Re: xmBlaster vs CORBA Events clarification

["Brett Palmer" <plum001 at hotmail.com>]

Here is some more information about the problem I am seeing:

The publishing clients sends the following messages to the queue:

  String[] saXmlKey = new String[5];                                     
String[] saContent = new String[5];

  //Five different messages
  saXmlKey[0] = "<?xml version='1.0' encoding='ISO-8859-1' ?>\n" +
                        "<key oid='' contentMime='text/xml'>\n" +
                        "<AGENT id='message_1' subId='1' type='generic'>" +
                        "<DRIVER id='FileProof' pollingFreq='10'>" +
                        "</DRIVER>"+
                        "</AGENT>" +
                        "</key>";
  saContent[0] = "Content: message_1";

  .... Four other messages are created using the same key and content 
except message becomes "message_2," "message_3,".. etc.

  The publishing client loops through each of the messages and submits them 
to the queue.  This process is repeated ten times and then the publishing 
client stops.

The subscribing client subscribes using an XPath query as follows:

        xmlKey = "<?xml version='1.0' encoding='ISO-8859-1' ?>\n" +
                          "<key oid='' queryType='XPATH'>\n" +
                          " /xmlBlaster/key/AGENT[ at id='message_3']" +
                          "</key>";
        try
                                {
           Log.trace(ME, "Subscribe to //AGENT[ at id='message_3']");
           xmlBlaster.subscribe(xmlKey, qos);
        }

     .....

     The subscribing client outputs the receiving message via the update() 
method as follows:

   public void update(String loginName, UpdateKey updateKey, byte[] 
content, UpdateQoS updateQoS)
  {
     Log.info(ME, "Receiving updateKey [" + updateKey.getUniqueKey() + 
"]");
     Log.info(ME, "Receiving message [" + (new String(content)) + "]");
  }


When the publishing and subscribing clients are run simulataneously it 
appears that the subscribing client is receiving all messages instead of the 
selected "message_3" message.  Here is a sample of my output:

...Receiving updateKey [ .....]
...Receiving message [Content: message_1]


...Receiving updateKey [ .....]
...Receiving message [Content: message_2]


...Receiving updateKey [ .....]
...Receiving message [Content: message_3]


...Receiving updateKey [ .....]
...Receiving message [Content: message_4]


...Receiving updateKey [ .....]
...Receiving message [Content: message_5]


If I run the publishing client and then start the subscribing client after 
it is finished, the subscribing client produces the following output (which 
is what I expected in both cases):


...Receiving updateKey [ .....]
...Receiving message [Content: message_3]

...Receiving updateKey [ .....]
...Receiving message [Content: message_3]

... Repeated 10 times for each time the publishing client submitted the set 
of messages to the queue.


As I explained previously, I am new to xmlBlaster and XPATH stuff.  I think 
my code is right, but it may be wrong.  Please let me know if you see 
anything wrong with my XPATH query.  I haven't had time to look at the 
xmlBlaster code to see if there is a contention problem with simulataneously 
publishing and subscribing to messages.

Thanks in advance for your help.


Brett

> >
> > 2. I have two small Java clients programs that publish and subscribe
> > respectfully. The publishing client submits 5 different messages to the
> > queue, and the subscribing client listens to just one of these messages
> > using an XPATH query.  The publishing client continually runs in a loop
> > submiting the 5 messages synchronously.  When both programs are running
> > simultaneously the subscribing client gets all of the other messages 
> even
> > though he is only listening to one type.
> Is your XPath query correct?
> Otherwise it would be a bug in xmlBlaster.
> Please send us informations (your publish key and XPath subscription)
> to check it.
>
> >  If I stop the publishing client
> > and start the subscribing client, the subscribing client gets the 
> correct
> > message that has been sent.
> >
> > Does anyone know why this would happen?
> >
>
> regards,
>
> Marcel
>
> --
> Marcel Ruff
> ruff at swand.lake.de
> http://www.lake.de/home/lake/swand/
> http://www.xmlBlaster.org
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