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Option

Default

Description

eager

true

Camel 2.0: Eager controls whether Camel adds the message to the repository before or after the exchange has been processed. If enabled before then Camel will be able to detect duplicate messages even when messages are currently in progress. By disabling Camel will only detect duplicates when a message has successfully been processed.

messageIdRepositoryRef

null

A reference to a IdempotentRepository to lookup in the registry. This option is mandatory when using XML DSL.

skipDuplicate

true

Camel 2.8: Sets whether to skip duplicate messages. If set to false then the message will be continued. However the Exchange has been marked as a duplicate by having the Exchange.DUPLICATE_MESSAG exchange property set to a Boolean.TRUE value.

Using the Fluent Builders

The following example will use the header myMessageId to filter out duplicates

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Wiki Markup
{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/SpringIdempotentConsumerTest.xml}

How to handle duplicate messages in the route

Available as of Camel 2.8

You can now set the skipDuplicate option to false which instructs the idempotent consumer to route duplicate messages as well. However the duplicate message has been marked as duplicate by having a property on the Exchange set to true. We can leverage this fact by using a Content Based Router or Message Filter to detect this and handle duplicate messages.

For example in the following example we use the Message Filter to send the message to a duplicate endpoint, and then stop continue routing that message.

Wiki Markup
{snippet:id=e1|lang=java|title=Filter duplicate messages|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/IdempotentConsumerTest.java}

The sample example in XML DSL would be:

Wiki Markup
{snippet:id=e1|lang=xml|title=Filter duplicate messages|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/SpringIdempotentConsumerNoSkipDuplicateFilterTest.xml}
Include Page
CAMEL:Using This Pattern
CAMEL:Using This Pattern