Re: Class Literal ???
On 3/18/2010 1:36 AM, Roedy Green wrote:
On Wed, 17 Mar 2010 17:25:54 -0700 (PDT), TheBigPJ
<thebigpj@gmail.com> wrote, quoted or indirectly quoted someone who
said :
Class<MyClass> x = MyClass.class; //Right way of doing it
This is so Alice in Wonderland. The whole reason you have a class
variable is because the precise class is variable and unknown at
compile time. With that generic form, you need to know the precise
class type at compile time. If you knew that, you would not need a
class variable.
I disagree, you can have a method which takes a Class<T> object. Perhaps
a bean utility method:
<T, E extends T> T convertToSubclass(T originalBean, Class<E> subclass);
The usage could then be something along the lines:
MySub sub = convertToSubclass(myOriginal, MySub.class);
While this is a contrived example, there are actual uses. And as you
have recently pointed out in an unrelated thread, isn't better to keep
information?
A more useful generic form is something like this:
final Class<? extends Configuration> configurationClass =
Class.forName( binaryClassName ).asSubclass( Configuration.class );
Which says you know the base class at compile time, but not the
particular extension.
Yes, that is another way to look at it.
--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>