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Posted by Jerry Stuckle on 11/28/06 21:25
Tony Marston wrote:
> "Jerry Stuckle" <jstucklex@attglobal.net> wrote in message
> news:PeudnRKltLJsufHYnZ2dnUVZ_u2dnZ2d@comcast.com...
>
>>Tony Marston wrote:
>>
>>>"Jerry Stuckle" <jstucklex@attglobal.net> wrote in message
>>>news:j9-dnQB80fVLOvbYnZ2dnUVZ_rOdnZ2d@comcast.com...
>>>
>>>
>>>>Tony Marston wrote:
>>>>
>>>>
>>>>>"Jerry Stuckle" <jstucklex@attglobal.net> wrote in message
>>>>>news:Ib6dna_BtYQSifbYnZ2dnUVZ_sSdnZ2d@comcast.com...
>>>>>
>>>>>
>>>>>
>>>>>>jopperdepopper wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>>You should read "can be accessed everywhere".
>>>>>>>>
>>>>>>>>Private members can be accessed by members of the class only.
>>>>>>>>Protected members can be accessed by members of the class or a
>>>>>>>>derived
>>>>>>>>class.
>>>>>>>>Public members can be accessed by anyone, including other classes,
>>>>>>>>functions and any other code.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>Thanks Jerry. I'm trying to make a bit of sense of the php 5 approach
>>>>>>>to classes, and so far having a hard time. I fail to see the 'why'
>>>>>>>behind the 'public, protected and private' and stuff like abstraction,
>>>>>>>interfaces and whatnot.
>>>>>
>>>>>
>>>>>Intefaces are not necessary in PHP. Once you have defined a method it is
>>>>>a total waste to time to also define an interface. Interfaces are a
>>>>>"fix" in those languages as a means of dealing with optional arguments
>>>>>and statyic typing. PHP has ifferent ways of dealing with bth of these,
>>>>>therefore interfaces serve no useful purpose.
>>>>>
>>>>
>>>>Ah, the great Tony Marston is back to trolling again.
>>>>
>>>>Wrong. In OO terms, the interface is the way to interact with the
>>>>object. It consists of all public members - both methods (functions, in
>>>>PHP) and variables. And for derived classes, the base class adds
>>>>protected members.
>>>>
>>>>A PHP interface is something entirely different.
>>>
>>>
>>>I disagree. It is possible to define a function (method) within a class,
>>>then to define a separate thing called an "interface". It is possible
>>>access
>>>the function without using the interface, therefore the interface is not
>>>necessary.
>>>
>>
>>Tony,
>>
>>You really need to learn about OO before spouting off. In OO terms, an
>>interface is something entirely different than a PHP interface.
>
>
> How so? All the documentation I have seen describes how an interface simply
> describes a method which it imlements. If it is possible to access a method
> (a function in PHP) without going though an interface, ten an interface is
> not necessary in any language.
>
You need to understand the difference between an interface as described
in OO terms and the PHP interface.
The PHP interface defines a set of methods (function) which are required
by the classes which implement the interface. Java is similar in that
respect. But both are a subset of the total interface.
>
>>PHP is not the only OO language. Some don't even have a term "interface"
>>as part of the language. But the still have an interface.
>>
>>Try some of the books by James Rumbaugh, Grady Booch and/or Ivar Jacobson.
>>
>>
>>>>>>>Feels like things are being over-complicated
>>>>>>>somehow... or it's just my being inexperienced on this...
>>>>>>>
>>>>>>>Any other reading material on this suggested, someone?
>>>>>>>
>>>>>>
>>>>>>Look for some good books on OO theory and design.
>>>>>>
>>>>>>Two of the concepts in OO are 'encapsulation' and 'methods'.
>>>>>>
>>>>>>Encapsulation means the internals of an object are managed only by that
>>>>>>object and are not available to anyone else. In PHP these are private
>>>>>>members.
>>>>>
>>>>>
>>>>>Wrong. Encapsulation means that the data and the functions which operate
>>>>>on that data are contained (encapsulated) within a single object. While
>>>>>the methods (functions) thenselves may be visible the code behind those
>>>>>methods (i.e. the implementaton behind those methods) is not.
>>>>>Encapslation is NOT about hiding information, it is about hiding the
>>>>>implementation. It is not necessary to use public/private/protected on
>>>>>any methods or properties. It does not add any functionality, it merely
>>>>>creates restrictions which often get in the way.
>>>>>
>>>>
>>>>Wrong again, Tony. Encapsulation means internal representations of the
>>>>object are not visible outside of the class. Just like the base &
>>>>mantissa are not visible outside of a floating point number.
>>>
>>>
>>>I disagree. Encapsulation means that both the data and the methods which
>>>operate on that data are contained within a single unit or "capsule". The
>>>data names and the method names may be visible, it is only the code which
>>>lies behind each method name which is invisible. A piece of data may be
>>>accessed directly, as in $object->var, or it may be accessed through a
>>>getter, as in $object->getVar().
>>>
>>>If you bothered to read the right books you will see that encapsulation
>>>means "implementation hiding" and not "information hiding".
>>>
>>
>>Again, read the experts before spouting off. You have repeatedly shown
>>how little you understand about OO programming techniques.
>>
>>And yes, encapsulation is "implementation hiding". And the variables are
>>part of the IMPLEMENTATION.
>
>
> I disagree. Inplementation is code, information is data. If you don't
> believe me then read "Encapsulation is not information hiding" at
> http://www.javaworld.com/javaworld/jw-05-2001/jw-0518-encapsulation.html and
> also "Abstraction, Encapsulation, and Information Hiding" at
> http://www.itmweb.com/essay550.htm
>
OK, so you quote a couple of blogs by people who have their own opinions.
Read books by the authors I mentioned. They are the experts on OO, not
just anyone who can post a blog or essay on the web.
>
>>>>>>Methods are implemented as functions in PHP. They operate on the
>>>>>>object.
>>>>>
>>>>>
>>>>>That's one thing you got right.
>>>>>
>>>>
>>>>More than you got right. Go crawl back into your hole and don't come out
>>>>again until you know what you're talking about.
>>>
>>>
>>>I do know what I'm talking about..
>>>
>>
>>Then why do you continually disagree with the recognized experts in the OO
>>community, like the ones I mentioned above?
>
>
> I disagree with YOU simply because you clam to be a recognised expert when
> in fact you are no such thing. I keep finding papers on the internet which
> disagree with your explanations, yet you persist in claiming that you are
> right and everybody who dares to disagree with you is wrong. Such arrogance!
>
No, you disagree with every recognized expert in the field. Read what
the authors I mentioned have to say about it. THEY are the recognized
experts in the field.
I can create a paper on the internet saying the sun rises in the west.
It's quite simple to do. But that doesn't make it a fact.
Now go home and do some reading. You might actually learn something.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================
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