Bounded generics

Hi -

I'm trying to extend Vector.  I want it to accept any generic class
that implements a particular interface.

This is my best attempt:

interface MyInterface {
}

class Type1 implements MyInterface {
}

class Type2 implements MyInterface {
}

class MyVector<T implements MyInterface> extends Vector<T> {
}

I want MyVector to accept both Type1 and Type2 as classes but nothing
else which does not implement MyInterface.

I based this code on an O'Reilly book which apparently was written
before 1.5 was released.  I've also tried wildcards without luck.

Thanks in advance.

On Fri, 22 Apr 2005 18:42:07 +0100, Brian <brian@notreal.com> wrote:

> Hi -
>
> I'm trying to extend Vector.  I want it to accept any generic class
> that implements a particular interface.
>
> This is my best attempt:
>
> interface MyInterface {
> }
>
> class Type1 implements MyInterface {
> }
>
> class Type2 implements MyInterface {
> }
>
> class MyVector<T implements MyInterface> extends Vector<T> {
> }
>
> I want MyVector to accept both Type1 and Type2 as classes but nothing
> else which does not implement MyInterface.
>
> I based this code on an O'Reilly book which apparently was written
> before 1.5 was released.  I've also tried wildcards without luck.
>
> Thanks in advance.


Try this:

class MyVector<T extends MyInterface> extends Vector<T> {

You have to use 'extends' rather than 'implements', even with interfaces.
This one got me the first time too.

Dan.


--
Daniel Dyer
http://www.footballpredictions.net

Daniel Dyer < dan@footballnospamformepleasepredictions
.net> wrote:
> Try this:

> 	class MyVector<T extends MyInterface> extends Vector<T> {

> You have to use 'extends' rather than 'implements', even with interfaces.
> This one got me the first time too.

> Dan.

That was it! Thanks Dan.