Notification Services—Creating a Notification Services Instance and Application

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Creating a Notification Services Instance and Application

The Notification Services instance named StockWatch and a Notification Services application named StockWatchApp are created in the Main( ) method of Example 18-1. The code follows—the code that creates the Notification Services instance and application is highlighted:

static void Main(string[] args)
{
  Server server = new Server("(local)");
 
  // create a new instance
  NotificationServices ns = 
    server.NotificationServices;
  nsi = new Instance(ns, "StockWatch");
  CreateDeliveryChannel( );
 
  // create a new application 
  // in the StockWatch instance
  a = new Application(nsi, "StockWatchApp");
  a.BaseDirectoryPath = baseDirectoryPath;
  CreateEventClass( );
  CreateSubscriptionClass( );
  CreateNotificationClass( );
  CreateHostedEventProvider( );
  CreateGenerator( );
  CreateDistributor( );
  CreateVacuumSchedule( );
  a.QuantumDuration = new TimeSpan(0, 0, 15);
  a.PerformanceQueryInterval = new TimeSpan(0, 0, 5);
  a.SubscriptionQuantumLimit = 1;
  a.ChronicleQuantumLimit = 1;
  a.VacuumRetentionAge = new TimeSpan(0, 0, 1);
  nsi.Applications.Add(a);
  Console.WriteLine("Added application.");
  nsi.Create( );
  nsi.RegisterLocal(serviceUserName, servicePassword);
  nsi.Enable( );
  Console.WriteLine("Application enabled." 
    + Environment.NewLine);
  CreateSubscriber( );
  CreateSubscription( );
  Console.WriteLine(Environment.NewLine 
    + "Press any key to continue.");
  Console.ReadKey( );
}

Figure 18-8. StockWatch notification email

The NotificationServices object represents a Notification Services server. The Instances property of the NotificationServices class returns an InstanceCollection object containing a collection of Notification Services instances as Instance objects. At a minimum, you must define a DeliveryChannel object and an Application object to create an Instance object—in this example, this is done by the CreateDeliveryChannel( ) and Main( ) methods.

The RegisterLocal( ) method of the Instance class registers an instance of Notification Services on the local computer. This is the same as registering a Notification Services instance using SQL Server Management Studio by right-clicking the Notification Services instance and selecting Tasks -> Register from the context menu. You can also register a Notification Services instance by using the nscontrol register command. Registering an instance creates or updates registry entries for the instance, creates performance counters, and optionally creates a Windows Service to run the instance.

The Enable( ) method of the Instance class enables all instance and application components, allowing event collection, notification generation, notification distribution, and subscription management. A NotificationServices instance is disabled when you create it.

The NMO classes used to manage Notification Services instances are described in Table 18-1.

Table 18-1. NMO classes for managing Notification Services instances

Class	Description
Instance	Represents a Notification Services instance.
InstanceCollection	Represents a collection of instances as Instance objects. The Instances property of the NotificationServices class returns the Notification Services instances on the server.

The Application object represents a Notification Services application. At a minimum, you must define a Generator object and a Distributor object for an Application object—in this example, this is done by the CreateGenerator( ) and CreateDistributor( ) methods.

This example configures the Application object by setting the following properties:

BaseDirectoryPath

Specifies the base directory path for the ADF

QuantumDuration

Specifies how frequently the generator tries to process work

PerformanceQueryInterval

Specifies how frequently the application updates its performance counters

SubscriptionQuantumLimit

Specifies how far the logical clock can fall behind the real-time clock before skipping subscription rule firings

ChronicleQuantumLimit

Specifies how far the logical clock can fall behind the real-time clock before skipping event chronicle firings

VacuumRetentionAge

Specifies the minimum age at which event and notification data is considered obsolete and can be removed

The NMO classes used to manage Notification Services applications are described in Table 18-2.

Table 18-2. NMO classes for managing applications

Class	Description
Application	Represents a Notification Services application.
ApplicationCollection	Represents a collection of Notification Services applications as Application objects. The Applications property of the Instance class returns the Notification Services applications hosted on the Notification Services instance.