Preface

Working on integration projects used to mean working with EAI products, each of which implemented its own stack of tools with proprietary technology. To switch from one EAI product to another meant learning the proprietary technology and toolset from that new product. Then, the market changed from EAI to SOA and ESB products, with more focus on open standards that emerged in the integration market. Examples of these open standards are Java Message Service (JMS), SOAP, XML, and WS-*. With open standards available, more and more open source projects began to implement these specifications.

Because we enjoyed working with open source frameworks in JEE application development, we watched the progress of integration frameworks with a lot of interest. Mule was one of the first projects that provided a large set of integration functionality; after a while, it was called an ESB. When we had the chance to design an SOA architecture of a new solution for our current employer in 2005, we chose Mule as the foundation product. It was delightful to work with an open source ESB to solve our integration needs, because it offered a rich set of integration functionality out of the box. Even when we had to add nonexistent functionality, the ease of development was striking.