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| volume4 |
 Posted: Wed Feb 21, 2007 7:26 am Post subject: Triggering a confirmation message from MQ w/ Java |
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Newbie
Joined: 21 Feb 2007
Posts: 9
Location: South Africa
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Hi there everyone,
I am using a Java class to get messages from a queue on MQ 5.3. The client wants me to send an acknowledgment via MQ when the app has successfully got the message from the queue.
Now my question is, is there a way that I can use this app to trigger this in MQ? I am not sure if MQ is even able to send such a message...?
Any help or pointers would be much appreciated.
Thanks!
Schalk |
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| Vitor |
| Posted: Wed Feb 21, 2007 7:33 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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Look up confirmation on delivery messages.
Be sure the client understands what he's asking for. This type of message is seldom necessary, but a lot of people think they are.
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Honesty is the best policy.
Insanity is the best defence. |
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| James_O_K |
| Posted: Wed Feb 21, 2007 1:35 pm Post subject: |
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Apprentice
Joined: 09 Mar 2006
Posts: 39
Location: UK
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| Yep, as Vitor mentions, people certainly think they are necessary, but because of the assured delivery mechanism and all that stuff, they arent really! I had a similar request a while back, in the end I just sent a reply message to them with a "IVE GOT YOUR MESSAGE" type message in the body. |
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| jefflowrey |
| Posted: Wed Feb 21, 2007 1:37 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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| James_O_K wrote: |
| I had a similar request a while back, in the end I just sent a reply message to them with a "IVE GOT YOUR MESSAGE" type message in the body. |
And then when you had an error, and rolled back your syncpoint, and then processed the same message again... you sent another reply?
  
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I am *not* the model of the modern major general. |
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| James_O_K |
| Posted: Thu Feb 22, 2007 1:35 am Post subject: |
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Apprentice
Joined: 09 Mar 2006
Posts: 39
Location: UK
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| jefflowrey wrote: |
| James_O_K wrote: |
| I had a similar request a while back, in the end I just sent a reply message to them with a "IVE GOT YOUR MESSAGE" type message in the body. |
And then when you had an error, and rolled back your syncpoint, and then processed the same message again... you sent another reply?
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I know what youre saying! But they wouldnt budge as they didnt "trust" the system... |
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| Vitor |
| Posted: Thu Feb 22, 2007 1:45 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| James_O_K wrote: |
| I know what youre saying! But they wouldnt budge as they didnt "trust" the system... |
That's always why they want acknowledgements....
Walk them through a few scenarios along the lines jefflowrey suggests and ask how they want them handled; preferably good, complex, multiple failure and rollback ones. That normally puts this acknowledge nonsense in the bin.
(Or tell them they can sue IBM when the message goes missing - accountants like that  )
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Insanity is the best defence. |
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| zpat |
| Posted: Thu Feb 22, 2007 1:52 am Post subject: |
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Jedi Council
Joined: 19 May 2001
Posts: 5866
Location: UK
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| jefflowrey wrote: |
| James_O_K wrote: |
| I had a similar request a while back, in the end I just sent a reply message to them with a "IVE GOT YOUR MESSAGE" type message in the body. |
And then when you had an error, and rolled back your syncpoint, and then processed the same message again... you sent another reply?
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Surely you would put the reply message under the same syncpoint as the request get, and then commit (or rollback) both request and reply together? |
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| Vitor |
| Posted: Thu Feb 22, 2007 2:11 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| zpat wrote: |
| Surely you would put the reply message under the same syncpoint as the request get, and then commit (or rollback) both request and reply together? |
It is surprisingly easy to get caught in this quasi-recursive message -> acknowledgement -> acknowledgement of acknowledgement -> acknowledgement of acknowledgement of acknowledgement -> etc loop.
After all, if the client doesn't trust that the message arrvies (even using syncpoint and persistence) how can they trust that the acknowledge has been recieved? Unless the original sending application acknowledges that the acknowledgement has been received? Then you can't trust that that acknowledgement has been received and round we go for another cycle...
People should trust more. Especially MQ which is demonstratably trustworthy.
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Honesty is the best policy.
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| James_O_K |
| Posted: Thu Feb 22, 2007 2:37 am Post subject: |
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Apprentice
Joined: 09 Mar 2006
Posts: 39
Location: UK
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| Vitor wrote: |
| zpat wrote: |
| Surely you would put the reply message under the same syncpoint as the request get, and then commit (or rollback) both request and reply together? |
It is surprisingly easy to get caught in this quasi-recursive message -> acknowledgement -> acknowledgement of acknowledgement -> acknowledgement of acknowledgement of acknowledgement -> etc loop.
After all, if the client doesn't trust that the message arrvies (even using syncpoint and persistence) how can they trust that the acknowledge has been recieved? Unless the original sending application acknowledges that the acknowledgement has been received? Then you can't trust that that acknowledgement has been received and round we go for another cycle...
People should trust more. Especially MQ which is demonstratably trustworthy. |
Yep, had pretty much your conversation with the people mentioned above. Management ofcourse, need i say more? |
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| volume4 |
| Posted: Tue Feb 27, 2007 10:54 pm Post subject: |
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Newbie
Joined: 21 Feb 2007
Posts: 9
Location: South Africa
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Hi everyone,
I have searched on Google and I have read the docs on the IBM public library but have not foun d a way to successfully generate this status message.
Has anyone on here implemented this successfully? If so, would it be possible to post some example code?
Thank you for all of your assistance. |
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| Vitor |
| Posted: Wed Feb 28, 2007 12:11 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| volume4 wrote: |
Has anyone on here implemented this successfully? If so, would it be possible to post some example code?
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A couple of times, under protest, and only to watch the auditors go recursive. 
It's not code, it's options and you'll find them described in (for starters) the Application Programming guide.
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| volume4 |
| Posted: Wed Feb 28, 2007 12:47 am Post subject: |
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Newbie
Joined: 21 Feb 2007
Posts: 9
Location: South Africa
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| So that would be open options set on the queue before getting the message? |
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| Vitor |
| Posted: Wed Feb 28, 2007 1:38 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| volume4 wrote: |
| So that would be open options set on the queue before getting the message? |
Not what I was thinking of. Where did you read this? (I could be wrong!)
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Honesty is the best policy.
Insanity is the best defence. |
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| volume4 |
| Posted: Wed Feb 28, 2007 1:43 am Post subject: |
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Newbie
Joined: 21 Feb 2007
Posts: 9
Location: South Africa
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No, I did not read it, it was just a thought. I am pretty new to MQ development with Java.
I do have the programming reference so can you give me an indication where I can find this information in that document?
Also, this is done via Java right? It is not something that is configured on MQ itself?
Thank you for all of your assistance. Much appreciated. |
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| Vitor |
| Posted: Wed Feb 28, 2007 1:50 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| volume4 wrote: |
| I do have the programming reference so can you give me an indication where I can find this information in that document? |
Report messages are described as part of the MQMD
| volume4 wrote: |
| Also, this is done via Java right? It is not something that is configured on MQ itself? |
No, they're generated by the queue manager in response to the relevant options being set.
| volume4 wrote: |
| I am pretty new to MQ development with Java |
You probably should spend a little time with the manuals. MQ is not the easiest thing to drive right in on, and as has been discussed in this post report messages are not the best idea. And tricky to get working properly for the reasons expressed.
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Insanity is the best defence. |
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