FilteredSubscriptionSymbol Struct Reference

This marker interface marks subscription symbol classes (like TimeSeriesSubscriptionSymbol) that attach "filters" to the actual symbols. More...

#include <FilteredSubscriptionSymbol.hpp>

Inheritance diagram for FilteredSubscriptionSymbol:

Detailed Description

This marker interface marks subscription symbol classes (like TimeSeriesSubscriptionSymbol) that attach "filters" to the actual symbols.

Filtered subscription symbols implement their operator == and std::hash<> based on their symbol only, without considering their "filter" part (for example, a TimeSeriesSubscriptionSymbol has a fromTime filter on a time range of events).

DXFeedSubscription has the following behavior for filtered symbols. There can be only one active filter per symbol. Adding new filtered symbol with the same symbol but different filter removes the old one from subscription, adds the new one, and notifies ObservableSubscriptionChangeListener about this subscription change. The later is a special behaviour for filtered subscription symbols, because on other types of symbols (like StringSymbol, for example) there is no notification when replacing one symbol with the other that is "equal" to the first one.