Howard Lewis Ship wrote:
There's an existing bug for this. I'm not sure how fixable it's going
to be; welcome to the implementation nitty gritty of generic types and
type erasure. Just cause you don't see the typecasts doesn't mean the
compiler has put them there.
Here's a challenge: what if there was a createWidget() method on your
class. How would you implement it, to create an instance of the
correct class? You can't do a new T() (the compiler won't let you,
since it doesn't know what T is).
As you say, the wonderful type erasure "feature" implies that you have
to have more information about your type. For instance, you need to pass
a "Class<T> type" to your create() method. Actually, it's not really an
acceptable solution, but the sole workaround I know (if somebody as
another idea, I would be glad to use it).
After that, you can use reflection :
8<-----------------------------
public class EditWidgetPage<T extends Widget> {
T widget;
T create(Class<T> type) {
widget = type..newInstance();
....
}
}
8<-----------------------------
A bunch of infos are available at www.angelikalanger.com FAQs, and more
precisely about your concern :
http://www.angelikalanger.com/GenericsFAQ/FAQSections/ProgrammingIdioms.html#How%20do%20I%20pass%20type%20information%20to%20a%20method?
Hope it may help...
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