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| #include <iostream>
#include <memory>
#include <string>
#include <vector>
class observer;
class subscriber : public std::enable_shared_from_this<subscriber> {
public:
subscriber(const std::string& user_name) : user_name_(user_name) {
}
void callback(const std::string& str) {
std::cout << user_name_ << ": " << str << std::endl;
}
private:
std::string user_name_;
};
class observer {
public:
void boardcast(const std::string& message) {
for (auto it = vec.begin(); it != vec.end();) {
auto sp = it->lock();
if (sp) {
sp->callback(message);
it++;
} else {
it = vec.erase(it);
}
}
}
void regist(std::weak_ptr<subscriber> wp) {
if (wp.lock()) {
vec.push_back(wp);
}
}
private:
std::vector<std::weak_ptr<subscriber>> vec;
};
int main() {
auto ob = std::make_shared<observer>();
auto sp1 = std::make_shared<subscriber> ("subscriber1");
ob->regist(sp1->weak_from_this());
auto sp2 = std::make_shared<subscriber> ("subscriber2");
ob->regist(sp2->weak_from_this());
{
auto sp3 = std::make_shared<subscriber> ("subscriber3");
ob->regist(sp3->weak_from_this());
auto sp4 = std::make_shared<subscriber> ("subscriber4");
ob->regist(sp4->weak_from_this());
ob->boardcast("start boardcast!");
}
ob->boardcast("boardcast again!");
return 0;
}
|