In this chapter we implemented the EPS application using only the core Web services technologies discussed in the first part of the book. Based on this core platform, we have been able to write a distributed application using industry standard messaging based on XML and HTTP.
The current EPS application certainly works, but there are numerous limitations to this application both in terms of functionality as well as manageability. For example, the current implementation provides a simple means to compare the prices or lead times from the two vendors, but the application does not actually procure the components, that is, it does not support transactions. The application also does not support access from mobile devices.
The application is also difficult to manage and maintain as more and more vendor Web services are added. As it stands now, each time a new Web service is added (or removed), significant development time is needed to re-architect the system, write additional program code, and subject the entire system to rigorous testing processes.
Applications that provide full functionality are no doubt quite useful. Enterprise applications must not only implement the required functionality, but they must also be architected to operate within enterprise environments and meet enterprise needs for manageability. In the next chapter, we expand on this application to support these additional needs for enterprises.