Channels

In the standard publish and subscribe model, clients subscribe to a subject and are served by a single object in Liberator. Liberator populates the object from a single subscription to a component deeper in the Caplin stack (ultimately from the integration layer).

This architecture has the following qualities:

The example below shows a simple architecture for supplying pricing data.

In the channel model, clients still subscribe to a single subject but internally that subject is mapped to a private object for each client. The private objects are differentiated by the presence of the clients' usernames or session names in the objects' subjects. The mapping process is invisible to clients, and clients are not aware of the private objects.

This architecture has the following qualities:

The example below shows how a single subject, '/PRIVATE/BLOTTER', can, through object mapping, be used to serve different data to each client.

A blotter channel is an example use of a channel by an integration adapter to send different data to each client. Each client subscribes to the same subject, '/PRIVATE/BLOTTER', but receives data that pertains to their trading activity alone.

The watchlist control channel is an example use of a channel to send commands to the Caplin Platform, in this case Transformer’s Watchlist Service.

The Watchlist Service on Transformer monitors the private control objects for commands to create, rename and destroy watchlists. Watchlists are private to each user; thus, it is important that the Watchlist Service distinguish between the commands of one user and the commands of another.

A trade channel is an example use of a channel by a client and adapter to exchange messages. Both ends of the channel publish and subscribe to the channel.

Integration APIs for serving blotter data from an Integration Adapter.

APIs for managing the exchange of messages over a channel.

See also: