[MVC 구현하기 1, 2단계] 하디(전동혁) 미션 제출합니다.

app/src/main/java/com/techcourse/DispatcherServlet.java

@@ -6,22 +6,32 @@
 import jakarta.servlet.http.HttpServletResponse;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-import webmvc.org.springframework.web.servlet.view.JspView;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+import webmvc.org.springframework.web.servlet.mvc.HandlerAdapter;
+import webmvc.org.springframework.web.servlet.mvc.asis.ControllerHandlerAdapter;
+import webmvc.org.springframework.web.servlet.mvc.tobe.AnnotationHandlerMapping;
+import webmvc.org.springframework.web.servlet.mvc.tobe.HandlerExecutionHandlerAdapter;
 
 public class DispatcherServlet extends HttpServlet {
 
     private static final long serialVersionUID = 1L;
     private static final Logger log = LoggerFactory.getLogger(DispatcherServlet.class);
 
-    private ManualHandlerMapping manualHandlerMapping;
+    private HandlerMappingRegistry handlerMappingRegistry = new HandlerMappingRegistry();
+    private HandlerAdapterRegistry handlerAdapterRegistry = new HandlerAdapterRegistry();
 
     public DispatcherServlet() {
     }
 
     @Override
     public void init() {
-        manualHandlerMapping = new ManualHandlerMapping();
-        manualHandlerMapping.initialize();
+        handlerMappingRegistry
+                .addHandlerMapping(new ManualHandlerMapping())
+                .addHandlerMapping(new AnnotationHandlerMapping());
+        handlerAdapterRegistry
+                .addHandlerAdapter(new ControllerHandlerAdapter())
+                .addHandlerAdapter(new HandlerExecutionHandlerAdapter());
+        handlerMappingRegistry.initialize();
     }
 
     @Override
@@ -30,22 +40,19 @@ protected void service(final HttpServletRequest request, final HttpServletRespon
         log.debug("Method : {}, Request URI : {}", request.getMethod(), requestURI);
 
         try {
-            final var controller = manualHandlerMapping.getHandler(requestURI);
-            final var viewName = controller.execute(request, response);
-            move(viewName, request, response);
+            Object handler = handlerMappingRegistry.getHandler(request)
+                    .orElseThrow(() -> new IllegalArgumentException("There is not matched handler"));
+            HandlerAdapter handlerAdapter = handlerAdapterRegistry.getHandlerAdapter(handler)
+                    .orElseThrow(() -> new IllegalArgumentException("Not Supported Handler"));
+            ModelAndView modelAndView = handlerAdapter.handle(request, response, handler);
+            render(modelAndView, request, response);
         } catch (Throwable e) {
             log.error("Exception : {}", e.getMessage(), e);
             throw new ServletException(e.getMessage());
         }
     }
 
-    private void move(final String viewName, final HttpServletRequest request, final HttpServletResponse response) throws Exception {
-        if (viewName.startsWith(JspView.REDIRECT_PREFIX)) {
-            response.sendRedirect(viewName.substring(JspView.REDIRECT_PREFIX.length()));
-            return;
-        }
-
-        final var requestDispatcher = request.getRequestDispatcher(viewName);
-        requestDispatcher.forward(request, response);
+    private void render(ModelAndView modelAndView, HttpServletRequest request, HttpServletResponse response) {
+        // TODO: 3단계?
     }
 }

app/src/main/java/com/techcourse/HandlerAdapterRegistry.java

@@ -0,0 +1,26 @@
+package com.techcourse;
+
+import webmvc.org.springframework.web.servlet.mvc.HandlerAdapter;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public class HandlerAdapterRegistry {
+
+    private final List<HandlerAdapter> handlerAdapters = new ArrayList<>();
+
+    public HandlerAdapterRegistry addHandlerAdapter(HandlerAdapter handlerAdapter) {
+        handlerAdapters.add(handlerAdapter);
+        return this;
+    }
+
+    public Optional<HandlerAdapter> getHandlerAdapter(Object handler) {
+        for (HandlerAdapter handlerAdapter : handlerAdapters) {
+            if (handlerAdapter.supports(handler)) {
+                return Optional.of(handlerAdapter);
+            }
+        }
+        return Optional.empty();
+    }
+}

app/src/main/java/com/techcourse/HandlerMappingRegistry.java

@@ -0,0 +1,32 @@
+package com.techcourse;
+
+import jakarta.servlet.http.HttpServletRequest;
+import webmvc.org.springframework.web.servlet.mvc.HandlerMapping;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public class HandlerMappingRegistry {
+
+    private final List<HandlerMapping> handlerMappings = new ArrayList<>();
+
+    public HandlerMappingRegistry addHandlerMapping(HandlerMapping handlerMapping) {
+        handlerMappings.add(handlerMapping);
+        return this;
+    }
+
+    public void initialize() {
+        handlerMappings.forEach(HandlerMapping::initialize);
+    }
+
+    public Optional<Object> getHandler(HttpServletRequest httpServletRequest) {
+        for (HandlerMapping handlerMapping : handlerMappings) {
+            Object handler = handlerMapping.getHandler(httpServletRequest);
+            if (handler != null) {
+                return Optional.of(handler);
+            }
+        }
+        return Optional.empty();
+    }
+}

