Support Quarkus / RestEasy ServerExceptionMapper annotation

[indiealexh]

Request to support RestEasy's @ServerExceptionMapper method annotation

This request is an extension of the feature developed in #220 and stems from this quarkus issue: quarkusio/quarkus#44035

smallrye-openapi can scan for @Provider ExceptionMappers and add them to endpoints that throw that exception. The same should be possible for exceptions mapped by using RestEasy's @ServerExceptionMapper method annotation.

Example for illustration

Here is an example of what I would like to do using @ServerExceptionMapper:

@Path("/bundles")
@Produces({MediaType.APPLICATION_JSON})
@Consumes(MediaType.APPLICATION_JSON)
@Tag(name = "Bundles")
public class BundlesResource {
    [...]
    @POST
    @Path("/{bundleId}/actions/render")
    @APIResponses({
            @APIResponse(responseCode = "200", description = "Render bundle"),
    })
    public Uni<BundleRender> renderBundle(@RestPath long bundleId, BundleRenderRequest bundleRenderRequest) throws BundleRenderValidationException {
        return bundleRenderService.renderBundle(bundleId, bundleRenderRequest);
    }

    @ServerExceptionMapper
    @APIResponse(
            responseCode = "400",
            description = "Validation of bundle failed",
            content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class))
    )
    public Response handleBundleRenderValidationException(BundleRenderValidationException exception) {
      return exception.getResponse();
    }
   [...]
}

public class BundleRenderValidationException extends WebApplicationException {
    public BundleRenderValidationException(String exceptionMessage) {
        super(
                Response
                        .status(Response.Status.BAD_REQUEST)
                        .entity(new ErrorResponse("Bundle Render Request failed validation", List.of(new String[]{exceptionMessage})))
                        .build()
        );
    }
}

Which would be the equivalent of the currently supported method:

@Path("/bundles")
@Produces({MediaType.APPLICATION_JSON})
@Consumes(MediaType.APPLICATION_JSON)
@Tag(name = "Bundles")
public class BundlesResource {
    [...]
    @POST
    @Path("/{bundleId}/actions/render")
    @APIResponses({
            @APIResponse(responseCode = "200", description = "Render bundle"),
    })
    public Uni<BundleRender> renderBundle(@RestPath long bundleId, BundleRenderRequest bundleRenderRequest) throws BundleRenderValidationException {
        return bundleRenderService.renderBundle(bundleId, bundleRenderRequest);
    }
   [...]
}

public class BundleRenderValidationException extends WebApplicationException {
    public BundleRenderValidationException(String exceptionMessage) {
        super(
                Response
                        .status(Response.Status.BAD_REQUEST)
                        .entity(new ErrorResponse("Bundle Render Request failed validation", List.of(new String[]{exceptionMessage})))
                        .build()
        );
    }
}

@Provider
public class BundleRenderValidationExceptionMapper implements ExceptionMapper<BundleRenderValidationException> {
    @Override
    @APIResponse(
            responseCode = "400",
            description = "Validation of bundle failed",
            content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class))
    )
    public Response toResponse(BundleRenderValidationException exception) {
        return exception.getResponse();
    }
}

which results in: