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Posted to dev@commons.apache.org by Lee Crawford <cr...@stadeon.com> on 2003/11/24 18:18:41 UTC
/PROPOSAL 1/ Additions to IteratorUtils
I'd like to propose the following simple additions to the
o.a.c.c.IteratorUtils
class.
The following is a simple convenience method for counting the number of
elements
in an iteration, something that I find myself recreating somewhat
frequently:
public static
int countElements (final Iterator iter) {
int cnt = 0;
while (iter.hasNext ()) {
cnt ++;
}
return cnt;
}
There isn't an EnumeratorUtils present that might contain an equivalent:
public static
int countElements (final Enumerator enum) {
int cnt = 0;
while (enum.hasNext ()) {
cnt ++;
}
return cnt;
}
Or the slightly less performant:
public static
int countElements (final Enumerator enum) {
return IteratorUtils.countElements (asIterator (enum));
}
Thoughts?
--lee
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Re: [collections] Re: /PROPOSAL 1/ Additions to IteratorUtils
Posted by Stephen Colebourne <sc...@btopenworld.com>.
It seems like an odd thing to want to do. If you need to know the size, hold
the data in a collection.
Stephen
----- Original Message ----- >
In the current CVS HEAD, you can do
>
> IteratorUtils.toArray(Iterator).length
> or
> IteratorUtils.toList(Iterator).size()
>
> But, your suggestion may be a good addition also.
>
> Also, I think that the method definitions you've provided will all cause
> infinite loops -- hasNext() will always return true if you don't call
> next(). We'd need to find a way to copy the iterator so we don't modify
> it's state when we count the elements.
>
> Anyone else have an opinion?
>
>
>
>
> Lee Crawford wrote:
> > I'd like to propose the following simple additions to the
> > o.a.c.c.IteratorUtils
> > class.
> >
> > The following is a simple convenience method for counting the number of
> > elements
> > in an iteration, something that I find myself recreating somewhat
> > frequently:
> >
> > public static
> > int countElements (final Iterator iter) {
> > int cnt = 0;
> > while (iter.hasNext ()) {
> > cnt ++;
> > }
> > return cnt;
> > }
> >
> > There isn't an EnumeratorUtils present that might contain an equivalent:
> >
> >
> > public static
> > int countElements (final Enumerator enum) {
> > int cnt = 0;
> > while (enum.hasNext ()) {
> > cnt ++;
> > }
> > return cnt;
> > }
> >
> > Or the slightly less performant:
> >
> > public static
> > int countElements (final Enumerator enum) {
> > return IteratorUtils.countElements (asIterator (enum));
> > }
> >
> > Thoughts?
> >
> > --lee
>
>
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>
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[collections] Re: /PROPOSAL 1/ Additions to IteratorUtils
Posted by __matthewHawthorne <ma...@phreaker.net>.
( Remember to prefix subject with [collections] )
In the current CVS HEAD, you can do
IteratorUtils.toArray(Iterator).length
or
IteratorUtils.toList(Iterator).size()
But, your suggestion may be a good addition also.
Also, I think that the method definitions you've provided will all cause
infinite loops -- hasNext() will always return true if you don't call
next(). We'd need to find a way to copy the iterator so we don't modify
it's state when we count the elements.
Anyone else have an opinion?
Lee Crawford wrote:
> I'd like to propose the following simple additions to the
> o.a.c.c.IteratorUtils
> class.
>
> The following is a simple convenience method for counting the number of
> elements
> in an iteration, something that I find myself recreating somewhat
> frequently:
>
> public static
> int countElements (final Iterator iter) {
> int cnt = 0;
> while (iter.hasNext ()) {
> cnt ++;
> }
> return cnt;
> }
>
> There isn't an EnumeratorUtils present that might contain an equivalent:
>
>
> public static
> int countElements (final Enumerator enum) {
> int cnt = 0;
> while (enum.hasNext ()) {
> cnt ++;
> }
> return cnt;
> }
>
> Or the slightly less performant:
>
> public static
> int countElements (final Enumerator enum) {
> return IteratorUtils.countElements (asIterator (enum));
> }
>
> Thoughts?
>
> --lee
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