refactor: List<Reservation>을 일급 컬렉션으로 래핑 (#39)

BE/src/main/java/org/team4/airbnb/reservation/ReservationService.java

@@ -1,8 +1,5 @@
 package org.team4.airbnb.reservation;
 
-import java.util.List;
-import java.util.Set;
-import java.util.stream.Collectors;
 import lombok.RequiredArgsConstructor;
 import org.springframework.data.domain.Pageable;
 import org.springframework.stereotype.Service;
@@ -46,17 +43,12 @@ public ReservationElement make(ReservationRequest reservationRequest) {
 
 	@Transactional(readOnly = true)
 	public ReservationResponse findAllByCustomerId(Long customerId, Pageable pageable) {
+		Reservations reservations = new Reservations(reservationRepository
+			.findAllByCustomerId(customerId, pageable));
 
-		List<Reservation> reservations = reservationRepository
-			.findAllByCustomerId(customerId, pageable);
+		accommodationRepository.findAllWithImagesByIdIn(reservations.getAccommodationIds());
 
-		Set<Long> accommodationIds = reservations.stream()
-			.map(Reservation::getAccommodationId)
-			.collect(Collectors.toSet());
-
-		accommodationRepository.findAllWithImagesByIdIn(accommodationIds);
-
-		return ReservationResponse.from(reservations);
+		return reservations.toReservationResponse();
 	}
 
 	@Transactional

BE/src/main/java/org/team4/airbnb/reservation/Reservations.java

@@ -0,0 +1,28 @@
+package org.team4.airbnb.reservation;
+
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+import org.team4.airbnb.reservation.dto.ReservationElement;
+import org.team4.airbnb.reservation.dto.ReservationResponse;
+
+public class Reservations {
+
+	private final List<Reservation> elements;
+
+	public Reservations(List<Reservation> elements) {
+		this.elements = elements;
+	}
+
+	public Set<Long> getAccommodationIds() {
+		return elements.stream()
+			.map(Reservation::getAccommodationId)
+			.collect(Collectors.toSet());
+	}
+
+	public ReservationResponse toReservationResponse() {
+		return new ReservationResponse(elements.stream()
+			.map(ReservationElement::new)
+			.collect(Collectors.toList()));
+	}
+}

BE/src/main/java/org/team4/airbnb/reservation/dto/ReservationElement.java

@@ -26,6 +26,6 @@ public ReservationElement(Reservation reservation) {
 		this.invoiceTotal = reservation.getInvoiceTotal();
 		this.hostName = reservation.getHostName();
 		this.accommodationType = reservation.getAccommodationTypeString();
-		this.accommodationImages = reservation.getAccommodationImageUrls();
+		this.accommodationImages = List.copyOf(reservation.getAccommodationImageUrls());
 	}
 }

BE/src/main/java/org/team4/airbnb/reservation/dto/ReservationResponse.java

@@ -1,20 +1,14 @@
 package org.team4.airbnb.reservation.dto;
 
 import java.util.List;
-import java.util.stream.Collectors;
 import lombok.Getter;
-import lombok.RequiredArgsConstructor;
-import org.team4.airbnb.reservation.Reservation;
 
-@RequiredArgsConstructor
 @Getter
 public class ReservationResponse {
 
 	private final List<ReservationElement> data;
 
-	public static ReservationResponse from(List<Reservation> reservations) {
-		return new ReservationResponse(reservations.stream()
-			.map(ReservationElement::new)
-			.collect(Collectors.toList()));
+	public ReservationResponse(List<ReservationElement> data) {
+		this.data = List.copyOf(data);
 	}
 }