blob: 596736a47c6ca0a805c8ed95a47dc7831cbb9ca3 (
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
|
/*
Copyright (C) 2005-2009 Michel de Boer <michel@twinklephone.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/**
* @file
* Abstract observer pattern.
*/
#ifndef _OBSERVER_H
#define _OBSERVER_H
#include <list>
#include "threads/mutex.h"
using namespace std;
namespace patterns {
/** Observer. */
class t_observer {
public:
virtual ~t_observer() {};
/**
* This method is called by an observed subject to indicate its state
* has changed.
*/
virtual void update(void) = 0;
/**
* This method is called when the subject is destroyed.
*/
virtual void subject_destroyed(void) = 0;
};
/** An observed subject. */
class t_subject {
private:
/** Mutex to protect access to the observers. */
mutable t_recursive_mutex mtx_observers;
list<t_observer *> observers; /** Observers of this subject. */
public:
virtual ~t_subject();
/**
* Attach an observer.
* @param o [in] The observer.
*/
void attach(t_observer *o);
/**
* Detach an observer.
* @param o [in] The observer.
*/
void detach(t_observer *o);
/**
* Notify all observers.
*/
void notify(void) const;
};
}; // namespace
#endif
|
