Listen(OracleQueueAgentCollection,Int32,OracleQueueDeliveryMode,OracleQueueDeliveryMode,OracleConnection) Method

In This Topic

Syntax
Example
See Also

Listens on one or more queues on behalf of a list of agents.

Syntax

Visual Basic
C#

public static OracleQueueAgent Listen( 
   OracleQueueAgentCollection agents,
   int waitTimeout,
   OracleQueueDeliveryMode listenDeliveryMode,
   out OracleQueueDeliveryMode messageDeliveryMode,
   OracleConnection connection
)

'Declaration
 
Public Overloads Shared Function Listen( _
   ByVal agents As OracleQueueAgentCollection, _
   ByVal waitTimeout As Integer, _
   ByVal listenDeliveryMode As OracleQueueDeliveryMode, _
   ByRef messageDeliveryMode As OracleQueueDeliveryMode, _
   ByVal connection As OracleConnection _
) As OracleQueueAgent

Parameters

agents: List of agents to listen for.
waitTimeout: Time out for the listen call in seconds. By default, the call will block forever.
listenDeliveryMode: The caller specifies whether it is interested in persistent, buffered messages or both types of messages, specifying a delivery mode. (Only for Oracle 10.2 and greater.)
messageDeliveryMode: Returns the message type along with the queue and consumer for which there is a message (only for Oracle 10.2 and greater).
connection: A OracleConnection that represents the connection to an instance of Oracle server.

Return Value

Agent with a message available for consumption.

Example

The following example demonstrates the usage of Listen(OracleQueueAgentCollection,Int32,OracleQueueDeliveryMode,OracleQueueDeliveryMode,OracleConnection) method.

csharp

OracleConnection oracleConnection = new OracleConnection(
        "User Id=system;Password=manager;Server=ora11;");
oracleConnection.Open();

OracleQueueTable oracleQueueTable = new OracleQueueTable(
        "QUEUE_TABLE_MESSAGE", oracleConnection);

// Set the table to serve multiple consumers.
oracleQueueTable.Options.MultipleConsumers = true;
oracleQueueTable.Options.PayloadTypeName = "RAW";
oracleQueueTable.CreateQueueTable();
OracleQueueAdmin oracleQueueAdmin = new OracleQueueAdmin(
        "MESSAGE_QUEUE", "QUEUE_TABLE_MESSAGE", oracleConnection);
oracleQueueAdmin.CreateQueue();
oracleQueueAdmin.StartQueue();

oracleQueueAdmin.AddSubscriber(new OracleQueueAgent("Bob"));

OracleQueue oracleEnqueueQueue = new OracleQueue("MESSAGE_QUEUE", oracleConnection);

OracleQueueMessage message = new OracleQueueMessage();
message.StringPayload = "Message for Bob.";
message.MessageProperties.RecipientList.Add(new OracleQueueAgent("Bob"));
oracleEnqueueQueue.Enqueue(message);

OracleQueue oracleDequeueQueue = new OracleQueue();
oracleDequeueQueue.Connection = oracleConnection;

OracleQueueAgentCollection coll = new OracleQueueAgentCollection();
coll.Add(new OracleQueueAgent("Bob", "MESSAGE_QUEUE"));

// listening only for 60 seconds instead of blocking thread forever
OracleQueueAgent agent = oracleDequeueQueue.Listen(coll, 60);
            
Console.WriteLine("The following consumer received a message: {0}", agent.Name);
oracleDequeueQueue.QueueName = agent.Address;
oracleDequeueQueue.DequeueOptions.ConsumerName = agent.Name;
Console.WriteLine("The message: {0}", oracleDequeueQueue.Dequeue().StringPayload);

oracleQueueAdmin.StopQueue();
oracleQueueAdmin.DropQueue();
oracleQueueTable.DropQueueTable();

oracleConnection.Close();

Visual Basic

Dim oracleConnection As New OracleConnection("User Id=system;Password=manager;Server=ora11;")
oracleConnection.Open()

Dim oracleQueueTable As New OracleQueueTable("QUEUE_TABLE_MESSAGE", oracleConnection)

' Set the table to serve multiple consumers.
oracleQueueTable.Options.MultipleConsumers = True
oracleQueueTable.Options.PayloadTypeName = "RAW"
oracleQueueTable.CreateQueueTable()
Dim oracleQueueAdmin As New OracleQueueAdmin("MESSAGE_QUEUE", "QUEUE_TABLE_MESSAGE", oracleConnection)
oracleQueueAdmin.CreateQueue()
oracleQueueAdmin.StartQueue()

oracleQueueAdmin.AddSubscriber(New OracleQueueAgent("Bob"))

Dim oracleEnqueueQueue As New OracleQueue("MESSAGE_QUEUE", oracleConnection)

Dim message As New OracleQueueMessage()
message.StringPayload = "Message for Bob."
message.MessageProperties.RecipientList.Add(New OracleQueueAgent("Bob"))
oracleEnqueueQueue.Enqueue(message)

Dim oracleDequeueQueue As New OracleQueue()
oracleDequeueQueue.Connection = oracleConnection

Dim coll As New OracleQueueAgentCollection()
coll.Add(New OracleQueueAgent("Bob", "MESSAGE_QUEUE"))

' listening only for 60 seconds instead of blocking thread forever
Dim agent As OracleQueueAgent = oracleDequeueQueue.Listen(coll, 60)

Console.WriteLine("The following consumer received a message: {0}", agent.Name)
oracleDequeueQueue.QueueName = agent.Address
oracleDequeueQueue.DequeueOptions.ConsumerName = agent.Name
Console.WriteLine("The message: {0}", oracleDequeueQueue.Dequeue().StringPayload)

oracleQueueAdmin.StopQueue()
oracleQueueAdmin.DropQueue()
oracleQueueTable.DropQueueTable()

oracleConnection.Close()

Reference

OracleQueue Class
OracleQueue Members
Overload List

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