X-Cart classes structure and namespaces

Introduction

This article describes the structure of X-Cart classes. Also, it describes how to generate namespaces correctly.

X-Cart classes

All X-Cart classes are located in the <X-Cart>/classes/ directory. Let us walk through each type of X-Cart classes:

• <X-Cart>/classes/XLite.php is the class of the whole application; you will never use it in new modules;
• <X-Cart>/classes/Base/ directory contains definitions of basic X-Cart interfaces including Decorator interface that allows applying changes to every part of X-Cart store without modifying core classes;
• <X-Cart>/classes/Controller/ directory contains definitions of classes that handle requests to X-Cart (controllers). Check general X-Cart workflow article in order to learn more about controller classes;
• <X-Cart>/classes/Core/ directory contains definitions of core X-Cart entities, such as database, HTTP request, Mailer etc;
• <X-Cart>/classes/DataSet/ directory includes the classes that defines different data structures; they are seldom used in the modules;
• <X-Cart>/classes/Logic/ folder contains the classes that describe the business logic of complex routines: order calculation, import/export, etc;
• <X-Cart>/classes/Model/ directory includes the classes that describe different X-Cart entities, such as products, orders, users, shipping and payment methods, menus etc;
• <X-Cart>/classes/Module/ folder contains files added by modules (default and 3rd party ones); if you write the module, you will put your files into this folder only; all module files (except templates) are stored in the <X-Cart>/classes/Module/<developer-ID>/<module-ID> directories;
• <X-Cart>/classes/Upgrade/ directory contains classes that are used during upgrade procedure;
• <X-Cart>/classes/View/ folder contains classes that manage X-Cart's output.

Generating namespaces

Namespaces are widely used constructions in OOP languages (PHP in particular). They allow to save time and not mix up different classes with the same name.

Namespace notation in X-Cart is straight-forward: it repeats the class' sub-path of the .php file in the <X-Cart>/classes/ directory.

• PHP class defined in the <X-Cart>/classes/XLite/Controller/Customer/Product.php file will have namespace XLite\Controller\Customer; i.e. namespace includes all names of folders after <X-Cart>/classes/ separated by backslash (****)
• The same way, PHP class defined in the <X-Cart>/classes/XLite/View/Header.php file will have namespace XLite\View;
• Namespace can be quite long, e.g. if the class is located in the <X-Cart>/classes/XLite/Module/CDev/AustraliaPost/Model/Shipping/Processor/AustraliaPost.php file, then its namespace will be XLite\Module\CDev\AustraliaPost\Model\Shipping\Processor;
• PHP class defined in the <X-Cart>/classes/XLite.php file will have no namespace.

Important note: if you have PHP class MyClass, it must be placed into the MyClass.php file. Name of the class must be the same as the name of the .php file it contains.