Since we're on a major migration process of this website, some component documents here are out of sync right now. In the meantime you may want to look at the asciidoc in the repository: https://github.com/apache/camel/blob/master/README.md https://github.com/apache/camel/blob/master/components/readme.adoc
To support various message exchange patterns like one way Event Message and Request Reply messages Camel uses an Exchange interface which has a pattern property which can be set to InOnly for an Event Message which has a single inbound Message, or InOut for a Request Reply where there is an inbound and outbound message.
Here is a basic example of sending a Message to a route in InOnly and InOut modes
Route Using the Fluent Builders
Route Using the Spring XML Extensions