在互联网上发送Android市场公钥(Sending Android market public key across the internet)

 这是一个使用Observer模式将观察者注册到登录系统的示例。 在示例中，我注册了一个观察者，在创建新用户时向管理员发送电子邮件： 
 
 首先，我们创建定义observable / observers行为的接口 
 
interface IObserver
{
     //an observer has to implement a function, that will be called when the observable changes
     //the function receive data (in this case the user name) and also the observable object (since the observer could be observing more than on system)
     function onUserAdded( $observable, $data );
}

interface IObservable
{
    //we can attach observers to the observable
    function attach( $observer );
}
 
 然后让您的主登录系统实现IObservable，实现attach函数，并保留一组观察者。 在内部，您实现了一个notify函数，在调用它时，迭代数组并通知每个观察者。 
 
 你做的是，在创建用户的所有正常行为之后，你调用你的通知函数。 
 
class LoginSystem implements IObservable
{
    private $observers = array();

    private function notify( $userName )
    {
        foreach( $this->observers as $o )
            $o->onUserAdded( $this, $userName );
    }

    public function attach( $observer )
    {
        $this->observers []= $observer;
    }

    public function createUser( $userName )
    {

        //all your logic to add it to the databse or whatever, and then:

        $this->notify($userName);

    }

}
 
 然后，您创建一个类而不是实现Iobserver。 在onUserAdded函数中，您可以在发生观察事件时执行任何操作。 在这个例子中，我只是将邮件发送到硬编码的电子邮件。 它可能会像你想要的那样复杂。 
 
class NewUserMailer implements IObserver
{
    public function  onUserAdded( $observable, $data ) 
    {
        mail("admin@yoursite.com", "new user", $data);
    }
}
 
 然后，行为就是在创建登录系统之后，您还创建了一个观察者，并且附加到登录系统 
 
$ls = new LoginSystem();
$ls->attach( new NewUserMailer() );
 
 有了这个，每次创建新用户时，邮件都会发送到“admin@yoursite.com” 

This is an example that uses the Observer pattern to register observers to your login system. In the example, i register an observer that sends a email to the admin when a new user is created:
 
First, we create the interfaces that define the behavior of the observable/observers
 
interface IObserver
{
     //an observer has to implement a function, that will be called when the observable changes
     //the function receive data (in this case the user name) and also the observable object (since the observer could be observing more than on system)
     function onUserAdded( $observable, $data );
}

interface IObservable
{
    //we can attach observers to the observable
    function attach( $observer );
}
 
Then you let your main login system implement IObservable, you implement the attach function, and keep an array of observers. internally, you implement a notify function that when it is called, iterate the array and notify every observer. 
 
What you do, is after all the normal behavior of creating an user, you call your notify function.
 
class LoginSystem implements IObservable
{
    private $observers = array();

    private function notify( $userName )
    {
        foreach( $this->observers as $o )
            $o->onUserAdded( $this, $userName );
    }

    public function attach( $observer )
    {
        $this->observers []= $observer;
    }

    public function createUser( $userName )
    {

        //all your logic to add it to the databse or whatever, and then:

        $this->notify($userName);

    }

}
 
Then, you create a class than implements Iobserver. in the onUserAdded function, you do whatever you want to happen when the observed event occurs. In this example i just send a mail to a hardcoded email. It could be as complex as you want. 
 
class NewUserMailer implements IObserver
{
    public function  onUserAdded( $observable, $data ) 
    {
        mail("admin@yoursite.com", "new user", $data);
    }
}
 
Then, the behavior is just, after creating the loginsystem, you also create an observer, and attach is to the login system
 
$ls = new LoginSystem();
$ls->attach( new NewUserMailer() );
 
With this, everytime a new user is created, a mail will be sent to "admin@yoursite.com"