|
|
Posted by Jerry Stuckle on 12/05/95 11:51
Tony Marston wrote:
> "Jerry Stuckle" <jstucklex@attglobal.net> wrote in message
> news:oMSdndxexPBAjzzZnZ2dnUVZ_tidnZ2d@comcast.com...
>
>>Tony Marston wrote:
>>
>>>"Jerry Stuckle" <jstucklex@attglobal.net> wrote in message
>>>news:IrOdnQkOaac8Gz3ZnZ2dnUVZ_omdnZ2d@comcast.com...
>>>
>>>
>>>>Henk Verhoeven wrote:
>>>>
>>>>
>>>>>Jerry Stuckle wrote:
>>>>>
>>>>>>Actually, things like private declarations are very important.
>>>>>
>>>>>IMHO private declarations are too rigid and therfore decrease
>>>>>reusability. I agree that it can be very usefull to know the intentions
>>>>>of the developer of some code one is evaluating to call or some member
>>>>>variable one is avaluating to access. But every now and then there are
>>>>>good reasons to do it anyway, even if it was intended to be private. For
>>>>>example lazy initialization and default reasoning both are often
>>>>>implemented using direct access to member variables. Another example is
>>>>>using a visitor to implement persistency.
>>>>>
>>>>>Now maybe you would say that i should change these member variables to
>>>>>protected or public. There are two problems with this:
>>>>>1. It may not be my own code. Then if i get an upgrade of this code,
>>>>>these member variables will once again be private, unless i re-apply my
>>>>>changes. This is uneccessary overhead.
>>>>>2. By changing the private declaration the intension of the other
>>>>>developer gets lost. Now i could put a comment in that it was intended
>>>>>to be private, but in that case: why not put the @private marker in the
>>>>>comment in the first place?
>>>>>
>>>>>The fundamental point is: With these private and protected declarations
>>>>>you get stuck with the uneccessarily limitations introduced by the
>>>>>author. Object-orientation can lead to more reusability then
>>>>>conventional parameterized code exactly because the code can be
>>>>>overridden and extended in ways the original author did not provide for.
>>>>>private and protected declarations are a step backwards that is only
>>>>>reasonable if you assume that future developers that will maintain or
>>>>>reuse your code will ignore your intentions becuase they are fools. If
>>>>>this is the case, i think you should tell your boss that you are
>>>>>limiting the reusability of your code because you are aniticipating him
>>>>>to hire fools and let them work on/with your code ;-)
>>>>>
>>>>>Greetings,
>>>>>
>>>>>Henk Verhoeven,
>>>>>www.phpPeanuts.org.
>>>>
>>>>Henk,
>>>>
>>>>Private declarations are key to OO programming.
>>>
>>>
>>>No they are not. Encapsulation is not the same as data hiding. Please
>>>refer to:
>>>http://www.javaworld.com/javaworld/jw-05-2001/jw-0518-encapsulation.html
>>>http://www.itmweb.com/essay550.htm
>>>
>>
>>Give it up, Tony. You obviously can't even understand the information you
>>reference.
>
>
> No, I won't give it up. Both those articles clearly state that private
> declarations (data hiding) is *not* one of the key concepts of OO.
> Encapsulation is about *implementation* hiding, not information* hiding.
>
Try reading from a real expert - like Booch, Rumbaugh or Iverson. Just because
someone posts something on the internet doesn't make them an expert. You've
proven that several times here.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================
Navigation:
[Reply to this message]
|