PHP版工厂方法模式

简单工厂其实不是一个设计模式，反而比较像是一种编程习惯。有些开发人员的确是把这个编程习惯误认为是“工厂模式”。

<?php
/*
 * 简单工厂
 * 其实不是一个设计模式，
 * 反而比较像是一种编程习惯。
 * 有些开发人员的确是把这个编程习惯误认为是“工厂模式”。
*/

//比萨商店
class PizzaStore{
	public $Factory;

	public function __construct($factory){
		$this->Factory = $factory;
	}

	public function orderPizza($type){
		$Pizza = $this->Factory->createPizza($type);

		$Pizza->prepare();
		$Pizza->bake();
		$Pizza->cut();
		$Pizza->box();

		return $Pizza;
	}	
}

//简单比萨工厂
class SimplePizzaFactory{
	public function createPizza($type){
		$Pizza = null;

		if ('cheese' == $type) {
			$Pizza = new CheesePizza();
		}elseif ('pepperoni' == $type){
			$Pizza = new PepperoniPizza();
		}

		return $Pizza;
	}	
}

工厂方法模式（Factory Method Pattern），定义了一个创建对象的接口，但由子类决定要实例化的是哪一个。工厂方法让类把实例化推迟到子类。

/*
 * 工厂方法模式
 * 定义了一个创建对象的接口，
 * 但由子类决定要实例化的是哪一个。
 * 工厂方法让类把实例化推迟到子类。
 */

//比萨接口
interface Pizza{
	public function prepare();
	public function bake();
	public function cut();
	public function box();
}

//比萨1
class CheesePizza implements Pizza{
	public function prepare(){
		echo 'CheesePizza prepare<br />';
	}

	public function bake(){
		echo 'CheesePizza bake<br />';
	}

	public function cut(){
		echo 'CheesePizza cut<br />';
	}

	public function box(){
		echo 'CheesePizza box<br />';
	}
}

//比萨2
class PepperoniPizza implements Pizza{
	public function prepare(){
		echo 'PepperoniPizza prepare<br />';
	}

	public function bake(){
		echo 'PepperoniPizza bake<br />';
	}

	public function cut(){
		echo 'PepperoniPizza cut<br />';
	}

	public function box(){
		echo 'PepperoniPizza box<br />';
	}
}

//纽约比萨1
class NYCheesePizza implements Pizza{
	public function prepare(){
		echo 'NYCheesePizza prepare<br />';
	}

	public function bake(){
		echo 'NYCheesePizza bake<br />';
	}

	public function cut(){
		echo 'NYCheesePizza cut<br />';
	}

	public function box(){
		echo 'NYCheesePizza box<br />';
	}
}

//纽约比萨2
class NYPepperoniPizza implements Pizza{
	public function prepare(){
		echo 'NYPepperoniPizza prepare<br />';
	}

	public function bake(){
		echo 'NYPepperoniPizza bake<br />';
	}

	public function cut(){
		echo 'NYPepperoniPizza cut<br />';
	}

	public function box(){
		echo 'NYPepperoniPizza box<br />';
	}
}

//芝加哥比萨1
class ChicagoCheesePizza implements Pizza{
	public function prepare(){
		echo 'ChicagoCheesePizza prepare<br />';
	}

	public function bake(){
		echo 'ChicagoCheesePizza bake<br />';
	}

	public function cut(){
		echo 'ChicagoCheesePizza cut<br />';
	}

	public function box(){
		echo 'ChicagoCheesePizza box<br />';
	}
}

//芝加哥比萨2
class ChicagoPepperoniPizza implements Pizza{
	public function prepare(){
		echo 'ChicagoPepperoniPizza prepare<br />';
	}

	public function bake(){
		echo 'ChicagoPepperoniPizza bake<br />';
	}

	public function cut(){
		echo 'ChicagoPepperoniPizza cut<br />';
	}

	public function box(){
		echo 'ChicagoPepperoniPizza box<br />';
	}
}

//定义比萨商店
abstract class PizzaStore{

	public function orderPizza($type){
		$Pizza = $this->createPizza($type);

		$Pizza->prepare();
		$Pizza->bake();
		$Pizza->cut();
		$Pizza->box();

		return $Pizza;
	}

	abstract protected function createPizza($type);
}

//纽约比萨店
class NYPizzaStore extends PizzaStore{
	public function createPizza($type){
		$Pizza = null;

		if ('cheese' == $type) {
			$Pizza = new NYCheesePizza();
		}elseif ('pepperoni' == $type){
			$Pizza = new NYPepperoniPizza();
		}

		return $Pizza;
	}
}

//芝加哥比萨店
class ChicagoPizzaStore extends PizzaStore{
	public function createPizza($type){
		$Pizza = null;

		if ('cheese' == $type) {
			$Pizza = new ChicagoCheesePizza();
		}elseif ('pepperoni' == $type){
			$Pizza = new ChicagoPepperoniPizza();
		}

		return $Pizza;
	}
}

$NYPizzaStore = new NYPizzaStore();
$ChicagoPizzaStore = new ChicagoPizzaStore();

$NYPizzaStore->orderPizza('cheese');
$ChicagoPizzaStore->orderPizza('pepperoni');

输出：
NYCheesePizza prepare
NYCheesePizza bake
NYCheesePizza cut
NYCheesePizza box
ChicagoPepperoniPizza prepare
ChicagoPepperoniPizza bake
ChicagoPepperoniPizza cut
ChicagoPepperoniPizza box