app/src/main/java/com/techcourse/LegacyHandlerMapping.java

@@ -0,0 +1,14 @@
+package com.techcourse;
+
+import jakarta.servlet.http.HttpServletRequest;
+import webmvc.org.springframework.web.servlet.mvc.HandlerMapping;
+
+public abstract class LegacyHandlerMapping implements HandlerMapping {
+
+    @Override
+    public Object getHandler(HttpServletRequest httpServletRequest) {
+        return getHandler(httpServletRequest.getRequestURI());
+    }
+
+    public abstract Object getHandler(String requestURI);
+}

app/src/main/java/com/techcourse/ManualHandlerMapping.java

@@ -9,12 +9,13 @@
 import java.util.HashMap;
 import java.util.Map;
 
-public class ManualHandlerMapping {
+public class ManualHandlerMapping extends LegacyHandlerMapping {
 
     private static final Logger log = LoggerFactory.getLogger(ManualHandlerMapping.class);
 
     private static final Map<String, Controller> controllers = new HashMap<>();
 
+    @Override
     public void initialize() {
         controllers.put("/", new ForwardController("/index.jsp"));
         controllers.put("/login", new LoginController());
@@ -28,6 +29,7 @@ public void initialize() {
                 .forEach(path -> log.info("Path : {}, Controller : {}", path, controllers.get(path).getClass()));
     }
 
+    @Override
     public Controller getHandler(final String requestURI) {
         log.debug("Request Mapping Uri : {}", requestURI);
         return controllers.get(requestURI);

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/HandlerAdapter.java

@@ -0,0 +1,12 @@
+package webmvc.org.springframework.web.servlet.mvc;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+
+public interface HandlerAdapter {
+
+    boolean supports(Object object);
+
+    ModelAndView handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler) throws Exception;
+}

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/HandlerMapping.java

@@ -0,0 +1,10 @@
+package webmvc.org.springframework.web.servlet.mvc;
+
+import jakarta.servlet.http.HttpServletRequest;
+
+public interface HandlerMapping {
+
+    void initialize();
+
+    Object getHandler(HttpServletRequest httpServletRequest);
+}

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/asis/ControllerHandlerAdapter.java

@@ -0,0 +1,23 @@
+package webmvc.org.springframework.web.servlet.mvc.asis;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+import webmvc.org.springframework.web.servlet.mvc.HandlerAdapter;
+import webmvc.org.springframework.web.servlet.view.JspView;
+
+public class ControllerHandlerAdapter implements HandlerAdapter {
+
+    @Override
+    public boolean supports(Object object) {
+        return object instanceof Controller;
+    }
+
+    @Override
+    public ModelAndView handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler) throws Exception {
+        Controller controller = (Controller) handler;
+        String viewName = controller.execute(httpServletRequest, httpServletResponse);
+        ModelAndView mav = new ModelAndView(new JspView(viewName));
+        return mav;
+    }
+}

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/tobe/AnnotationHandlerMapping.java

@@ -1,13 +1,18 @@
 package webmvc.org.springframework.web.servlet.mvc.tobe;
 
 import jakarta.servlet.http.HttpServletRequest;
+import org.reflections.Reflections;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import web.org.springframework.web.bind.annotation.RequestMapping;
+import web.org.springframework.web.bind.annotation.RequestMethod;
+import webmvc.org.springframework.web.servlet.mvc.HandlerMapping;
 
-import java.util.HashMap;
-import java.util.Map;
+import java.lang.reflect.Method;
+import java.util.*;
+import java.util.stream.Collectors;
 
-public class AnnotationHandlerMapping {
+public class AnnotationHandlerMapping implements HandlerMapping {
 
     private static final Logger log = LoggerFactory.getLogger(AnnotationHandlerMapping.class);
 
@@ -19,11 +24,60 @@ public AnnotationHandlerMapping(final Object... basePackage) {
         this.handlerExecutions = new HashMap<>();
     }
 
+    @Override
     public void initialize() {
-        log.info("Initialized AnnotationHandlerMapping!");
+        log.info("Initializing AnnotationHandlerMapping starts!");
+        for (Object base : basePackage) {
+            ControllerScanner controllerScanner = new ControllerScanner(new Reflections(base));
+            Map<Class<?>, Object> controllers = controllerScanner.getControllers();
+            Set<Method> methods = getRequestMappingMethods(controllers.keySet());
+            for (Method method : methods) {
+                RequestMapping requestMapping = method.getAnnotation(RequestMapping.class);
+                addHandlerExecutions(controllers, method, requestMapping);
+            }
+        }
+        log.info("Initializing AnnotationHandlerMapping succeeds!");
     }
 
