Groups > comp.lang.java.programmer > #8582

Re: DataInputStream

Date	2011-10-05 15:15 -0700
From	Patricia Shanahan <pats@acm.org>
Newsgroups	comp.lang.java.programmer
Subject	Re: DataInputStream
References	(2 earlier) <6cf66421-77a9-4088-b810-3bcc958cc8ca@i28g2000yqn.googlegroups.com> <2ec7550a-a3d9-40a9-bca1-e1fd2586429d@g33g2000yqc.googlegroups.com> <02b9b80f-ff02-499d-8f33-056080b114bb@s9g2000yql.googlegroups.com> <64b13101-4846-42d7-bc75-458eb326f73f@n8g2000yqd.googlegroups.com> <20878450.465.1317851548409.JavaMail.geo-discussion-forums@prcs9>
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On 10/5/2011 2:52 PM, Lew wrote:
...
> As another respondent suggested, NIO lets you alias typed
> 'ByteBuffer' instances as other types of 'Buffer'.
>
> But this defeats the purpose of 'DataInputStream', which handles
> those mechanics for you under the hood, so why in the world reinvent
> the wheel?  Just read your array of floats from the DIS.

I don't know whether this is one of those cases, but there are
situations in which the main limitation on data read speed is data
copying. There are two things that can reduce copy cost:

1. Do as few copies as possible.

2. When a copy is necessary, do it in bulk rather than element-by-element.

I think the NIO buffer aliasing may be a way of eliminating some
element-by-element copying.

Sometimes, in trade-offs between performance and code simplicity,
performance has to win.

Patricia

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DataInputStream bob <bob@coolgroups.com> - 2011-10-04 22:34 -0700
  Re: DataInputStream Robert Klemme <shortcutter@googlemail.com> - 2011-10-05 08:02 +0200
    Re: DataInputStream bob <bob@coolgroups.com> - 2011-10-04 23:17 -0700
      Re: DataInputStream Robert Klemme <shortcutter@googlemail.com> - 2011-10-05 00:07 -0700
        Re: DataInputStream bob <bob@coolgroups.com> - 2011-10-05 07:17 -0700
          Re: DataInputStream markspace <-@.> - 2011-10-05 08:27 -0700
          Re: DataInputStream Patricia Shanahan <pats@acm.org> - 2011-10-05 08:38 -0700
          Re: DataInputStream Robert Klemme <shortcutter@googlemail.com> - 2011-10-05 08:58 -0700
            Re: DataInputStream Lew <lewbloch@gmail.com> - 2011-10-05 14:52 -0700
              Re: DataInputStream Patricia Shanahan <pats@acm.org> - 2011-10-05 15:15 -0700
              Re: DataInputStream Robert Klemme <shortcutter@googlemail.com> - 2011-10-06 00:11 -0700
                Re: DataInputStream Lew <lewbloch@gmail.com> - 2011-10-06 07:08 -0700
                Re: DataInputStream Patricia Shanahan <pats@acm.org> - 2011-10-06 07:49 -0700
          Re: DataInputStream Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-10-05 21:16 -0400
      Re: DataInputStream Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-10-05 08:12 +0000
        Re: DataInputStream bob <bob@coolgroups.com> - 2011-10-05 07:12 -0700
  Re: DataInputStream Roedy Green <see_website@mindprod.com.invalid> - 2011-10-06 02:48 -0700

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