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| Publishing to a topic using java classes |
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| Author |
Message
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| shellj |
 Posted: Fri Nov 11, 2011 7:06 am Post subject: Publishing to a topic using java classes |
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Newbie
Joined: 07 Nov 2011
Posts: 5
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Hello, I am having trouble getting a publish/subscribe workflow to work properly.
Using MQ Explorer I created a queue called sub_test. I then created a topic with topic name test1, and topic string test2. I then created a subscription linking that topic with that queue.
When I do "test publication" on my topic the message I input gets sent to sub_test queue just fine, so I know my subscription works properly.
My problem, however, is that I cannot seem to publish to my topic from a java application. I get no exceptions or errors, but the message never ends up in the sub_test queue.
Can someone point out what I am doing wrong? Here is the java program I wrote to test this:
| Code: |
import com.ibm.mq.MQException;
import com.ibm.mq.MQGetMessageOptions;
import com.ibm.mq.MQMessage;
import com.ibm.mq.MQPutMessageOptions;
import com.ibm.mq.MQQueue;
import com.ibm.mq.MQQueueManager;
import com.ibm.mq.constants.MQConstants;
import com.ibm.mq.MQEnvironment;
import com.ibm.mq.MQTopic;
import com.ibm.mq.constants.CMQC;
public class MQSubWriter
{
private static final String param_queue_manager = "my_queue_manager";
private static final String param_queue_name = "sub_test";
private static final String param_host_name = "my_qm_server";
private static final String param_channel_name = "my_qm_channel";
public static void main(String args[])
{
try
{
MQEnvironment.hostname = param_host_name;
MQEnvironment.channel = param_channel_name;
MQQueueManager queue_manager = new MQQueueManager(param_queue_manager);
MQTopic publisher = queue_manager.accessTopic("test2", "test1", CMQC.MQTOPIC_OPEN_AS_PUBLICATION, CMQC.MQOO_OUTPUT);
MQMessage message = new MQMessage();
String message_text = "Sample publisher message";
message.writeString(message_text);
MQPutMessageOptions put_message_options = new MQPutMessageOptions();
publisher.put(message, put_message_options);
publisher.close();
queue_manager.disconnect();
}
catch (MQException ex)
{
System.out.println("A WebSphere MQ Error occured : Completion Code " + ex.completionCode + " Reason Code " + ex.reasonCode);
ex.printStackTrace();
for (Throwable t = ex.getCause(); t != null; t = t.getCause())
{
System.out.println("... Caused by ");
t.printStackTrace();
}
}
catch (java.io.IOException ex)
{
System.out.println("An IOException occured whilst writing to the message buffer: " + ex);
}
}
}
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I thought I might be sending the parameters in the wrong order in the accessTopic method, so I swapped test1 and test2 but this just threw an exception saying that the topic didn't exist. This leads me to believe that I am publishing to the correct topic, but it doesn't seem to work. |
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| mqjeff |
| Posted: Fri Nov 11, 2011 7:25 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| could it be that you're having issues with 'topic1' versus 'TOPIC1'? |
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| shellj |
| Posted: Fri Nov 11, 2011 7:30 am Post subject: |
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Newbie
Joined: 07 Nov 2011
Posts: 5
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| My actual names are in all caps, and so is the code. I replaced them with generic terms when posting here since this is for a work project and I don't think they would appreciate me divulging anything. |
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| shellj |
| Posted: Fri Nov 11, 2011 8:07 am Post subject: |
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Newbie
Joined: 07 Nov 2011
Posts: 5
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I solved my problem. It turns out I was misunderstanding what a topic string meant, since the IBM documentation seems to like not being very clear. It turns out topic string isn't supposed to be used at all when publishing to a topic, only the topic name is used.
Accessing the topic like so fixed my problem:
MQTopic publisher = queue_manager.accessTopic("", "topic1", CMQC.MQTOPIC_OPEN_AS_PUBLICATION, CMQC.MQOO_OUTPUT); |
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