Groups > comp.lang.java.programmer > #7405

Style Police (a rant)

From	Eric Sosman <esosman@ieee-dot-org.invalid>
Newsgroups	comp.lang.java.programmer
Subject	Style Police (a rant)
Date	2011-08-26 20:56 -0400
Organization	A noiseless patient Spider
Message-ID	<j39fdc$1hi$1@dont-email.me> (permalink)

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     In recent days I've encountered a tool called "Checkstyle," that
parses Java code and flags various departures from its baked-in rules.
Some of these are worthwhile: It will whine if you override equals()
without overriding hashCode(), it will shriek if a method's Javadoc
omits a @param or @throws, it will moan if a static final field isn't
ALL_CAPS, and so on.  Some are less so: It insists that all method
parameters should be final, it forbids the ?: operator, it tut-tuts
at `x << 8' for using a "magic number."

     But the subject of this rant is its complaint that a class is "not
designed for extension."  You write a perfectly ordinary class with
methods foo() and bar(), and Checkstyle throws up its hands and gibbers
that your class is "not designed for extension."  Say, what?

     Well, it turns out that "not designed for extension" means that
your class has one or more methods that are not either final, abstract,
or empty.  That's it, that's The Rule.

     You can "design for extension" by having final methods, methods
that a subclass cannot override even if it needs to.

     You can "design for extension" by having abstract methods, methods
with no implementation that a subclass must implement on its own.

     Or you can "design for extension" by having methods that do
nothing at all.  (A peculiar measure of productivity, it seems to me.)

     BUT if you have a concrete non-final method that actually *does*
something, you have not "designed for extension."  It's all in aid of
somebody's theory about programming style: You're all right as long as
you freeze your methods against overriding or ensure they're impotent.

    I wonder what this Checkstyle tool would think of the concrete,
non-final, non-empty equals(), hashCode(), clone(), toString(), and
finalize() methods of ... java.lang.Object, the one class *no* Java
program can avoid extending.  If java.lang.Object is "not designed for
extension," is there any hope left for the language?

     Enforcing good style is difficult.  I wish the purveyors of the
enforcement tools would realize it's beyond their powers to do it well.

-- 
Eric Sosman
esosman@ieee-dot-org.invalid

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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) "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) "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) 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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