Components

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:

• Controllers

• One or more views

• A Model

Together they form a component.

The use of components is integrated in the MVC design pattern.

You are in SAP Web AS 6.20.

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 outlined in the following graphic:

Central features of components are:

• 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 subcontrollers 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 subcontrollers.

  • Basis class CL_BSP_CONTROLLER2 controls the subcontrollers. The controller developer is responsible for controlling the view and the model.

    Note

    If you want to use data binding functionality, you can add a model class to your component. For more information, see Data Binding.

• Create the top-level controller

• Create a component

• Call the component

• Determine the input processing