However, the bespoke approach is expensive in terms of both development and support and is not flexible. EAI is in itself a new and distinct field of computing that is still in the early stages of formation. Vendors of such tools claim to offer an architecture to satisfy most of the application integration needs of an enterprise, enabling connectivity and integration to a wide variety of computing platforms, database systems, TP monitors and ERP packages. It does this by layering the transport technologies. Active X controls and so on.
All applications connect to a central hub, which connects to many application spokes.
The hub provides the centralized services whilst connectors or adapters provide the services for each spoke or integration point. Adapters serve to provide integration with the centralized hub for a specific resource such as a relational database or a java application, enabling transfer of information or invocation of a process against a specific resource. Whilst the scope of technologies deployed can be vast, we are now seeing the emergence of EAI products with adapters which can support many resource types. Whilst there are EAI tools to tightly couple two or more systems, there are several major challenges to consider which limit the value of tools. Consider a scenario where you have three different systems that need to be integrated.