Re: generic arrays
On Jan 2, 12:21 am, "Mike Schilling" <mscottschill...@hotmail.com>
wrote:
Roedy Green wrote:
On Tue, 1 Jan 2008 20:11:37 -0800, "Mike Schilling"
<mscottschill...@hotmail.com> wrote, quoted or indirectly quoted
someone who said :
T[] things = (T[])new Object[10];
I still get a warning when I do that.
"unchecked cast".
Yup. No way around that. Using an array generically is inherently
unsafe.
I guess the problem is it can't really do anything to check.
Also (String[]) new Object[10]; would always fail.
There is the complicating matter of an Object[] where all elts are
strings and String[] when all elts are Strings.
All true. What exactly is it that you're trying to do? If it's
return an array of the correct element type to the caller, you'd have
to do something like pass the class type in and use reflection to
create the array.
Wild guess: Roedy's implementing a library of sort algorithms, using
generics (or adapting an existing one to be "generics correct" for
some value of "correct") and is trying to implement a non-in-place
merge sort.
And therefore needs to be able to create holding arrays of the same
element type as the input array.
Roedy: have you thought about cloning the array you're passed and then
blanking it? You might also want to look at the source for
ArrayList.toArray(Object[]), which uses some reflective monkeying to
create an array "sufficiently large" and of the same element type as
the passed array, if the passed array is not large enough to hold the
list.
-o