Yes, I think you might be right, Richard, and that the problem is with the use
of Generics.
This would be the concrete FE class:
public class StartingPositionOfPremiseUFE<Premise> extends
StartingPositionOfPropositionUFE {
public static String FN_STARTINGPOSITIONOFPROPOSITION =
"StartingPositionOfPremise";
@Override
List<Premise> getPropositions(JCas jcas, int start, int end) {
return JCasUtil.selectCovered(jcas, Premise.class, start, end);
}
}
The call to selectCovered(…) gives the described error. The method
getPropositions(…) is defined as abstract in the super-class, which looks like
this:
abstract public class StartingPositionOfPropositionUFE<T extends Proposition>
extends FeatureExtractorResource_ImplBase implements
ClassificationUnitFeatureExtractor{
...
public List<Feature> extract(JCas jcas, TextClassificationUnit
classificationUnit) {
List<? extends Proposition> props = (List<? extends Proposition>)
getPropositions(jcas, start, end);
if( props != null && props.size() > 0) {
Proposition firstProposition = props.get(0);
startingPos = firstProposition.getBegin();
}
List<Feature> featList = new ArrayList<Feature>();
featList.add(new Feature(FN_STARTINGPOSITIONOFPROPOSITION,
startingPos));
return featList;
}
abstract List<?> getPropositions(JCas jcas, int start, int end);
}
I’ve removed the irrelevant bits to make it more concise.
Cheers,
Martin
> Am 01.08.2015 um 16:14 schrieb Richard Eckart de Castilho <[email protected]>:
>
> 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
>
