As Camel wants to support the InOut(Request/Reply) and InOnly message exchange pattern at the same time.
If the previous exchange has no out message, camel pipe line processor which is used to chain all the processors together uses the in message to feed the other processor, but if previous exchange has the out message, it use the out message as the in message of the exchange to feed the next processor. -- Willem Jiang Red Hat, Inc. Web: http://www.redhat.com Blog: http://willemjiang.blogspot.com (English) http://jnn.iteye.com (Chinese) Twitter: willemjiang Weibo: 姜宁willem On June 27, 2014 at 4:44:38 AM, Matt Sicker ([email protected]) wrote: > I don't understand what the point of using the out message is. It doesn't > copy headers. It doesn't signify the end of a route as far as I can tell. > It's not used for a reply message. I don't think any of the official Camel > components even use the out message. What good is it for? > > In my own project, I've created a final processor that copies the in > message to the out message and selectively fills in headers that were > configured for that processor. I don't even know why I do this other than > as a way to get rid of the myriad JMS headers that get passed around from > using JMS (and occasionally rogue HTTP headers returned from a SOAP call > somewhere). > > Are there any good resources or explanations as to the point of the out > message? It seems to complicate things as it doesn't seem as though you can > send a dual-message of anything by using both the in and out messages. > > -- > Matt Sicker >
