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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  package org.apache.myfaces.trinidad.context;
20  
21  import java.io.IOException;
22  
23  import java.util.Map;
24  
25  import javax.faces.context.ExternalContext;
26  
27  import javax.faces.context.FacesContext;
28  
29  import org.apache.myfaces.trinidad.event.WindowLifecycleListener;
30  
31  /**
32   * <p>
33   * Manages the set of Windows currently in the Session and allows listeners on the Windows'
34   * lifecycles to be registered.
35   * </p>
36   * @see org.apache.myfaces.trinidad.context.RequestContext#getWindowManager
37   */
38  abstract public class WindowManager
39  {
40    /**
41     * @param extContext ExternalContext so that the WindowManager may be called before the
42     * FacesContext is available
43     * @return The Window that contains the document making the current request
44     */
45    public abstract Window getCurrentWindow(ExternalContext extContext);
46    
47    /**
48     * @param extContext ExternalContext so that the WindowManager may be called before the
49     * FacesContext is available
50     * @return The Unmodifiable Map of WindowIds to Windows
51     */
52    public abstract Map<String, ? extends Window> getWindows(ExternalContext extContext);
53  
54    /**
55     * <p>
56     * Registers a listener that will be informed of changes to the Lifecylce state of any of
57     * the known Windows.
58     * </p>
59     * <p>
60     * WindowLifecycleListener may be registered automatically by adding a file
61     * containing the names of the classes implementing the WindowListener in a file named
62     * <code>org.apache.myfaces.trinidad.event.WindowListener</code> inside of
63     * the <code>META_INF/services</code> directory.
64     * </p>
65     * @param extContext ExternalContext so that the WindowManager may be called before the
66     * FacesContext is available
67     * @param windowListener
68     */
69    public abstract void addWindowLifecycleListener(
70      ExternalContext extContext, WindowLifecycleListener windowListener);
71  
72    /**
73     * Removes a listener that will be informed of changes to the Lifecylce state of any of
74     * the known Windows
75     * @param extContext ExternalContext so that the WindowManager may be called before the
76     * FacesContext is available
77     * @param windowListener
78     */
79    public abstract void removeWindowLifecycleListener(
80      ExternalContext extContext, WindowLifecycleListener windowListener);
81  
82    /**
83     * Performs any necessary action to embed the current window identifier into the output
84     * @param context FacesContext to use to write the output
85     * @throws IOException if an output exception occurs
86     */
87    public abstract void writeState(FacesContext context) throws IOException;
88  }