Groups > comp.lang.java.programmer > #7501

Re: Style Police (a rant)

From	Lew <lewbloch@gmail.com>
Newsgroups	comp.lang.java.programmer
Subject	Re: Style Police (a rant)
Date	2011-08-30 09:43 -0700
Organization	http://groups.google.com
Message-ID	<236d40a3-d367-4576-ada3-c0d842282483@glegroupsg2000goo.googlegroups.com> (permalink)
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Patricia Shanahan wrote:
> Eric Sosman wrote:
> ...
>> Almost. It checks exactly what somebody tells it to check in the
>> config file that somebody requires me to use.
> ...
>> I'm just ranting at the absurdity of a criterion that says Object
>> itself is "not designed for extension."
>>
> 
> The criterion could be described better. Maybe it should be something
> like "needs very careful design and documentation to achieve correct
> extension". A big chunk of the Object API documentation, for example,
> discusses the rules for equals, hashCode, and the relationship between
> them in classes that override them.
> 
> It seems to me that the best use of this type of tool for that sort of
> check is to prevent such things being done casually. The extra
> hoop-jumping for turning off the check in a class is not that big
> compared to the work that needs to be done to ensure correct extension.
> 
> Of course, if the powers-that-be forbid turning off the check, there is
> a much bigger problem.

What we're overlooking here is that 'Object' actually does violate the rule, and that it's not actually a bad rule.

The exception probes the rule - what we need to understand is _why_ 'Object' breaks the rule, and the dangerous behaviors it permits thereby.

As Patricia aptly points out, it takes a mountain of documentation, comprising not only the voluminous Javadocs but volumes of articles, chapters in _Effective Java_, and innumerable blog posts to prevent errors involving mismatches between 'equals()', 'hashCode()', 'toString()', and where applicable, 'compareTo()', because 'Object' is most definitively not "designed for extension" in the sense intended by the principle.

A class designed for extension in this context means designed *for the compiler to enforce extensibility*.  The downside to the rule-breaking (intentional though it be) in 'Object' is that it allows, nay encourages error.  The exact sort of error that Checkstyle is trying to prevent you from committing.

So shut the front up, get over yourself, and understand the reasons for the rule.  Yes, it can and even should be violated under certain circumstances.  But don't present 'Object' as a counterexample when in fact it is the poster child for why the rule is valid.

