Groups > comp.lang.java.programmer > #3189

Re: Partially overriding a method?

Path	csiph.com!x330-a1.tempe.blueboxinc.net!usenet.pasdenom.info!gegeweb.org!eternal-september.org!feeder.eternal-september.org!.POSTED!not-for-mail
From	markspace <-@.>
Newsgroups	comp.lang.java.programmer
Subject	Re: Partially overriding a method?
Date	Thu, 21 Apr 2011 11:37:49 -0700
Organization	A noiseless patient Spider
Lines	40
Message-ID	<iopti2$n7o$1@dont-email.me> (permalink)
References	<ea560a6d-7156-4801-87c5-3b533b57c420@cu4g2000vbb.googlegroups.com>
Mime-Version	1.0
Content-Type	text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding	7bit
Injection-Date	Thu, 21 Apr 2011 18:37:55 +0000 (UTC)
Injection-Info	mx01.eternal-september.org; posting-host="8H8O82p94repkEapFAzX5w"; logging-data="23800"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+uAgPST6xzRgCroAEV4gKAuwUTVSevdoM="
User-Agent	Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.15) Gecko/20110303 Thunderbird/3.1.9
In-Reply-To	<ea560a6d-7156-4801-87c5-3b533b57c420@cu4g2000vbb.googlegroups.com>
Cancel-Lock	sha1:H/6pX4Gn9qQgkItQ0zsnTh7bML8=
Xref	x330-a1.tempe.blueboxinc.net comp.lang.java.programmer:3189

Show key headers only | View raw

On 4/21/2011 8:31 AM, raphfrk@gmail.com wrote:
> I was wondering if it is possible to override a method but only for
> certain sub-classes of the method that the super-class supports.


Yes and no.  As you discovered, overriding is all or nothing.  You 
either override or you don't.

But you could add your own processing to do what you want with the 
"super" keyword.

<http://download.oracle.com/javase/tutorial/java/IandI/super.html>

>
> For example:
>
> class MainClass {
>      public static void main(String[] args) {
>          System.out.println("Started");
>          MainClass mc = new SubClass();
>          mc.check("Testing");
>          mc.check(7);
>      }
>      void check(Object x) {
>          System.out.println(x.toString());
>      }
> }
>
> class SubClass extends MainClass {
        void check(Object x) {
            if( x instanceof String ) {
               System.out.println("Sub class: " + x);
            } else {
               super.check( x );
            }
>      }
> }
>

The code changes above are untested.

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Partially overriding a method? "raphfrk@gmail.com" <raphfrk@gmail.com> - 2011-04-21 08:31 -0700
  Re: Partially overriding a method? Lew <noone@lewscanon.com> - 2011-04-21 12:42 -0400
  Re: Partially overriding a method? markspace <-@.> - 2011-04-21 11:37 -0700
    Re: Partially overriding a method? Lew <noone@lewscanon.com> - 2011-04-21 15:58 -0400
  Re: Partially overriding a method? Michal <kleku75@gmail.com> - 2011-04-21 21:00 +0200
  Re: Partially overriding a method? Roedy Green <see_website@mindprod.com.invalid> - 2011-04-21 12:59 -0700
  Re: Partially overriding a method? Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-04-21 21:10 -0400
    Re: Partially overriding a method? "raphfrk@gmail.com" <raphfrk@gmail.com> - 2011-04-24 09:39 -0700

csiph-web