Hi devs,
after a long discussion on php-general [1], searching the archives and
trying every proposed solution without success I'm asking for your help to
solve the following problem:
class Car {
function drive() {
// I need the name of the calling class here
// in my case it should be 'Porsche'
}
}
class Porsche extends Car {
}
Porsche::drive();
With PHP4 it was possible to get the correct class name with
debug_backtrace(). This behaviour has been changed in PHP5.
How can I get the name of the extending class that invoked the method in
drive()?
Thanks in advance!
Best regards, Torsten Roehr
[1] http://marc.theaimsgroup.com/?t=110546013200009&r=1&w=2 (following the
thread with a news client might be easier)
With PHP4 it was possible to get the correct class name with
debug_backtrace(). This behaviour has been changed in PHP5.
How can I get the name of the extending class that invoked the method in
drive()?
There was a short discussion on this on this list, too some month ago. The
result was that there is (at least currently) no way to get the right
class. My CVS Log tells me that I needed this last April so I think the
discussion was around that time, maybe a bit later - if someone wants to
search the archives.
johannes
"Johannes Schlueter" johannes@php.net wrote in message
news:20050112161637.86918.qmail@pb1.pair.com...
With PHP4 it was possible to get the correct class name with
debug_backtrace(). This behaviour has been changed in PHP5.
How can I get the name of the extending class that invoked the method in
drive()?There was a short discussion on this on this list, too some month ago. The
result was that there is (at least currently) no way to get the right
class.
That's what I found out as well while searching the archives. Any more
ideas?
Something so straightforward and fundamental should be possible!?!
Best regards, Torsten Roehr
Torsten Roehr wrote:
Something so straightforward and fundamental should be possible!?!
Maybe is isn't as fundamental as you think? I never came across this
problem in years of PHP programming. But then again I use classes with
static calls for nothing but separate namespaces :-)
I'm pretty sure there is another (possibly more elegant) solution. This
is not a flame but a suggestion to rethink the problem you are trying to
solve.
- Chris
"Christian Schneider" cschneid@cschneid.com wrote in message
news:41E5790D.2090402@cschneid.com...
Torsten Roehr wrote:
Something so straightforward and fundamental should be possible!?!
Maybe is isn't as fundamental as you think? I never came across this
problem in years of PHP programming. But then again I use classes with
static calls for nothing but separate namespaces :-)I'm pretty sure there is another (possibly more elegant) solution. This
is not a flame but a suggestion to rethink the problem you are trying to
solve.
- Chris
Hi Chris,
no problem - not feeling flamed here ;) Maybe I should elaborate a bit more
what I'm needing this for. I would like to write a load method in a
superclass that can be used by all subclasses. I'm just passing in the SQL
statement as a parameter. The load method commits the query, loops through
the result set and creates/returns a collection of objects. The method needs
to know the name of the class to create objects of this class.
Example:
$persons = Person::load($sql); // returns collection of Person objects
$cars = Car::load($sql); // returns collection of Car objects
All classes can use the same load method and the database access (for
selects) is only needed in this method and can therefore be changed easily.
It's a bit simplified but I hope you get the idea. Also from the heated
discussion on php-general you can see that there are quite a few people
facing the described problem.
Best regards, Torsten Roehr
Hey Torsten,
Torsten Roehr wrote:
$persons = Person::load($sql); // returns collection of Person objects
$cars = Car::load($sql); // returns collection of Car objects
Simple solutions:
- $persons = DB::load('Person', $sql); foreach ($persons as $person)...
- $person = new Person($sql); while ($person->iterate())...
- Adding
get_class()to all DB classes (like Person) as suggested by
Daniel Convissor.
Solution 1) is IMHO close enough to your solution. Personally I prefer
(and we are using) solution 2) here as it also is more space efficient
for large number of results returned from the DB (only one Person object
is needed). On top of that we create classes automatically at runtime
from DB tables which removed the need to write stub classes (and makes
solution 3) feasible again).
I suggest that we take this discussion off-line now as it is not really
an internals discussion anymore.
- Chris
Christian Schneider wrote:
Torsten Roehr wrote:
Something so straightforward and fundamental should be possible!?!
