[Basic] AppConfig

• AppConfig를 통해 OrderServiceImpl에 있는 DiscountPolicy에 주입해준다.

public class AppConfig {
	public MemberService memberService() {
 		return new MemberServiceImpl(new MemoryMemberRepository());
 	}
	public OrderService orderService() {
     	return new OrderServiceImpl(
     			new MemoryMemberRepository(),
     			new FixDiscountPolicy());
     }
}

//중복 고려한 리팩터링
public class AppConfig {
	public MemberService memberService() {
		return new MemberServiceImpl(memberRepository());
	}
     public OrderService orderService() {
     	return new OrderServiceImpl(
                 memberRepository(),
                 discountPolicy());
     }
     public MemberRepository memberRepository() {
     	return new MemoryMemberRepository();
     }
     public DiscountPolicy discountPolicy() {
     	return new FixDiscountPolicy();
     }
}