Secretly, my wife still harbors a little regret about the lost weekends I spent coding Mule, but without her, Mule would not have been created and the book you are reading would not exist.

Like thousands of developers before me, I was continually struggling with the complexities of systems integration. The problem was that the proprietary solutions of the day —there were no open source alternatives back then—set out to address integration by adding another piece of complexity to the problem. These products made too many assumptions about the environment and architecture, masking the ugliness with doodleware, slick demo applications, and suave salesmen. I used to work long hours trying to work around integration products rather than being able to leverage them. This resulted in me venting to the point where my wife firmly suggested that I stop complaining and do something about it. A Mule was born.

Six years on, and Mule represents a shift in the way we integrate applications. It provides a focus on service orientation and assembly instead of building monolithic application stacks. Integration and service orientation are becoming increasingly important parts of application developers’ lives, since organizations never throw anything away. Couple this with the rise of SaaS, Web 2.0, and Cloud computing, and we have an evolution from traditional application development to an assembly model, where data is served in many forms from many sources inside and outside of our company firewalls.

This book provides the first thorough coverage of all aspects of Mule. It provides examples for everything you will need to do with Mule, from creating and consuming services to working with various technologies such as JMS, Web Services, and FTP. Importantly, it covers how to test, deploy, monitor, and tune Mule applications, topics that can trip up new users due to the flexibility of the Mule platform.

The great yet subtle element of this book is that the authors have captured the essence of pragmatism that is the founding principle of Mule. The notion that you can start small and build a complete ESB architecture over time is prevalent. Each chapter explains the tools provided by Mule for building service-oriented applications. The chapters cover everything, including configuration basics, message routing, data transformation, publishing services, and working with the Mule Galaxy registry.

This publication marks a significant milestone for the Mule project. It demonstrates that the ideals of open source and community building do work. The authors, David Dossot and John D’Emic, have been long-time community members and have made many other contributions to the project; this is a significant and lasting addition. I can see this book becoming the must-have guide for all current and prospective Mule users since it walks the reader through all aspects of Mule in the right amount of detail, focusing on the areas most important for building applications. Read on to learn how to unlock the power of Mule.

Ross Mason
Creator of Mule