Re: [PHP] class variables and methods
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/)
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
To contact the list administrators, e-mail: [EMAIL PROTECTED]
--
--
Andrew Libby
Director
RE: [PHP] class variables and methods
But when designing classes, isn't it normal to have private and public
variables or properties. Granted my OOP experience is very limited, having
access to OOP development in CA-Visual Objects, Clipper, VB, and ASP. But
it was normal to have a series of public properties one could access
directly and then properties that could only be access by the class itself.
Of course in VB and ASP these were defined with Get, Let and Set methods,
but you could still access them directly. You could also design properties
that were read only as well. Perhaps this is because of operator
overloading??
-Original Message-
From: Tom Carter [mailto:[EMAIL PROTECTED]]
Sent: Sunday, August 19, 2001 2:19 AM
To: Andrew Libby; Joe Sheble (Wizaerd)
Cc: General PHP List
Subject: Re: [PHP] class variables and methods
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
Re: [PHP] class variables and methods
There is a distinct chance of many difference schools of thought... my
background is Java (mostly at IBM.. so of course could be very different)..
but all the java gurus I've known have worked on the principle private
variable and public methods.. declaring all variables (except constants..
php doesn't really have a comparably concept) as private and always using
methods.
I would be very interested to hear others opinion on this...
But when designing classes, isn't it normal to have private and public
variables or properties. Granted my OOP experience is very limited,
having
access to OOP development in CA-Visual Objects, Clipper, VB, and ASP. But
it was normal to have a series of public properties one could access
directly and then properties that could only be access by the class
itself.
Of course in VB and ASP these were defined with Get, Let and Set methods,
but you could still access them directly. You could also design
properties
that were read only as well. Perhaps this is because of operator
overloading??
-Original Message-
From: Tom Carter [mailto:[EMAIL PROTECTED]]
Sent: Sunday, August 19, 2001 2:19 AM
To: Andrew Libby; Joe Sheble (Wizaerd)
Cc: General PHP List
Subject: Re: [PHP] class variables and methods
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
[PHP] class variables and methods
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/)
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
To contact the list administrators, e-mail: [EMAIL PROTECTED]
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/)
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
To contact the list administrators, e-mail: [EMAIL PROTECTED]
--
--
Andrew Libby
Director of Technology
CommNav, Inc
[EMAIL PROTECTED]
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
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