Examples of Observer Pattern Definition and Usage of PHP Design Pattern

This paper illustrates the definition and usage of observer pattern of PHP design pattern. Share it for your reference, as follows:

<?php
/**
 * Interface Observable
 * define a observable interface
 * @author jichao.wang
 */
interface Observable
{
  function attach(Observer $observer);
  function detach(Observer $observer);
  function notify();
}
/**
 * Class Login
 * @author jichao.wang
 */
class Login implements Observable
{
  private $observers;
  public $status;
  public $ip;
  const LOGIN_ACCESS = 1;
  const LOGIN_WRONG_PASS = 2;
  const LOGIN_USER_UNKNOWN = 3;
  function __construct()
  {
    $this->observers = array();
  }
  /**
   * @param Observer $observer
   * @author jichao.wang
   * attach a observer
   */
  function attach(Observer $observer)
  {
    $this->observers[] = $observer;
  }
  /**
   * @param Observer $observer
   * @author jichao.wang
   * detach a observer
   */
  function detach(Observer $observer)
  {
    $newObservers = array();
    foreach ($this->observers as $key => $obs) {
      if ($obs !== $observer) {
        $newObservers[] = $obs;
      }
    }
    $this->observers = $newObservers;
  }
  /**
   * @author jichao.wang
   * handle observer notify
   */
  function notify()
  {
    foreach ($this->observers as $obs) {
      $obs->update($this);
    }
  }
  /**
   * @author jichao.wang
   *  Execute login 
   */
  function handleLogin()
  {
    $ip = rand(1,100);
    switch (rand(1, 3)) {
      case 1:
        $this->setStatus(self::LOGIN_ACCESS, $ip);
        $ret = true;
        break;
      case 2:
        $this->setStatus(self::LOGIN_WRONG_PASS, $ip);
        $ret = false;
        break;
      case 3:
        $this->setStatus(self::LOGIN_USER_UNKNOWN, $ip);
        $ret = false;
        break;
    }
    /**
     * handle event
     */
    $this->notify();
    return $ret;
  }
  /**
   * @param $status
   * @author jichao.wang
   * set login status
   */
  function setStatus($status,$ip)
  {
    $this->status = $status;
    $this->ip = $ip;
  }
  /**
   * @return mixed
   * @author jichao.wang
   * get login status
   */
  function getStatus()
  {
    return $this->status;
  }
}
/**
 * Interface Observer
 * @author jichao.wang
 */
interface Observer {
  function update(Observable $observable);
}
/**
 * Class EmailObserver
 * @author jichao.wang
 */
class EmailObserver implements Observer {
  function update (Observable $observable) {
    $status = $observable->getStatus();
    if($status == Login::LOGIN_ACCESS){
//      $this->sendMail(' Users ip:'.$observable->ip.' Successful login !');
      echo __CLASS__.' Users ip:'.$observable->ip.' Successful login !'.'------------------';
    }
    if($status == Login::LOGIN_WRONG_PASS){
//      $this->sendMail(' Users ip:'.$observable->ip.' Login failed, password error !');
      echo __CLASS__.' Users ip:'.$observable->ip.' Login failed, password error !'.'------------------';
    }
    if($status == Login::LOGIN_USER_UNKNOWN){
//      $this->sendMail(' Users ip:'.$observable->ip.' Login failed, there is no such user !');
      echo __CLASS__.' Users ip:'.$observable->ip.' Login failed, there is no such user !'.'------------------';
    }
  }
}
/**
 * Class PhoneObserver
 * @author jichao.wang
 */
class PhoneObserver implements Observer {
  function update (Observable $observable) {
    $status = $observable->getStatus();
    if($status == Login::LOGIN_ACCESS){
//      $this->sendMail(' Users ip:'.$observable->ip.' Successful login !');
      echo __CLASS__.' Users ip:'.$observable->ip.' Successful login !'.'------------------';
    }
    if($status == Login::LOGIN_WRONG_PASS){
//      $this->sendMail(' Users ip:'.$observable->ip.' Login failed, password error !');
      echo __CLASS__.' Users ip:'.$observable->ip.' Login failed, password error !'.'------------------';
    }
    if($status == Login::LOGIN_USER_UNKNOWN){
//      $this->sendMail(' Users ip:'.$observable->ip.' Login failed, there is no such user !');
      echo __CLASS__.' Users ip:'.$observable->ip.' Login failed, there is no such user !'.'------------------';
    }
  }
}
class AbcObserver implements Observer {
  function update (Observable $observable) {
    $status = $observable->getStatus();
    if($status == Login::LOGIN_ACCESS){
//      $this->sendMail(' Users ip:'.$observable->ip.' Successful login !');
      echo __CLASS__.' Users ip:'.$observable->ip.' Successful login !'.'------------------';
    }
    if($status == Login::LOGIN_WRONG_PASS){
//      $this->sendMail(' Users ip:'.$observable->ip.' Login failed, password error !');
      echo __CLASS__.' Users ip:'.$observable->ip.' Login failed, password error !'.'------------------';
    }
    if($status == Login::LOGIN_USER_UNKNOWN){
//      $this->sendMail(' Users ip:'.$observable->ip.' Login failed, there is no such user !');
      echo __CLASS__.' Users ip:'.$observable->ip.' Login failed, there is no such user !'.'------------------';
    }
  }
}
// Instantiate login information 
$login = new Login();
// Implement email observer 
$login->attach(new EmailObserver());
// Realize the observer of sending verification code 
$login->attach(new PhoneObserver());
// Implement other observers 
$login->attach(new AbcObserver());
// Start landing 
$login->handleLogin();
?>

Run results:

EmailObserver user ip: 41 login failed, no such user! ------------PhoneObserver user ip: 41 login failed, no such user! -----------AbcObserver User ip: 41 Log-in failed, no such user! -----

More readers interested in PHP can check out the topics of this site: "Introduction to php Object-Oriented Programming", "Encyclopedia of PHP Array (Array) Operation Skills", "Introduction to PHP Basic Grammar", "Summary of PHP Operation and Operator Usage", "Summary of php String (string) Usage", "Introduction to php+mysql Database Operation" and "Summary of php Common Database Operation Skills"

I hope this article is helpful to everyone's PHP programming.