Web Dynpro for Java

The following documentation on Web Dynpro technology is part of the Development Manual and describes the concepts and procedures required by application developers for working with Web Dynpro. Information on Web Dynpro technology as part of the IT scenario Application Development, Configuration, and Adaptation is available in the variant description Developing Java Applications with Web Dynpro. Here you will find a list of the processes and process steps of the Web Dynpro Java variant.

 

Web Dynpro is used to design user interfaces for Java and ABAP applications. The current description concentrates on Web Dynpro for Java; while the documentation for user interface development on the ABAP platform can be found under Web Dynpro for ABAP.

Purpose

Web Dynpro is a client-independent programming model of the SAP NetWeaver technology platform for developing user interfaces for professional business applications. It is based on the model view controller paradigm which ensures that the business logic is separated from the presentation logic. This architecture is visible in the Web Dynpro perspective of the SAP NetWeaver Developer Studio (NWDS).

Web Dynpro helps you during the development of Web applications by:

●      Ensuring platform-independence with the meta model approach

●      Minimizing the implementation effort through declarative programming

●      Supporting a structured design process by applying the model view controller paradigm

●      Providing reuse and better maintainability by using components

●      Providing graphical support with tools in the Web Dynpro perspective

●      Providing the SAP NetWeaver Java Development Infrastructure (NWDI), which supports team work with various services, such as source code versioning and the Central Build Service.

Meta Model and Declarative Programming

When you program an application using the Web Dynpro tools, the system generates a platform-independent meta model. From this meta model, the system then creates the Java classes that are executed at runtime on the J2EE Engine in the NetWeaver Application Server. For more complex applications, you need to make a number of adjustments and changes to the generated source code. In specially designated areas, you can edit the generated code and implement you own code.

Model View Controller Paradigm

The model view controller paradigm (MVC paradigm) is based on a clear separation of business logic and presentation logic.

●      The model represents the business logic and the persistence on the back end.
See Creating Connections to the Back End.

●      The view is the central logical element for the layout and the processing of the presentation logic.
See View – Programming UI and Navigation.

●      The controller is responsible for managing the program. This includes managing the flow of data between view and model, and handling events.
See Controller und Context.

Componentization

At the NWDI level, you work with development components (DC) that you can group together to form larger units known as software components (SC). This allows you to structure large-scale projects in the team.

In a DC or a local Web Dynpro project, the clear separation of the different layers by the MVC programming model ensures a high degree of reuse. You can also structure the DC or the local Web Dynpro project using the component concept. You can embed Web Dynpro components in another Web Dynpro component, and define references to other Web Dynpro components.

Web Dynpro Tools

The Web Dynpro perspective in the NWDS provides a number of graphical tools. The Web Dynpro Explorer, for example, has a tree structure which provides a logical view of the DC or the Web Dynpro project. Model tools help you to implement the data access and the business logic, while View Designer helps you when designing the layout.

See Web Dynpro Tools.

Executing Web Dynpro Applications

If the application is executed on SAP NetWeaver Portal, the functions in this portal can be used too. SAP NetWeaver Portal offers role-based and secure access to information, and provides you with event handling, navigation and personalization functions.

See Web Dynpro Applications in the Portal.

You can also execute Web Dynpro applications online or using mobile devices. To develop mobile applications, you need only adjust the user interface for the smaller displays. See also Mobile Web Dynpro.

Security Guide for Web Dynpro for Java

Information about the security aspects of Web applications programmed using Web Dynpro technology is available in the special security chapter which is also part of this documentation. See Security Aspects of Web Dynpro for Java