PHP学习之工厂方法模式

<?php
//工厂方法模式
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(){}
}

class CatFactory implements Factory
{
    static function createDoing()
    {
        return new Cat();
    }
}

class DogFactory implements Factory
{
    static function createDoing()
    {
        return new Dog();
    }
}