root/tags/lgt2311/library/monitor.lgt

:- category(monitor,
    implements(monitorp)).

    :- info([
        version is 1.1,
        author is 'Paulo Moura',
        date is 2004/3/31,
        comment is 'Monitor predicates.']).

    :- private(spy_point_/4).
    :- dynamic(spy_point_/4).
    :- mode(spy_point_(?event, ?object, ?callable, ?object), zero_or_more).
    :- info(spy_point_/4, [
        comment is 'Stores current spy points.',
        argnames is ['Event', 'Object', 'Message', 'Sender']]).

    monitor_activated :-
        self(Self),
        once(current_event(_, _, _, _, Self)).

    activate_monitor :-
        self(Self),
        abolish_events(before, _, _, _, Self),
        abolish_events(after, _, _, _, Self),
        forall(
            ::spy_point_(Event, Object, Message, Sender),
            define_events(Event, Object, Message, Sender, Self)).

    suspend_monitor :-
        self(Self),
        abolish_events(before, _, _, _, Self),
        abolish_events(after, _, _, _, Self).

    reset_monitor :-
        self(Self),
        abolish_events(before, _, _, _, Self),
        abolish_events(after, _, _, _, Self),
        ::retractall(spy_point_(_, _, _, _)).

    spy_point(Event, Object, Message, Sender) :-
        ::spy_point_(Event, Object, Message, Sender).

    set_spy_point(Event, Object, Message, Sender) :-
        ::retractall(spy_point_(Event, Object, Message, Sender)),
        once((var(Event); Event = before; Event = after)),
        ::assertz(spy_point_(Event, Object, Message, Sender)).

    del_spy_points(Event, Object, Message, Sender) :-
        ::retractall(spy_point_(Event, Object, Message, Sender)).

:- end_category.