This is a pattern for implementing the consumer endpoint, and is only relevant to programmers who need to develop a custom component in Apache Camel. Existing components already have a consumer implementation pattern hard-wired into them.
These Consumers that conform to this pattern will provide a method that is automatically called by the messaging channel or transport layer whenever an incoming message is received.
One of the aspects of this event-driven consumer pattern is that the consumer endpoint does not provide any threads to process the incoming messages. Instead, the underlying transport or messaging channel provides a processor thread when it invokes the exposed event method.