[만들면서 배우는 헥사고날 아키텍처 설계와 구현] 1-1 도메인 헥사곤

programmer-study/java-practice/designing-hexagonal-architecture-with-java at main · lkdcode/programmer-study

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https://github.com/lkdcode/programmer-study/tree/main/java-practice/designing-hexagonal-architecture-with-java

도메인 헥사곤

Entity

import java.util.List;
import java.util.function.Predicate;
import java.util.stream.Collectors;

public class Router {
    private final RouterType routerType;
    private final RouterId routerId;

    public Router(RouterType routerType, RouterId routerId) {
        this.routerType = routerType;
        this.routerId = routerId;
    }

    private static Predicate<Router> isCore() {
        return p -> p.getRouterType() == RouterType.CORE;
    }

    private static Predicate<Router> isEdge() {
        return p -> p.getRouterType() == RouterType.EDGE;
    }

    public static List<Router> retrieveRouter(
            List<Router> routers,
            Predicate<Router> predicate
    ) {
        return routers.stream()
                .filter(predicate)
                .collect(Collectors.<Router>toList());
    }

    public RouterType getRouterType() {
        return routerType;
    }
}

값 객체

public enum RouterType {
    EDGE,
    CORE,
    ;
}

애플리케이션 헥사곤

유스케이스

import java.util.List;
import java.util.function.Predicate;

public interface RouterViewUseCase {
    List<Router> getRouters(Predicate<Router> filter);
}

입력 포트

import java.util.List;
import java.util.function.Predicate;

public class RouterViewInputPort implements RouterViewUseCase {
    private RouterViewOutputPort routerListOutputPort;

    public RouterViewInputPort(RouterViewOutputPort routerListOutputPort) {
        this.routerViewOutputPort = routerListOutputPort;
    }

    @Override
    public List<Router> getRouters(Predicate<Router> filter) {
        var routers = routerListOutputPort.fetchRouters();
        return Router.retrieveRouter(routers, filter);
    }
}

출력 포트

public interface RouterViewOutputPort {
    List<Router> fetchRouters();
}

프레임워크 헥사곤

드라이빙 오퍼레이션과 입력 어댑터

import java.util.List;

public class RouterViewCLIAdapter {
    RouterViewUseCase routerViewUseCase;

    public RouterViewCLIAdapter() {
        setAdapters();
    }

    public List<Router> obtainRelatedRouters(String type) {
        return routerViewUseCase.getRouters(
                outer.filterRouterByType(RouterType.valueOf(type))
        );
    }

    private void setAdapters() {
        this.routerViewUseCase =
                new RouterViewInputPort(RouterViewFileAdapter.getInstance());
    }
}

드리븐 오퍼레이션과 출력 어댑터

import java.util.ArrayList;
import java.util.List;

public class RouterViewFileAdapter implements RouterViewOutputPort {
    @Override
    public List<Router> fetchRouters() {
        return readFileAsString();
    }

    private static List<Router> readFileAsString() {
        List<Router> routers = new ArrayList<>();
        try (Stream<String> stream = new BufferedReader(
                new InputeStreamReader(RouterViewFileAdapter.class.getClassLoader()
                        .getResourceAsStream("routers.txt"))).lines()) {
            stream.forEach(line -> {
                String[] routerEntry = line.split(";");
                var id = routerEntry[0];
                var type = routerEntry[1];
                Router router = new Router(RouterType.valueOf(type), RouterId.of(id));
                routers.add(router);
            });
        } catch (Exception e) {
            e.printStackTrace();
        }

        return routers;
    }
}

헥사고날 접근 방식의 장점

변경 허용(Change-tolerant)

유지보수성(Maintainability)

테스트 용이성(Testability)

요약