View Javadoc

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       */
41      public void initView();
42  
43      /**
44       * This method will be invoked before any "action" callbacks related to buttons,
45       * links, etc. are invoked on backing beans for the current request.
46       * <p>
47       * For JSF, there is an exception: for command components marked as "immediate",
48       * the associated action method is invoked before this callback occurs. If that
49       * method then performs navigation then this callback will not occur at all.
50       * <p>
51       * Note also that for JSF, if validation failures occur then this callback will
52       * not be invoked (as actions are skipped).  
53       */
54      public void preProcess();
55      
56      /**
57       * This method will be invoked just before starting to render output to the user.
58       */
59      public void preRenderView();
60  }