Example code for asyncroneous notification with OracleQueue
Posted: Fri 13 Jun 2008 08:52
Hello,
I am looking for an example code on how to properly dequeue a message in the OracleQueue.OnMessage handler.
...or should it be more like this:
...or more like this?
Thanks in advance for any help!
Greetings - Richie
I am looking for an example code on how to properly dequeue a message in the OracleQueue.OnMessage handler.
- Is OracleQueue thread safe so that concurrent invokes of Dequeue() (from the OnMessage handler) are supported?
- Is it asserted that OnMessage is invoked for each and every received message?
- Is there a possibility to invoke OracleQueue.Dequeue() in nonblocking mode or is it possible to check for pending messages?
- The OracleQueueMessageEventArgs only provides OracleQueueMessageProperties, but not the OracleQueueMessage itself. What is the best way to fetch the acutal OracleMessage that raises the OnMessage event?
Code: Select all
private void OracleQueue_OnMessage(object sender,
OracleQueueMessageEventArgs args)
{
OracleQueue oracleQueue = (OracleQueue)sender;
//We tweack the DequeueOptions of the oracle queue to only dequeue
//the message of out interest
OracleQueueMessageId originalMessageId =
oracleQueue.DequeueOptions.MessageId;
oracleQueue.DequeueOptions.MessageId = args.MessageId;
OracleQueueMessage message = oracleQueue.Dequeue();
oracleQueue.DequeueOptions.MessageId = originalMessageId;
//proceed with message from here
}
Code: Select all
private void OracleQueue_OnMessage(object sender,
OracleQueueMessageEventArgs args)
{
OracleQueue oracleQueue = (OracleQueue)sender;
//Dirty HACK because OracleQueueDequeueOptions does not implement ICloneable
OracleQueueDequeueOptions dequeueOptions = (OracleQueueDequeueOptions)
typeof(OracleQueueDequeueOptions).GetMethod("MemberwiseClone",
BindingFlags.NonPublic | BindingFlags.Instance, null,
Type.EmptyTypes, null).Invoke(oracleQueue, null);
dequeueOptions.MessageId = args.MessageId;
OracleQueueMessage message = oracleQueue.Dequeue(dequeueOptions);
//proceed with message from here
}
Code: Select all
private void OracleQueue_OnMessage(object sender,
OracleQueueMessageEventArgs args)
{
OracleQueue oracleQueue = (OracleQueue)sender;
//Ignore args.MessageId because it cannot be decently handeled
//We just get any next message and dont care which message it has
OracleQueueMessage message = oracleQueue.Dequeue();
//proceed with message from here
}
Greetings - Richie