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NNTP-Posting-Date: Fri, 30 Dec 2011 07:40:43 -0600
Date: Fri, 30 Dec 2011 05:40:38 -0800
From: Patricia Shanahan <pats@acm.org>
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Subject: Re: Inner class and interface question (I posted some really long code)
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On 12/29/2011 11:02 PM, GGolf wrote:
> On 12/28/2011 11:59 AM, Chad wrote:
>> I'm want to put the getHead() method in the BagInterface. However, I
>> can't do this because the compiler keeps saying it can't find 'class
>> Node' in Location BagInterface<T>. I guess this is because Node is an
>> inner class of my LinkedList class. Ideas how to fix this? Ideally I
>> want to preserve the inner class.
>
> Referencing an inner class in the way you have described doesn't seem
> quite right. An interface shouldn't have any knowledge of its
> implementors. You should probably extract the class so that it's no
> longer an inner class.

I disagree. It is very reasonable for a linked list implementation to
have an inner class representing the nodes that will be linked together.
I think it should remain, and indeed be made private.

I do not think the interface should say anything at all about Node.
There are other ways of implementing a bag that do not have any such
class. The interface should deal entirely in terms of the generic type
T, the payload data type.

Patricia