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Groups > comp.lang.java.programmer > #36216

Re: class parameter with generic type on a factory

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On 1/22/2017 6:02 AM, Andreas Leitgeb wrote:
> Arne Vajhøj <arne@vajhoej.dk> wrote:
>> Some experimentation ended up with this:
>>    public static interface MyInterface<T> ...
>>    public static class MyClass<T> implements MyInterface<T> ...
>>    public static class MyFactory<T> {
>>       public MyFactory(Class<? extends MyClass<T>> clz) ...
>>    }
>
> Indeed, the factory method can specify a type-parameterized class for
> its argument, which removes the "dirty" unchecked cast from inside the
> factory, but there is no way to completely get rid of the unchcked cast.
>
>>    public static void main(String[] args) throws [...] {
>>       @SuppressWarnings("unchecked")
>>       MyFactory<String> mf = new MyFactory<String>(
>>          (Class<? extends MyClass<String>>)MyClass.class
>>       );
>
> Actually, I think leaving the cast inside the factory makes for cleaner
> code.

It was the best that my limited creativity and the Java
compiler could agree on.

:-)

Arne

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class parameter with generic type on a factory Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2017-01-21 08:19 -0800
  Re: class parameter with generic type on a factory Andreas Leitgeb <avl@logic.at> - 2017-01-21 19:33 +0000
    Re: class parameter with generic type on a factory Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2017-01-21 11:51 -0800
      Re: class parameter with generic type on a factory Andreas Leitgeb <avl@logic.at> - 2017-01-21 20:11 +0000
  Re: class parameter with generic type on a factory Arne Vajhøj <arne@vajhoej.dk> - 2017-01-21 23:04 -0500
    Re: class parameter with generic type on a factory Andreas Leitgeb <avl@logic.at> - 2017-01-22 11:02 +0000
      Re: class parameter with generic type on a factory Arne Vajhøj <arne@vajhoej.dk> - 2017-01-22 14:00 -0500
  Re: class parameter with generic type on a factory Marcel Mueller <news.5.maazl@spamgourmet.org> - 2017-01-22 09:14 +0100

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