Nick Stinemates wrote:
Data Hiding IS Encapsulation.
But, you have to agree,
<?php
class Lol {
private $bar;
public function getBar() { return $bar }
public function setBar($bar) { $this->bar = $bar}
}
?>
Is no different than:
<?php
class Lol {
public $bar;
}
?>
Here's a more thought out argument from
http://www.javaworld.com/javaworld/jw-09-2003/jw-0905-toolbox.html :
A fundamental precept of OO systems is that an object should not expose
any of its implementation details. This way, you can change the
implementation without changing the code that uses the object. It follows
then that in OO systems you should avoid getter and setter functions
since they mostly provide access to implementation details.
To see why, consider that there might be 1,000 calls to a getX() method
in your program, and each call assumes that the return value is of a
particular type. You might store getX()'s return value in a local
variable, for example, and that variable type must match the return-value
type. If you need to change the way the object is implemented in such a
way that the type of X changes, you're in deep trouble.
No,but in the first one, you can control, from within the class/method,
what data is actually allowed to be injected into that variable. Whereas
the second example would allow you to stuff any type of data into that
class variable. That might not be a good thing.
That's a relatively narrow minded response to my point, since I gave
a pretty concrete example of exactly what I meant, followed by a great
article which furthered my point.
Let me quote, you said this: "Is no different than" You are wrong, in fact it
IS different. Having your own custom methods to get or set data allows you to
have more control over what data is injected into your object.
I would call is a personal preference which may not work for you, but works fine
for me.
All I can say is that all my __set methods do data sanitizing and validation,
which is were I think it should be done. If anybody thinks this might be a bad
thing, please by all means explain why it is bad.
The general rule of encapsulation is: Don't ask an object for data, ask
the object to work with the data.
I hope it checks the data first before using it. If you don't then you might
end up with something you had not planned on.
If I am not to ask an object for data how is my db class/object ever going to
return me data from my database?
--
Jim Lucas
"Some men are born to greatness, some achieve greatness,
and some have greatness thrust upon them."
Twelfth Night, Act II, Scene V
by William Shakespeare
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