+    @Override
     public Object getHandler(final HttpServletRequest request) {
-        return null;
+        String uri = request.getRequestURI();
+        try {
+            RequestMethod requestMethod = RequestMethod.valueOf(request.getMethod());
+            HandlerKey handlerKey = new HandlerKey(uri, requestMethod);
+            return handlerExecutions.get(handlerKey);
+        } catch (IllegalArgumentException e) {
+            log.error("Unsupported request method.");
+            return null;
+        }
+    }
+
+    private void addHandlerExecutions(Map<Class<?>, Object> controllers, Method method, RequestMapping requestMapping) {
+        HandlerExecution handlerExecution = mapHandlerExecution(controllers, method);
+        RequestMethod[] requestMethods = requestMapping.method();
+        List<HandlerKey> handlerKeys = mapHandlerKeys(requestMapping.value(), requestMethods);
+        for (HandlerKey handlerKey : handlerKeys) {
+            handlerExecutions.put(handlerKey, handlerExecution);
+        }
+    }
+
+    private HandlerExecution mapHandlerExecution(Map<Class<?>, Object> controllers, Method method) {
+        Object instance = controllers.get(method.getDeclaringClass());
+        return new HandlerExecution(instance, method);
+    }
+
+    private List<HandlerKey> mapHandlerKeys(String url, RequestMethod[] requestMethods) {
+        return Arrays.stream(requestMethods)
+                .map(requestMethod -> new HandlerKey(url, requestMethod))
+                .collect(Collectors.toList());
+    }
+
+    private Set<Method> getRequestMappingMethods(Set<Class<?>> controllers) {
+        return controllers
+                .stream()
+                .map(Class::getMethods)
+                .flatMap(Arrays::stream)
+                .filter(method -> method.isAnnotationPresent(RequestMapping.class))
+                .collect(Collectors.toSet());
     }
 }

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/tobe/ControllerScanner.java

@@ -0,0 +1,53 @@
+package webmvc.org.springframework.web.servlet.mvc.tobe;
+
+import context.org.springframework.stereotype.Controller;
+import org.reflections.Reflections;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.InvocationTargetException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+public class ControllerScanner {
+
+    private static final Logger log = LoggerFactory.getLogger(ControllerScanner.class);
+
+    private final Reflections reflections;
+
+    public ControllerScanner(Reflections reflections) {
+        this.reflections = reflections;
+    }
+
+    public Map<Class<?>, Object> getControllers() {
+        Set<Class<?>> controllers = reflections.getTypesAnnotatedWith(Controller.class);
+        return instantiateControllers(controllers);
+    }
+
+    private Map<Class<?>, Object> instantiateControllers(Set<Class<?>> controllers) {
+        Map<Class<?>, Object> controllerWithInstances = new HashMap<>();
+        try {
+            for (Class<?> controller : controllers) {
+                Object instance = controller.getDeclaredConstructor().newInstance();
+                controllerWithInstances.put(controller, instance);
+            }
+            return controllerWithInstances;
+        } catch (NoSuchMethodException e) {
+            log.error("NoArgConstructor doesn't exist.");
+        } catch (SecurityException e) {
+            log.error("Check permission");
+        } catch (IllegalAccessException e) {
+            log.error("Constructor is not accessible.");
+        } catch (IllegalArgumentException e) {
+            log.error("Type of Arguments doesn't matched.");
+        } catch (InstantiationException e) {
+            log.error("The instance is abstract class.");
+        } catch (InvocationTargetException e) {
+            log.error("Exception occurs during constructing.");
+        } catch (ExceptionInInitializerError error) {
+            log.error("Initializing fails.");
+        }
+        throw new IllegalArgumentException("Getting instance using constructor fails.");
+    }
+}

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/tobe/HandlerExecution.java

@@ -4,9 +4,19 @@
 import jakarta.servlet.http.HttpServletResponse;
 import webmvc.org.springframework.web.servlet.ModelAndView;
 
+import java.lang.reflect.Method;
+
 public class HandlerExecution {
 
+    private final Object instance;
+    private final Method method;
+
+    public HandlerExecution(Object instance, Method method) {
+        this.instance = instance;
+        this.method = method;
+    }
+
     public ModelAndView handle(final HttpServletRequest request, final HttpServletResponse response) throws Exception {
-        return null;
+        return (ModelAndView) method.invoke(instance, request, response);
     }
 }

mvc/src/main/java/webmvc/org/springframework/web/servlet/mvc/tobe/HandlerExecutionHandlerAdapter.java

@@ -0,0 +1,19 @@
+package webmvc.org.springframework.web.servlet.mvc.tobe;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import webmvc.org.springframework.web.servlet.ModelAndView;
+import webmvc.org.springframework.web.servlet.mvc.HandlerAdapter;
+
+public class HandlerExecutionHandlerAdapter implements HandlerAdapter {
+
+    @Override
+    public boolean supports(Object object) {
+        return object instanceof HandlerExecution;
+    }
+
+    @Override
+    public ModelAndView handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler) throws Exception {
+        return ((HandlerExecution) handler).handle(httpServletRequest, httpServletResponse);
+    }
+}