10. 빈 조회

조회한 빈이 모두 필요할 때, List, Map

의도적으로 정말 해당 타입의 스프링 빈이 다 필요한 경우도 있다.
예를 들어서 할인 서비스를 제공하는데, 클라이언트가 할인의 종류(rate, fix)를 선택할 수 있다고
가정해보자. 스프링을 사용하면 소위 말하는 전략 패턴을 매우 간단하게 구현할 수 있다.

package hello.core.autowired;
import hello.core.AutoAppConfig;
import hello.core.discount.DiscountPolicy;
import hello.core.member.Grade;
import hello.core.member.Member;
import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import java.util.List;
import java.util.Map;
import static org.assertj.core.api.Assertions.assertThat;

public class AllBeanTest {
    @Test
    void findAllBean() {
        ApplicationContext ac = new
        AnnotationConfigApplicationContext(AutoAppConfig.class, DiscountService.class);
        
        DiscountService discountService = ac.getBean(DiscountService.class);
        
        Member member = new Member(1L, "userA", Grade.VIP);
        int discountPrice = discountService.discount(member, 10000,
        "fixDiscountPolicy");
        assertThat(discountService).isInstanceOf(DiscountService.class);
        assertThat(discountPrice).isEqualTo(1000);
    }
    
    static class DiscountService {

        private final Map<String, DiscountPolicy> policyMap;
        private final List<DiscountPolicy> policies;

        public DiscountService(Map<String, DiscountPolicy> policyMap,
        List<DiscountPolicy> policies) {
            
            this.policyMap = policyMap;
            this.policies = policies;
            
            System.out.println("policyMap = " + policyMap);
            System.out.println("policies = " + policies);
        }
        public int discount(Member member, int price, String discountCode) {
            
            DiscountPolicy discountPolicy = policyMap.get(discountCode);
            
            System.out.println("discountCode = " + discountCode);
            System.out.println("discountPolicy = " + discountPolicy);
            
            return discountPolicy.discount(member, price);
        }
    }
}