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设计模式之工厂模式

时间:2014-05-26 04:51:42      阅读:233      评论:0      收藏:0      [点我收藏+]

标签:设计模式

本章分三部分:简单工厂,工厂方法模式,抽象工厂模式。

一、简单工厂:简单工厂其实不是一个设计模式,只是一种编程习惯。示例如下:

PizzaStore.java

package headfirst.factory.pizzas;

public class PizzaStore {
	SimplePizzaFactory factory;
 
	public PizzaStore(SimplePizzaFactory factory) { 
		this.factory = factory;
	}
 
	public Pizza orderPizza(String type) {
		Pizza pizza;
 
		pizza = factory.createPizza(type);
 
		pizza.prepare();
		pizza.bake();
		pizza.cut();
		pizza.box();

		return pizza;
	}
}

SimplePizzaFactory.java

package headfirst.factory.pizzas;

public class SimplePizzaFactory {

	public Pizza createPizza(String type) {
		Pizza pizza = null;

		if (type.equals("cheese")) {
			pizza = new CheesePizza();
		} else if (type.equals("pepperoni")) {
			pizza = new PepperoniPizza();
		} else if (type.equals("clam")) {
			pizza = new ClamPizza();
		} else if (type.equals("veggie")) {
			pizza = new VeggiePizza();
		}
		return pizza;
	}
}

Pizza类是一个抽象基类,其他具体Pizza类均继承自他,在此不再列出代码。

测试:

package headfirst.factory.pizzas;

public class PizzaTestDrive {
 
	public static void main(String[] args) {
		SimplePizzaFactory factory = new SimplePizzaFactory();
		PizzaStore store = new PizzaStore(factory);

		Pizza pizza = store.orderPizza("cheese");
		System.out.println("We ordered a " + pizza.getName() + "\n");
 
		pizza = store.orderPizza("veggie");
		System.out.println("We ordered a " + pizza.getName() + "\n");
	}
}


二、工厂方法模式

此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类是哪一个。工厂方法让类把实例化推迟到子类。

简单描述:由子类决定要创建的具体类是哪一个

示例:

PizzaStore.java(createPizza()声明成抽象方法,由子类实现,从而由子类决定要创建的具体pizza是什么)

package headfirst.factory.pizzafm;

public abstract class PizzaStore {
 
	abstract Pizza createPizza(String item);
 
	public Pizza orderPizza(String type) {
		Pizza pizza = createPizza(type);
		System.out.println("--- Making a " + pizza.getName() + " ---");
		pizza.prepare();
		pizza.bake();
		pizza.cut();
		pizza.box();
		return pizza;
	}
}

NYPizzaStore.java(具体的pizza店类)

package headfirst.factory.pizzafm;

public class NYPizzaStore extends PizzaStore {

	Pizza createPizza(String item) {
		if (item.equals("cheese")) {
			return new NYStyleCheesePizza();
		} else if (item.equals("veggie")) {
			return new NYStyleVeggiePizza();
		} else if (item.equals("clam")) {
			return new NYStyleClamPizza();
		} else if (item.equals("pepperoni")) {
			return new NYStylePepperoniPizza();
		} else return null;
	}
}

其他代码就不贴了,这两个类已经足于展示工厂方法模式的原理。

测试:

package headfirst.factory.pizzafm;

public class PizzaTestDrive {
 
	public static void main(String[] args) {
		PizzaStore nyStore = new NYPizzaStore();
		PizzaStore chicagoStore = new ChicagoPizzaStore();
 
		Pizza pizza = nyStore.orderPizza("cheese");
		System.out.println("Ethan ordered a " + pizza.getName() + "\n");
 
		pizza = chicagoStore.orderPizza("cheese");
		System.out.println("Joel ordered a " + pizza.getName() + "\n");

		pizza = nyStore.orderPizza("clam");
		System.out.println("Ethan ordered a " + pizza.getName() + "\n");
 
		pizza = chicagoStore.orderPizza("clam");
		System.out.println("Joel ordered a " + pizza.getName() + "\n");

		pizza = nyStore.orderPizza("pepperoni");
		System.out.println("Ethan ordered a " + pizza.getName() + "\n");
 
		pizza = chicagoStore.orderPizza("pepperoni");
		System.out.println("Joel ordered a " + pizza.getName() + "\n");

		pizza = nyStore.orderPizza("veggie");
		System.out.println("Ethan ordered a " + pizza.getName() + "\n");
 
		pizza = chicagoStore.orderPizza("veggie");
		System.out.println("Joel ordered a " + pizza.getName() + "\n");
	}
}


三、抽象工厂模式

定义:提供一个接口,用于创建相关或依赖对象的家族,而不需要明确指定具体类。

简单描述:允许客户创建对象的家族,而无需指定他们的具体类
OO原则:依赖抽象,不要依赖具体类。

示例:

PizzaIngredientFactory.java(原料工厂抽象类)

package headfirst.factory.pizzaaf;

public interface PizzaIngredientFactory {
 
	public Dough createDough();
	public Sauce createSauce();
	public Cheese createCheese();
	public Veggies[] createVeggies();
	public Pepperoni createPepperoni();
	public Clams createClam();
 
