Builder pattern-生成器模式

参考文献：
http://en.wikipedia.org/wiki/Builder_pattern

    生成器（英：Builder）是一种设计模式，又名：建造模式，是一种对象构建模式。它可以将复杂对象的建造过程抽象出来（抽象类别），使这个抽象过程的不同实现方法可以构造出不同表现（属性）的对象。


参与者
Builder
创建对象的抽象接口。
Concrete Builder
提供Builder的实现。
Director
负责管理对象创建的正确顺序。I
Product
由Director使用Builder创建的最终对象。

package com.sinosoft.train.gof.cp;

/** "Product"－建造的最终产品－比萨饼 */
class Pizza {
	private String dough = "";
	private String sauce = "";
	private String topping = "";

	public void setDough(String dough) {
		this.dough = dough;
	}

	public void setSauce(String sauce) {
		this.sauce = sauce;
	}

	public void setTopping(String topping) {
		this.topping = topping;
	}

	@Override
	public String toString() {
		return dough + "-" + sauce + "-" + topping;
	}
}

/** "Abstract Builder"－比萨饼抽象生成器 */
abstract class PizzaBuilder {
	protected Pizza pizza;

	public Pizza getPizza() {
		return pizza;
	}

	public void createNewPizzaProduct() {
		pizza = new Pizza();
	}

	public abstract void buildDough();

	public abstract void buildSauce();

	public abstract void buildTopping();
}

/** "ConcreteBuilder"－夏威夷人的比萨饼生成器 */
class HawaiianPizzaBuilder extends PizzaBuilder {
	public void buildDough() {
		pizza.setDough("cross");
	}

	public void buildSauce() {
		pizza.setSauce("mild");
	}

	public void buildTopping() {
		pizza.setTopping("ham+pineapple");
	}
}

/** "ConcreteBuilder" －辛辣的比萨饼生成器 */
class SpicyPizzaBuilder extends PizzaBuilder {
	public void buildDough() {
		pizza.setDough("pan baked");
	}

	public void buildSauce() {
		pizza.setSauce("hot");
	}

	public void buildTopping() {
		pizza.setTopping("pepperoni+salami");
	}
}

/** "Director" － 厨师 */
class Cook {
	private PizzaBuilder pizzaBuilder;

	public void setPizzaBuilder(PizzaBuilder pb) {
		pizzaBuilder = pb;
	}

	public Pizza getPizza() {
		return pizzaBuilder.getPizza();
	}

	public void constructPizza() {
		pizzaBuilder.createNewPizzaProduct();
		pizzaBuilder.buildDough();
		pizzaBuilder.buildSauce();
		pizzaBuilder.buildTopping();
	}
}

/** A given type of pizza being constructed. */
public class Builder {
	public static void main(String[] args) {
		Cook cook = new Cook();
		PizzaBuilder hawaiianPizzaBuilder = new HawaiianPizzaBuilder();
		PizzaBuilder spicyPizzaBuilder = new SpicyPizzaBuilder();

		cook.setPizzaBuilder(hawaiianPizzaBuilder);
		cook.constructPizza();

		Pizza hawaiian = cook.getPizza();
		System.out.println(hawaiian);
		cook.setPizzaBuilder(spicyPizzaBuilder);
		cook.constructPizza();

		Pizza spicy = cook.getPizza();
		System.out.println(spicy);
	}
}