Generic update API

generic-update-api.java

public class Booking {
	String uniqueId;
	User guest;
	User host;
	Date bookingTime;
	Date confirmationTime;
	Date cancellationTime;
	Status status; //PENDING, CONFIRMED, CANCELLED_BY_GUEST, CANCELLED_BY_HOST
	User lastUpdatedBy;
}
public class BookingUpdateRequest {
	Date updateTime;
	Booking updatedBooking;
}
// In Booking Service
public void updateBooking(BookingUpdateRequest request) {
	Booking originalBooking = readFromDB(request.updatedBooking.uniqueId);
	if ((originalBooking.status == PENDING || originalBooking.status == CONFIRMED) &&
		(request.updatedBooking.status == CANCELLED_BY_GUEST)) {
		originalBooking.lastUpdatedBy = originalBooking.guest;
		originalBooking.cancellationTime = request.updateTime
		// Trigger notification to host
		// Trigger refund if payment was taken
	} else if ((originalBooking.status == PENDING || originalBooking.status == CONFIRMED) &&
		(request.updatedBooking.status == CANCELLED_BY_HOST)) {
		originalBooking.lastUpdatedBy = originalBooking.host;
		// Trigger notification to guest
		// Trigger refund if payment was taken
	} 
	// else if ........ more conditions to handle other combinations of new/old variables
}