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| Vin |
 Posted: Tue Apr 02, 2002 8:12 pm Post subject: |
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Master
Joined: 25 Mar 2002
Posts: 212
Location: India
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If I use an option of MQWI_WAITUNLIMITED as my GMO (get message options)is this equivalent to a MessageListener in JMS? The thing I'm trying to acheive is get messages from the group as soon as they arrive. Is there the correct way of doing it or do I need to use the WAIT INTERVAL? I wanted to know the difference and which one is more efficient. Thanks for your time.
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| kolban |
| Posted: Tue Apr 02, 2002 8:42 pm Post subject: |
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Grand Master
Joined: 22 May 2001
Posts: 1072
Location: Fort Worth, TX, USA
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JMS is an industry standard messaging and queueing API in the Java space. MQSeries is a proprietary product from IBM. Using the MQWI_WAITUNLIMITED blocks the calling thread and returns immediately that there is a message available.
The JMS MessageListener is an interface you implement and register with the queueReceiver object and, when a message arrives, a new thread will be created and the thread passed a reference to the received message.
These are quite radically different programming styles. One is single threaded where you have control (remember, you can spawn a thread and issue the block within the thread), the other is inherently asynchronous. Note that you can also do blocking gets (receives) in JMS too.
In IBM's implementation, the blocking get is more efficient. |
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| Vin |
| Posted: Wed Apr 03, 2002 10:34 am Post subject: |
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Master
Joined: 25 Mar 2002
Posts: 212
Location: India
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Kolban,
Thanks for the answer. If I'm using MQJava which approach is more efficient. WAIT_UNLIMITED or WAIT_INTERVAL specified? also I'm trying to get this statement
in your answer.
remember, you can spawn a thread and issue the block within the thread?
Can you point me to any code samples which spawn a thread the above mentioned way? I really need them badly. Thanks. |
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| kolban |
| Posted: Wed Apr 03, 2002 11:46 am Post subject: |
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Grand Master
Joined: 22 May 2001
Posts: 1072
Location: Fort Worth, TX, USA
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Both WAIT_INTERVAL and WAIT_UNLIMITED have identical performance attributes. The difference is one will wake up from the get after a configurable period of time even if no message arrives.
In Java, you can create a new thread. See the Thread class documentation supplied as part of your JDK. In this thread, you can create an MQQueueManager and MQQueue objects and perform your work in this thread allowing your other threads to progress in parallel. |
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| Vin |
| Posted: Wed Apr 03, 2002 5:42 pm Post subject: |
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Master
Joined: 25 Mar 2002
Posts: 212
Location: India
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Kolban,
Just trying to get you right here. My application uses a request/reply paradigm. When I post a message on to a queue, I'm waiting for a response on a different queue, so in my get method I spawn a thread which will create a new QueueManager and Queue objects in its run method and start a while loop which will wait for all the messages to arrive and then terminate, is this the right approach? Since this is a request/reply application performance is fairly critical, any suggestions on this are most welcome.Thanks for all the help. |
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| kolban |
| Posted: Wed Apr 03, 2002 8:43 pm Post subject: |
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Grand Master
Joined: 22 May 2001
Posts: 1072
Location: Fort Worth, TX, USA
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Now if you'd asked this in the first place 
The logic should be something like:
| Code: |
Get an MQQueueManager object for my queue manager;
Get an MQQueue object for my request queue;
Get an MQQueue object for my reply queue;
Put the request message to my request queue;
Get the response message from my response queue, waiting for (say 5 seconds max)
If a message was returned
Process the reply
else
Process no reply
End
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| Vin |
| Posted: Wed Apr 03, 2002 9:51 pm Post subject: |
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Master
Joined: 25 Mar 2002
Posts: 212
Location: India
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Kolban,
Actually I need to wait in the while loop until all the messages arrive on the response queue Thanks. |
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