topic Re: dynamically define cJMS destination queue in Talend Studio

dynamically define cJMS destination queue

_AnonymousUser — Sat, 16 Nov 2024 11:51:09 GMT

Hi
Is it possible to define the destination queue of the cJMS component dynamically?
I tried to define the destination by a context variable but if I change the value of the context variable within the route, the new value is not known in the cJMS component.
Any ideas?
thanks, laci

Re: dynamically define cJMS destination queue

Anonymous — Thu, 31 Oct 2013 03:12:07 GMT

Hi,
You can use context value in cJMS destination queue.

I tried to define the destination by a context variable but if I change the value of the context variable within the route, the new value is not known in the cJMS component.

Please give us the screenshots of your current contexts setting so that we can address your issue.
Best regards
Sabrina

Re: dynamically define cJMS destination queue

_AnonymousUser — Thu, 31 Oct 2013 10:48:19 GMT

Hi Sabrina
Yes, I know that I can use a context Variable. What I tried is to set the value of a context variable in a cProcessor Component
context.put("destinationEvita", "new.queue");
the cProcessor component leads to the cJMS component which uses context.destinationEvita as Destination.
But when you look at the source code, you will see that the Destination which the cJMS component will use is set in a initialization phase when the route starts. So setting the value of that context variable at runtime has no effect.
Any other way to set the Destination field of the cJMS component dynamically?
Thanks,
Laci

Re: dynamically define cJMS destination queue

Anonymous — Fri, 01 Nov 2013 02:39:18 GMT

Hi,
Why don't you set the context value in "Contexts" view? It seems what you put value to a global variable?
Best regards
Sabrina

Re: dynamically define cJMS destination queue

_AnonymousUser — Mon, 04 Nov 2013 08:18:16 GMT

Hi Sabrina
sorry, you don't seem to understand what I mean.
I want to set the queue dynamically in the cJMS component. That means, that I want to be able to change the queue during the process of my route.
For example: Say, I have a header variable QueueName="queue1"
then I want to send my message to queue1.
If the value of my header variable is QueueName="queue2"
then I want to send my message to queue2
That's why I tried to change the value of the context variable.

How can I upload a screenshot here? I can't find a button for that.
Best, Laci

Re: dynamically define cJMS destination queue

Anonymous — Mon, 04 Nov 2013 08:22:18 GMT

Hi,
You should register and log in as a Community member first, then you'll get a Image upload box that allows to upload screen captures and images up to 200KB.(20 images per post, each image must be less then 1024x768 pixels and 200 KB)
For registered users, please clicking on "post reply" (not through the quick post").
Best regards
Sabrina

Re: dynamically define cJMS destination queue

Anonymous — Mon, 04 Nov 2013 09:13:04 GMT

If you are familiar with Camel, you can use Camel Properties.
http://camel.apache.org/properties.html

Re: dynamically define cJMS destination queue

_AnonymousUser — Mon, 04 Nov 2013 13:35:15 GMT

Thanks camsellem, that helped a bit further.
In a cProcessor component I have the following code:
org.apache.camel.component.properties.PropertiesComponent pc = new org.apache.camel.component.properties.PropertiesComponent();
pc.setLocation("file:/home/talend/msp.properties");
org.apache.camel.CamelContext camelContext = getCamelContextMap().get("TestCntx-ctx");
camelContext.addComponent("properties", pc);
(TestCntx-ctx is the name of my route)
the cProcessor component leads to a cMessagingEndpoint with the URI:
"{{destination.queue}}"
which is defined in the file /home/talend/msp.properties as follows:
destination.queue=myQueue
When I run it in Talend Studio I get the error:
Failed to create route cJMS_1 at: >>> To <<< in route: Route] -> [pr... because of PropertiesComponent with name properties must be defined in CamelContext to support property placeholders.

I suspect that it doesn't work because the PropertiesComponent object is not registered correctly. But how do I do it?
Thanks for your help,
Laci

Re: dynamically define cJMS destination queue

_AnonymousUser — Tue, 05 Nov 2013 07:36:38 GMT

ok, I found the solution.
I have to define the PropertiesComponent in a cConfig component like this:
org.apache.camel.component.properties.PropertiesComponent pc = new org.apache.camel.component.properties.PropertiesComponent();
pc.setLocation("file:/home/talend/msp.properties");
camelContext.addComponent("properties", pc);

And then I can use a cJMS component with destination:
"{{destination.queue}}"
where
destination.queue=queue.name
is defined in /home/talend/msp.properties

Re: dynamically define cJMS destination queue

_AnonymousUser — Tue, 05 Nov 2013 09:48:18 GMT

... but how can I change the value of a Camel Property at runtime?

Re: dynamically define cJMS destination queue

Anonymous — Tue, 05 Nov 2013 20:08:20 GMT

Hi Laci,
You can manipulate what queue cJMS will use at runtime by changing a header on the Camel Exchange.
Please see:
http://camel.apache.org/jms.html
Heading: Reuse endpoint and send to different destinations computed at runtime
You can use the cSetHeader component (or your custom processor) to set the CamelJmsDestinationName header to the desired queue name.
Hope that helps!
-Ben

Re: dynamically define cJMS destination queue

_AnonymousUser — Wed, 06 Nov 2013 07:24:23 GMT

Hi Ben
Thanks a lot. A simple and working way to do it!
Best,
Laci

Re: dynamically define cJMS destination queue

_AnonymousUser — Mon, 06 Oct 2014 11:38:15 GMT

hi ,
i want to set Content-Type value dynamically from database in cHttp ?
Can anyone tell me how to do this?

Re: dynamically define cJMS destination queue

Anonymous — Mon, 06 Oct 2014 14:45:01 GMT

Hi Suresh,
Please post your question as a new thread. When you do, try and be more descriptive about your use case.

Re: dynamically define cJMS destination queue

Anonymous — Mon, 13 Jul 2015 15:16:37 GMT

Hi Suresh,
This example uses XPath to pull a value from an XML message and use it as the queue name in the following cJMS component. The appearance is a little different from 5.x because it's 6.0.
Hope this helps.

Re: dynamically define cJMS destination queue

vharcq — Fri, 23 Oct 2015 06:36:32 GMT

Hi guys
I had similar question recently in a Message Dispatcher need.
Here was my approach
I choosed a combination of

cProcessor (or anything else) that sets a Header variable

"MYQUEUE"

(depending of my logic)
cRecipientList with a Simple expression

"cMQConnectionFactory1:queue:"+"${in.header.MYQUEUE}"

The trick is the URI that uses the JMS Connection Factory
Vincent

Re: dynamically define cJMS destination queue

Loko — Fri, 14 Apr 2017 10:05:58 GMT

Yes, just have to change the "CamelJmsDestinationName" header and that's all

One thing to understand with contexts is they behave completly differet in routes/camel than in jobs. They are read at route startup but if you change their values they never will be taken in account. So they are only constant values. Headers and properties are the main stuff for dynamic variables.

Loko

Re: dynamically define cJMS destination queue

davidferguson — Mon, 06 Aug 2018 14:24:19 GMT

Hey Loko,

that's not exactly true! Have a look hereto check out how to change your contexts with the help of external config files - it's pretty useful!

Thanks for the tip about the JMS Header!

David.

Re: dynamically define cJMS destination queue

Loko — Wed, 29 Aug 2018 14:53:48 GMT

Hi David.
I know that .cfg file option, but what I said stays 100% true ! Once the value has been initialized, in the route itself or overriden by the cfgFile, it will never change. You could manually change its value in a cProcessor for instance, but the change would be lost for the nexr steps of your route.

Re: dynamically define cJMS destination queue

davidferguson — Wed, 29 Aug 2018 15:33:06 GMT

@Loko,

maybe I'm not understanding you correctly...

Here's an example of what I mean:

Simple REST Service set-up

Contents of cSetBody with context variable usage

Context variable initialisation

GET REST call with browser

Getting ID

Updating config for the already deployed service

Second GET REST call to service after update

Can you show me an example of what you mean? I'm still quite new to Routes in Talend ESB and still trying to get my head around them, so it's quite possible that I'm missing something. In any case, if you have anything to teach me about Routes, I'll gladly take the advice!

Thanks,

David.