@Documented
@Constraint(validatedBy = CapacityValidator.class)
@Target( {ElementType.TYPE_USE, ElementType.METHOD, ElementType.FIELD })
@Retention(RetentionPolicy.RUNTIME)
public @interface Capacity {

    String message() default "All fields at once must be filled in or empty!";
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
    int min();
   // int max();
}