Parsing recursive annotations

[roded]

Hello,
Does the JSON schema generator support recursive annotations?
I.e., consider the following annotation:

@Pattern(regexp = "^[a-zA-Z#@$][a-zA-Z#@$0-9]*$")
@Size(min = 1, max = 8)
@Constraint(validatedBy = {})
@Target({ElementType.PARAMETER, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotation {

    String message() default "";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};
}

Could I somehow mark a field with this annotation and have the JSON schema generator pick up the Pattern and Size annotations?

Thanks

[CarstenWickner]

Hi @roded,

Not out-of-the-box right now.
Edit: starting with release 4.30.0, this is in fact supported by the jakarta and javax validation modules without requiring further configuration. Until then, the below workaround can still be used.

I've created an example, that covers this requirement at least partially:

public class GroupedAnnotationExample {

    public ObjectNode generateSchema() {
        SchemaGeneratorConfig config = new SchemaGeneratorConfigBuilder(SchemaVersion.DRAFT_2019_09, OptionPreset.PLAIN_JSON)
                .with(new GroupedAnnotationAwareJakartaValidationModule(JakartaValidationOption.INCLUDE_PATTERN_EXPRESSIONS))
                .build();
        SchemaGenerator generator = new SchemaGenerator(config);
        return generator.generateSchema(Example.class);
    }

    static class GroupedAnnotationAwareJakartaValidationModule extends JakartaValidationModule {

        GroupedAnnotationAwareJakartaValidationModule(JakartaValidationOption... options) {
            super(options);
        }

        @Override
        protected <A extends Annotation> A getAnnotationFromFieldOrGetter(MemberScope<?, ?> member, Class<A> annotationClass,
                Function<A, Class<?>[]> validationGroupsLookup) {
            A annotation = super.getAnnotationFromFieldOrGetter(member, annotationClass, validationGroupsLookup);
            if (annotation != null) {
                return annotation;
            }
            if (!member.isFakeContainerItemScope()) {
                Optional<A> groupedAnnotationFromMember = this.getGroupedAnnotationFromMember(member, annotationClass);
                if (!groupedAnnotationFromMember.isPresent()) {
                    MemberScope<?, ?> alternativeMember;
                    if (member instanceof FieldScope) {
                        alternativeMember = ((FieldScope) member).findGetter();
                    } else if (member instanceof MethodScope) {
                        alternativeMember = ((MethodScope) member).findGetterField();
                    } else {
                        return null;
                    }
                    if (alternativeMember != null) {
                        groupedAnnotationFromMember = this.getGroupedAnnotationFromMember(alternativeMember, annotationClass);
                    }
                }
                return groupedAnnotationFromMember.orElse(null);
            }
            return null;
        }

        private <A extends Annotation> Optional<A> getGroupedAnnotationFromMember(MemberScope<?, ?> member, Class<A> annotationClass) {
            for (Annotation otherAnnotation : member.getMember().getAnnotations()) {
                A annotation = otherAnnotation.annotationType().getDeclaredAnnotation(annotationClass);
                if (annotation != null) {
                    return Optional.of(annotation);
                }
            }
            return Optional.empty();
        }
    }

    static class Example {
        @CustomIdentifier
        private String identifier;
    }

    @Pattern(regexp = "^[a-zA-Z#@$][a-zA-Z#@$0-9]*$")
    @Size(min = 1, max = 8)
    @Constraint(validatedBy = {})
    @Target({ElementType.PARAMETER, ElementType.FIELD})
    @Retention(RetentionPolicy.RUNTIME)
    public @interface CustomIdentifier {

        String message() default "";

        Class<?>[] groups() default {};

        Class<? extends Payload>[] payload() default {};
    }
}

The generated schema looks like this then:

{
  "$schema" : "https://json-schema.org/draft/2019-09/schema",
  "type" : "object",
  "properties" : {
    "identifier" : {
      "type" : "string",
      "minLength" : 1,
      "maxLength" : 8,
      "pattern" : "^[a-zA-Z#@$][a-zA-Z#@$0-9]*$"
    }
  }
}

[CarstenWickner]

Hi @roded,

I've just merged #341, which means this kind of annotation on another annotation will be supported out-of-the-box with the next release (4.30.0) by both the jakarta and javax validation modules.

[roded]

Thanks again @CarstenWickner . I eagerly await 4.30.0.

[CarstenWickner]

Release v4.30.0 has been published. 🚀

[roded]

@CarstenWickner When can we expect the 4.30.0 artifact to be available in mavenCentral? Thanks!

[CarstenWickner]

The release was published successfully to the OSSRH repository. It usually takes a couple of hours to propagate. I suggest you check again every few hours.
I'd assume it is available some time today, but it's out of my control.