optimistic locking / transactional spring

[tame violet]

@AllArgsConstructor
@NoArgsConstructor
@Getter
@Setter
@Builder
@Entity
public class Car {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
private String brand;
private double width;
private String typeFuel;
private double price;
@ManyToOne
@JoinColumn(name = "garage_id" , nullable = false)
private Garage garage;
@Version
private Long version;
}

@Transactional
public CarDto save(CreateCarCommand command) {
Garage garage = garageRepository.findWithLockingById(command.getGarageId())
.orElseThrow(() -> new EntityNotFoundException(MessageFormat
.format("Garage with id ={0} , not exist", command.getGarageId())));
if (garage.getNumberOfSpaces() <= garage.getCars().size()) {
throw new IllegalStateException("slot not available");
}
Car car = command.toEntity();
car.setGarage(garage);
return CarDto.fromEntity(carRepository.save(car));
}

REST API spring oobt , I have two entity Garage and Car , garage has numberOfSpaces , I need do locking beacuse if in the same time I send two request , created overbooking - numberOfSpaces 2 and size list 3 , how to impleement optimistic / pessimistic locking / transactional ? somone can help me on priv ?

[flint hollow]

<@&1004656351647117403> please have a look, thanks.

[flint hollow]

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private Long id;

@Version
private int version;

private String make;
private String model;
private int year;

}

@Transactional annotation is used to indicate that a method or class should be executed within a transaction. This ensures that all database operations performed within the annotated method or class are atomic and consistent.

@AllArgsConstructor annotation is used to generate a constructor with all arguments. This constructor can be used to initialize all fields of the Car class.

@NoArgsConstructor annotation is used to generate a constructor with no arguments. This constructor can be used to create an instance of the Car class with default values for all fields.

@Getter and @Setter annotations are used to generate getter and setter methods for all fields of the Car class.

@Builder annotation is used to generate a builder pattern for creating instances of the Car class. This allows for more flexible and readable object creation code.