[[ExchangePattern-ExchangePattern]]
=== Exchange Pattern

There are many different _Message Exchange Patterns_ you can use in
messaging. This concept is also demonstrated in WSDL and JBI's MEPs.

From there link:enterprise-integration-patterns.adoc[Enterprise
Integration Patterns] the common examples are

* Request Reply
* Event Message (or one way)

In Camel we have an
http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/ExchangePattern.html[ExchangePattern]
enumeration which can be configured on the *exchangePattern* property on
the Message Exchange indicating if a message
exchange is a one way Event Message (InOnly) or
a Request Reply message exchange (InOut).

For example to override the default pattern on a <<jms-component,JMS>>
endpoint you could use this URI

[source,java]
---------------------------------
jms:MyQueue?exchangePattern=InOut
---------------------------------