Mule in Action, Second Edition

Chapter 2. Processing messages with Mule

This chapter covers

• What role flows play in Mule
• How messages are created
• The structure of Mule messages
• The Mule Expression Language

Mule is a workhorse whose sole purpose in life is to move your messages around. It actually does way more than just moving messages: it’s also able to transform, enrich, and smartly route them. Picture a mail delivery service that would automatically rewrite letters in the preferred language of the recipient, while decorating them with illustrations that appeal to the culture of the addressee.

Where does such capacity come from? The answer is two words: control and abstraction.

Mule gives you complete control over the way messages flow through it. We said the word: ...