策略模式

<?php
interface FlyBehavior{
    public function fly();
}
 
class FlyWithWings implements FlyBehavior{
    public function fly(){
        echo "Fly With Wings \n";
    }
}
 
class FlyWithNo implements FlyBehavior{
    public function fly(){
        echo "Fly With No Wings \n";
    }
}
class Duck{
    private $_flyBehavior;
    public function performFly(){
        $this->_flyBehavior->fly();
    }
 
    public function setFlyBehavior(FlyBehavior $behavior){
        $this->_flyBehavior = $behavior;
    }
}
 
class RubberDuck extends Duck{
}
// Test Case
$duck = new RubberDuck();
 
/*  想让鸭子用翅膀飞行 */
$duck->setFlyBehavior(new FlyWithWings());
$duck->performFly();            
 
/*  想让鸭子不用翅膀飞行 */
$duck->setFlyBehavior(new FlyWithNo());
$duck->performFly();