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;}@Overridepublic 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);}}