Enqueuing Messages

This topic includes examples for enqueuing RAW (string of characters) and user-defined type messages.

Note: For more information about sample code, see Sample Code and Applications.

Enqueuing RAW (String of Characters) Messages:

#include <oracl.h>

OSession osess ;

int EnqueueRaw();

int main(int argc, char **argv)

{

int retVal = 0;

OStartup(OSTARTUP_MULTITHREADED);

try

{

osess.Open();

if ( ! osess.IsOpen() )

{

cout << "Session not opened: Error: " << osess.GetErrorText() << endl;

osess.Close();

OShutdown();

return -1;

}

// Enqueue a payload of raw type

retVal = EnqueueRaw();

osess.Close();

OShutdown();

}

catch(OException oerr)

{

cout << "Exception while dequeuing message : " << oerr.GetErrorText() << endl;

retVal = -1;

}

return retVal;

}

// This function enqueues a message of default

// type (string of characters) to the queue.

// Sets the message attributes and queue attributes before enqueuing

int EnqueueRaw()

{

ODatabase odb;

const char *msgid = 0;

OAQ oaq;

OAQMsg oaqmsg;

odb.Open(osess, "ExampleDB", "SCOTT", "TIGER");

// Open the 'raw_msg_queue'

oaq.Open(odb,"raw_msg_queue");

// Get an instance of the default message(of RAW type)

oaqmsg.Open(oaq);

// Enqueue the message

// Set the actual message value

OValue oval = "My first message through OO4O ClassLibrary";

oaqmsg.SetValue(oval);

msgid = oaq.Enqueue();

const char *msgval = oval;

if ( msgid )

cout<<"Message : '"<<msgval<<"' Enqueued Successfully"<<endl;

// Set Message attributes - priority,Correlation identifier etc

oaqmsg.SetPriority(-6);

oaqmsg.SetCorrelation("FOR AQ");

// Set the actual message value

oval = "Another message";

oaqmsg.SetValue(oval);

// Enqueue the message

msgid = oaq.Enqueue();

msgval = oval;

if ( msgid )

cout<<"Message : '"<<msgval<<"' Enqueued Successfully"<<endl;

// Close all of the objects

oaqmsg.Close();

oaq.Close();

odb.Close();

return 0;

}

Enqueuing User-Defined Type Messages:

// This function enqueues a message of user-defined type MESSAGE_TYPE

// from the msg_queue.

// Sets the message attributes and queue attributes before enqueuing

int EnqueueObject()

{

OAQMsg oaqmsg;

OAQ oaq;

ODatabase odb;

const char *msgid = 0;

OValue oval;

char text[255];

odb.Open(osess, "ExampleDB", "SCOTT", "TIGER");

// Open the 'msg_queue'

oaq.Open(odb,"msg_queue");

// Get an instance of the udt MESSAGE_TYPE

// (check out schema for details)

oaqmsg.Open(oaq, OTYPE_OBJ,"MESSAGE_TYPE");

// Enqueue a message

// Set the actual message value

OObject msgval(odb,"MESSAGE_TYPE");

msgval.SetAttrValue("SUBJECT", "BUY");

msgval.SetAttrValue("text", "ORCL >= 87");

oval = msgval;

oaqmsg.SetValue(oval);

msgid = oaq.Enqueue();

msgval.GetAttrValue("text",text,255);

if ( msgid )

cout<<"Message : '"<<text<< "' Enqueued Successfully"<<endl;

// Set Message attributes - priority,Correlation identifier etc

oaqmsg.SetPriority(-6);

oaqmsg.SetCorrelation("FOR SCOTT");

// Set the actual message value

msgval.SetAttrValue("subject", "SELL");

msgval.SetAttrValue("text", "MSFT < 120");

oval = msgval;

oaqmsg.SetValue(oval);

// Enqueue a message

msgid = oaq.Enqueue();

msgval.GetAttrValue("text",text,255);

cout<<"Message : '"<<text<<"' Enqueued Successfully"<<endl;

// Close all of the objects

oaqmsg.Close();

oaq.Close();

odb.Close();

return 0;

}