From Joomla! Documentation
The "API15" namespace is an archived namespace. This page contains information for a Joomla! version which is no longer supported. It exists only as a historical reference, it will not be improved and its content may be incomplete and/or contain broken links.
|authenticate||Finds out if a set of login credentials are valid by asking all obvserving objects to run their respective authentication routines.|
|getInstance||Returns a reference to a global authentication object, only creating it if it doesn't already exist.|
jimport( 'joomla.user.authentication' );