30. 유연한 컨트롤러2 - V5

FrontControllerServlet5에 ControllerV4기능도 추가해보았다.

package hello.servlet.web.frontcontroller.V5;

import hello.servlet.web.frontcontroller.ModelView;
import hello.servlet.web.frontcontroller.MyView;
import hello.servlet.web.frontcontroller.V3.ControllerV3;
import hello.servlet.web.frontcontroller.V3.controller.MemberFormControllerV3;
import hello.servlet.web.frontcontroller.V3.controller.MemberListControllerV3;
import hello.servlet.web.frontcontroller.V3.controller.MemberSaveControllerV3;
import hello.servlet.web.frontcontroller.V5.adapter.ControllerV3HandlerAdapter;
import hello.servlet.web.frontcontroller.V5.adapter.ControllerV4HandlerAdapter;
import hello.servlet.web.frontcontroller.v4.controller.MemberFormControllerV4;
import hello.servlet.web.frontcontroller.v4.controller.MemberListControllerV4;
import hello.servlet.web.frontcontroller.v4.controller.MemberSaveControllerV4;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@WebServlet(name="frontControllerServletV5",urlPatterns = "/front-controller/v5/*")
public class FrontControllerServletV5 extends HttpServlet {

    private final Map<String, Object> handlerMappingMap = new HashMap<>();
    private final List<MyHandlerAdapter> handlerAdapters = new ArrayList<>();

    private void initHandlerMappingMap() {
        handlerMappingMap.put("/front-controller/v5/v3/members/new-form", new MemberFormControllerV3());
        handlerMappingMap.put("/front-controller/v5/v3/members/save", new MemberSaveControllerV3());
        handlerMappingMap.put("/front-controller/v5/v3/members", new MemberListControllerV3());
        //V4 추가
        handlerMappingMap.put("/front-controller/v5/v4/members/new-form", new MemberFormControllerV4());
        handlerMappingMap.put("/front-controller/v5/v4/members/save", new MemberSaveControllerV4());
        handlerMappingMap.put("/front-controller/v5/v4/members", new MemberListControllerV4());
    }
    public FrontControllerServletV5() {
        initHandlerMappingMap();
        initHandlerAdapters();
    }

    private void initHandlerAdapters() {
        handlerAdapters.add(new ControllerV3HandlerAdapter());
        handlerAdapters.add(new ControllerV4HandlerAdapter());
    }

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        Object handler = getHandler(request);
        if (handler == null) {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        MyHandlerAdapter adapter = getHandlerAdapter(handler);

        ModelView mv = adapter.handle(request, response, handler);

        String viewName = mv.getViewName();
        MyView view = viewResolver(viewName);

        view.render(mv.getModel(), request, response);

    }

    private MyHandlerAdapter getHandlerAdapter(Object handler) {
        MyHandlerAdapter a;
        for (MyHandlerAdapter adapter : handlerAdapters) {
            if (adapter.supports(handler)) {
                return adapter;
            }
        }
        throw new IllegalArgumentException("handler adapter를 찾을 수 없습니다. handler=" + handler);
    }

    private Object getHandler(HttpServletRequest request) {
        String requestURI = request.getRequestURI();
        return handlerMappingMap.get(requestURI);
    }

    private MyView viewResolver(String viewName) {
        return new MyView("/WEB-INF/views/" + viewName + ".jsp");
    }
}

핸들러 매핑에 controllerV4를 사용하는 컨트롤러를 추가하고 해당 컨트롤러를 처리할 수 있는

어댑터인 ControllerV4HandlerAdapter도 추가하였다.

 

package hello.servlet.web.frontcontroller.V5.adapter;

import hello.servlet.web.frontcontroller.ModelView;
import hello.servlet.web.frontcontroller.V5.MyHandlerAdapter;
import hello.servlet.web.frontcontroller.v4.ControllerV4;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class ControllerV4HandlerAdapter implements MyHandlerAdapter {
    @Override
    public boolean supports(Object handler) {
        return (handler instanceof ControllerV4);
    }

    @Override
    public ModelView handle(HttpServletRequest request, HttpServletResponse response, Object handler) throws ServletException, IOException {
        ControllerV4 controller = (ControllerV4) handler;

        Map<String, String> paramMap = createParamMap(request);
        HashMap<String,Object> model = new HashMap<>();

        String viewName = controller.process(paramMap, model);

        ModelView mv = new ModelView(viewName);
        mv.setModel(model);

        return mv;
    }
    private Map<String, String> createParamMap(HttpServletRequest request) {
        Map<String, String> paraMap = new HashMap<>();
        request.getParameterNames().asIterator()
                .forEachRemaining(paramName -> paraMap.put(paramName, request.getParameter(paramName)));
        return paraMap;
    }
}

supports()는 

handler가 ControllerV4인 경우에만 처리하는 어댑터이다.

 

handler를 ControllerV4로 캐스팅하고, paramMap, model을 만들어서 해당 컨트롤러를 호출하고

viewName을 반환받는다.

 

어댑터가 호출하는 ControllerV4는 뷰의 이름을 반환한다. 그런데 어댑터는 뷰의 이름이 아니라 ModelView를 만들어서

반환해야한다. 여기서 어댑터의 최대 기능이 나온다.

ControllerV4는 뷰의 이름을 반환했지만 , 어댑터는 이것을 ModelView로 만들어서 형식을 맞추어 반환한다.