Groups > comp.lang.java.programmer > #10384

Re: state design pattern: question: inner or outer class: which is better?

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From	Lew <lewbloch@gmail.com>
Newsgroups	comp.lang.java.programmer
Subject	Re: state design pattern: question: inner or outer class: which is better?
Date	Wed, 30 Nov 2011 14:28:56 -0800 (PST)
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Gene Wirchenko wrote:
> Lew wrote:
> [snip]
> 
>> As with non-inner nested classes, if the type is needed by any other class
>>  and its semantics are not tightly bound to those of the proposed
>> outer class, a standalone class is probably more appropriate.
>>
>> If the semantics are tightly bound to the proposed outer class, and the sprite 
> state does not depend on the outer class instance's state, then a
>       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>      I do not follow this.  Please explain.
> 
>  nested class might be appropriate.

If an instance of the prospective nested class does not use any of the instance state of the prospective outer class, then it should not be an inner class, but it might be a candidate for a nested class.

If it does depend on the state of the outer-class instance, for example if it references an instance variable of the outer-class instance, then it will have to be an inner class.  This follows directly from the inability of a static member to access an instance member.

-- 
Lew

Thread

state design pattern: question: inner or outer class: which is better? John Goche <johngoche99@googlemail.com> - 2011-11-30 09:22 -0800
  Re: state design pattern: question: inner or outer class: which is better? Lew <lewbloch@gmail.com> - 2011-11-30 11:22 -0800
    Re: state design pattern: question: inner or outer class: which is better? Gene Wirchenko <genew@ocis.net> - 2011-11-30 14:04 -0800
      Re: state design pattern: question: inner or outer class: which is better? Lew <lewbloch@gmail.com> - 2011-11-30 14:28 -0800
        Re: state design pattern: question: inner or outer class: which is better? Gene Wirchenko <genew@ocis.net> - 2011-11-30 15:03 -0800
          Re: state design pattern: question: inner or outer class: which is better? Lew <lewbloch@gmail.com> - 2011-11-30 19:10 -0800
            Re: state design pattern: question: inner or outer class: which is better? Gene Wirchenko <genew@ocis.net> - 2011-11-30 19:23 -0800
  Re: state design pattern: question: inner or outer class: which is better? Roedy Green <see_website@mindprod.com.invalid> - 2011-12-02 01:47 -0800
    Re: state design pattern: question: inner or outer class: which is better? Lew <lewbloch@gmail.com> - 2011-12-02 07:27 -0800
  Re: state design pattern: question: inner or outer class: which is better? Arne Vajhøj <arne@vajhoej.dk> - 2011-12-02 21:32 -0500

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