Components 

Use

Complex BSP applications that are based on the MVC Design Pattern have many extensive components. Each individual part, consisting of a complex BSP application, contains precise application logic and well thought out presentation logic. It makes sense to create the individual BSP components as reusable modules. These reusable modules are:

A component consists of a controller, whose class is derived from CL_BSP_CONTROLLER2, as well as one or more views, which can result in regular nesting. This is outlines in the following graphic:

• With components, there are complex call sequences during an HTTP request.
• The individual parts, of which a page in the browser consists, are dynamically assembled during runtime.
• One component can call a different component. It should therefore be placed in a view. This is done using the <bsp:call> element.

• Initialization can be called by the controller using method create_controller. This method is available for all controller classes. It creates a controller or finds an existing one.

• The parent controller contains a list of the individual sub-controllers and forwards all input to the relevant controller. This is done by prefixing all IDs with the path of the controller IDs.
• The controller has a hierarchical tree. Every controller controls its view or views, its model as well as the list of sub-controllers.
• Basis class CL_BSP_CONTROLLER2 controls the sub-controllters. The controller developer is responsible for controlling the view and the model.

1. Create the top-level controller
2. Create a component
3. Call the component
4. Determine the input processing