How to: Add a Failure Notification Callback (Velocity)

Similar to adding a callback for cache notifications, adding a callback for failure notifications involves two steps. First, create a method that should be invoked when a failure notification is triggered. The method you invoke with the failure notification must accept the same parameters as the DataCacheFailureNotificationCallback delegate. Second, add a callback for the failure notification using the AddFailureNotificationCallback method. Use the name of the method you created in the first step for the failureDelegate parameter.

Note 
In order for your application to use notifications, you need to enable them on a named cache. Use the notificationsEnabled parameter with the New-Cache or Set-CacheConfig commands. For more information, see Cache Administration with PowerShell (Velocity).

How to add a failure notification callback
Create the method you want to be triggered by the failure notification. Make sure that the method you invoke with the failure notification accepts the same parameters as the DataCacheFailureNotificationCallback delegate.

Add a callback for the failure notification using the AddFailureNotificationCallback method. Use the name of the method that you want to invoke when the failure notification occurs in the failureDelegate parameter.

Example
The first step when adding a failure notification callback is to create a method that you want to be invoked by the notification. The method called by the notification must accept the same parameters as the DataCacheFailureNotificationCallback delegate. This example shows one example of a method that can be invoked by a failure notification.

Visual Basic  Copy Code
'method invoked by failure notification "ndNotificationFailure"
Public Sub myNotificationFailureDelegate(ByVal myCacheName As String, _
    ByVal nd As DataCacheNotificationDescriptor)

    Console.WriteLine("===============================")
    Console.WriteLine("Invoked by failure notification")
    Console.WriteLine("===============================")
End Sub

C#  Copy Code
//method invoked by failure notification "ndNotificationFailure"
public void myNotificationFailureDelegate(string myCacheName,
    DataCacheNotificationDescriptor nd)
{
    Console.WriteLine("===============================");
    Console.WriteLine(" Invoked by failure notification");
    Console.WriteLine("===============================");
}

The second step is to add a callback for the failure notification. In this example, a failure notification is created to invoke the method from the previous example.

Visual Basic  Copy Code
'add failure notification callback
Dim ndNotificationFailure As DataCacheNotificationDescriptor
ndNotificationFailure = _
    myTestCache.AddFailureNotificationCallback(AddressOf myNotificationFailureDelegate)

C#  Copy Code
//add failure notification callback
DataCacheNotificationDescriptor ndNotificationFailure
    = myTestCache.AddFailureNotificationCallback(myNotificationFailureDelegate);

How to: Add a Cache Notification Callback (Velocity)

Adding a cache notification callback requires two steps. First, create a method that should be invoked when a cache notification is triggered by one or more cache operations. The method you invoke with the cache notifications must accept the same parameters as the DataCacheNotificationCallback delegate. Second, add a callback using one of the three available methods from the DataCache object: AddCacheLevelCallback, AddRegionLevelCallback, or AddItemLevelCallback. Use the filter parameter to define the types of cache operations you want to trigger cache notifications. Use the name of the method you created in the first step for the clientDelegate parameter.

Note 
In order for your application to use notifications, you need to enable them on a named cache. Use the notificationsEnabled parameter with the New-Cache or Set-CacheConfig commands. For more information, see Cache Administration with PowerShell (Velocity).

How to add a callback for one or more cache operations
Create the method you want to be triggered by the cache notification. Make sure the method accepts the same parameters as the DataCacheNotificationCallback delegate.

Add a callback. Use one of the three available methods from the DataCache object to define the notification scope: AddCacheLevelCallback, AddRegionLevelCallback, or AddItemLevelCallback.

Use the DataCacheOperation enumeration in the filter parameter to specify what type of cache operations you want to trigger notifications. Select more than one enumeration by separating the enumerations with the binary OR operator to perform a bitwise OR. To do this, use the | character in C#, and the Or operator in Visual Basic.

Use the name of the method you want to invoke when these notifications occur in the clientDelegate parameter.

Set the add callback method equal to a DataCacheNotificationDescriptor object that you can use elsewhere in your program to remove the cache notification callback.