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From: =?UTF-8?Q?Arne_Vajh=c3=b8j?= <arne@vajhoej.dk>
Newsgroups: comp.lang.java.programmer
Subject: Re: class parameter with generic type on a factory
Date: Sun, 22 Jan 2017 14:00:03 -0500
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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