There was a long discussion on this in a java forum I am part of, the
product of which was basically this...
1. All variables in a class are best left to be private (not sure PHP has
this, but the programmer can work the principle in mind.. that is only the
class can access them).
2. Generic variable access/store methods should be avoided - the principle
is that the internal variable can change name etc. without the external
interface having to worry about it.
3. Method to set/fetch each variable - it may seem a counter intuitive way
of doing it, especially when it is possible to do something "nice" like the
set method below. This seems a very "un-web" way.. and this is where a
difference comes in. Web is not inherently OO, and a lot of the practices of
web programmers are at conflict with more "traditional" apps programmers.
Web tends to go for speed and simplicity, rather than good design etc.
4. Some situations could theoretically arise where it is necessary to set an
unknown amount of variables within a class, however it would be far more
sensible to put these into an array.
In summary, in good OOP you should have a method for every get/set operation
on variables that is required, using arrays as appropiate.
Going back to the original point on whether or not to access the variable
directly or build a set function in, they are both as bad as each other,
just about. They both access variables directly and require the outside
program to have knowledge of variable names etc. and it doesn't allow for
checking for "correct" values being set ( a useful thin with the above
method)
Hope this helps, let me know if I can provide any more advice.
Tom
----- Original Message -----
From: "Andrew Libby" <[EMAIL PROTECTED]>
To: "Joe Sheble (Wizaerd)" <[EMAIL PROTECTED]>
Cc: "General PHP List" <[EMAIL PROTECTED]>
Sent: Sunday, August 19, 2001 3:34 AM
Subject: Re: [PHP] class variables and methods
> Joe,
> There are varying opinions on this issue. The argument for
> methods is that it hides the internal structure of your class. This
> is always a good thing. This means that the internals of the class
> can be changed, but the user interface (the user is the programmer here)
> does not change. So this alternative implementation of someclass
>
>
> class someclass
> var $data = false;
>
> function set($key,$val) {
> $this->data[$key] = $val;
> }
> }
>
> is no different the the calling code. In general, I tend to have an
> accessor/mutator method for each 'property' that I would like to
> provide access to. I'd have a method for each $key that I want to
> support (this may not apply in your case).
>
> class someclass
> var $name = false;
> var $age = false;
>
> function name()
> if(func_num_args()) $this->name = func_get_arg(0);
> return $this->name;
> }
>
> function age()
> if(func_num_args()) $this->age= func_get_arg(0);
> return $this->age;
> }
> }
>
> Now, this gets a big annoying to code since the lions share of my
> classes have the name method implementations. I've been hunting
> for a way to create methods dynamically, but I've only found one.
> To create class definitions on the fly and eval() them. This
> works great when you've got a huge number of properties
> (class/instance vars). I'll construct a static method on the
> class that processes examines the class vars (get_class_vars())
> and defines a class extending my implementation. The
> sub class has the methods implemented for accessing/mutating
> the properties I'd like to have methods for. If anyone knows
> of a means to do this to an existing class (say using create_function()
> or something), I'd love to hear about it.
>
> Andy
>
>
> On Sat, Aug 18, 2001 at 07:09:08PM -0700, Joe Sheble (Wizaerd) wrote:
> > I've been doing some reading up on OOP in PHP, and looking at some of
the
> > classes available on the web, and I've got what is probably a stupid
> > question. I've seen this many many times..
> >
> > class someclass {
> > var $somevar = "someval";
> >
> > function set( $key, $val ) {
> > $this->$key = $val;
> > }
> > }
> >
> > $myClass = new someclass;
> > $myClass->set( "somevar", "someotherval" );
> >
> > why write a set method when you can just as easily call
> > $myClass->somevar = "someotherval";
> >
> > Is there a reason for this?
> >
> > Also, alot of the different table classes (an OOP approach to HTML
tables)
> > stores the data in arrays, but at what point is it too much to store
into an
> > array? Say you have a forum and the text entered for a single respone
could
> > be quite lengthy, much less for 100 replies... wouldn't that be a bit
much
> > to store into an array? I know it depends on the system resources, but
is
> > there a practical limit that people follow?
> >
> >
> >
> > --
> > PHP General Mailing List (http://www.php.net/)
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> >
>
> --
> --------------------------------------------------
> Andrew Libby
> Director of Technology
> CommNav, Inc
> [EMAIL PROTECTED]
>
>
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