoot.COMPONENT_TYPE).
53 UIViewRoot newViewRoot = (UIViewRoot) application.createComponent(
54 context, UIViewRoot.COMPONENT_TYPE, null);
55 UIViewRoot oldViewRoot = context.getViewRoot();
56 if (oldViewRoot == null)
57 {
58 // If not, this method must call calculateLocale() and calculateRenderKitId(), and store the results
59 // as the values of the locale and renderKitId, proeprties, respectively, of the newly created
60 // UIViewRoot.
61 ViewHandler handler = application.getViewHandler();
62 newViewRoot.setLocale(handler.calculateLocale(context));
63 newViewRoot.setRenderKitId(handler.calculateRenderKitId(context));
64 }
65 else
66 {
67 // If there is an existing UIViewRoot available on the FacesContext, this method must copy its locale
68 // and renderKitId to this new view root
69 newViewRoot.setLocale(oldViewRoot.getLocale());
70 newViewRoot.setRenderKitId(oldViewRoot.getRenderKitId());
71 }
72
73 // TODO: VALIDATE - The spec is silent on the following line, but I feel bad if I don't set it
74 newViewRoot.setViewId(viewId);
75
76 return newViewRoot;
77 }
78 catch (InvalidViewIdException e)
79 {
80 // If no viewId could be identified, or the viewId is exactly equal to the servlet mapping,
81 // send the response error code SC_NOT_FOUND with a suitable message to the client.
82 sendSourceNotFound(context, e.getMessage());
83
84 // TODO: VALIDATE - Spec is silent on the return value when an error was sent
85 return null;
86 }
87 }
88
89 /**
90 * {@inheritDoc}
91 */
92 @Override
93 public UIViewRoot restoreView(FacesContext context, String viewId)
94 {
95 checkNull(context, "context");
96 //checkNull(viewId, "viewId");
97
98 Application application = context.getApplication();
99
100 ViewHandler applicationViewHandler = application.getViewHandler();
101
102 String renderKitId = applicationViewHandler.calculateRenderKitId(context);
103
104 UIViewRoot viewRoot = application.getStateManager().restoreView(context, viewId, renderKitId);
105
106 return viewRoot;
107 }
108
109 /**
110 * Calculates the effective view identifier for the specified raw view identifier.
111 *
112 * @param context le current FacesContext
113 * @param viewId the raw view identifier
114 *
115 * @return the effective view identifier
116 */
117 protected abstract String calculateViewId(FacesContext context, String viewId);
118
119 /**
120 * Send a source not found to the client. Although it can be considered ok in JSP mode,
121 * I think it's pretty lame to have this kind of requirement at VDL level considering VDL
122 * represents the page --> JSF tree link, not the transport layer required to send a
123 * SC_NOT_FOUND.
124 *
125 * @param context le current FacesContext
126 * @param message the message associated with the error
127 */
128 protected abstract void sendSourceNotFound(FacesContext context, String message);
129
130 /**
131 * Check if the specified value of a param is <code>null</code>.
132 *
133 * @param o the parameter's value
134 * @param param the parameter's name
135 *
136 * @throws NullPointerException if the value is <code>null</code>
137 */
138 protected void checkNull(final Object o, final String param)
139 {
140 if (o == null)
141 {
142 throw new NullPointerException(param + " can not be null.");
143 }
144 }
145 }