PHP学习之工厂模式

<?php
//工厂模式
interface doing
{
    function eat();
    function sleep();
}

class cat implements doing
{
    function eat()
    {
        echo '猫正在吃东西！<br />';
    }

    function sleep()
    {
        echo '猫正在睡觉！<br />';
    }
}

class dog implements doing
{
    function eat()
    {
        echo '狗正在吃东西！<br />';
    }

    function sleep()
    {
        echo '狗正在睡觉！<br />';
    }
}

class factory
{
    static function createdoing($type)
    {
        switch($type){
            case 'cat':
                return new cat();
                break;
            case 'dog':
                return new dog();
                break;
        }
    }
}

$cat=factory::createdoing('cat');
$dog=factory::createdoing('dog');