OpenEdge Development:<br />Messaging and ESB Publishing and subscribing with a TextMessage

The procedures example1.p and example2.p (1 of 2) demonstrate basic Pub/Sub messaging. The procedure example1.p publishes a TextMessage to a topic, and the procedure example2.p (1 of 2) subscribes to a topic and receives a TextMessage.

Run example2.p (1 of 2) so the subscriber is running before you publish, as shown:

example2.p
/* Subscribes and receives a Text message. / DEFINE VARIABLE pubsubsession AS HANDLE. DEFINE VARIABLE consumerH AS HANDLE. / Creates a session object. / RUN jms/pubsubsession.p PERSISTENT SET pubsubsession("-H localhost -S 5162 "). RUN setBrokerURL IN pubsubsession ("localhost:2506"). RUN beginSession IN pubsubsession. / Subscribe to the GolfTopic topic. Messages are handled by the "golfHandler" internal procedure. / RUN createMessageConsumer IN pubsubsession ( THIS-PROCEDURE, / This proc will handle it / "golfHandler", / name of internal procedure / OUTPUT consumerH). RUN subscribe IN pubsubsession ( "GolfTopic", / name of topic / ?, / Subscription is not durable / ?, / No message selector / no, / Want my own messages too / consumerH). / Handles the incoming messages/ / Start receiving messages / RUN startReceiveMessages IN pubsubsession. / Wait to receive the messages. Any other IO-blocked statements can be used for receiving messages. */ WAIT-FOR u1 OF THIS-PROCEDURE.
PROCEDURE golfHandler: DEFINE INPUT PARAMETER messageH AS HANDLE. DEFINE INPUT PARAMETER msgConsumerH AS HANDLE. DEFINE OUTPUT PARAMETER replyH AS HANDLE. /* Display the message - we assume that reply is not required. */ DISPLAY "Message text: " DYNAMIC-FUNCTION('getText':U IN messageH) FORMAT "x(70)". RUN deleteMessage IN messageH. APPLY "U1" TO THIS-PROCEDURE. END.

example2.p

/* Subscribes and receives a Text message. */ 
DEFINE VARIABLE pubsubsession AS HANDLE. 
DEFINE VARIABLE consumerH AS HANDLE. 
/* Creates a session object. */ 
RUN jms/pubsubsession.p PERSISTENT SET pubsubsession("-H localhost -S 
5162 "). 
RUN setBrokerURL IN pubsubsession ("localhost:2506"). 
RUN beginSession IN pubsubsession. 
/* Subscribe to the GolfTopic topic. Messages are handled by the 
   "golfHandler" internal procedure. 
*/ 
RUN createMessageConsumer IN pubsubsession ( 
                  THIS-PROCEDURE, /* This proc will handle it */ 
                  "golfHandler",  /* name of internal procedure */ 
                  OUTPUT consumerH). 
RUN subscribe IN pubsubsession (
              "GolfTopic",     /* name of topic */ 
              ?,               /* Subscription is not durable */ 
              ?,               /* No message selector */ 
              no,              /* Want my own messages too */ 
              consumerH).      /* Handles the incoming messages*/ 
/* Start receiving messages */ 
RUN startReceiveMessages IN pubsubsession. 
/* Wait to receive the messages. Any other IO-blocked statements can be
   used for receiving messages.  
*/ 
WAIT-FOR u1 OF THIS-PROCEDURE.

PROCEDURE golfHandler: 
DEFINE INPUT PARAMETER messageH AS HANDLE.  
DEFINE INPUT PARAMETER msgConsumerH AS HANDLE. 
DEFINE OUTPUT PARAMETER replyH AS HANDLE. 
    /* Display the message - we assume that reply is not required. */ 
    DISPLAY "Message text: " DYNAMIC-FUNCTION('getText':U IN messageH) 
      FORMAT "x(70)". 
    RUN deleteMessage IN messageH. 
    APPLY "U1" TO THIS-PROCEDURE.  
END.

Run example1.p to publish the TextMessage to a topic, as shown:

example1.p
/* Publishes A Text message. / DEFINE VARIABLE pubsubsession AS HANDLE. DEFINE VARIABLE messageH AS HANDLE. / Creates a session object. / RUN jms/pubsubsession.p PERSISTENT SET pubsubsession ("-H localhost -S 5162 "). RUN setBrokerURL IN pubsubsession ("localhost:2506"). RUN beginSession IN pubsubsession. / Create a text message / RUN createTextMessage IN pubsubsession (OUTPUT messageH). RUN setText IN messageH ("Golf shoes on sale today"). / Publish the message on the "GolfTopic" topic */ RUN publish IN pubsubsession ("GolfTopic", messageH, ?, ?, ?). RUN deleteMessage IN messageH. RUN deleteSession IN pubsubsession.

example1.p

/* Publishes A Text message. */ 
DEFINE VARIABLE pubsubsession AS HANDLE. 
DEFINE VARIABLE messageH AS HANDLE. 
/* Creates a session object. */ 
RUN jms/pubsubsession.p PERSISTENT SET pubsubsession  
                                  ("-H localhost -S 5162 "). 
RUN setBrokerURL IN pubsubsession ("localhost:2506"). 
RUN beginSession IN pubsubsession. 
/* Create a text message */ 
RUN createTextMessage IN pubsubsession (OUTPUT messageH).  
RUN setText IN messageH ("Golf shoes on sale today"). 
/* Publish the message on the "GolfTopic" topic */ 
RUN publish IN pubsubsession ("GolfTopic", messageH, ?, ?, ?). 
RUN deleteMessage IN messageH. 
RUN deleteSession IN pubsubsession.