For each type of market data, there is a factory object and a subscriber object. The factory object for each type of market data provides the same actions. Likewise, the subscriber object for each type of market data provides the same actions.

Each factory object creates its eponymous subscriber object. In addition, each factory object provides the most common actions you would execute on the associated subscriber object. Many of these interfaces provide pairs of actions in which one takes a user-defined callback and one does not, for example, TradeSubscriber.subscribe() and TradeSubscriber.subscribeCb()

For example, the BBASubscriberFactory object lets you create a BBA subscriber, or create and also subscribe to BBA data. A subscription can be for a single symbol or for multiple symbols. The BBASubscriber object lets you manage the subscription to BBA data. You use it to subscribe, unsubscribe, set subscription parameters, override default error behavior, manage callbacks, and obtain information about the subscription.

This object provides the possible values for the errorType parameter in a com.apama.utils.Error event of an error callback of a subscriber. They also provide the possible keys for the extraParams dictionary.