2006/8/29, Spark Shen <[EMAIL PROTECTED]>:
Krzysztof Sobolewski 写道:
> Spark Shen wrote:
>
>
>> Did you (refer to thread [app] ant with ecj) put
>>
>> Eclipse compiler JAR on Ant's
>> execution classpath to execute the javac task.
>>
>> If so, may be that's why It always gives you "unchecked cast" warning,
>> no errors.
>>
>
> Well, I created a new EnumSet class in completly unrelated environment... So
> it is perfectly possible that there's a classpath conflict somewhere. I
> can't verify that because don't have the Harmony build here :)
>
> BTW: another experiment revealed that
> EnumSet<? extends Enum<E>> set = (EnumSet<? extends Enum<E>>)collection;
> compiles without warnings. No matter how much I think I understand generics,
> there's always something that surprises me ;)
>
Conceptually speaking, I think EnumSet<? extends Enum<E>> still has
potential pitfall:
In the signature of addAll(Collection<? extends E> collection) method, ?
denotes subclass of E.
While in EnumSet<? extends Enum<E>>, ? denotes subclass of Enum<E>. But
consider the relationship
between E and Enum<E>, E is subclass of Enum<E>. So, we can not
guarantee that subclass of E is definitely
subclass of Enum<E>.
Hmm, as E is a subclass of Enum<E>, subclasses of E definitely have
Enum<E> among ancestors ;)
Correct me if I am wrong.
Best regards
> -KS
>
>
--
Spark Shen
China Software Development Lab, IBM
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