PHP设计模式—外观模式

/**
 * Class SubSystemOne
 */
class SubSystemOne
{
    public function methodOne()
    {
        return ‘子系统方法一‘ . ‘<br>‘;
    }
}

/**
 * Class SubSystemTwo
 */
class SubSystemTwo
{
    public function methodTwo()
    {
        return ‘子系统方法二‘ . ‘<br>‘;
    }
}

/**
 * Class SubSystemThree
 */
class SubSystemThree
{
    public function methodThree()
    {
        return ‘子系统方法三‘ . ‘<br>‘;
    }
}

/**
 * Class SubSystemFour
 */
class SubSystemFour
{
    public function methodFour()
    {
        return ‘子系统方法四‘ . ‘<br>‘;
    }
}

$subSystemOne = new SubSystemOne();
$subSystemTwo = new SubSystemTwo();
$subSystemThree = new SubSystemThree();
$subSystemFour = new SubSystemFour();

echo $subSystemOne->methodOne();
echo $subSystemTwo->methodTwo();
echo $subSystemThree->methodThree();
echo $subSystemFour->methodFour();

/**
 * 外观类，整合需要调用的子系统代码，给客户端调用，如果子系统发生变化，只用修改外观类代码
 * Class Facade
 */
class Facade
{
    /**
     * @var
     */
    private $subSystemOne;

    /**
     * @var
     */
    private $subSystemTwo;

    /**
     * @var
     */
    private $subSystemThree;

    /**
     * @var
     */
    private $subSystemFour;

    /**
     * Facade constructor.
     */
    public function __construct()
    {
        $this->subSystemOne = new SubSystemOne();
        $this->subSystemTwo = new SubSystemTwo();
        $this->subSystemThree = new SubSystemThree();
        $this->subSystemFour = new SubSystemFour();
    }


    /**
     * 整合方法
     */
    public function method()
    {
        echo $this->subSystemOne->methodOne();
        echo $this->subSystemTwo->methodTwo();
        echo $this->subSystemThree->methodThree();
        echo $this->subSystemFour->methodFour();
    }
}

$facade = new Facade();
// 客户端可以不用知道子系统的存在，调用外观类中提供的方法就可以
$facade->method();

子系统方法一
子系统方法二
子系统方法三
子系统方法四