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From "Stephen Colebourne" <scolebou...@btopenworld.com>
Subject Re: [collections] TreeList
Date Tue, 04 May 2004 23:46:19 GMT
The default iterator is picked up from AbstractList. For each next() it uses
get(index) on the list to retrieve the element. As you might imagine,
ArrayList can easily beat this with a dedicated implementation going
straight to the array.

The two possible solutions are to have each node in the tree refer to its
parent, or to have the iterator dynamically use an ArrayStack to build up
the parent structure as it navigates it. I favour the latter if possible.

Stephen

----- Original Message -----
From: "Jörg Schmücker" <joerg.schmuecker@ekkono.com>
> Can you tell me how the iterator is implemented?  Currently, I have not
> implemented such forward/backward linking to improve iteration
performance.
>
> Regards,
>
> Joerg
>
> -----Original Message-----
> From: Stephen Colebourne [mailto:scolebourne@btopenworld.com]
> Sent: Monday, May 03, 2004 4:00 PM
> To: Jakarta Commons Developers List
> Cc: Jörg Schmücker
> Subject: Re: [collections] TreeList
>
>
> Thanks. Forwarded to commons-dev for reference.
>
> I will be checking the class in shortly. It does need a proper iterator
> implementation, as the default is slow. This can be added later though.
>
> Stephen
>
> ----- Original Message -----
> From: "Jörg Schmücker" <joerg.schmuecker@ekkono.com>
> > Sorry for the hassle.  I am very happy to contribute the code.  Next
time
> I
> > will contribute with the standard Apache licence.
> >
> > I am hoping that I'll have the time to finish the tree-based class to
> > implement a ordered subset of a set witht the same order and fast
> insertion.
> > That was the original reason I started implementing it as a tree. The
idea
> > that it will be much faster came to me only during the development.
Don't
> > know if it is a standard algorithm, but I did not copy it anywhere.
> > AVL-Trees should not be a problem.
> >
> > Regards,
> >
> > Joerg
> >
> > -----Original Message-----
> > From: Stephen Colebourne [mailto:scolebourne@btopenworld.com]
> > Sent: Sunday, May 02, 2004 11:34 AM
> > To: Jörg Schmücker
> > Subject: Re: [collections] TreeList
> >
> >
> > You're essentially stating that you haven't blatently ripped the code
off
> > from somewhere else (except standard computer science algorithm books).
> Also
> > that, if it was written for a company, that the company doesn't claim
any
> > ownership.
> >
> > IANAL, but my understanding is that legally you are donating a COPY of
> your
> > code to Apache that will then be OWNED by Apache. Both you and Apache
can
> > then do as they please with the code - in Apache's case release it with
> > commons collections.
> >
> > Effectively, you are saying that you COULD sign
> > http://www.apache.org/licenses/#clas without having to go through the
> hassle
> > of doing so.
> >
> > BTW, I am only having to mail you this because you didn't submit your
> > original code with an Apache licence. If you had, I would have taken
that
> as
> > the sign of donation!
> >
> > Stephen
> >
> > ----- Original Message -----
> > From: "Jörg Schmücker" <joerg.schmuecker@ekkono.com>
> > > Stephen,
> > >
> > > Could you give me a reason, why I should not be in the position to
> donate
> > > the class?  I don't think there is one but I just want to make sure.
> > >
> > > Joerg
> > >
> > > -----Original Message-----
> > > From: Stephen Colebourne [mailto:scolebourne@btopenworld.com]
> > > Sent: Saturday, May 01, 2004 11:57 PM
> > > To: js@ekkono.com
> > > Cc: Jakarta Commons Developers List
> > > Subject: [collections] TreeList
> > >
> > >
> > > Joerg,
> > > I have been looking at integrating your tree based list into commons
> > > collections. Can you confirm that you are in a position to donate the
> > class
> > > to Apache please? A reply to confirm this will allow its inclusion.
> > >
> > > Stephen


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