Extending oxconfig with static methods

Hi there,

I’m trying to extend the oxconfig class via an Oxid Module. Things work fine, except when adding static methods.

What I’m trying to achieve with this module is basically having the reverse of the checkSpecialChars & checkParamSpecialChars methods.

Am I doing something wrong, or this is not achievable via the Oxid extend?

Thanks in advance!

Extracts from the relevant code:

metadata.php


        'extend' => array(
                'oxconfig' => 'my_module/my_class_oxconfig',
        ),

my_class_oxconfig.php


class my_class_oxconfig extends my_class_oxconfig_parent{
    // calls to this method fail
    public static function checkSpecialChars_decode( $sValue, $aRaw = null )
    {
        return oxRegistry::getConfig()->checkParamSpecialChars_decode( $sValue, $aRaw );
    }
    // calls to this method work as expected
    public function checkParamSpecialChars_decode( $sValue, $aRaw = null )
    {
        return 'decoded value';
    }
}

my_controller.php


$sMessage = oxConfig::getParameter( 'c_message' );
// works fine
$sMessage = oxRegistry::getConfig()->checkParamSpecialChars_decode( $sMessage );
// fails with PHP Fatal error:
// Call to undefined method oxConfig::checkSpecialChars_decode() in my_controller.php
$sMessage = oxConfig::checkSpecialChars_decode( $sMessage );

The extension via Module is done on runtime when “oxnew” is called and an instance is created.
If you call oxconfig statically, you just call oxconfig. Oxconfig instance is a singleton, why do you need static methods?