Meta Annotations

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.ANNOTATION_TYPE, ElementType.FIELD})
public @interface Mask {
    int preclear() default 0;
    int postclear() default 0;
    char with() default '*';
}

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD})
@Mask(preclear = 6, postclear = 4)
public @interface MaskCardNumber {
}