feat: 새로 사용할 커스텀 예외 객체 및 예외 코드 정의

src/main/kotlin/roomescape/common/exception/CommonErrorCode.kt

@@ -0,0 +1,20 @@
+package roomescape.common.exception
+
+import org.springframework.http.HttpStatus
+
+enum class CommonErrorCode(
+        override val httpStatus: HttpStatus,
+        override val errorCode: String,
+        override val message: String,
+) : ErrorCode {
+    INVALID_INPUT_VALUE(
+            httpStatus = HttpStatus.BAD_REQUEST,
+            errorCode = "C001",
+            message = "요청 값이 잘못되었어요."
+    ),
+    UNEXPECTED_SERVER_ERROR(
+            httpStatus = HttpStatus.INTERNAL_SERVER_ERROR,
+            errorCode = "C999",
+            message = "서버에 예상치 못한 오류가 발생했어요. 관리자에게 문의해주세요.",
+    ),
+}

src/main/kotlin/roomescape/common/exception/ErrorCode.kt

@@ -0,0 +1,9 @@
+package roomescape.common.exception
+
+import org.springframework.http.HttpStatus
+
+interface ErrorCode {
+    val httpStatus: HttpStatus
+    val errorCode: String
+    val message: String
+}

src/main/kotlin/roomescape/common/exception/RoomException.kt

@@ -0,0 +1,6 @@
+package roomescape.common.exception
+
+open class RoomException(
+        open val errorCode: ErrorCode,
+        override val message: String? = errorCode.message
+) : RuntimeException(message)