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Message-ID: <005d01c3b2dd$97ecc920$f7518051@oemcomputer>
From: "Stephen Colebourne" <scolebourne@btopenworld.com>
To: "Jakarta Commons Developers List" <commons-dev@jakarta.apache.org>
References: <00d401c3b2af$01e14fb0$6601a8c0@trilobyte>
 <3FC24191.30908@phreaker.net>
Subject: Re: [collections] Re: /PROPOSAL 1/ Additions to IteratorUtils
Date: Mon, 24 Nov 2003 22:52:09 -0000
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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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