생성패턴 : Builder 패턴

분류 : 생성패턴(Creational Patterns)

정의 :

복잡한 객체의 생성을 표현과 분리함으로써 같은 생성절차를 가지면서 다른 표현들을 만들수 있게 함.

용도 :

• Builder 패턴은 복잡한 객체를 단계적으로 생성하는 것에 초점을 둠.
• Builder 패턴은 종종 Composite 패턴을 만듬.

구조 :

Builder : 객체를 생성하기위한 추상 인터페이스

Concrete Builder : Builder에 대한 구현을 제공. 다른 객체들을 생성할수 있는 객체임.

코드 :

/** Product */
public 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; }
	
    public String getDough(){ return dough; }
    public String getSauce(){ return sauce; }
    public String getTopping(){ return topping; }
}

/** Abstract Builder */
public 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 */
public class HawaiianPizzaBuilder extends PizzaBuilder{
    public void buildDough()   { pizza.setDough("cross"); }
    public void buildSauce()   { pizza.setSauce("mild"); }
    public void buildTopping() { pizza.setTopping("ham+pineapple"); }
}

/** ConcreteBuilder */
public 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 */
public class Waiter {
	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();
	}
}

public class BuilderExample {

	/**
	 * A customer ordering a pizza
	 */
	public static void main(String[] args) {
		Waiter waiter = new Waiter();
        PizzaBuilder hawaiianPizzaBuilder = new HawaiianPizzaBuilder();
        PizzaBuilder spicyPizzaBuilder = new SpicyPizzaBuilder();
 
        //이 부분에서 hawaiianPizzaBuilder, spicyPizzaBuilder를 번갈아서 입력하면서 출력되는 내용을 확인해 보면 됨.
        waiter.setPizzaBuilder( spicyPizzaBuilder );
        waiter.constructPizza();
 
        Pizza pizza = waiter.getPizza();
        
        System.out.println(pizza.getDough());
        System.out.println(pizza.getSauce());
        System.out.println(pizza.getTopping());
	}

}

참고자료

GoF의 디자인패턴, 피어슨에듀케이션코리아, 2002

http://en.wikipedia.org/wiki/Builder_pattern