Joomla! Documentation™

The 1.5 and 1.6 versions of the Joomla! CMS are based on a three-tiered system that consists of the following:

Joomla! 1.5 Architecture

1. The top, Extensions layer, consists of Extensions to the Joomla Framework and its applications:
   • Modules
   • Components
   • Templates
2. The middle, Application layer, consists of applications that extend the Framework JApplication class. Currently, there are four applications included in the Joomla distribution:
   • JInstallation is responsible for installing Joomla on a web server and is deleted after the installation procedure has been completed.
   • JAdministrator is responsible for the back-end website administration.
   • JSite is responsible for the front-end of the website.
   • XML-RPC supports remote administration of the Joomla website.
3. The bottom, Framework layer, consists of:
   • the Joomla! Framework itself, whose classes are listed here.
   • Libraries that are required by the Framework or are installed for use by third-party developers.
   • Plugins extend the functionality available in the Framework.