What I have found is, that the exchange object which is passed to the
DataFormat is only used for getting the CamelContext.
I searched a little bit further and found a processor for unmarshalling:
org.apache.camel.processor.UnmarshalProcessor.process(Exchange,
AsyncCallback)
And there is a note
Object result = dataFormat.unmarshal(exchange, stream);
if (result instanceof Exchange) {
if (result != exchange) {
// it's not allowed to return another exchange other than the one
provided to dataFormat
throw new RuntimeCamelException("The returned exchange " + result +
" is not the same as " + exchange + " provided to the DataFormat");
The logic of that processor is:
- get the object from the stream
- if it is an exchange, throw that exception
- if it is a message, store as 'out' on the exchange-parameter
- if it is something else, store it as body of the 'out' message
So have you tried setting the header on the 'out' message?
Jan
> -----Ursprüngliche Nachricht-----
> Von: Chris [mailto:cwolf.a...@gmail.com]
> Gesendet: Mittwoch, 18. September 2013 22:58
> An: users@camel.apache.org
> Betreff: How to set a header in custom DataFormat?
>
> I implemented a custom DataFormat and in the "unmarshal(Exchange
> exchange, InputStream stream)" implementation I set a header, but upon
> attempting to retrieve the header downstream from the "unmarshal" call,
> the header is not there. Since the pattern is inOnly, I added the
> header to the in Message. I've done similar with custom Processors and
> in that case, it works. What is different with DataFormat? Is there
> any way to set header(s) from DataFormat marshal/unmarshal?
>
> Thanks,
>
> Chris
