Groups > comp.lang.java.programmer > #6953

Re: setSize ArrayList, when will it come?

From	Jan Burse <janburse@fastmail.fm>
Newsgroups	comp.lang.java.programmer
Subject	Re: setSize ArrayList, when will it come?
Date	2011-08-10 09:04 +0200
Organization	albasani.net
Message-ID	<j1tahl$4jm$1@news.albasani.net> (permalink)
References	(5 earlier) <j1rk6u$8li$1@dont-email.me> <j1rnb5$bv0$1@news.albasani.net> <j1s8uj$16a$1@dont-email.me> <j1scg8$s3l$1@news.albasani.net> <j1snbc$rtm$1@dont-email.me>

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Joshua Cranmer schrieb:
> Or you could use addAll and Collections.nCopies to implement setSize,
> and use ListIterator to do reverse iteration.

No you didn't get it. I need a fast specialized
setSize() as argued in the bug reference. According
to the collections documentation, the nCopies method
does create an extra object:

	http://download.oracle.com/javase/1.4.2/docs/api/java/util/Collections.html#nCopies%28int,%20java.lang.Object%29
	... The newly allocated data object is tiny (it contains
	a single reference to the data object). ...

But it is not only that this tiny object of type
Collections.CopiesList will be created. For addAll
call an Iterator AbstractList.Itr will be
created I guess, not sure.

But most likely given the abstract implementation of
addAll, the abstract way it treats its argument, and
in the particular situation that the argument is a
CopiesList.

So this is already two temporary objects on the heap.

Don't have a good feeling with this.

Bye

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setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 00:47 +0200
  Re: setSize ArrayList, when will it come? Knute Johnson <september@knutejohnson.com> - 2011-08-08 16:53 -0700
    Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 02:30 +0200
  Re: setSize ArrayList, when will it come? Arne Vajhøj <arne@vajhoej.dk> - 2011-08-08 20:50 -0400
  Re: setSize ArrayList, when will it come? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-08-08 21:09 -0400
    Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 04:16 +0200
      Re: setSize ArrayList, when will it come? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-08-08 21:39 -0500
        Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 09:33 +0200
          Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 09:42 +0200
        Re: setSize ArrayList, when will it come? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-08-09 07:56 +0000
          Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 11:18 +0200
          Re: setSize ArrayList, when will it come? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-08-09 10:36 -0500
            Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 18:30 +0200
              Re: setSize ArrayList, when will it come? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-08-09 16:30 -0500
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-10 00:31 +0200
                Re: setSize ArrayList, when will it come? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-08-09 20:36 -0500
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-10 09:04 +0200
                Re: setSize ArrayList, when will it come? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-08-10 08:50 +0000
                Re: setSize ArrayList, when will it come? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-08-10 18:16 -0500
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-11 01:55 +0200
      Re: setSize ArrayList, when will it come? Patricia Shanahan <pats@acm.org> - 2011-08-09 01:33 -0700
        Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 11:16 +0200
          Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 11:32 +0200
            Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-09 11:35 +0200
          Re: setSize ArrayList, when will it come? Patricia Shanahan <pats@acm.org> - 2011-08-09 04:00 -0700
          Re: setSize ArrayList, when will it come? Arne Vajhøj <arne@vajhoej.dk> - 2011-08-09 20:11 -0400
      Re: setSize ArrayList, when will it come? Robert Klemme <shortcutter@googlemail.com> - 2011-08-10 10:21 +0200
        Re: setSize ArrayList, when will it come? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-08-10 09:14 +0000
        Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-10 12:29 +0200
          Re: setSize ArrayList, when will it come? Robert Klemme <shortcutter@googlemail.com> - 2011-08-10 19:27 +0200
            Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-10 20:22 +0200
              Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-10 20:37 +0200
                Re: setSize ArrayList, when will it come? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-08-10 18:22 -0500
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-11 01:52 +0200
                Re: setSize ArrayList, when will it come? Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-08-10 21:43 -0500
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-11 14:19 +0200
              Re: setSize ArrayList, when will it come? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-08-10 22:23 +0000
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-11 01:47 +0200
                Re: setSize ArrayList, when will it come? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-08-11 00:23 +0000
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-11 09:19 +0200
                Re: setSize ArrayList, when will it come? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-08-12 15:06 +0000
  Re: setSize ArrayList, when will it come? Roedy Green <see_website@mindprod.com.invalid> - 2011-08-09 09:58 -0700
    Re: setSize ArrayList, when will it come? Patricia Shanahan <pats@acm.org> - 2011-08-09 10:25 -0700
      Re: setSize ArrayList, when will it come? Tom Anderson <twic@urchin.earth.li> - 2011-08-09 22:38 +0100
        Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-10 00:36 +0200
          Re: setSize ArrayList, when will it come? Roedy Green <see_website@mindprod.com.invalid> - 2011-08-09 15:55 -0700
          Re: setSize ArrayList, when will it come? Knute Johnson <september@knutejohnson.com> - 2011-08-09 16:03 -0700
            Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-10 09:18 +0200
              Re: setSize ArrayList, when will it come? Mayeul <mayeul.marguet@free.fr> - 2011-08-10 11:26 +0200
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-10 12:35 +0200
              Re: setSize ArrayList, when will it come? Lew <lewbloch@gmail.com> - 2011-08-10 09:33 -0700
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-10 20:22 +0200
          Re: setSize ArrayList, when will it come? Patricia Shanahan <pats@acm.org> - 2011-08-09 22:13 -0700
            Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-11 02:01 +0200
              Re: setSize ArrayList, when will it come? Patricia Shanahan <pats@acm.org> - 2011-08-10 18:42 -0700
                Re: setSize ArrayList, when will it come? Jan Burse <janburse@fastmail.fm> - 2011-08-11 14:21 +0200
    Re: setSize ArrayList, when will it come? Arne Vajhøj <arne@vajhoej.dk> - 2011-08-09 20:09 -0400
  Re: setSize ArrayList, when will it come? Roedy Green <see_website@mindprod.com.invalid> - 2011-08-09 16:02 -0700
    Re: setSize ArrayList, when will it come? Arne Vajhøj <arne@vajhoej.dk> - 2011-08-09 20:13 -0400

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