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
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Application
Development, Configuration, and Adaptation
Web Dynpro is used to design user
interfaces for Java and ABAP applications. The current description
concentrates on Web Dynpro for Java; the documentation for user interface
development on the ABAP platform is available under
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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 paradim 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 with 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 different services such as source code versioning and the Central Build Service.
Meta Model and Declarative Programming
When you program an applicaton using the Web Dynpro tools, the system generates a platform-independent meta model. From this meta model, the system then creates the Java classes which are executed at runtime on the J2EE Engine in the SAP Web Application Server. For more complex applications, you are required to make some adjustments and changes to the source code generated. In special areas marked as such, you can edit the code generated and implement you own code there.
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 backend.
See also Model
and Java Dictionary.
·
The view is the
central logical element for the layout and the processing of the presentation
logic.
See also View
– Programming UI and Navigation.
·
The controller is
responsible for programm control, determining the data flow between the view
and the model and handling events.
See also Controller and
Context.
Componentization
On NWDI level you work with development components (DC) which you can group together to form larger units called the software components (SC). This allows you to structure large-scale projects in teams.
Within a DC or a local Web Dynpro project, the clear separation of the different layers due to the MVC programming model ensures a high degree of reuse. In addition, you can 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 various 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, and the View Designer supports you with designing the layout.
See also Web Dynpro Tools.
Executing Web Dynpro Applications
When the application is executed on the SAP Enterprise Portal, you can use its functions. The SAP Enterprise Portal offers a role-based and safe access to information and enables you to use the event handling, navigation functions, as well as personalization.
See also Web Dynpro Applications in the Portal.
You can also execute Web Dynpro applications online or using mobile devices. If you want to develop mobile applications, you simply need to adjust the user interface for the smaller displays. See also Mobile Web Dynpro.
Security Guide for Web Dynpro for Java
Information about security 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