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| marcin.kasinski |
 Posted: Sat Apr 28, 2007 11:59 am Post subject: JMS and setting MessageID |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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Hi,
Do you know why I can not set MessageID with JMS ?
I red this is IBM JMS limitation.
My question is "why ?".
Why there is such limitation ?
Is there any reason ?
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Marcin |
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| jefflowrey |
| Posted: Sat Apr 28, 2007 3:47 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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The real question is - why do you need to set the MsgId?
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| markt |
| Posted: Sat Apr 28, 2007 5:11 pm Post subject: |
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Knight
Joined: 14 May 2002
Posts: 508
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| And the real reason is that the JMS specification REQUIRES that the msgid is a read-only property. |
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| marcin.kasinski |
| Posted: Sat Apr 28, 2007 11:45 pm Post subject: |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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| jefflowrey wrote: |
| The real question is - why do you need to set the MsgId? |
Yes,
I know this question. 
My scenario is different
We have JMS server application.
When we send response we would like to read msgid of request and place it as msgid of reply.
We do like this with apps written with base classes.
We would like to do the same with JMS
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Marcin |
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| fjb_saper |
| Posted: Sun Apr 29, 2007 4:35 am Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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| marcin.kasinski wrote: |
| jefflowrey wrote: |
| The real question is - why do you need to set the MsgId? |
Yes,
I know this question.
My scenario is different
We have JMS server application.
When we send response we would like to read msgid of request and place it as msgid of reply.
We do like this with apps written with base classes.
We would like to do the same with JMS |
Wrong pattern! The standard pattern for a request / Reply in JMS calls for the correlation Id to be passed into the response's correlationId if it is set. If the correlationId is not set the messageId gets moved into the response's correlationId.
So deal with it! 
Any way messageId is supposed to be unique. With your way there is no uniqueness to the messageId anymore.... 
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| jefflowrey |
| Posted: Sun Apr 29, 2007 5:54 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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It sounds like you're out of luck with JMS.
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| marcin.kasinski |
| Posted: Sun Apr 29, 2007 9:27 am Post subject: |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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| fjb_saper wrote: |
Wrong pattern! ... |
Yes, yes, yes.
I know.
I found this pattern.
I'm trying to change it gradually.
It was just theoretical question.
Why I can do it with base classes but I can't with JMS.
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Marcin |
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| Vitor |
| Posted: Sun Apr 29, 2007 10:30 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| marcin.kasinski wrote: |
| Why I can do it with base classes but I can't with JMS. |
You still shouldn't do it with the base classes.
Identify replies with correlId.
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Insanity is the best defence. |
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| marcin.kasinski |
| Posted: Sun Apr 29, 2007 11:21 am Post subject: |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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Hi Vitor,
It was just theoretical question.
| Quote: |
I found this pattern.
I'm trying to change it gradually.
It was just theoretical question. |
Another my question ( still theoretical ) is:
Why with MQ base classes I can set messageID although everybody (me too) doesn't recommend it ?
Why does IBM MQ API allow to do it ?
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Marcin |
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| Vitor |
| Posted: Sun Apr 29, 2007 11:43 pm Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| marcin.kasinski wrote: |
Why with MQ base classes I can set messageID although everybody (me too) doesn't recommend it ?
Why does IBM MQ API allow to do it ? |
For the same reason my car allows me to accelerate to 120mph. It's very seldom a good idea, but there could be a set of exceptional circumstances where I need to. Road subsiding behind me due to earhtquake for instance. It's unlikely and would still not a good idea but it might just be the best option under the circumstances. Circumstances I'd look to change as soon as possible.
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| marcin.kasinski |
| Posted: Mon Apr 30, 2007 12:05 am Post subject: |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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| Vitor wrote: |
For the same reason my car allows me to accelerate to 120mph. It's very seldom a good idea, ... |
Of course, I see.
You said it's very seldom a good idea.
Can you give me example when setting messageID is a good idea.
I personally can not find such example.
I'm trying to understand it.
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| Vitor |
| Posted: Mon Apr 30, 2007 12:22 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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Something like -
You're converting an existing fixed record length file based system to MQ. There's a key in the front of the file which the existing applications use to identify given records. You've no access to transformation technology (WMB or similar) and limited time or resources to recode the application.
Under these restrictive circumstances you might need to replace the file key with the msg id until you can re-architect the solution to eliminate this need, i.e. you've outrun the earthquake and the road's stopped collapsing.
Perhaps I should clarify my original comment.
| Vitor wrote: |
| It's very seldom a good idea |
A good idea is one that allows you to implement your project on time and functional. In the same way a good landing is one you can walk away from. Even if the plane's sitting on the runway because the wheels have collapsed.
Setting msg id is never a good idea in the sense of being clever.
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| EddieA |
| Posted: Mon Apr 30, 2007 11:45 am Post subject: |
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Jedi
Joined: 28 Jun 2001
Posts: 2453
Location: Los Angeles
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| marcin.kasinski wrote: |
| Can you give me example when setting messageID is a good idea. |
The CICS Bridge has some very specific requirements on MessageID and CorrelationID, to indentify psuedo-conversational transactions.
Cheers.
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Eddie Atherton
IBM Certified Solution Developer - WebSphere Message Broker V6.1
IBM Certified Solution Developer - WebSphere Message Broker V7.0 |
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| marcin.kasinski |
| Posted: Mon Apr 30, 2007 12:34 pm Post subject: |
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Sentinel
Joined: 21 Dec 2004
Posts: 850
Location: Poland / Warsaw
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I see,
I'm not familiar with CICS.
Thanks
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Marcin |
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