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Java > Open Source Codes > nextapp > echo2 > webrender > UserInstanceUpdateManager


1 /*
2  * This file is part of the Echo Web Application Framework (hereinafter "Echo").
3  * Copyright (C) 2002-2005 NextApp, Inc.
4  *
5  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
6  *
7  * The contents of this file are subject to the Mozilla Public License Version
8  * 1.1 (the "License"); you may not use this file except in compliance with
9  * the License. You may obtain a copy of the License at
10  * http://www.mozilla.org/MPL/
11  *
12  * Software distributed under the License is distributed on an "AS IS" basis,
13  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
14  * for the specific language governing rights and limitations under the
15  * License.
16  *
17  * Alternatively, the contents of this file may be used under the terms of
18  * either the GNU General Public License Version 2 or later (the "GPL"), or
19  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
20  * in which case the provisions of the GPL or the LGPL are applicable instead
21  * of those above. If you wish to allow use of your version of this file only
22  * under the terms of either the GPL or the LGPL, and not to allow others to
23  * use your version of this file under the terms of the MPL, indicate your
24  * decision by deleting the provisions above and replace them with the notice
25  * and other provisions required by the GPL or the LGPL. If you do not delete
26  * the provisions above, a recipient may use your version of this file under
27  * the terms of any one of the MPL, the GPL or the LGPL.
28  */
29
30 package nextapp.echo2.webrender;
31
32 import java.io.Serializable JavaDoc;
33 import java.util.HashSet JavaDoc;
34 import java.util.Set JavaDoc;
35
36 /**
37  * Provides information about changes to <code>UserInstance</code> properties
38  * of which the client engine needs to be informed.
39  */
40 public class UserInstanceUpdateManager
41 implements Serializable JavaDoc {
42
43     private static final String JavaDoc[] EMPTY_STRING_ARRAY = new String JavaDoc[0];
44     private Set JavaDoc updatedPropertyNames = new HashSet JavaDoc();
45     
46     /**
47      * Retrieves the names of updated properties.
48      * This method is queried by the <code>SynchronizeService</code>.
49      *
50      * @return an array of the updated property names (returns an empty array
51      * if no properties have changed)
52      */
53     public String JavaDoc[] getPropertyUpdateNames() {
54         int size = updatedPropertyNames.size();
55         if (size == 0) {
56             return EMPTY_STRING_ARRAY;
57         }
58         return (String JavaDoc[]) updatedPropertyNames.toArray(new String JavaDoc[size]);
59     }
60     
61     /**
62      * Processes a property update from the <code>UserInstance</code>, storing
63      * the name of the property in the list of properties to be updated.
64      *
65      * @param name the name of the property
66      */
67     void processPropertyUpdate(String JavaDoc name) {
68         updatedPropertyNames.add(name);
69     }
70     
71     /**
72      * Purges list of updated property names.
73      * This method is invoked by the <code>SynchronizeService</code> when it
74      * has finished rendering the updates to the client.
75      */
76     public void purge() {
77         updatedPropertyNames.clear();
78     }
79 }
80
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