Maybe is isn't as fundamental as you think? I never came across this
problem in years of PHP programming. But then again I use classes with
static calls for nothing but separate namespaces :-)I'm pretty sure there is another (possibly more elegant) solution. This
is not a flame but a suggestion to rethink the problem you are trying to
solve.
- Chris
Hi Chris,
I have faced this limitation of the languagee when I was trying to simplify
code which uses Singleton and uses to have n-time the code for caching
copied around. Every new class that one subclass has to copy the code. A bit
overwork, isn't it? At the end we agreed on a solution with CLASS in the
extending classes.
class Foo {
function getInstanceInt($params, $class_name= CLASS) {
var_dump($params, $class_name);
/.../
}
}
class Bar extends Foo {
function getInstance() {
Foo::getInstanceInt(func_get_args(), CLASS);
}
}
$a= Bar::getInstance(1,2,3);
So the getInstance() in the subclasses is quite simple. One also
may declare argument names. Here I haven't done that for simplicity.
Regards,
Andrey
"Andrey Hristov" php@hristov.com wrote in message
news:41E774CA.8040808@hristov.com...
Christian Schneider wrote:
Torsten Roehr wrote:
Something so straightforward and fundamental should be possible!?!
Maybe is isn't as fundamental as you think? I never came across this
problem in years of PHP programming. But then again I use classes with
static calls for nothing but separate namespaces :-)I'm pretty sure there is another (possibly more elegant) solution. This
is not a flame but a suggestion to rethink the problem you are trying to
solve.
- Chris
Hi Chris,
I have faced this limitation of the languagee when I was trying to
simplify
code which uses Singleton and uses to have n-time the code for caching
copied around. Every new class that one subclass has to copy the code. A
bit
overwork, isn't it? At the end we agreed on a solution with CLASS in
the
extending classes.class Foo {
function getInstanceInt($params, $class_name= CLASS) {
var_dump($params, $class_name);
/.../
}
}
class Bar extends Foo {
function getInstance() {
Foo::getInstanceInt(func_get_args(), CLASS);
}
}
$a= Bar::getInstance(1,2,3);So the getInstance() in the subclasses is quite simple. One also
may declare argument names. Here I haven't done that for simplicity.Regards,
Andrey
Hi Andrey,
thanks for your posts. It seems that this is the only viable solution -
passing the class name in as a parameter.
Thanks and best regards, Torsten Roehr
Torsten:
How can I get the name of the extending class that invoked the method in
drive()?
class Car {
function drive($child) {
echo "parent driven in a $child\n";
}
}
class Porsche extends Car {
function drive() {
parent::drive(get_class());
}
}
Porsche::drive();
--Dan
--
T H E A N A L Y S I S A N D S O L U T I O N S C O M P A N Y
data intensive web and database programming
http://www.AnalysisAndSolutions.com/
4015 7th Ave #4, Brooklyn NY 11232 v: 718-854-0335 f: 718-854-0409
"Daniel Convissor" danielc@analysisandsolutions.com wrote in message
news:20050112173425.GA1234@panix.com...
Torsten:
How can I get the name of the extending class that invoked the method in
drive()?class Car {
function drive($child) {
echo "parent driven in a $child\n";
}
}class Porsche extends Car {
function drive() {
parent::drive(get_class());
}
}Porsche::drive();
--Dan
Hi Dan,
thanks for your answer. I know about this solution - but it requires the
definition of drive() in every subclass. An alternative would be passing
in the class name as a parameter:
class Car {
function drive($className) {
echo 'parent driven in a $className';
}
}
class Porsche extends Car {
}
Porsche::drive('Porsche');
But this seems kind of stupid, doesn't it?
Best regards, Torsten Roehr
"Torsten Roehr" roehr@zilleon.com writes:
Hi devs,
after a long discussion on php-general [1], searching the archives and
trying every proposed solution without success I'm asking for your help to
solve the following problem:class Car {
function drive() {
// I need the name of the calling class here
// in my case it should be 'Porsche'
}
}class Porsche extends Car {
}Porsche::drive();
You're previous thread says that you want drive() to be static, but you're not
declaring it static. If it needn't be static, then you can do this:
class Car
{
function drive()
{
echo get_class($this) . "\n";
}
}
class Porsche extends Car
{
}
$carType = new Porsche();
$carType->drive();