The DB XA Module provides enhancements to the existing DB Interface Module class hierarchy in the form of new implementations of some existing classes. These changes enable the use of SourcePro DB in an XA-compliant distributed transaction processing environment.
For information about the complete set of DB Interface Module classes, see the Chapter 3, "Class Overview," in the DB Interface Module User's Guide.
In the SourcePro DB environment, two main classes are involved in the interaction between a client and a server: RWDBDatabase and RWDBConnection. The DB XA Module extends these classes to make them XA-enabled. The changes in RWDBConnection provide a bridge between the resource manager and the application programmer. Changes to RWDBDatabase allow it to produce and manage XA-compliant RWDBConnection objects.
The DB XA Module also enhances the functionality of class RWDBManager to produce XA-appropriate RWDBDatabase instances when the propertyString passed has an XA key.
The following criteria influenced the design of the new class and the extensions:
The DB XA Module is an add-on to the existing DB Interface Module class library. The new classes must be transparent to any existing DB Interface Module code. Therefore, none of your existing classes or any portions of your existing code will refer to the DB XA Module implementation.
Like the DB Interface Module, the DB XA Module follows both the producer/product paradigm and the interface/implementation design pattern.
Additional information about these classes appears in Chapter 4 and in the Reference Guide.
As in the DB Interface Module, the DB XA implementation of the RWDBDatabase class is designed around the interface/implementation design pattern. In this pattern, a common interface hides the implementation differences of different databases.
The implementation for the XA version of each access module derives from the corresponding non-XA access module. These XA-specific implementations re-implement methods whose behavior in an XA-environment differs from that in a non-XA environment. For example, the XA-specific Oracle OCI Access Module provides an implementation class called RWDBOCIXADatabaseImp. This class derives from the non-XA implementation class RWDBOCIDatabaseImp, and re-implements the connection() method to produce XA-enabled, database-specific RWDBConnection objects. RWDBOCIXADatabaseImp also re-implements other methods that have XA-specific behaviors.
Figure 2 illustrates the architecture of RWDBDatabase classes.
As in the DB Interface Module, the DB XA implementation of the RWDBConnection class is designed around the interface/implementation design pattern. In this pattern, a common interface hides the implementation differences of different database connections.
The DB XA version of each access module includes a new connection implementation class that derives from the corresponding connection implementation in the non-XA access module. For example, Oracle OCI has a new implementation class called RWDBOCIXAConnectionImp. This class derives from the non-XA implementation class RWDBOCIConnectionImp, and redefines the behavior of several methods.
Figure 3 illustrates the architecture of RWDBConnection classes.
Copyright © Rogue Wave Software, Inc. All Rights Reserved.
The Rogue Wave name and logo, and SourcePro, are registered trademarks of Rogue Wave Software. All other trademarks are the property of their respective owners.
Provide feedback to Rogue Wave about its documentation.