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Re: can this be done with generics?

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On Sunday, November 24, 2013 7:55:56 PM UTC-5, Andreas Leitgeb wrote:
>
> 
> Alternatives, that do NOT satisfy me: 
>   a) use an explicit cast to (Bar) 
>       ((Bar)(new Bar().foo1().foo42().foo84())).bar();
>      Would turn into a nightmare, when more of Bar's 
>      methods got mixed into the chain.
> 
...
> Thanks in advance!
A variant of this approach that might be clearer is to have

    class Foo {
       ....
       Bar toBar() {
           return (Bar) this;  // Throws exception if called inappropriately
       }
     }

Then you can write a long sequence as:

     new Bar().foo1().foo2().toBar().bar3().bar4().foo5().toBar().bar6()...

and simply insert a toBar() whenever you want a foo followed by a bar.
However this would require Foo to know about Bar.  

This you might be able to get around that with generics...

     class <T> Foo {
        ...
        T toType() {
             return (T) this;
        }
      }

      class <T> Bar extends Foo {...}


and then

      new Bar<Bar>.foo1().foo2().toType().bar1().bar2().foo3().toType().bar3();

I assumed you have all of your fooN and barN methods defined as
      Foo<T> or Bar<T>
in their return type.


Regards,
Tom McGlynn
      

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Thread

can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-25 00:55 +0000
  Re: can this be done with generics? Arne Vajhøj <arne@vajhoej.dk> - 2013-11-24 21:11 -0500
    Re: can this be done with generics? Saxo <jeti789@web.de> - 2013-11-25 01:43 -0800
      Re: can this be done with generics? Saxo <jeti789@web.de> - 2013-11-25 01:47 -0800
      Re: can this be done with generics? Arne Vajhøj <arne@vajhoej.dk> - 2013-11-26 21:32 -0500
    Re: can this be done with generics? Silvio <silvio@internet.com> - 2013-11-25 11:30 +0100
      Re: can this be done with generics? Saxo <jeti789@web.de> - 2013-11-25 02:36 -0800
      Re: can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-25 10:45 +0000
      Re: can this be done with generics? Arne Vajhøj <arne@vajhoej.dk> - 2013-11-26 21:35 -0500
        Re: can this be done with generics? Silvio <silvio@internet.com> - 2013-11-27 10:48 +0100
        Re: can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-27 10:18 +0000
  Re: can this be done with generics? Patrick Roemer <sangamon@netcologne.de> - 2013-11-25 12:59 +0100
    Re: can this be done with generics? Robert Klemme <shortcutter@googlemail.com> - 2013-11-25 22:31 +0100
      Re: can this be done with generics? Patrick Roemer <sangamon@netcologne.de> - 2013-11-26 12:03 +0100
      Re: can this be done with generics? v_borchert@despammed.com (Volker Borchert) - 2013-11-26 21:32 +0000
        Re: can this be done with generics? Robert Klemme <shortcutter@googlemail.com> - 2013-11-26 23:30 +0100
      Re: can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-27 18:53 +0000
        Re: can this be done with generics? Sebastian <news@seyweiler.dyndns.org> - 2013-11-28 22:28 +0100
          Re: can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-30 14:21 +0000
  Re: can this be done with generics? Mike Amling <mamling@chaff.us> - 2013-11-25 09:02 -0600
    Re: can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-26 01:04 +0000
      Re: can this be done with generics? Robert Klemme <shortcutter@googlemail.com> - 2013-11-26 08:16 +0100
        Re: can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-26 20:42 +0000
    Re: can this be done with generics? Arne Vajhøj <arne@vajhoej.dk> - 2013-11-26 21:38 -0500
      Re: can this be done with generics? Mike Amling <mamling@chaff.us> - 2013-11-27 11:05 -0600
  Re: can this be done with generics? taqmcg@gmail.com - 2013-11-25 08:36 -0800
    Re: can this be done with generics? taqmcg@gmail.com - 2013-11-25 09:04 -0800
      Re: can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-26 00:50 +0000
        Re: can this be done with generics? Arivald <NOSPAMarivald@interia.pl> - 2013-11-26 07:10 +0100
          Re: can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-27 18:58 +0000
  Re: can this be done with generics? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-12-07 09:04 -0800
    Re: can this be done with generics? Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-12-07 19:20 +0000
      Re: can this be done with generics? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2013-12-10 11:14 -0800

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