php记录者模式

观察者模式(Observer),当一个对象的状态发生改变时，依赖他的对象会全部收到通知，并自动更新。

一个事件发生后,要执行一连串更新操作.传统的编程方式,就是在事件的代码之后直接加入处理逻辑,当更新得逻辑增多之后,代码会变得难以维护.这种方式是耦合的,侵入式的,增加新的逻辑需要改变事件主题的代码,而观察者模式实现了低耦合,非侵入式的通知与更新机制

要用到注册树模式中的注册功能，把观察者对象注册到事件类的成员变量中去。

interface Observable
{
public function attach(Observer $observer);
public function detach(Observer $observer);
public function notify();
}

<?php

class Login implements Observable
{
private $observers;
public $status;
public $ip;
const LOGIN_ACCESS = 1;
const LOGIN_WRONG_PASS = 2;
const LOGIN_USER_UNKNOWN = 3;

public function __construct()
{
$this->observers = array();
}

/**

• @param Observer $observer
• attach a observer
  */
  public function attach(Observer $observer)
  {
  $this->observers[] = $observer;
  }

/**

• @param Observer $observer
• detach a observer
  */
  public function detach(Observer $observer)
  {
  $newObservers = array();
  foreach ($this->observers as $key => $obs) {
  if ($obs !== $observer) {
  $newObservers[] = $obs;
  }
  }
  $this->observers = $newObservers;
  }

/**

• handle observer notify
  */
  public function notify()
  {
  foreach ($this->observers as $obs) {
  $obs->update($this);
  }
  }

/**

• 执行登陆
  */
  public 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 $status
• set login status
  */
  public function setStatus($status,$ip)
  {
  $this->status = $status;
  $this->ip = $ip;
  }

/**

• @return mixed
• get login status
  */
  public function getStatus()
  {
  return $this->status;
  }
  }

interface Observer {
public function update(Observable $observable);
}

class EmailObserver implements Observer {
public function update (Observable $observable) {
$status = $observable->getStatus();
if($status == Login::LOGIN_ACCESS){
//            $this->sendMail(用户ip:.$observable->ip.登陆成功!);
echo __CLASS__.用户ip:.$observable->ip.登陆成功!.------------------;
}
if($status == Login::LOGIN_WRONG_PASS){
//            $this->sendMail(用户ip:.$observable->ip.登陆失败，密码错误!);
echo __CLASS__.用户ip:.$observable->ip.登陆失败，密码错误!.------------------;
}
if($status == Login::LOGIN_USER_UNKNOWN){
//            $this->sendMail(用户ip:.$observable->ip.登陆失败，无此用户!);
echo __CLASS__.用户ip:.$observable->ip.登陆失败，无此用户!.------------------;
}
}
}

/**

• Class PhoneObserver
  */
  class PhoneObserver implements Observer {
  public function update (Observable $observable) {
  $status = $observable->getStatus();
  if($status == Login::LOGIN_ACCESS){
  //            $this->sendMail(用户ip:.$observable->ip.登陆成功!);
  echo __CLASS__.用户ip:.$observable->ip.登陆成功!.------------------;
  }
  if($status == Login::LOGIN_WRONG_PASS){
  //            $this->sendMail(用户ip:.$observable->ip.登陆失败，密码错误!);
  echo __CLASS__.用户ip:.$observable->ip.登陆失败，密码错误!.------------------;
  }
  if($status == Login::LOGIN_USER_UNKNOWN){
  //            $this->sendMail(用户ip:.$observable->ip.登陆失败，无此用户!);
  echo __CLASS__.用户ip:.$observable->ip.登陆失败，无此用户!.------------------;
  }
  }
  }

class OtherObserver implements Observer {
public function update (Observable $observable) {
$status = $observable->getStatus();
if($status == Login::LOGIN_ACCESS){
//            $this->sendMail(用户ip:.$observable->ip.登陆成功!);
echo __CLASS__.用户ip:.$observable->ip.登陆成功!.------------------;
}
if($status == Login::LOGIN_WRONG_PASS){
//            $this->sendMail(用户ip:.$observable->ip.登陆失败，密码错误!);
echo __CLASS__.用户ip:.$observable->ip.登陆失败，密码错误!.------------------;
}
if($status == Login::LOGIN_USER_UNKNOWN){
//            $this->sendMail(用户ip:.$observable->ip.登陆失败，无此用户!);
echo __CLASS__.用户ip:.$observable->ip.登陆失败，无此用户!.------------------;
}
}
}

//实例化开始登录
$login = new Login();
//实现发邮件观察者
$login->attach(new EmailObserver());
//实现发验证码观察者
$login->attach(new PhoneObserver());
//实现其他观察者
$login->attach(new OtherObserver());
//开始登录
$login->handleLogin();