PHP设计模式 -桥梁（桥接）模式

<?php
interface Color {

    public function applyColor();
}

class Red implements Color{
    public function applyColor()    {
        return "red";
    }
}
class Blue implements Color{
    public function applyColor(){
        return "blue";
    }
}
abstract class Shape{
   
    protected $color;

    public function __construct(Color $color)
    {
        $this->color = $color;
    }
    abstract public function draw();

}
class Circle extends Shape {

    public function draw(){

        return "圆形填充了：". $this->color->applyColor();
    }

}
$red = new Red();

$circle = new Circle($red);