-- 
Lew

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Style Police (a rant) Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-08-26 20:56 -0400
  Re: Style Police (a rant) Robert Klemme <shortcutter@googlemail.com> - 2011-08-27 09:58 +0200
  Re: Style Police (a rant) Rajiv Gupta <rajiv@invalid.com> - 2011-08-27 18:02 +1000
    Re: Style Police (a rant) v_borchert@despammed.com (Volker Borchert) - 2011-08-27 08:40 +0000
  Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-27 13:27 +0200
    Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-27 13:33 +0200
      Re: Style Police (a rant) Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-08-27 11:08 -0400
      Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-27 08:34 -0700
        Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-27 08:37 -0700
        Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-27 17:59 +0200
          Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-27 18:06 +0200
            Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-27 18:08 +0200
            Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-27 09:50 -0700
              Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-27 19:15 +0200
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-27 13:09 -0700
                Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-27 23:18 +0200
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-27 16:10 -0700
                Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-28 01:59 +0200
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-27 18:59 -0700
                Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-28 15:32 +0200
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-28 13:09 -0700
                Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-29 04:02 +0200
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-28 19:20 -0700
                Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-29 09:44 +0200
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-29 08:30 -0700
                Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-08-29 16:37 +0000
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-29 12:10 -0700
                Re: Style Police (a rant) Robert Klemme <shortcutter@googlemail.com> - 2011-08-29 18:21 +0200
                Re: Style Police (a rant) Jan Burse <janburse@fastmail.fm> - 2011-08-29 04:06 +0200
    Re: Style Police (a rant) Wanja Gayk <brixomatic@yahoo.com> - 2011-09-10 06:45 +0200
      Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-09-10 11:40 +0000
        Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-09-10 14:06 -0700
          Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-09-11 14:07 +0000
            Re: Style Police (a rant) Arne Vajhøj <arne@vajhoej.dk> - 2011-09-11 10:55 -0400
              Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-09-11 23:34 +0000
            Re: Style Police (a rant) Arne Vajhøj <arne@vajhoej.dk> - 2011-09-11 10:58 -0400
              Re: Style Police (a rant) Patricia Shanahan <pats@acm.org> - 2011-09-11 10:12 -0700
            Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-09-11 09:47 -0700
              Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-09-11 23:32 +0000
            Re: Style Police (a rant) Wanja Gayk <brixomatic@yahoo.com> - 2011-09-11 21:20 +0200
              Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-11 17:11 -0400
                Re: Style Police (a rant) Wanja Gayk <brixomatic@yahoo.com> - 2011-09-12 01:22 +0200
                Re: Style Police (a rant) Arne Vajhøj <arne@vajhoej.dk> - 2011-09-11 21:13 -0400
                Re: Style Police (a rant) Retahiv Oopsiscame <roopsisc@gmail.com> - 2011-09-11 16:54 -0700
                Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-11 23:42 -0400
                Re: Style Police (a rant) Retahiv Oopsiscame <roopsisc@gmail.com> - 2011-09-12 21:54 -0700
                Re: Style Police (a rant) "Cthun" <cthun_117@qmail.net.au> - 2011-09-13 07:18 -0400
                Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-13 10:07 -0400
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-09-13 08:15 -0700
                Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-13 12:00 -0400
                Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-13 10:10 -0400
                Re: Style Police (a rant) Retahiv Oopsiscame <roopsisc@gmail.com> - 2011-09-13 09:55 -0700
                Re: Style Police (a rant) "Cthun" <cthun_117@qmail.net.au> - 2011-09-12 04:56 -0400
                Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-12 05:12 -0400
                Re: Style Police (a rant) "Cthun" <cthun_117@qmail.net.au> - 2011-09-12 04:59 -0400
                Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-12 05:13 -0400
              Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-09-11 23:17 +0000
                Re: Style Police (a rant) Arne Vajhøj <arne@vajhoej.dk> - 2011-09-11 21:12 -0400
                Re: Style Police (a rant) Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-09-12 07:36 -0300
              Re: Style Police (a rant) "Cthun" <cthun_117@qmail.net.au> - 2011-09-12 04:58 -0400
                Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-12 05:12 -0400
        Re: Style Police (a rant) Wanja Gayk <brixomatic@yahoo.com> - 2011-09-11 15:33 +0200
          Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-09-11 09:42 -0700
            Re: Style Police (a rant) Lars Enderin <lars.enderin@telia.com> - 2011-09-11 20:35 +0200
              Re: Style Police (a rant) Retahiv Oopsiscame <roopsisc@gmail.com> - 2011-09-11 16:55 -0700
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-09-11 20:36 -0700
                Re: Style Police (a rant) Lars Enderin <lars.enderin@telia.com> - 2011-09-12 10:05 +0200
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-09-12 15:35 -0700
                Re: Style Police (a rant) Lars Enderin <lars.enderin@telia.com> - 2011-09-13 10:35 +0200
                Re: Style Police (a rant) Retahiv Oopsiscame <roopsisc@gmail.com> - 2011-09-13 09:48 -0700
                Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-09-13 12:18 -0700
                Re: Style Police (a rant) Retahiv Oopsiscame <roopsisc@gmail.com> - 2011-09-13 17:30 -0700
                Re: Style Police (a rant) Retahiv Oopsiscame <roopsisc@gmail.com> - 2011-09-12 21:59 -0700
                Re: Style Police (a rant) Retahiv Oopsiscame <roopsisc@gmail.com> - 2011-09-12 21:58 -0700
                Re: Style Police (a rant) "Cthun" <cthun_117@qmail.net.au> - 2011-09-12 04:52 -0400
                Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-12 05:14 -0400
                Re: Style Police (a rant) "Cthun" <cthun_117@qmail.net.au> - 2011-09-12 06:42 -0400
                Re: Style Police (a rant) Cthun <cthun_117@qmail.net.au> - 2011-09-12 07:20 -0400
                Re: Style Police (a rant) "Cthun" <cthun_117@qmail.net.au> - 2011-09-12 08:46 -0400
                Re: Style Police (a rant) thoolen <th00len@th0lenbot.thorium> - 2011-09-12 21:03 -0400
              Re: Style Police (a rant) Tom Anderson <twic@urchin.earth.li> - 2011-09-12 20:18 +0100
            Re: Style Police (a rant) Wanja Gayk <brixomatic@yahoo.com> - 2011-09-11 21:20 +0200
              Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-09-11 13:52 -0700
          Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-09-12 00:17 +0000
      Re: Style Police (a rant) Arne Vajhøj <arne@vajhoej.dk> - 2011-09-10 21:32 -0400
        Re: Style Police (a rant) Wanja Gayk <brixomatic@yahoo.com> - 2011-09-11 13:27 +0200
          Re: Style Police (a rant) Arne Vajhøj <arne@vajhoej.dk> - 2011-09-11 11:05 -0400
        Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-09-11 13:23 +0000
          Re: Style Police (a rant) Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-09-11 10:04 -0400
            Re: Style Police (a rant) Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-09-11 12:45 -0300
              Re: Style Police (a rant) Arne Vajhøj <arne@vajhoej.dk> - 2011-09-11 16:53 -0400
          Re: Style Police (a rant) Arne Vajhøj <arne@vajhoej.dk> - 2011-09-11 10:59 -0400
            Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-09-11 21:25 +0000
  Re: Style Police (a rant) Tom Anderson <twic@urchin.earth.li> - 2011-08-27 14:00 +0100
    Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-27 08:42 -0700
    Re: Style Police (a rant) Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-08-27 11:58 -0400
  Re: Style Police (a rant) "John B. Matthews" <nospam@nospam.invalid> - 2011-08-28 08:21 -0400
    Re: Style Police (a rant) Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-08-28 18:07 -0300
  Re: Style Police (a rant) Roedy Green <see_website@mindprod.com.invalid> - 2011-08-29 04:20 -0700
  Re: Style Police (a rant) Tim Slattery <Slattery_T@bls.gov> - 2011-08-29 09:11 -0400
    Re: Style Police (a rant) Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-08-29 20:50 -0400
      Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-08-30 11:27 +0000
        Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-30 09:36 -0700
          Re: Style Police (a rant) Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-08-30 17:51 +0000
      Re: Style Police (a rant) Tim Slattery <Slattery_T@bls.gov> - 2011-08-30 08:51 -0400
      Re: Style Police (a rant) Patricia Shanahan <pats@acm.org> - 2011-08-30 09:04 -0700
        Re: Style Police (a rant) Lew <lewbloch@gmail.com> - 2011-08-30 09:43 -0700
          Re: Style Police (a rant) Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2011-08-31 00:31 +0200

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