Support for meta-annotations

[marceloverdijk]

Consider this example:

    @Query("continents")
    @Description("Get a page of continents.")
    public @NonNull ContinentPageType getContinents(
            @Name("page")
            @DefaultValue("0")
            @Description("The page number.")
            Integer page,
            @Name("size")
            @DefaultValue("10")
            @Description("The page size.")
            Integer size) {

The page and size arguments will occur many times in my api.

So I thought about creating a page annotation like:

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Name("page")
@DefaultValue("10")
@Description("The page size.")
public @interface PageSize {

}

Unfortunately this won't work as:

1. @DefaultValue has only @Target({ElementType.PARAMETER,ElementType.FIELD,ElementType.METHOD}) and not ElementType.ANNOTATION_TYPE. Maybe this could be added to make use of meta-annotations; probably this could be added to other MicroProfile GraphQL annotations as well.

2. @Description("The page size.") does not generate the expected description in the schema (probably SmallRye implementation specific).

With meta annotation it should be possible to override on a lower level as well.

So with the example above:

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Name("page")
@DefaultValue("10")
@Description("The page size.")
public @interface PageSize {

}

it should be possible to do:

    @Query("continents")
    @Description("Get a page of continents.")
    public @NonNull ContinentPageType getContinents(
            @Name("page")
            @DefaultValue("0")
            @Description("The page number.")
            Integer page,
            @PageSize
            Integer size) {

but also:

    @Query("continents")
    @Description("Get a page of continents.")
    public @NonNull ContinentPageType getContinents(
            @Name("page")
            @DefaultValue("0")
            @Description("The page number.")
            Integer page,
            @PageSize
            @DefaultValue("20")
            Integer size) {

[phillip-kruger]

Hi @marceloverdijk . Thanks for this. Also see issue #29 that will solve your specific use case. However it won't solve othe cases of repeated annotations. I am also not sure if this is a GraphQL spec issue, or a general issue ( meaning you will have the same issue in JAX-RS and other places )

[marceloverdijk]

Yes I’m aware of #29 and I was about to comment on that one as well in a couple of minutes 😊

[t1]

This is a part of the issue as we discussed on the MP mailing list about mixins and other annotation magic. Stereotypes is just one of the features we discussed.

[t1]

It's a separate requirement, but I hope we can fix it with the same toolset as #111.