Re: How do you copy multidimension array from Vector to Object[][] ?
- From: "Ronin" <jkoorts@xxxxxxxxx>
- Date: 4 Jan 2007 22:40:44 -0800
Hi Chris thanks but I cant use ArrayList as I'm using J2ME. The API
does not have that class.
the thing is im reading data from a server and I dont know the size
beforehand. So I'm first dropping it into a Vector than move it to a
Object[][] so to save the whole casting shebang when im iterating
through it.
If there is no solution to port to Object[][] from vector.copyInto,
then yes I'll have to write my own little Vector class. I'll keep my
eye on this thread for a while.
cheers
Chris wrote:
Ronin wrote:
I have absolutely no idea how to do this. I inserted a [] array into a
vector, which then ofcourse became a [][] array, but now can't get it
out back to a Object[][].
Vector vector = new Vector();
vector.addElement(new Object[]{"A","B"});
vector.addElement(new Object[]{"C","D"});
Object obj[] = new Object[m.size()]; //this works so far
m.copyInto((Object[]) obj); //this works so far
Object[][] attribute = (Object[][]) obj; //BANG!!!
why the hell wont it work?
for now I'll just use the crappy m.elementAt() function and cast to [].
All this casting in a loop eats CPU though.
Some random, maybe not-useful ideas:
-- Don't use Vector. Use ArrayList.
-- ArrayList.toArray() is helpful
-- One of the problems with the Collection classes is that you have to
cast everything. Generics don't help, because it still does a cast
internally. If you have a performance-intensive app, don't use
Collections. Write your own wrapper around an array of the proper type.
(But *only* if know for sure that casts are causing a performance problem).
.
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