Implementing the Data Flow 

The controllers are responsible for the data flow within a Web Dynpro application. Each controller type has a context in which the active part is programmed. In the development environment, a graphical tool, the Controller/Context Editor, is available for defining context nodes and context attributes. There are also wizards for creating events, actions, and methods.

Mapping and data binding are the possible forms of data flow in a Web Dynpro application. Mapping is data transfer by copy, while data binding involves working with references to data. Data binding only takes place when data is passed to the front end or transferred between the Web Dynpro model and the back end; in the case of all other data flow definitions, mapping takes place, as the following graphics show.

You can also access the source code of the controller classes from the Web Dynpro perspective. You implement the event and action handlers within predefined commented areas of the file. The Web Dynpro Generator does not write within these edited areas and the application developer’s entries remain intact.