Yeah I remember reading about the problems with losing message headers
somewhere on this list...
To be perfectly honest I think that the number of mails on this thread
indicates the importance of documenting these rules and how things work.
Claus, you are most definitely the man to do it. I've got your book (haven't
read the last updates though) and it certainly warrants a place there.
Perhaps it should also be on the wiki somewhere.
/Bengt
2010/9/14 Claus Ibsen <claus.ib...@gmail.com>
> On Tue, Sep 14, 2010 at 2:16 PM, Bengt Rodehav <be...@rodehav.com> wrote:
> > I think that was very useful information. I hadn't thought of a Processor
> as
> > very low level - it's definitely a level that a lot of us will use. Then
> I
> > guess that in some circumstances (like when coding a custom processor)
> you
> > need to set the out messsage if the MEP is "out capable" otherwise you
> just
> > set the in message. Are there more situations where this is needed?
> >
>
> If the MEP is out capable you can still just change the IN message.
> If the OUT is null, then Camel will re-use the IN (which you just
> changed) and thus still route whatever you have changed.
>
> You only need to use OUT if you want to create a totally 100% new
> message which is not related to the IN message at all.
> And this is only needed in special cases.
>
> Otherwise you get the problem with: Why do I lose my message headers etc.
>
>
>
> > I think that this subject is definitely complicated enough to warrant a
> good
> > documentation somewhere. I think it's really important for developers to
> > understand core concepts instead of just using boilerplate samples
> (although
> > they are very useful).
> >
> > /Bengt
> >
> > 2010/9/14 Claus Ibsen <claus.ib...@gmail.com>
> >
> >> On Tue, Sep 14, 2010 at 10:23 AM, Christian Müller
> >> <christian.muel...@gmail.com> wrote:
> >> > Hello Claus!
> >> >
> >> > That's not (in my opinion) how it works currently. At present I work
> on a
> >> > route which looks like this:
> >> >
> >> > errorHandler(
> >> > defaultErrorHandler()
> >> > .retryAttemptedLogLevel(LoggingLevel.DEBUG)
> >> > .retriesExhaustedLogLevel(LoggingLevel.INFO));
> >> >
> >> > onException(IllegalArgumentException.class)
> >> > .handled(true)
> >> > .maximumRedeliveries(0)
> >> > .beanRef("myResultProvider", "failureResponse");
> >> >
> >> > from("cxf:bean:MyCoolService")
> >> > .processRef("myValidator") // validates conditional rules
> >> > .inOut("direct:mySubroute")
> >> > .beanRef("myResultProvider", "successResponse")
> >> >
> >> >
> >> > If my validator throws a IllegalArgumentException and the result
> provider
> >> > writes the response into the in message, the web service will return
> >> null.
> >> > But if I write the response into the out message, the web service will
> >> > return it. So, I changes my bean to the following "pattern":
> >> >
> >>
> >> Well that could CXF Bean component having a bug.
> >>
> >> If you decide to use a Processor and work on Exchange then you use the
> >> low level Camel API and then you have to handle the IN/OUT stuff
> >> yourself.
> >>
> >>
> >>
> >>
> >> > if (exchange.getPattern().isOutCapable()) {
> >> > exchange.getOut().setBody(response);
> >> > } else {
> >> > exchange.getIn().setBody(response);
> >> > }
> >> >
> >> > And that's the same how the
> >> org.apache.camel.processor.ConvertBodyProcessor
> >> > works (I know you know this, but for the other guys.. :o) )
> >> >
> >> > public class ConvertBodyProcessor implements Processor {
> >> > ...
> >> > public void process(Exchange exchange) throws Exception {
> >> > Message in = exchange.getIn();
> >> > if (charset != null) {
> >> > exchange.setProperty(Exchange.CHARSET_NAME, charset);
> >> > }
> >> > Object value = in.getMandatoryBody(type);
> >> >
> >> > if (exchange.getPattern().isOutCapable()) {
> >> > Message out = exchange.getOut();
> >> > out.copyFrom(in);
> >> > out.setBody(value);
> >> > } else {
> >> > in.setBody(value);
> >> > }
> >> > }
> >> > ...
> >> > }
> >> >
> >> > Should our custom processors/beans/.. not work in the same way?
> >> >
> >> > Cheers,
> >> > Christian
> >> >
> >>
> >>
> >>
> >> --
> >> Claus Ibsen
> >> Apache Camel Committer
> >>
> >> Author of Camel in Action: http://www.manning.com/ibsen/
> >> Open Source Integration: http://fusesource.com
> >> Blog: http://davsclaus.blogspot.com/
> >> Twitter: http://twitter.com/davsclaus
> >>
> >
>
>
>
> --
> Claus Ibsen
> Apache Camel Committer
>
> Author of Camel in Action: http://www.manning.com/ibsen/
> Open Source Integration: http://fusesource.com
> Blog: http://davsclaus.blogspot.com/
> Twitter: http://twitter.com/davsclaus
>
