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1 /*
2 * $Id: NavigationHandler.java,v 1.15 2007/04/27 22:00:02 ofung Exp $
3 */
4
5 /*
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
7 *
8 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
9 *
10 * The contents of this file are subject to the terms of either the GNU
11 * General Public License Version 2 only ("GPL") or the Common Development
12 * and Distribution License("CDDL") (collectively, the "License"). You
13 * may not use this file except in compliance with the License. You can obtain
14 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
15 * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
16 * language governing permissions and limitations under the License.
17 *
18 * When distributing the software, include this License Header Notice in each
19 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
20 * Sun designates this particular file as subject to the "Classpath" exception
21 * as provided by Sun in the GPL Version 2 section of the License file that
22 * accompanied this code. If applicable, add the following below the License
23 * Header, with the fields enclosed by brackets [] replaced by your own
24 * identifying information: "Portions Copyrighted [year]
25 * [name of copyright owner]"
26 *
27 * Contributor(s):
28 *
29 * If you wish your version of this file to be governed by only the CDDL or
30 * only the GPL Version 2, indicate your decision by adding "[Contributor]
31 * elects to include this software in this distribution under the [CDDL or GPL
32 * Version 2] license." If you don't indicate a single choice of license, a
33 * recipient has the option to distribute your version of this file under
34 * either the CDDL, the GPL Version 2 or to extend the choice of license to
35 * its licensees as provided above. However, if you add GPL Version 2 code
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38 * holder.
39 */
40
41 package javax.faces.application;
42
43
44 import javax.faces.context.FacesContext;
45
46
47 /**
48 * <p>A <strong>NavigationHandler</strong> is passed the outcome string
49 * returned by an application action invoked for this application, and will
50 * use this (along with related state information) to choose the view to
51 * be displayed next.</p>
52 *
53 * <p>A default implementation of <code>NavigationHandler</code> must be
54 * provided by the JSF implementation, which will be utilized unless
55 * <code>setNavigationHandler()</code> is called to establish a different one.
56 * This default instance will compare the view identifier of the current
57 * view, the specified action binding, and the specified outcome against
58 * any navigation rules provided in <code>faces-config.xml</code> file(s).
59 * If a navigation case matches, the current view will be changed by a call
60 * to <code>FacesContext.setViewRoot()</code>. Note that a <code>null</code>
61 * outcome value will never match any navigation rule, so it can be used as an
62 * indicator that the current view should be redisplayed.</p>
63 */
64
65 public abstract class NavigationHandler {
66
67
68 /**
69 * <p>Perform navigation processing based on the state information
70 * in the specified {@link FacesContext}, plus the outcome string
71 * returned by an executed application action.</p>
72 *
73 * @param context The {@link FacesContext} for the current request
74 * @param fromAction The action binding expression that was evaluated
75 * to retrieve the specified outcome, or <code>null</code> if the
76 * outcome was acquired by some other means
77 * @param outcome The logical outcome returned by a previous invoked
78 * application action (which may be <code>null</code>)
79 *
80 * @throws NullPointerException if <code>context</code>
81 * is <code>null</code>
82 */
83 public abstract void handleNavigation(FacesContext context,
84 String fromAction,
85 String outcome);
86
87
88 }