}

NYPizzaIngredientFactory.java(具体类)

package headfirst.factory.pizzaaf;

public class NYPizzaIngredientFactory implements PizzaIngredientFactory {
 
	public Dough createDough() {
		return new ThinCrustDough();
	}
 
	public Sauce createSauce() {
		return new MarinaraSauce();
	}
 
	public Cheese createCheese() {
		return new ReggianoCheese();
	}
 
	public Veggies[] createVeggies() {
		Veggies veggies[] = { new Garlic(), new Onion(), new Mushroom(), new RedPepper() };
		return veggies;
	}
 
	public Pepperoni createPepperoni() {
		return new SlicedPepperoni();
	}

	public Clams createClam() {
		return new FreshClams();
	}
}

Pizza.java(抽象类)

package headfirst.factory.pizzaaf;

public abstract class Pizza {
	String name;

	Dough dough;
	Sauce sauce;
	Veggies veggies[];
	Cheese cheese;
	Pepperoni pepperoni;
	Clams clam;

	abstract void prepare();

	void bake() {
		System.out.println("Bake for 25 minutes at 350");
	}

	void cut() {
		System.out.println("Cutting the pizza into diagonal slices");
	}

	void box() {
		System.out.println("Place pizza in official PizzaStore box");
	}

	void setName(String name) {
		this.name = name;
	}

	String getName() {
		return name;
	}

	public String toString() {
		StringBuffer result = new StringBuffer();
		result.append("---- " + name + " ----\n");
		if (dough != null) {
			result.append(dough);
			result.append("\n");
		}
		if (sauce != null) {
			result.append(sauce);
			result.append("\n");
		}
		if (cheese != null) {
			result.append(cheese);
			result.append("\n");
		}
		if (veggies != null) {
			for (int i = 0; i < veggies.length; i++) {
				result.append(veggies[i]);
				if (i < veggies.length-1) {
					result.append(", ");
				}
			}
			result.append("\n");
		}
		if (clam != null) {
			result.append(clam);
			result.append("\n");
		}
		if (pepperoni != null) {
			result.append(pepperoni);
			result.append("\n");
		}
		return result.toString();
	}
}

CheesePizza.java(pizza具体类,利用相关的工厂生产原料,所生产的原料依赖所使用的工厂,Pizza类根本不关心这些原料,它只知道如何制作Pizza。)

package headfirst.factory.pizzaaf;

public class CheesePizza extends Pizza {
	PizzaIngredientFactory ingredientFactory;
 
	public CheesePizza(PizzaIngredientFactory ingredientFactory) {
		this.ingredientFactory = ingredientFactory;
	}
 
	void prepare() {
		System.out.println("Preparing " + name);
		dough = ingredientFactory.createDough();
		sauce = ingredientFactory.createSauce();
		cheese = ingredientFactory.createCheese();
	}
}

PizzaStore.java(抽象类)

package headfirst.factory.pizzaaf;

public abstract class PizzaStore {
 
	protected abstract Pizza createPizza(String item);
 
	public Pizza orderPizza(String type) {
		Pizza pizza = createPizza(type);
		System.out.println("--- Making a " + pizza.getName() + " ---");
		pizza.prepare();
		pizza.bake();
		pizza.cut();
		pizza.box();
		return pizza;
	}
}

NYPizzaStore.java(具体类)

package headfirst.factory.pizzaaf;

public class NYPizzaStore extends PizzaStore {
 
	protected Pizza createPizza(String item) {
		Pizza pizza = null;
		PizzaIngredientFactory ingredientFactory = 
			new NYPizzaIngredientFactory();
 
		if (item.equals("cheese")) {
  
			pizza = new CheesePizza(ingredientFactory);
			pizza.setName("New York Style Cheese Pizza");
  
		} else if (item.equals("veggie")) {
 
			pizza = new VeggiePizza(ingredientFactory);
			pizza.setName("New York Style Veggie Pizza");
 
		} else if (item.equals("clam")) {
 
			pizza = new ClamPizza(ingredientFactory);
			pizza.setName("New York Style Clam Pizza");
 
		} else if (item.equals("pepperoni")) {

			pizza = new PepperoniPizza(ingredientFactory);
			pizza.setName("New York Style Pepperoni Pizza");
 
		} 
		return pizza;
	}
}

其他类不列出,测试类如下:

package headfirst.factory.pizzaaf;

public class PizzaTestDrive {
 
	public static void main(String[] args) {
		PizzaStore nyStore = new NYPizzaStore();
		PizzaStore chicagoStore = new ChicagoPizzaStore();
 
		Pizza pizza = nyStore.orderPizza("cheese");
		System.out.println("Ethan ordered a " + pizza + "\n");
 
		pizza = chicagoStore.orderPizza("cheese");
		System.out.println("Joel ordered a " + pizza + "\n");

		pizza = nyStore.orderPizza("clam");
		System.out.println("Ethan ordered a " + pizza + "\n");
 
		pizza = chicagoStore.orderPizza("clam");
		System.out.println("Joel ordered a " + pizza + "\n");

		pizza = nyStore.orderPizza("pepperoni");
		System.out.println("Ethan ordered a " + pizza + "\n");
 
		pizza = chicagoStore.orderPizza("pepperoni");
		System.out.println("Joel ordered a " + pizza + "\n");

		pizza = nyStore.orderPizza("veggie");
		System.out.println("Ethan ordered a " + pizza + "\n");
 
		pizza = chicagoStore.orderPizza("veggie");
		System.out.println("Joel ordered a " + pizza + "\n");
	}
}



设计模式之工厂模式,布布扣,bubuko.com

设计模式之工厂模式

标签:设计模式

原文地址:http://blog.csdn.net/viviwen123/article/details/26674369

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