Web Services Case Study - Provide a mechanism whereby new applications could use existing legacy application functionality.

The Challenge

With parts of core business functionality tied up (in legacy systems) and other parts being built into new applications, it became a challenge to perform transactions involving pieces from both the old and the new.

The Solution

• A custom SOAP layer was designed to expose the needed legacy system functionality. This layer was implemented using .NET SOAP.
• Transactions involving multiple core pieces were identified and rolled up into single SOAP service calls.
• Original use cases belonging to the old application were re-visited and combined into single use cases that would encompass the old and the new application.
• Custom SOAP exceptions were defined to handle failure cases.
• Unit tests were written to submit sample transactions with pre-configured data.
• The end result was a single point of access (SOAP layer) for all new applications that needed to use existing legacy functionality. All 'backdoor' entry routes were eliminated. This eventually provided cleaner data, eliminated duplication and other data inconsistencies.