PHP設計模式之裝飾者模式代碼執行個體_php技巧

定義：

裝飾者模式就是不修改原類代碼和繼承的情況下動態擴充類的功能。傳統的編程模式都是子類繼承父類實現方法重載，使用裝飾器模式，只需添加一個新的裝飾器對象，更加靈活，避免類數量和層次過多。

角色：

Component（被裝飾對象基類）
ConcreteComponent（具體被裝飾對象）
Decorator（裝飾者基類）
ContreteDecorator（具體的裝飾者類）

範例程式碼：

//被裝飾者基類interface Component{  public function operation();} //裝飾者基類abstract class Decorator implements Component{  protected $component;   public function __construct(Component $component)  {    $this->component = $component;  }   public function operation()  {    $this->component->operation();  }} //具體裝飾者類class ConcreteComponent implements Component{  public function operation()  {    echo 'do operation'.PHP_EOL;  }} //具體裝飾類Aclass ConcreteDecoratorA extends Decorator {  public function __construct(Component $component) {    parent::__construct($component);   }   public function operation() {    parent::operation();    $this->addedOperationA();  // 新增加的操作  }   public function addedOperationA() {    echo 'Add Operation A '.PHP_EOL;  }} //具體裝飾類Bclass ConcreteDecoratorB extends Decorator {  public function __construct(Component $component) {    parent::__construct($component);   }   public function operation() {    parent::operation();    $this->addedOperationB();  }   public function addedOperationB() {    echo 'Add Operation B '.PHP_EOL;  }}  class Client {   public static function main() {    /*    do operation    Add Operation A    */    $decoratorA = new ConcreteDecoratorA(new ConcreteComponent());    $decoratorA->operation();      /*    do operation    Add Operation A     Add Operation B     */    $decoratorB = new ConcreteDecoratorB($decoratorA);    $decoratorB->operation();  } } Client::main();