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comparison Framework/Toolbox/ObserversRegistry.h @ 0:351ab0da0150

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author Sebastien Jodogne <s.jodogne@gmail.com>
date Fri, 14 Oct 2016 15:34:11 +0200
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1 /**
2 * Stone of Orthanc
3 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
4 * Department, University Hospital of Liege, Belgium
5 *
6 * This program is free software: you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation, either version 3 of the
9 * License, or (at your option) any later version.
10 *
11 * In addition, as a special exception, the copyright holders of this
12 * program give permission to link the code of its release with the
13 * OpenSSL project's "OpenSSL" library (or with modified versions of it
14 * that use the same license as the "OpenSSL" library), and distribute
15 * the linked executables. You must obey the GNU General Public License
16 * in all respects for all of the code used other than "OpenSSL". If you
17 * modify file(s) with this exception, you may extend this exception to
18 * your version of the file(s), but you are not obligated to do so. If
19 * you do not wish to do so, delete this exception statement from your
20 * version. If you delete this exception statement from all source files
21 * in the program, then also delete it here.
22 *
23 * This program is distributed in the hope that it will be useful, but
24 * WITHOUT ANY WARRANTY; without even the implied warranty of
25 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
26 * General Public License for more details.
27 *
28 * You should have received a copy of the GNU General Public License
29 * along with this program. If not, see <http://www.gnu.org/licenses/>.
30 **/
31
32
33 #pragma once
34
35 #include "../Orthanc/Core/OrthancException.h"
36
37 #include <boost/noncopyable.hpp>
38 #include <boost/thread/mutex.hpp>
39 #include <set>
40
41 namespace OrthancStone
42 {
43 template <
44 typename Source,
45 typename Observer = typename Source::IChangeObserver
46 >
47 class ObserversRegistry : public boost::noncopyable
48 {
49 private:
50 struct ChangeFunctor : public boost::noncopyable
51 {
52 void operator() (Observer& observer,
53 const Source& source)
54 {
55 observer.NotifyChange(source);
56 }
57 };
58
59 typedef std::set<Observer*> Observers;
60
61 boost::mutex mutex_;
62 Observers observers_;
63 bool empty_;
64
65 public:
66 ObserversRegistry() : empty_(true)
67 {
68 }
69
70 template <typename Functor>
71 void Notify(const Source* source,
72 Functor& functor)
73 {
74 if (empty_)
75 {
76 // Optimization to avoid the unnecessary locking of the mutex
77 return;
78 }
79
80 if (source == NULL)
81 {
82 throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange);
83 }
84
85 boost::mutex::scoped_lock lock(mutex_);
86
87 for (typename Observers::const_iterator observer = observers_.begin();
88 observer != observers_.end(); ++observer)
89 {
90 functor(**observer, *source);
91 }
92 }
93
94 template <typename Functor>
95 void Notify(const Source* source)
96 {
97 // Use the default functor
98 Functor functor;
99 Notify(source, functor);
100 }
101
102 void NotifyChange(const Source* source)
103 {
104 Notify<ChangeFunctor>(source);
105 }
106
107 void Register(Observer& observer)
108 {
109 empty_ = false;
110
111 boost::mutex::scoped_lock lock(mutex_);
112 observers_.insert(&observer);
113 }
114
115 void Unregister(Observer& observer)
116 {
117 boost::mutex::scoped_lock lock(mutex_);
118 observers_.erase(&observer);
119
120 if (observers_.empty())
121 {
122 empty_ = true;
123 }
124 }
125
126 bool IsEmpty()
127 {
128 #if 0
129 boost::mutex::scoped_lock lock(mutex_);
130 return observers_.empty();
131 #else
132 return empty_;
133 #endif
134 }
135 };
136 }