Interface ITopic

Contains properties and methods required for a topic. It is implemented by Topic.

Namespace:

Assembly: Alachisoft.NCache.Runtime.dll

Syntax

public interface ITopic : IDisposable

Properties

ExpirationTime

Default Expiry time of messsage for this topic. Its default value is TimeSpan.MaxValue.

Declaration

TimeSpan ExpirationTime { get; set; }

Property Value

Type	Description
TimeSpan

IsClosed

Is topic closed or not?

Declaration

bool IsClosed { get; }

Property Value

Type	Description
System.Boolean

Name

Topic's name

Declaration

string Name { get; }

Property Value

Type	Description
System.String

OnTopicDeleted

Topic deletion events are delivered through this callback.

Declaration

TopicDeletedCallback OnTopicDeleted { set; }

Property Value

Type	Description
TopicDeletedCallback

Remarks

You can use this event to perform the tasks when a topic is deleted. For more information on how to use this callback see the documentation for TopicDeletedCallback.

Methods

CreateSubscription(MessageReceivedCallback)

Subscribes for receiving messages of a particular topic.

Declaration

ITopicSubscription CreateSubscription(MessageReceivedCallback messageReceivedCallback)

Parameters

Type	Name	Description
MessageReceivedCallback	messageReceivedCallback	Message is delivered through this callback

Returns

Type	Description
ITopicSubscription	Returns the created topic subscription

Examples

The following example demonstrates how to create a subscription on topic.

First initialize cache.

Cache cache = NCache.InitializeCache("myCache");

Then get messaging service from cache.

IMessagingService messagingService=cache.MessagingService;

Then get topic from messagingService

ITopic topic=messagingService.GetTopic("mytopic");  
if(topic==null)  //If topic not exists create it.
{
  topic=messagingService.CreateTopic("mytopic");
}

Then create subscription

void MessageReceivedCallback(object sender, MessageEventArgs args)
{

}

topic.CreateSubscription(MessageReceivedCallback);

Publish(Message, DeliveryOption, Boolean)

Method used to publish message on topic

Declaration

void Publish(Message message, DeliveryOption deliverOption, bool notifyDeliveryFailure = false)

Parameters

Type	Name	Description
Message	message	Message to be published
DeliveryOption	deliverOption	Delivery Option
System.Boolean	notifyDeliveryFailure	Is MessageDeliveryFailure event required for this message

Examples

The following example demonstrates how to publish message on a topic.

First initialize cache.

Cache cache = NCache.InitializeCache("myCache");

Then get messaging service from cache.

IMessagingService messagingService=cache.MessagingService;

Then get topic from messagingService

ITopic topic=messagingService.GetTopic("mytopic");  
if(topic==null)  //If topic not exists create it.
{
  topic=messagingService.CreateTopic("mytopic");
}

Then publish message on topic.

object payload = "mymessage"; 
Message message = new Message(payload);   //creating message
topic.Publish(message, DeliveryOption.All);

Events

MessageDeliveryFailure

Subscribe for Message delivery failure events

Declaration

event MessageDeliveryFailureCallback MessageDeliveryFailure

Event Type

Type	Description
MessageDeliveryFailureCallback

Remarks

You can use this event to perform the tasks when message delivery fails. For more information on how to use this callback see the documentation for MessageDeliveryFailureCallback.