Overview

Get more out of what you already have
Some companies have a very large amount of legacy technology and replacing it with either an off-the-shelf solution or custom development would take too long or cost too much.

In this case Enterprise Application Integration (EAI), the process of integrating legacy applications together to form one integrated suite, is the only feasible option. While integration by design is more desirable, an EAI initiative is the only way to integrate the disparate applications into one cohesive unit in a timely, cost effective manner. The advantage of interoperability and shared data outweighs the disadvantage of the lack of integration by design.

EAI is made up of two fundamental concepts: unified process management, the ability to manage all processes across all systems in a similar manner, and data synchronization, the ability to synchronize data across all systems.

Common EAI design patterns address those two concerns with the Publish/Subscribe design metaphor, and suggest a process bus (facility to manage processes uniformly) and a data bus (facility to synchronize data).

Useful tools that implement the publish/subscribe metaphor are workflow/business process engines to manage the processes, and publish/subscribe data systems to handle data synchronization. Another key technology in EAI is the use of XML transformations to replace the expensive and outdated EDI transformations.

Strategy Five is to use business process engines, the publish/subscribe metaphor, and xml technologies to implement EAI solutions when legacy components must be integrated together. A system that also supports web services is also desirable, offering further flexibility with regards to legacy integration/abstraction.