Hi Martin,
assuming this constellation
- Proposition extends Annotation
- Conclusion extends Proposition
- Premise extends Proposition
then the following lines should all be valid:
- selectCovered(jcas, Annotation.class, 0, 100);
- selectCovered(jcas, Proposition.class, 0, 100);
- selectCovered(jcas, Conclusion.class, 0, 100);
- selectCovered(jcas, Premise.class, 0, 100);
more generically, this should also be valid:
<T extends Proposition> void doSomething(JCas jcas, Class<T> aClazz) {
selectCovered(jcas, aClazz, 0, 100);
}
If you can show a minimal example that doesn't work, I may be able to say more.
To me, so far it looks like a problem with the generics in your code, not with
uimaFIT.
Cheers,
-- Richard
On 31.07.2015, at 22:00, Martin Wunderlich <[email protected]> wrote:
> Hi all,
>
> I am currently developing some feature extractors in the DKPro framework and
> I have come across a problem with the Class type in the following method in
> org.apache.uima.fit.util.JCasUtil:
>
> public static <T extends Annotation> List<T> selectCovered(JCas jCas, final
> Class<T> type,
> int begin, int end) {
> return cast(CasUtil.selectCovered(jCas.getCas(), getType(jCas, type),
> begin, end));
> }
>
> In my type system I have a base type „Proposition" that extends „Annotation"
> and two more types which are derived from the base type: „Conclusion“ and
> „Premise". If I use the base type for the generic type parameter T in this
> method above, it works fine. If I use one of the sub-types of the base type,
> I get the following error:
>
> - Bound mismatch: The generic method selectCovered(JCas, Class<T>, int,
> int) of type JCasUtil is not applicable for the arguments (JCas,
> Class<Conclusion>, int, int). The
> inferred type Conclusion is not a valid substitute for the bounded
> parameter <T extends Annotation>
>
> Background is that I would like to use one abstract feature extractor for
> common code which is parameterized with <T extends Proposition> and the two
> concrete sub-class FE’s, which are parameterized with the two sub-types.
>
> Maybe I have some misunderstanding regarding the use of Generics here. Could
> it be that in the definition of selectCovered() the clause <T extends
> Annotation> allows only direct sub-types of Annotation? Interestingly enough,
> if I don’t parameterize the sub-class FEs, I don’t get any errors.
> Thanks a lot.
>
> Cheers,
>
> Martin
