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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.tomahawk.util;
21  
22  import javax.faces.application.NavigationHandler;
23  import javax.faces.application.ViewHandler;
24  import javax.faces.component.UIViewRoot;
25  import javax.faces.context.FacesContext;
26  
27  /**
28   * An alternative implementation of the standard JSF NavigationHandler API which
29   * directly using the outcome of an action as the name of the page to navigate to.
30   * <p>
31   * This bypasses the "logical navigation" approach of standard JSF, so that pages
32   * can be wired together by using actual urls in command actions and action-method
33   * return values.
34   * <p>
35   * When this navigation-handler is configured, all navigation-rule entries in
36   * faces-config.xml files are ignored completely.
37   * <p>
38   * This navigation handler does not work well in combination with other custom
39   * navigation handlers, as it never passes any calls down to underlying
40   * implementations. Having another NavigationHandler decorate this one will
41   * work; having this navigation handler decorate another will not as the
42   * decorated handler will never be invoked. Therefore if multiple navigation
43   * handlers are to be used (eg the Tomahawk RedirectTrackerNavigationHandler
44   * in combination with this one), then this should be listed first in the
45   * faces-config.xml file so that the other handlers decorate this one. 
46   */
47  public class DirectNavigationHandler extends NavigationHandler
48  {
49      /**
50       * Gives the handleNavigation() method an alternative behaviour. Linking
51       * is now processed directly to the given url (e.g. action="/pages/site.jsp").
52       *
53       * There is no check if the outcome value really points to a valid page.
54       */
55      public void handleNavigation(FacesContext context, String fromAction, String outcome)
56      {
57          if(outcome == null || outcome.length()==0)
58          {
59              return;
60          }
61  
62          ViewHandler viewHandler=context.getApplication().getViewHandler();
63          UIViewRoot viewRoot=viewHandler.createView(context,outcome);
64          context.setViewRoot(viewRoot);
65          context.renderResponse();
66      }
67  }