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
20 package org.apache.myfaces.orchestra.viewController;
21
22 /**
23 * An interface for use with the InterfaceViewControllerExecutor.
24 * <p>
25 * When the InterfaceViewControllerExecutor has been selected as the technique for mapping
26 * lifecycle events onto bean methods, then the target bean must implement this interface
27 * in order to get callbacks.
28 * <p>
29 * Note that the expression "view controller bean" is used to generally refer to an object
30 * that can handle lifecycle events for a view. Such beans may implement this interface, but
31 * may not - they might be accessed via the ReflectiveViewControllerExecutor or other
32 * implementations that do not require this interface.
33 */
34 public interface ViewController
35 {
36 /**
37 * This method will <i>always</i> be called before any other method is invoked
38 * on any backing bean for the current request. It is invoked once for each
39 * request.
40 * <p>
41 * This callback could possibly be better named "notifyBeginRequestUsingThisView"
42 * or similar, as it is invoked per request.
43 * <p>
44 * There are three different situations in which initView callbacks occur:
45 * <ol>
46 * <li>
47 * A view is just being rendered.<br>
48 * The initView callback gets called once (at BeforeRender)
49 * </li>
50 * <li>
51 * A postback is processed, no navigation occurs.<br>
52 * The initView callback gets called once (at AfterRestoreView)
53 * </li>
54 * <li>
55 * A postback occurs, navigation to a different view instance occurs.<br>
56 * The initView callback gets called once for the original view, and then once for the new view.
57 * </li>
58 * </ol>
59 * <p>
60 * Note that the condition tested is whether the <i>view instance</i> has changed; if navigation causes
61 * a new view root to be created then the initView callback occurs even if that view root has the
62 * same viewId [1].
63 * <p>
64 * Note [1]: Orchestra versions 1.3 and earlier test only the viewId string.
65 */
66 public void initView();
67
68 /**
69 * This method will be invoked before any "action" callbacks related to buttons,
70 * links, etc. are invoked on backing beans for the current request.
71 * <p>
72 * For JSF, there is an exception: for command components marked as "immediate",
73 * the associated action method is invoked before this callback occurs. If that
74 * method then performs navigation then this callback will not occur at all.
75 * <p>
76 * Note also that for JSF, if validation failures occur then this callback will
77 * not be invoked (as actions are skipped).
78 */
79 public void preProcess();
80
81 /**
82 * This method will be invoked just before starting to render output to the user.
83 */
84 public void preRenderView();
85 }