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Re: Why not String compare?

From Andreas Leitgeb <avl@logic.at>
Newsgroups comp.lang.java.programmer
Subject Re: Why not String compare?
Date 2016-08-31 09:45 +0000
Organization A noiseless patient Spider
Message-ID <slrnnsd9q3.456.avl@login.logic.tuwien.ac.at> (permalink)
References (1 earlier) <e2ba8jF67mfU1@mid.individual.net> <1c9ad1a1-ee44-4a9f-a307-1dab14c4a921@googlegroups.com> <e2bo9iF9m4nU1@mid.individual.net> <d9d392a6-7361-4743-aaef-22ec3d126722@googlegroups.com> <e2nb40F26seU1@mid.individual.net>

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Robert Klemme <shortcutter@googlemail.com> wrote:
> The implementor must ensure sgn(x.compareTo(y)) == -sgn(y.compareTo(x)) 
> for all x and y. (This implies that x.compareTo(y) must throw an 
> exception iff y.compareTo(x) throws an exception.)

An equivalent "symmetry" could be expected from .equals, but isn't. 

It's not "symmetry" as such, that implied the requirement.  It was
just pragmatically defined so for .compareTo while not for .equals.

Any usecase for including null into the natural ordering of certain
Comparable objects is just flawed.

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Thread

Why not String compare? Eric Douglas <e.d.programmer@gmail.com> - 2016-08-26 09:00 -0700
  Re: Why not String compare? Robert Klemme <shortcutter@googlemail.com> - 2016-08-26 18:49 +0200
    Re: Why not String compare? Eric Douglas <e.d.programmer@gmail.com> - 2016-08-26 10:09 -0700
      Re: Why not String compare? Robert Klemme <shortcutter@googlemail.com> - 2016-08-26 22:48 +0200
        Re: Why not String compare? Eric Douglas <e.d.programmer@gmail.com> - 2016-08-26 13:55 -0700
          Re: Why not String compare? Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-08-26 17:29 -0400
          Re: Why not String compare? Lew <lewbloch@gmail.com> - 2016-08-30 22:20 -0700
          Re: Why not String compare? Robert Klemme <shortcutter@googlemail.com> - 2016-08-31 08:17 +0200
            Re: Why not String compare? Andreas Leitgeb <avl@logic.at> - 2016-08-31 09:45 +0000
              Re: Why not String compare? Robert Klemme <shortcutter@googlemail.com> - 2016-08-31 19:24 +0200
                Re: Why not String compare? Andreas Leitgeb <avl@logic.at> - 2016-09-01 10:17 +0000
                Re: Why not String compare? Robert Klemme <shortcutter@googlemail.com> - 2016-09-02 18:29 +0200
  Re: Why not String compare? Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-08-26 13:24 -0400
    Re: Why not String compare? Eric Douglas <e.d.programmer@gmail.com> - 2016-08-26 10:48 -0700
      Re: Why not String compare? Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-08-26 14:50 -0400
        Re: Why not String compare? Eric Douglas <e.d.programmer@gmail.com> - 2016-08-26 12:19 -0700
      Re: Why not String compare? Lothar Kimmeringer <news200709@kimmeringer.de> - 2016-09-01 20:42 +0200
        Re: Why not String compare? Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-09-01 17:57 -0400
    Re: Why not String compare? Eric Douglas <e.d.programmer@gmail.com> - 2016-08-26 11:03 -0700
      Re: Why not String compare? Lothar Kimmeringer <news200709@kimmeringer.de> - 2016-09-02 21:54 +0200

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