Interceptor patterns can be used to apply business rules and validations on messages that are either sent from the channel or received on it. The following four interceptors are available:

public interface ChannelInterceptor {
  Message<?> preSend(Message<?> message, MessageChannel channel);
  void postSend(Message<?> message, MessageChannel channel, boolean sent);
  boolean preReceive(MessageChannel channel);
  Message<?> postReceive(Message<?> message, MessageChannel channel);
}

Adding an interceptor is straightforward: define a class that implements the ChannelInterceptor interface and then inject a reference of it in the channel definition. Here is a quick code snippet to show this:

<int:channel id="resultChannel">
  <int:interceptors>
    <ref bean="resultValidationInterceptor"/>
  </int:interceptors>
</int:channel>

Here are the methods exposed by the ChannelInterceptor interface: