SAP Webdynpro ABAP

Web Dynpro for ABAP: Tutorials for Beginners:

Tutorial 1 - Create a Simple Web Dynpro Application                
The first tutorial shows how easy it is to create a Web Dynpro application and shows off the new ABAP environment for developing Web Dynpro ABAP applications.

Tutorial 2 - BAPI Usage                  
Learn how to use BAPIs within Web Dynpro for ABAP and get hands-on experience with new Web Dynpro tools - such as the Service Call Generator and the Web Dynpro Code Wizard - provided in the ABAP Workbench.

Tutorial 3 - Navigation                
This tutorial demonstrates how easy it is to navigate between different views of the same Web Dynpro application.

Tutorial 4 - Display Bookings for Selected Flights             
In this tutorial, the BAPINAV component introduced in Tutorial 3 is further enhanced to display a list of bookings for a selected flight. The context that contains the flight information is enhanced with a subnode for the corresponding bookings. It also shows how the booking information is retrieved in a supply function and the context node is bound to a new table UI element in the Main View.

Tutorial 5 - Component and Application Configuration               
The fifth tutorial in the series describes component usage, personalization and configuration and offers an alternative solution to that presented in the Tutorial 3.

Tutorial 6 - Component Usage                
In this tutorial, you will develop an example for component usage in Web Dynpro ABAP and further build on tutorial 4 to display customer data of a particular booking using his customer_id as a foreign key.

What is Web Dynpro?

Generic Definition : WebDynpro is a great modeling environment whitch stores the user-interface details in the form of metadata. We can write less code and fix bugs in a shorter time with lesser effort. It increases a programmer’s productivity by manifolds.

Webdynpro is nothing but one framework for developement of user interface for use with SAP NetWeaver.It support programming for different platform such as JAVA ,ABAP,.NET .

In case of JAVA webdynpro comes with extensive design tool .Thease tools are based upon Eclipse framework ans SAP’s NWDS

Technical Definition : WebDynpro is a client-independent programming model used for developing sophisticated user interfaces for web based business applications.

History: The name WebDynpro , Dynpro means Dynamic Program it is SAP’s Legacy technology for interactive UI’s.It is to Combine High Interactivity (dynamic GUI) and Zero Installation.

What are the naming conventions to be followed while developing Web Dynpro applications?

Web Dynpro context names should use only the characters A..Z, a..z, 0..9, _ . Digits can be used only from 2nd position. The JAVA naming conventions can be followed but avoid using unicode characters to keep the names simple. However one should avoid using the prefixes wd, WD or IWD since these are the prefixes used during generation of internal coding entities.

Basic Concepts

1. View – is the central logical layout element in the Web Dynpro application.It is responsible for the presentation logic and for the browser layout.

Description of a visible screen area
Contains and lays out controls (aka widgets)
Defines actions (i.e. relevant input on controls by the user), which trigger event handling

2. Controller – active part of web dynpro application,handles the data flow between the model and the view in both directions

Performs event handling
Each component has a component controller
Each view has a view controller
Custom controllers may be added for further structuring

3. Model – is the interface to the back end systm and is responsible for providing data to the entire application.

Represents the data in the backend

4. Component

Reusable UI program package
Mostly contains views, often uses models
Communicates with other components via component interfaces

5. Application

Something runnable (from client application, i.e. web browser)
Identified by URL
Running an application means starting a component, navigating” to an initial view in an initial window.

6. Windows

Single UI unit representing a component’s user Interface/View Composition needed for embedding purposes.

7. Context

A controller contains a context which holds the data. The data flow between the contexts is referred to as context mapping..

Web Dynpro Architecture 

Definition

Web Dynpro is the SAP NetWeaver programming model for user interfaces and provides support when developing the Web representation of business applications. The Web Dynpro model is based on the Model View Controller paradigm, and has the following features that build on the classic dynpro model:

·        Clear separation of business logic and display logic

·        Uniform metamodel for all types of user interfaces

·        Execution on a number of client platforms.

·        Extensive platform independence of interfaces

Structure

In Web Dynpro, each user interface is always made up of the same basic elements (such as UI elements or events triggered by the user). These basic elements are declared using Web Dynpro tools. The event handling is programmed in separate source code areas which are executed automatically at runtime when the event is triggered.

Metamodel Concept

When creating a Web Dynpro application, you use the Web Dynpro tools to describe the properties and functions of the application. The data created in this way is stored in tables as metadata. At a later time, the necessary source code, which is executed at runtime, is created from this metadata. Therefore, the metadata itself is independent of the rendering technique used at runtime.

Graphical Development Tools

To support this declarative concept, the SAP NetWeaver Developer Studio contains a range of Web Dynpro tools. You can therefore generate a large proportion of a Web Dynpro application using the tools provided, without having to create your own source code. This applies to the following parts of the application:

·        Data flow between the front end and back end

·        Layout of the user interface

·        Properties of user interface elements

The Web Dynpro tools enable you to create source text areas manually within generated source texts. These areas are not changed if the source code is regenerated.

Separation of Business Logic and Display Logic

Implementing Web Dynpro enables you to clearly separate business logic and display logic. A Web Dynpro application runs on the front end and has local or remote access to the back end system via a service. This means that the display logic is contained in the Web Dynpro application, while the business logic and the persistence of the business objects run in the back end system. The following options are currently available for connecting Web Dynpro applications and the back end system:

·        An interface generated using adaptive RFC, through which BAPIs of an SAP system can be called

·        An interface for calling Web services

·        A self-generated interface

The source code required for connecting the Web Dynpro application can be generated from a UML definition of the Web Dynpro interface. A UML definition can be imported into the Web Dynpro tools as an XML file.

Implementation of the Model View Controller Paradigm

Every Web Dynpro application is structured according to the Model View Controller paradigm:

·        The model forms the interface to the back end system and thus enables the Web Dynpro application access to data.

·        The view is responsible for the representation of the data in the browser.

·        The controller lies between the view and the model. The controller formats the model data to be displayed in the view, processes the user entries made by the user, and returns them to the model.

The creation of applications using Web Dynpro is structured in Web Dynpro components. The following sections provide a detailed description of the most important parts of a Web Dynpro component.