Classes implementing this interface implement the context filtering of POJO objects
The predicate implements the filter specified in ObjectFilter and is responsible
for the filter of objects according to the current context filters
This class provides an empty implementation of OQLListener,
which can be extended to create a listener which only needs to handle a subset
of the available methods.
This class provides an empty implementation of OQLVisitor,
which can be extended to create a visitor which only needs to handle a subset
of the available methods.