What I forgot to write:
from("jms") should be from("jms:queuename").
Some small explanation how your servicebean behaves in this. If the
method call succeeds the message is automatically committed and so
removed from the queue. If the method call throws an exception the
message is automatically rolled back and will be redelivered. If the
server does down while processing the message the message is also retried.
You can even have several services with a route like this and they will
do failover and loadbalancing without further code.
Christian
Am 19.04.2011 08:26, schrieb Christian Schneider:
Hi Alph,
your problem seems to really cry for jms. So if you do not absolutely
have to use soap/http for your webservice I advise to do the following.
I am not exactly sure how to do the database polling but you ssound as
if you know how to do it. So I absstract this away. As your service is
completely asynchronous you can also nicely skip the soap part and
instead I would send a jaxb serialized data class.
from("db").to("bean:transfomer").to("jms")
from("jms").transactional().to("bean:servicebean")
So the idea is to poll the database somehow then use a bean to
transform to your data class. If the classs is jaxb annotated it will
be serialized to xml before calling jms. You only have to have the
camel-jaxb jar on the classpath.
So the bean transformer would be defined in spring and has a method
like this:
DataClass transform(WhateverTheFatabasePollingProduces source) {
};
On the service sidde you have a similar bean with:
void service(DataClasss) {
};
Now to achieve the behaviour with the guaranteed deliver and error
handling you require you can set the queue options so it does several
redelivery attempts and then move the message to an error queue if
that fails.
This may sound a bit unusual if you are not experienced with jms but
this iss exactly the case jms is best in.
Christian
Am 19.04.2011 03:32, schrieb alpheratz:
Looking for advice on the best way to tackle the following...
Need a process to:
+ poll a database table for the arrival of a new record
+ transform the record to the XML appropriate for a document-literal
SOAP
webservice
+ send to the webservice
All this is relatively easy; here are the issues:
+ the webservice will respond with an immediate communication status
(ok/fail)
+ the service will also respond at some later time with an asynchronous
processing status (ok/fail)
+ outgoing message (n + 1) should only be sent on receipt of the
processing
status response for message (n); polling may be paused waiting for
this or
it may continue (requiring messages to be buffered, presumably...this
is the
easier alternative maybe?)
+ the incoming async response message may never arrive, of course, so
timeout handling will be required
+ the communication status should ideally allow one to distinguish
between
transient comms failures and permanent ones. In the case of transient
one
should retry while permanent errors should result in the message being
logged
I'm not a COMPLETE neophyte with Camel but I'd appreciate any expert
advice
on the best way to structure a solution. Pointers to examples/blogs/etc.
would be great!
Thoughts/suggestions gratefully accepted.
Thanks in advance.
Cheers,
Alph
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