Reply messages from aggregator

[Sven Bauhan <sv...@ast.dfs.de>]

Hi,

I'm quite new to Camel and I have a problem to understand the basic 
principle of sending replys back to a sender.
I try to implement a protocol that aggregates segments to a complete 
message. For each segment a reply message is expected by the sender.
My route is now:

         JaxbDataFormat jaxb = new JaxbDataFormat();
         ATSMAggregationStrategy aggregation = new 
ATSMAggregationStrategy();
         from("direct:atsm-segment")
             .unmarshal(jaxb).aggregate(xpath("/MSG/MID"), aggregation)
             .completionPredicate(aggregation).to("direct:atsm-out");

Do I have to set the exchange pattern of the aggregator to InOut? How 
can I do this?
How is the reply message defined? Do I have to set the out message in 
the aggregation strategy?
How do I trigger sending of a reply message?
How is the reply messages routed back to the sender?
Is the reply messages processed automatically (JAXB)?

Thanks,
Sven Bauhan

Re: Reply messages from aggregator

[Henryk Konsek <he...@gmail.com>]

Hi Sven,

> I have to implement a protocol called ATS-M.

I'm afraid that we still don't get the protocol you want to implement.
Could you elaborate this topic a little bit?

> By the way, I did not understand yet, what seda means and what is the
> difference to direct.

Seda [1] is in-memory message queue. It's a little bit like the
"asynchronous direct" component :) .

Best regards.

[1] http://camel.apache.org/seda.html

--
Henryk Konsek
http://henryk-konsek.blogspot.com

Re: Reply messages from aggregator

[Sven Bauhan <sv...@ast.dfs.de>]

On 03/10/13 02:53, Christian Müller wrote:
> Can you explain in more detail what you want to do? I didn't understand
> your requirement...
I have to implement a protocol called ATS-M. It splits messages into 
segments for transmission. At the receiver the segments are aggregated 
to the original message.
> One question: Your "aggregation" object implements Predicate *AND*
> AggregationStrategy?
Sure, the predicate belongs to the aggregation. So I put them in the 
same class as they belong together.
> By looking a your example, your direct endpoint receives (String/Byte
> array/...) messages and convert it into a JAXB annotated Java Object. You
> aggregate all messages based on the "MSG/MID" element until your
> aggregation predicate indicates the end. Afterwards you send the aggregated
> messages to another direct endpoint.
correct

> *IF* you want to send back a message at the time it receives in the
> aggregator, I would do something like this


The problem is, that I cannot just send a reply if a message is 
received. The aggregator has to parse the message and then it replies an 
ACK or a fault message. This can only be done in the aggregator, cause 
the new segment has to be checked against the incomplete message in the 
aggregator.
So what I need is a second output port from the aggregator where the 
reply messages are sent and which can be taken into a camel route.

> from("direct:atsm-segment")
>    .unmarshal(jaxb)
>    .inOnly("seda:aggregator")
>    .inOut("bean:myResponseBuilder")
>    .marshal(jaxb);
>
> from("seda:aggregator")
>    .aggregate(xpath("/MSG/MID"),
> aggregation).completionPredicate(aggregation)
>    .to("direct:atsm-out");
By the way, I did not understand yet, what seda means and what is the 
difference to direct.

A jaxb marshaling is not needed. I want to process the data internally.
I added a processor to the route to put the header information in the 
XML structure into the camel message header:

         from("direct:atsm-segment")
         .unmarshal(jaxb)
         .process(atsm_process)
         .aggregate(header("MID"), 
aggregation).completionPredicate(aggregation)
         // .reply_to("")
         .to("direct:atsm-out");

Thanks, Sven

Re: Reply messages from aggregator

[Christian Müller <ch...@gmail.com>]

Can you explain in more detail what you want to do? I didn't understand
your requirement...
One question: Your "aggregation" object implements Predicate *AND*
AggregationStrategy?

By looking a your example, your direct endpoint receives (String/Byte
array/...) messages and convert it into a JAXB annotated Java Object. You
aggregate all messages based on the "MSG/MID" element until your
aggregation predicate indicates the end. Afterwards you send the aggregated
messages to another direct endpoint.
*IF* you want to send back a message at the time it receives in the
aggregator, I would do something like this

from("direct:atsm-segment")
  .unmarshal(jaxb)
  .inOnly("seda:aggregator")
  .inOut("bean:myResponseBuilder")
  .marshal(jaxb);

from("seda:aggregator")
  .aggregate(xpath("/MSG/MID"),
aggregation).completionPredicate(aggregation)
  .to("direct:atsm-out");

Best,
Christian

On Fri, Mar 1, 2013 at 2:29 PM, Sven Bauhan <sv...@ast.dfs.de> wrote:

> Hi,
>
> I'm quite new to Camel and I have a problem to understand the basic
> principle of sending replys back to a sender.
> I try to implement a protocol that aggregates segments to a complete
> message. For each segment a reply message is expected by the sender.
> My route is now:
>
>         JaxbDataFormat jaxb = new JaxbDataFormat();
>         ATSMAggregationStrategy aggregation = new
> ATSMAggregationStrategy();
>         from("direct:atsm-segment")
>             .unmarshal(jaxb).aggregate(**xpath("/MSG/MID"), aggregation)
>             .completionPredicate(**aggregation).to("direct:atsm-**out");
>
> Do I have to set the exchange pattern of the aggregator to InOut? How can
> I do this?
> How is the reply message defined? Do I have to set the out message in the
> aggregation strategy?
> How do I trigger sending of a reply message?
> How is the reply messages routed back to the sender?
> Is the reply messages processed automatically (JAXB)?
>
> Thanks,
> Sven Bauhan
>
>


--