}
//实现可被观察对象
//负责维护关注列表，并发送消息
class UserList implements IObservable
{
private $_observers = array();
public function addCustomer($name)
{
foreach ($this->_observers as $obs) {
$obs->onChanged($this, $name);
}
}
public function addObserver($observer)
{
$this->_observers[] = $observer;
}
}
//实现一个观察者
class UserListLogger implements IObserver
{
public function onChanged($sender, $args)
{
echo "'{$args}' added to user list\n";
}
}
$ul = new UserList();
//观察者列表
$ul->addObserver(new UserListLogger());
//添加观察者至观察者列表
$ul->addCustomer("Jack");
//添加用户，并将消息发送给观察者
{
echo "'{$args}' send to UserListLogger\n";
}
public function getName()
{
return 'UserListLogger';
}
}
class OtherObserver implements IObserver
{
public function onSendMsg($sender, $args)
{
echo "'{$args}' send to OtherObserver\n";
}
public function getName()
{
return 'OtherObserver';
}
}
$ul = new UserList();
//被观察者
$ul->addObserver(new UserListLogger());
//增加观察者
$ul->addObserver(new OtherObserver());
//增加观察者
$ul->sendMsg("Jack");
//发送消息到观察者
$ul->removeObserver('UserListLogger');
//移除观察者
$ul->sendMsg("hello");
//发送消息到观察者