Feature: 처리 제한을 초과한 사용자의 요청은 대기열로 들어가야 한다.

src/main/java/com/thirdparty/ticketing/domain/waitingroom/RunningRoom.java

@@ -0,0 +1,5 @@
+package com.thirdparty.ticketing.domain.waitingroom;
+
+public interface RunningRoom {
+    boolean contains(UserInfo userInfo);
+}

src/main/java/com/thirdparty/ticketing/domain/waitingroom/UserInfo.java

@@ -0,0 +1,8 @@
+package com.thirdparty.ticketing.domain.waitingroom;
+
+import lombok.Data;
+
+@Data
+public class UserInfo {
+    private final String email;
+}

src/main/java/com/thirdparty/ticketing/domain/waitingroom/WaitingAspect.java

@@ -0,0 +1,27 @@
+package com.thirdparty.ticketing.domain.waitingroom;
+
+import org.aspectj.lang.ProceedingJoinPoint;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.context.SecurityContextHolder;
+
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public class WaitingAspect {
+
+    private final WaitingManager waitingManager;
+
+    private Object waitingRequest(ProceedingJoinPoint joinPoint) throws Throwable {
+        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
+        String email = (String) authentication.getPrincipal();
+        UserInfo userInfo = new UserInfo(email);
+        if (waitingManager.isReadyToHandle(userInfo)) {
+            return joinPoint.proceed();
+        } else {
+            long waitingNumber = waitingManager.enterWaitingRoom(userInfo);
+            return ResponseEntity.status(HttpStatus.TEMPORARY_REDIRECT).body(waitingNumber);
+        }
+    }
+}

src/main/java/com/thirdparty/ticketing/domain/waitingroom/WaitingCounter.java

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+package com.thirdparty.ticketing.domain.waitingroom;
+
+public interface WaitingCounter {
+
+    /**
+     * @return 사용자에게 부여되는 고유한 카운트를 반환한다.
+     */
+    long getNextCount();
+}

src/main/java/com/thirdparty/ticketing/domain/waitingroom/WaitingLine.java

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+package com.thirdparty.ticketing.domain.waitingroom;
+
+public interface WaitingLine {
+
+    /**
+     * 사용자를 대기열에 넣는다.
+     *
+     * @param userInfo 사용자의 정보
+     * @param waitingCounter 사용자의 고유한 카운트 값
+     */
+    void enter(UserInfo userInfo, long waitingCounter);
+}

src/main/java/com/thirdparty/ticketing/domain/waitingroom/WaitingManager.java

@@ -0,0 +1,18 @@
+package com.thirdparty.ticketing.domain.waitingroom;
+
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public class WaitingManager {
+
+    private final RunningRoom runningRoom;
+    private final WaitingRoom waitingRoom;
+
+    public boolean isReadyToHandle(UserInfo userInfo) {
+        return runningRoom.contains(userInfo);
+    }
+
+    public long enterWaitingRoom(UserInfo userInfo) {
+        return waitingRoom.enter(userInfo);
+    }
+}

src/main/java/com/thirdparty/ticketing/domain/waitingroom/WaitingRoom.java

@@ -0,0 +1,18 @@
+package com.thirdparty.ticketing.domain.waitingroom;
+
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public abstract class WaitingRoom {
+
+    private final WaitingLine waitingLine;
+    private final WaitingCounter waitingCounter;
+
+    /**
+     * 사용자를 대기열에 넣고, 대기공간에 보관한다.
+     *
+     * @param userInfo 사용자의 정보
+     * @return 사용자의 남은 순번을 반환한다.
+     */
+    public abstract long enter(UserInfo userInfo);
+}