[PHP] Re: runtime access to static variable
Unfortunately, in the inherited DeployTask::execute(), self::$STEPS does not refer to UpdateTask::$STEPS, it refers to DeployTask::$STEPS Use parent::$STEPS and call it done? Yes, I know, if you add another layer of class in between, then it's not parent:: anymore, but it seems a bit less convoluted than the reflection solution, to this naive user... -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] Re: runtime access to static variable
this does beg the question why don't you know the classname at runtime..
seems to be a slight design flaw and may make sense for you to post the
full problem (you must have chosen to implement this for a reason..)
The full problem is: I started off with a DeployTask for deploying a
new instance of my web project to DreamHost:
http://cgi.sfu.ca/~jdbates/tmp/php/200812170/DeployTask.class.phps
(It is a task in the symfony framework, but basically the
DeployTask::execute() method gets called)
The task takes about thirty minutes to run, so I broke it up into steps.
After each step, it updates a database row so that a user who started
the task through a web interface can monitor its progress.
Great so far. Now I decided to create an UpdateTask for updating
deployed instances to the latest version of my code:
http://cgi.sfu.ca/~jdbates/tmp/php/200812170/UpdateTask.class.phps
Of course it also takes a long time to run, so my first iteration just
extends the DeployTask and defines different steps. UpdateTask inherits
DeployTask::execute(), which drives the steps and updates the database.
Unfortunately, in the inherited DeployTask::execute(), self::$STEPS
does not refer to UpdateTask::$STEPS, it refers to DeployTask::$STEPS
: (
I gather with late static bindings in PHP 5.3, static::$STEPS does
what I want? Anyway, DeployTask::execute() is not static, so I know
whether $this is an instance of DeployTask of UpdateTask:
get_class($this) returns it. Which brought me to my contrived example:
ket% cat test.php
?php
class Test
{
public static
$STEPS = array(
'foo',
'bar');
}
$className = 'Test';
var_dump($className::$STEPS);
ket%
Except that in real life, $className = get_class($this)
Check this out:
http://us2.php.net/manual/en/language.oop5.static.php
It actually won't work until 5.3.0 when they add late static binding.
I ran my contrived example with PHP 5.3alpha3, and it worked!
$className::$STEPS is not a parse error in 5.3, which is cool : )
Except that in 5.3, I will probably just use static::$STEPS anyway : P
In the meantime, I will probably use reflection as suggested:
// HACK: Use static::$STEPS in PHP 5.3:
// http://php.net/oop5.late-static-bindings
$class = new ReflectionClass($this);
$steps = $class-getStaticPropertyValue('STEPS');
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[PHP] Re: runtime access to static variable
Jack Bates wrote:
this does beg the question why don't you know the classname at runtime..
seems to be a slight design flaw and may make sense for you to post the
full problem (you must have chosen to implement this for a reason..)
The full problem is: I started off with a DeployTask for deploying a
new instance of my web project to DreamHost:
http://cgi.sfu.ca/~jdbates/tmp/php/200812170/DeployTask.class.phps
(It is a task in the symfony framework, but basically the
DeployTask::execute() method gets called)
The task takes about thirty minutes to run, so I broke it up into steps.
After each step, it updates a database row so that a user who started
the task through a web interface can monitor its progress.
Great so far. Now I decided to create an UpdateTask for updating
deployed instances to the latest version of my code:
http://cgi.sfu.ca/~jdbates/tmp/php/200812170/UpdateTask.class.phps
Of course it also takes a long time to run, so my first iteration just
extends the DeployTask and defines different steps. UpdateTask inherits
DeployTask::execute(), which drives the steps and updates the database.
Unfortunately, in the inherited DeployTask::execute(), self::$STEPS
does not refer to UpdateTask::$STEPS, it refers to DeployTask::$STEPS
: (
Yup I follow, been here myself too; infact doing very similar at the mo
making an event handler / listener for the hell of it!
anyhow.. stick this in you're DeployTask and run it :p
protected function execute($arguments = array(), $options = array()) {
// you're existing code here up to..
$job-pid = getmypid();
$thisClass = new ReflectionClass( get_class($this) );
$steps = $thisClass-getStaticPropertyValue('STEPS');
while ($job-step count($steps))
{
$job-save();
call_user_func(array($this, $steps[$job-step]), $arguments, $options);
$job-step++;
}
$job-delete();
}
untested but should work :)
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[PHP] Re: runtime access to static variable
Jack Bates wrote:
How do I access a static variable when I do not know the name of the
class until runtime?
I have the following example PHP:
ket% cat test.php
?php
class Test
{
public static
$STEPS = array(
'foo',
'bar');
}
$className = 'Test';
var_dump($className::$STEPS);
ket%
Unfortunately when I run it I get:
ket% php test.php
Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM
in /home/jablko/trash/test.php on line 13
ket%
I can call a static function using call_user_func(array($className,
'functionName')), and I can access a class constant using
constant($className.'::CONSTANT_NAME'). How do I access a static
variable?
this does beg the question why don't you know the classname at runtime..
seems to be a slight design flaw and may make sense for you to post the
full problem (you must have chosen to implement this for a reason..)
if you really really must do this, you'd be best off to have a look at
reflection..
?php
class TestClass {
public static $STEPS = array( 'foo' , 'bar' );
}
$testClass = new TestClass;
$rTestClass = new ReflectionClass( get_class($testClass) );
print_r( $rTestClass-getStaticPropertyValue('STEPS') );
?
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[PHP] Re: runtime access to static variable
Jack Bates wrote:
How do I access a static variable when I do not know the name of the
class until runtime?
I have the following example PHP:
ket% cat test.php
?php
class Test
{
public static
$STEPS = array(
'foo',
'bar');
}
$className = 'Test';
var_dump($className::$STEPS);
ket%
Unfortunately when I run it I get:
ket% php test.php
Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM
in /home/jablko/trash/test.php on line 13
ket%
I can call a static function using call_user_func(array($className,
'functionName')), and I can access a class constant using
constant($className.'::CONSTANT_NAME'). How do I access a static
variable?
this is also a not great but usable, stricter and faster solution:
?php
class TestClass {
public static $STEPS = array( 'foo' , 'bar' );
public function steps() {
return self::getSteps();
}
public static function getSteps() {
return self::$STEPS;
}
public static function setSteps( $steps ) {
self::$STEPS = $steps;
}
}
$testClass = new TestClass;
print_r( $testClass-steps() );
?
really though why..?
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