Embedded Template Library 1.0
delegate_observer.h
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3/******************************************************************************
4The MIT License(MIT)
5
6Embedded Template Library.
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10Copyright(c) 2023 John Wellbelove
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30
31#ifndef ETL_DELEGATE_OBSERVER_INCLUDED
32#define ETL_DELEGATE_OBSERVER_INCLUDED
33
34#include "algorithm.h"
35
36#include "platform.h"
37#include "delegate.h"
38#include "vector.h"
39#include "exception.h"
40#include "error_handler.h"
41#include "utility.h"
42
43namespace etl
44{
45 //***************************************************************************
48 //***************************************************************************
50 {
51 public:
52
53 delegate_observer_exception(string_type reason_, string_type file_name_, numeric_type line_number_)
54 : exception(reason_, file_name_, line_number_)
55 {
56 }
57 };
58
59 //***************************************************************************
62 //***************************************************************************
64 {
65 public:
66
67 delegate_observer_list_full(string_type file_name_, numeric_type line_number_)
68 : delegate_observer_exception(ETL_ERROR_TEXT("delegate_observable:full", ETL_DELEGATE_OBSERVER_FILE_ID"A"), file_name_, line_number_)
69 {
70 }
71 };
72
73 //*********************************************************************
77 //*********************************************************************
78 template <typename TNotification, const size_t MAX_OBSERVERS>
80 {
81 public:
82
83 typedef etl::delegate<void(TNotification)> observer_type;
84
85 private:
86
87 //***********************************
88 // Item stored in the observer list.
89 //***********************************
90 struct observer_item
91 {
92 observer_item(observer_type observer_)
93 : observer(observer_)
94 , enabled(true)
95 {
96 }
97
99 bool enabled;
100 };
101
102 //***********************************
103 // How to compare an observer with an observer list item.
104 //***********************************
105 struct compare_observers
106 {
107 compare_observers(observer_type& observer_)
108 : observer(&observer_)
109 {
110 }
111
112 bool operator ()(const observer_item& item) const
113 {
114 return observer == item.observer;
115 }
116
118 };
119
121
122 public:
123
124 typedef size_t size_type;
125 typedef TNotification notification_type;
126
127 //*****************************************************************
132 //*****************************************************************
134 {
135 // See if we already have it in our list.
136 typename Observer_List::iterator i_observer_item = find_observer(observer);
137
138 // Not there?
139 if (i_observer_item == observer_list.end())
140 {
141 // Is there enough room?
142 ETL_ASSERT_OR_RETURN(!observer_list.full(), ETL_ERROR(etl::observer_list_full));
143
144 // Add it.
145 observer_list.push_back(observer_item(observer));
146 }
147 }
148
149 //*****************************************************************
153 //*****************************************************************
155 {
156 // See if we have it in our list.
157 typename Observer_List::iterator i_observer_item = find_observer(observer);
158
159 // Found it?
160 if (i_observer_item != observer_list.end())
161 {
162 // Erase it.
163 observer_list.erase(i_observer_item);
164 return true;
165 }
166 else
167 {
168 return false;
169 }
170 }
171
172 //*****************************************************************
176 //*****************************************************************
177 void enable_observer(observer_type& observer, bool state = true)
178 {
179 // See if we have it in our list.
180 typename Observer_List::iterator i_observer_item = find_observer(observer);
181
182 // Found it?
183 if (i_observer_item != observer_list.end())
184 {
185 i_observer_item->enabled = state;
186 }
187 }
188
189 //*****************************************************************
191 //*****************************************************************
193 {
194 // See if we have it in our list.
195 typename Observer_List::iterator i_observer_item = find_observer(observer);
196
197 // Found it?
198 if (i_observer_item != observer_list.end())
199 {
200 i_observer_item->enabled = false;
201 }
202 }
203
204 //*****************************************************************
206 //*****************************************************************
208 {
209 observer_list.clear();
210 }
211
212 //*****************************************************************
214 //*****************************************************************
215 size_type number_of_observers() const
216 {
217 return observer_list.size();
218 }
219
220 //*****************************************************************
224 //*****************************************************************
225 void notify_observers(TNotification n)
226 {
227 typename Observer_List::iterator i_observer_item = observer_list.begin();
228
229 while (i_observer_item != observer_list.end())
230 {
231 if (i_observer_item->enabled)
232 {
233 i_observer_item->p_observer->notification(n);
234 }
235
236 ++i_observer_item;
237 }
238 }
239
240 protected:
241
243 {
244 }
245
246 private:
247
248 //*****************************************************************
251 //*****************************************************************
252 typename Observer_List::iterator find_observer(observer_type& observer_)
253 {
254 return etl::find_if(observer_list.begin(), observer_list.end(), compare_observers(observer_));
255 }
256
258 Observer_List observer_list;
259 };
260}
261
262#endif
Declaration.
Definition: delegate_cpp03.h:175
ETL_CONSTEXPR exception(string_type reason_, string_type, numeric_type line_)
Constructor.
Definition: exception.h:69
Definition: exception.h:47
void add_observer(observer_type &observer)
Definition: delegate_observer.h:133
void notify_observers(TNotification n)
Definition: delegate_observer.h:225
void enable_observer(observer_type &observer, bool state=true)
Definition: delegate_observer.h:177
void clear_observers()
Clear all observers from the list.
Definition: delegate_observer.h:207
bool remove_observer(observer_type &observer)
Definition: delegate_observer.h:154
void disable_observer(observer_type &observer)
Disable an observer.
Definition: delegate_observer.h:192
size_type number_of_observers() const
Returns the number of observers.
Definition: delegate_observer.h:215
Definition: delegate_observer.h:80
Definition: delegate_observer.h:50
Definition: delegate_observer.h:64
Definition: observer.h:100
Definition: observer.h:321
Definition: observer.h:83
iterator begin()
Definition: vector.h:100
void push_back(const_reference value)
Definition: vector.h:432
void clear()
Clears the vector.
Definition: vector.h:414
iterator end()
Definition: vector.h:118
bool full() const
Definition: vector.h:977
size_type size() const
Definition: vector.h:959
iterator erase(iterator i_element)
Definition: vector.h:865
bitset_ext
Definition: absolute.h:38