ABAP Classes in Workflow

By Anwesha Bhattacharya , Capgemini India

1.                  ABAP Classes and Business Workflow: 

We can use ABAP classes in the definition and runtime components of SAP WebFlow Engine in the same way as object types defined in the Business object Repository (BOR). 

Before proceeding further we need to know where to create and maintain ABAP Classes and ABAP Interfaces. 

2.                  What is Class Builder and its purpose? 

The Class Builder allows us to create and maintain global ABAP classes and interfaces. Both of these object types, like global data types, are defined in the ABAP Repository, thus composing a central class library. Together, they form a central class library and are visible throughout the system. We can display existing classes and interfaces in the class library using the Class Browser.

We can define local classes as well as global classes. They are defined locally in programs, function groups or as auxiliary classes of global classes of the class pools. Local classes are only visible within the defining module.

ABAP classes are processed using the Class Builder.

3.                  How to reach Class Builder? 

To reach the initial screen of the Class Builder, choose Development à Class Builder from the initial screen of the ABAP Workbench or enter transaction code SE24.  

4.                  How does it integrate? 

The Class Builder allows us to create Web development objects within the ABAP Workbench. We can use the Class Browser to display and maintain existing global object types from the class library.  

The diagram below illustrates the architecture of the Class Builder and the relationships between its components (including the Class Browser)

 From here, we can either display the contents of the class library or edit a class using the Class Editor. Once we have defined an object type, we can implement its methods. From the initial screen or the Class Editor, we can also access the Class Builder’s test environment. We can define the object types immediately after implementing the method in the ABAP Editor. It is also possible to access the test environment from the initial screen or Class Editor.

 5.                  How to use the Class Builder?

Use the Class Builder to:

•  Display an overview (in the Class Browser) of global object types and their relationships.

• Maintain existing global classes or interfaces.

• Create new global classes and interfaces.

• Implement inheritance between global classes.

• Create compound interfaces.

• Create and specify the attributes, methods, and events of global classes and interfaces.

• Define internal types in classes.

• Implement methods.

• Redefine methods.

• Maintain local auxiliary classes.

• Test classes or interfaces in a simulated runtime environment. 

6.                  What are the constraints?

We cannot define object types on the basis of graphical object modeling.

7.                  Note before creating global classes and interfaces:

Global classes and interfaces that we create in the Class Builder are stored in the class library and administered by the R/3 Repository: they therefore have the same namespace as all other Repository objects. It is therefore necessary to have naming conventions for object types and their components and to use them uniformly within program development. 

8.                  Naming Conventions in ABAP Objects:  

The following naming convention has been conceived for use within the SAP namespace. If we do not observe the naming conventions for object types (classes and interfaces), conflicts will occur when the system creates persistent classes, since it will be unable to generate the necessary co-classes. 

9.                  Conventions for Object Types: 

 10. Conventions for Components: 

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