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Camel supports two kinds of interceptors

• intercept interceptFrom that intercepts incoming Exchange in the route.
• interceptSendToEndpoint new in Camel 2.0 that intercepts when an Exchange is about to be sent to the given Endpoint.

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• Predicate using when to only trigger the interceptor in certain conditions
• proceed when used with interceptFrom to continue routing from the point of interception when the interceptor is finished. proceed is default and can be omitted.
• stop when used with intercept interceptFrom will stops routing the Exchange completely. Camel will by default not stop.
• skip when used with interceptSendToEndpoint will skip sending the Exchange to the original intended endpoint. Camel will by default not skip.

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InterceptFrom

Intercept InterceptFrom is for intercepting any incoming Exchange, that is it intercepts the from DSL. This allows you to do some custom behavior for received Exchanges.

So lets start with the logging example. We want to log all the incoming requests so we use intercept interceptFrom to route to the Log component. As proceed is default then the Exchange will continue its route, and thus it will continue to mock:first.

{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/intercept/InterceptorSimpleLogTestInterceptFromSimpleLogTest.java}

You can also attach a Predicate to only trigger if certain conditions is meet. For instance in the route below we intercept when a test message is send to us, so we can do some custom processing before we continue routing:

{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/intercept/InterceptorSimplePredicateTestInterceptFromSimplePredicateTest.java}

And if we want to filter out certain messages we can use the stop() to instruct Camel to stop continue routing the Exchange:

{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/intercept/InterceptorSimplePredicateWithStopTestInterceptFromSimplePredicateWithStopTest.java}

Using from Spring DSL

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{snippet:id=example|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/SpringInterceptorTestSpringInterceptFromTest.xml}

InterceptSendToEndpoint

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{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/InterceptEndpointTestintercept/InterceptSendToEndpointTest.java}

And this time we add the Predicate so its only when the message body is Hello World we intercept.

{snippet:id=e2|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/InterceptEndpointTestintercept/InterceptSendToEndpointTest.java}

And to skip sending to the mock:foo endpoint we use the *skip() DSL in the route at the end to instruct Camel to skip sending to the original intended endpoint.

{snippet:id=e3|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/intercept/InterceptEndpointTestInterceptSendToEndpointTest.java}

Using from Spring DSL

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

And the 2nd. Notice how we can leverage the Simple language for the Predicate:

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

And the 3rd with the skip, notice skip is set with the skipSendToOriginalEndpoint attribute on the interceptSendToEndpoint tag:

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