Designing Web Dynpro Applications 
Purpose
Similar to the development of other software, the development cycle of a Web Dynpro application consists of the following phases:
· Analysis phase
· Design phase
· Implementation phase
Process Flow
In the analysis phase, you determine and describe the application requirements. The result should describe the requirements completely, concisely, and without contradictions, using an analysis model. The analysis model is an abstraction of what the application must be able to do, but not how this is achieved. A good analysis model can be used by users who are not developers. They should be able to understand and criticize it.
The design phase can be divided into architecture design and detail design. The basis of the architecture design is the analysis model. In this phase, the global problem-solving strategy for the application implementation is developed. The architecture design consists of decisions on the role of the application in subapplications, the assignment of subapplications to components and other decisions on concepts and procedures that outline the detail design. The detail design determines the complete definition of the components used in the implementation and their structure. In the detail design, internal objects are added for the implementation – for example, data structures, methods, events, and event handlers.
The implementation phase follows the design process and adapts the design decisions to the peculiarities of a particular language. After having made all the difficult decisions in the design, the decisions for the implementation should add up only to a small part of the work, making it easy to perform changes and enhancements.
The following sections describe a procedure for the top-down design of Web Dynpro applications. We start on the development component level, go on to the Web Dynpro project level and the Web Dynpro component level and finally reach the Web Dynpro windows level.
The SAP NetWeaver Developer Studio provides the appropriate design tools both for the Web Dynpro Component level and for the Web Dynpro windows level. These design tools are described in the respective sections of the design process. For the development component level and the Web Dynpro project level, the SAP NetWeaver Developer Studio does not yet provide any design tools. However, this should not prevent the Web Dynpro application developer from modeling these levels as described. As soon as design tools for these two levels are available, this procedure will be enhanced accordingly.
This document aims at describing a procedure for the design of Web Dynpro applications that allows you to keep track even of complex projects; a procedure that keeps all developers in a team informed about the Web Dynpro applications developed there, that leads to more appropriate design decisions and minimizes the implementation and maintenance effort.
The document assumes that you are familiar with the Web Dynpro concepts, terminology and tools.
Example
We do not only describe the individual steps during the design of a Web Dynpro application in theory, but also illustrate them by an example used in the practical field. This example depicts a travel portal called Book2Fly. Book2Fly offers several services for planning trips: A flight booking system Flights, an information guide Guides, and a route planning tool Routes.
The flight booking system Flights demonstrates different model connections. The flight data is provided by an SAP system, the customer data by a Java backend, and a Web service is used to send a confirmation. The travel guide formats country and town information using presentation graphics. The route planning tool demonstrates the use of geo services within a Web Dynpro application.
