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
