/**

• 優(yōu)才網(wǎng)公開課示例代碼
• 觀察者模式 Observer
• @author 優(yōu)才網(wǎng)全棧工程師教研組
• @seehttp://www.ucai.cn
  */
  function output($string) {
  echo $string . "\n";
  }
  //訂單數(shù)據(jù)對象簡單模擬，這個是實際需要被觀察的對象(Subject)，但是我們將其獨立伺绽，然后
  //通過構(gòu)造方法傳入到我們模式中的Subject中，這樣使具體業(yè)務更加獨立
  class Order{
  //訂單號
  private $id = '';
  //用戶ID
  private $userId = '';
  //用戶名
  private $userName = '';
  //價格
  private $price = '';
  //下單時間
  private $orderTime = '';
  //訂單數(shù)據(jù)填充簡單模擬鉴吹，實際應用中可能會讀取用戶表單輸入并處理
  public function __set($name, $value){
  if(isset($this->$name)){
  $this->$name = $value;
  }
  }
  //獲取訂單屬性
  public function __get($name){
  if(isset($this->$name)) {
  return $this->$name;
  }
  return "";
  }
  }
  //被觀察者, 負責維護觀察者并在變化發(fā)生是通知觀察者
  class OrderSubject implements SplSubject {
  private $observers;
  private $order;
  public function __construct(Order $order) {
  $this->observers = new SplObjectStorage();
  $this->order = $order;
  }
  //增加一個觀察者
  public function attach(SplObserver $observer) {
  $this->observers->attach($observer);
  }
  //移除一個觀察者
  public function detach(SplObserver $observer) {
  $this->observers->detach($observer);
  }
  //通知所有觀察者
  public function notify() {
  foreach ($this->observers as $observer) {
  $observer->update($this);
  }
  }
  //返回主體對象的具體實現(xiàn)东揣，供觀察者調(diào)用
  public function getOrder() {
  return $this->order;
  }
  }
  //記錄業(yè)務數(shù)據(jù)日志 (ActionLogObserver)，實際可能還要抽象一層以處理不同的Action(業(yè)務操作)铲敛，這里省略
  class ActionLogObserver implements SplObserver{
  public function update(SplSubject $subject) {
  $order = $subject->getOrder();
  //實際應用可能會寫到日志文件中待错，這里直接輸出
  output( "[OrderId:{$order->id}] [UseId:{$order->userId}][Price:{$order->price}]" );
  }
  }
  //給用戶發(fā)送訂單確認郵件 (UserMailObserver)
  class UserMailObserver implements SplObserver{
  public function update(SplSubject $subject) {
  $order = $subject->getOrder();
  //實際應用會調(diào)用郵件發(fā)送服務如sendmail籽孙，這里直接輸出
  output( "Dear {$order->userName}: Your order {$order->id} wasconfirmed!" );
  }
  }
  //給管理人員發(fā)訂單處理通知郵件 (AdminMailObserver)
  class AdminMailObserver implements SplObserver{
  public function update(SplSubject $subject) {
  $order = $subject->getOrder();
  //實際應用會調(diào)用郵件發(fā)送服務如sendmail，這里直接輸出
  output( "Dear Manager: User{$order->userName}(ID:{$order->userId}) submitted a new order{$order->id}, please handle it ASAP!" );
  }
  }
  //假設(shè)的DB類火俄，便于測試犯建，實際會存入真實數(shù)據(jù)庫
  class FakeDB{
  public function save($data){
  return true;
  }
  }
  class Client {
  public static function test() {
  //初始化一個訂單數(shù)據(jù)
  $order= new Order();
  $order->id = 1001;
  $order->userId = 9527;
  $order->userName = "God";
  $order->price = 20.0;
  $order->orderTime = time();
  //綁定觀察者
  $subject = new OrderSubject($order);
  $actionLogObserver = new ActionLogObserver();
  $userMailObserver = newUserMailObserver();
  $adminMailObserver = new AdminMailObserver();
  $subject->attach($actionLogObserver);
  $subject->attach($userMailObserver);
  $subject->attach($adminMailObserver);
  //向數(shù)據(jù)庫保存訂單
  $db =new FakeDB();
  $result = $db->save($order);
  if($result){
  //通知觀察者
  $subject->notify();
  }
  }
  }
  Client::test();
  ?>