On 09/24/2010 03:16 PM, Hadrian Zbarcea wrote: > That's a bit extreme, but yes, that's the idea. More precisely, not when you > want to change the Exchange, you cannot do that, but when you want the > message processed by the remaining of the route to be different. > > One more thing to keep in mind is that there are 2 kinds of "headers", we > call them headers and properties. The headers are on the message, and > normally re not propagated. That means that if you produce and out, that will > have it's own headers, and if you want headers from the original in to be > propagated it's up to you copy them into the new message. The properties are > on the Exchange, and they do get propagated, regardless of a Processor > producing an out or not. That's for instance the place for security > credentials, etc. > > Not to self: since a picture is worth 1000 words, we need better diagrams on > the camel site. Thanks for the clarification. I would love to se a pointer in the getIn and getOut javadocs to a more detailed discussion about the differences of the two, for example in the package file. Would that be possible?
Regards, Tarjei > Cheers, > Hadrian > > > On Sep 24, 2010, at 9:03 AM, Tarjei Huse wrote: > >> Hi, >> On 09/24/2010 10:36 AM, Claus Ibsen wrote: >>> I also added a couple of FAQs as well, such as >>> https://cwiki.apache.org/confluence/display/CAMEL/Using+getIn+or+getOut+methods+on+Exchange >> Maybe the FAQ item could be flashed out with something like: >> >> getIn and getOut are not related to the messaging style used. >> >> You should only use getOut() when you change the exchange completely and >> want all traces of the incomming message (headers etc) removed. >> >> ? >> T >> >>>>> /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 >>>>>> >>>> >>>> -- >>>> 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 >>>> >>> >> >> -- >> Regards / Med vennlig hilsen >> Tarjei Huse >> Mobil: 920 63 413 >> -- Regards / Med vennlig hilsen Tarjei Huse Mobil: 920 63 413
