blob: 758fb4034c52ee7f48e2789f9c230a6f46821de4 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
/*
Wotonomy: OpenStep design patterns for pure Java applications.
Copyright (C) 2000 Intersect Software Corporation
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see http://www.gnu.org
*/
package net.wotonomy.control;
import java.util.Observable;
import java.util.Observer;
/**
* This is an abstract class for receiving coalesced
* notifications of changes from objects.
* This class also implements Observer for greater
* compatibility.
* The point of EODelayedObservers is that when
* they receive a willChange message, they
* queue themselves with a EODelayedObserverQueue
* so they can receive a single subjectChanged()
* after all changes from an observed object take
* place.
*
* @author michael@mpowers.net
* @author $Author: cgruber $
* @version $Revision: 894 $
*/
public abstract class EODelayedObserver
implements EOObserving, Observer
{
/**
* Notified immediately.
*/
public static final int ObserverPriorityImmediate = 0;
public static final int ObserverPriorityFirst = 1;
public static final int ObserverPrioritySecond = 2;
public static final int ObserverPriorityThird = 3;
public static final int ObserverPriorityFourth = 4;
public static final int ObserverPriorityFifth = 5;
public static final int ObserverPrioritySixth = 6;
public static final int ObserverPriorityLater = 7;
public static final int ObserverNumberOfPriorities = 8;
/**
* Default constructor.
*/
public EODelayedObserver ()
{
}
/**
* Removes this observer from the observer queue
* for a currently pending notification.
*/
public void discardPendingNotification ()
{
observerQueue().dequeueObserver( this );
}
/**
* Returns the observer queue to which this observer
* belongs. This implementation returns the default
* EODelayedObserverQueue.
* Override to use a different one.
*/
public EODelayedObserverQueue observerQueue ()
{
return EODelayedObserverQueue.defaultObserverQueue();
}
/**
* Returns the priority of this observer in the queue.
* This implementation returns ObserverPriorityThird.
* Override to be notified before other observers.
*/
public int priority ()
{
return ObserverPriorityThird;
}
/**
* Notifies observer that one or more objects that
* it is observing have changed. The observer should
* check all objects it is observing for changes.
*/
public abstract void subjectChanged ();
// interface EOObserving
/**
* Called when the specified object is about to change.
* This implementation puts this observer on a
* notification queue.
*/
public void objectWillChange ( Object anObject )
{
observerQueue().enqueueObserver( this );
}
// interface Observer
/**
* Called when the specified object has changed,
* with the specified argument.
* This method is included for interacting with
* the java.lang.Observer pattern.
* This implementation simply objectWillChange(anObject)
* so that the observer still gets a single subjectChanged
* call in response to multiple changes.
*/
public void update ( Observable anObject, Object aValue )
{
objectWillChange( anObject );
}
}
/*
* $Log$
* Revision 1.2 2006/02/16 16:47:14 cgruber
* Move some classes in to "internal" packages and re-work imports, etc.
*
* Also use UnsupportedOperationExceptions where appropriate, instead of WotonomyExceptions.
*
* Revision 1.1 2006/02/16 13:19:57 cgruber
* Check in all sources in eclipse-friendly maven-enabled packages.
*
* Revision 1.2 2001/10/26 18:38:10 mpowers
* Reordered priorities.
*
* Revision 1.1.1.1 2000/12/21 15:46:38 mpowers
* Contributing wotonomy.
*
* Revision 1.3 2000/12/20 16:25:35 michael
* Added log to all files.
*
*
*/
|
