AutoFactory: allow annotating factories

[cgrushko]

My manually-written factories sometimes have annotations to allow some compile-time validating. Would be awesome if I could write

@AutoFactory(annotate = BlaBlaAnnotation) public Foo();

to have this generated:

@BlaBlaAnnotation class FooFactory {}

[gk5885]

Since this API would only work for valueless annotations, I don't think that this is going to get much traction. The ability to add annotations to the generated types might be nice, but I'm not coming up with a decent way to specify them.

[cgrushko]

Perhaps this can be achieved using an interface:

class foo() {

  @AutoFactory(implements = Factory)
  public foo(...) { .. }

  @BlaBlaAnnotation(value = "2")
  interface Factory {
    ...
  }
}

All annotations appearing on the interface Factory will be copied over to the generated factory.

[shevek-nebula]

+1

The annotation I want is Spring's @Component - while this is zero-args (fine), but since that's an autoscanned annotation, adding it to an interface may throw up unexpected warnings in Spring.

[shevek-nebula]

Best effort so far is to tell AutoFactory to extend an abstract superclass with the relevant annotations, and ensure that the client of the annotations inspects the superclass.

[shevek-nebula]

For Spring framework, make the generated factory implement a marker interface (e.g. FactoryComponent, then add:

@ComponentScan(basePackageClasses = ApplicationBackend.class,
        includeFilters = {
    @ComponentScan.Filter(type = FilterType.ASSIGNABLE_TYPE, value = FactoryComponent.class)
})

[arend-von-reinersdorff]

I would like to add another use case for annotating factories:

Since CDI 1.1 a CDI bean must have a scope annotation like @Dependent to be discovered. If a generated factory has no such annotation, it is not discovered as a CDI bean.

This is the new default behavior (bean-discovery-mode="annotated") since CDI 1.1. See also the specification: http://docs.jboss.org/cdi/spec/1.1/cdi-spec.html#bean_archive

For this usecase valueless annotations would work fine.

[hu-chia]

there is a AnnotationsToApply.