Release 10.1A: OpenEdge Development:
Messaging and ESB

Publishing with message properties and subscribing selectively

The procedure example3.p publishes a TextMessage from Super Golf Center to Sub Par Golf using the setStringProperty procedure. The procedure example4.p (1 of 2) subscribes to a topic and only receives messages addressed to Sub Par Golf (by passing a selector to the subscribe procedure call).

To run example3.p and example4.p:

Run example4.p (1 of 2) first so the subscriber is running before you publish, as shown:

example4.p

/* Receives a Text message with the "TO" property equals to "Sub Par Golf" */ 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. /* Subscribes 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 */              "TO = 'Sub Par Golf'",  /* Only messages from Sub Par Golf */              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(30)"        "Message from: " DYNAMIC-FUNCTION('getCharProperty':U IN                                           messageH,                                           "FROM").     RUN deleteMessage IN messageH.     APPLY "U1" TO THIS-PROCEDURE. END.

Run example3.p, as shown:

example3.p

/* Publishes a Text message with properties. */ 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."). /* Set the "FROM:" and the "TO:" properties */ RUN setStringProperty IN messageH ("FROM", "Super Golf Center"). RUN setStringProperty IN messageH ("TO", "Sub Par Golf"). /* Publish the message on to the golf topic */ RUN publish IN pubsubsession ("GolfTopic", messageH, ?, ?, ?).