抽象工厂模式——Head First Design Patterns

定义：创建一组相似或者相互依赖的对象，但是创建方法不返回具体的类。

 

使用场景： 1）当需要创建多个系列的产品时，想要保证同一系列的产品在同一个工厂里面

 

类图：

 

代码样例：

public class ChicagoPizzaIngredientFactory implements PizzaIngredientFactory {public Dough createDough() {return new ThickCrustDough();}public Sauce createSauce() {return new PlumTomatoSauce();}public Cheese createCheese() {return new MozzarellaCheese();}public Veggies[] createVeggies() {Veggies veggies[] = { new BlackOlives(),                       new Spinach(),                       new Eggplant() };return veggies;}public Pepperoni createPepperoni() {return new SlicedPepperoni();}public Clams createClam() {return new FrozenClams();}}

 

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();}}

 

public class ChicagoPizzaStore extends PizzaStore {protected Pizza createPizza(String item) {Pizza pizza = null;PizzaIngredientFactory ingredientFactory =new ChicagoPizzaIngredientFactory();if (item.equals("cheese")) {pizza = new CheesePizza(ingredientFactory);pizza.setName("Chicago Style Cheese Pizza");} else if (item.equals("veggie")) {pizza = new VeggiePizza(ingredientFactory);pizza.setName("Chicago Style Veggie Pizza");} else if (item.equals("clam")) {pizza = new ClamPizza(ingredientFactory);pizza.setName("Chicago Style Clam Pizza");} else if (item.equals("pepperoni")) {pizza = new PepperoniPizza(ingredientFactory);pizza.setName("Chicago Style Pepperoni Pizza");}return pizza;}}

 

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();}}

 

 

优点：1）将一组功能相关的产品放在一个工厂里面

 

缺点：1）每加一种新方法都要改变

 

类似的设计模式：1）工厂方法模式；抽象工厂模式侧重于产生一系列产品组，而工厂方法模式侧重于产生一个产品组

 

配套的内功心法：1）