Integration based on using business logic or methods usually requires the most pervasive changes to existing applications. The goal is to share business logic that exists within the company. For example, updating information on customers probably occurs in several applications. Using shared business logic, a single method for updating customer information is shared by all applications that require this function. This strategy also simplifies maintenance and later updates. When changes are implemented to the business logic, the code only requires change in one place rather than in several separate applications. However, this power comes at a stiff price. All of the existing applications that need this feature would require modification to call the new shared method. As a consequence, this technique requires the most extensive changes to existing applications.
A number of approaches are available for implementing and hosting shared business logic. If a suitable method already exists within an application, it is possible in some cases to share this business logic by wrapping it as a distributed object using DCOM or CORBA. Then this business logic (object) can be called from other applications. An application server or transaction program (TP) monitor such as the Microsoft Distributed Transaction Coordinator (DTC) is used to host a repository of shared methods or business objects. The method is incorporated as part of a framework (the Microsoft .NET common language runtime, for example). Sharing methods is also based on using Web Services to host this business logic using the Simple Object Access Protocol (SOAP) for access.
The following figure shows an overview of integration using shared business logic and methods.
Integration using shared business logic and methods