Daniel@0: /* Part of DML (Digital Music Laboratory)
Daniel@0: 	Copyright 2014-2015 Samer Abdallah, University of London
Daniel@0: 	 
Daniel@0: 	This program is free software; you can redistribute it and/or
Daniel@0: 	modify it under the terms of the GNU General Public License
Daniel@0: 	as published by the Free Software Foundation; either version 2
Daniel@0: 	of the License, or (at your option) any later version.
Daniel@0: 
Daniel@0: 	This program is distributed in the hope that it will be useful,
Daniel@0: 	but WITHOUT ANY WARRANTY; without even the implied warranty of
Daniel@0: 	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Daniel@0: 	GNU General Public License for more details.
Daniel@0: 
Daniel@0: 	You should have received a copy of the GNU General Public
Daniel@0: 	License along with this library; if not, write to the Free Software
Daniel@0: 	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
Daniel@0: */
Daniel@0: 
Daniel@0: :- module(dml_misc, [ periodically/2, current_periodical/3, remove_periodical/1 ]).
Daniel@0: /** <module> Miscellaneous hooks and initialisations
Daniel@0: 
Daniel@0:    This module implements some hooks for managing the context graphs
Daniel@0:    which appear at the bottom of individual resource pages.
Daniel@0: 
Daniel@0:    It also loads some miscellanous RDF graphs.
Daniel@0: 
Daniel@0: */
Daniel@0: :- use_module(library(semweb/rdf_db)).
Daniel@0: :- use_module(library(semweb/rdfs)).
Daniel@0: :- use_module(library(memo)).
Daniel@0: :- use_module(cliopatria(hooks)).
Daniel@0: 
Daniel@0: :- rdf_meta context_graph_class(r).
Daniel@0: 
Daniel@0: :- meta_predicate periodically(+,0).
Daniel@0: :- meta_predicate current_periodical(-,0,-).
Daniel@0: 
Daniel@0: cliopatria:context_graph(URI, Triples, _) :-
Daniel@0:    context_graphable(URI), !,
Daniel@0:    maplist(rdf_global_id,[rdf:type, prov:wasDerivedFrom],Excludes),
Daniel@0:    findall(T, context_triple(Excludes,URI,[],T), T1),
Daniel@0:    sort(T1,Triples).
Daniel@0: 
Daniel@0: context_triple(Excludes,URI,Visited,T) :-
Daniel@0:    edge(URI,Pred,URI1,Triple),
Daniel@0:    \+member(Pred,Excludes),
Daniel@0:    (  T=Triple
Daniel@0:    ;  \+member(URI1,Visited), 
Daniel@0:       %context_graphable(URI1), % this follows a lot of link
Daniel@0:       rdfs_individual_of(URI1,event:'Event'),
Daniel@0:       context_triple(Excludes,URI1,[URI|Visited],T)
Daniel@0:    ).
Daniel@0: 
Daniel@0: edge(URI,Pred,URI1,rdf(URI,Pred,URI1)) :- rdf(URI,Pred,URI1), URI1\=literal(_).
Daniel@0: edge(URI,Pred,URI1,rdf(URI1,Pred,URI)) :- rdf(URI1,Pred,URI).
Daniel@0: 
Daniel@0: context_graphable(URI) :-
Daniel@0:    context_graph_class(Class),
Daniel@0:    rdfs_individual_of(URI,Class).
Daniel@0: 
Daniel@0: context_graph_class(event:'Event').
Daniel@0: context_graph_class(mo:'Signal').
Daniel@0: context_graph_class(mo:'MusicalWork').
Daniel@0: context_graph_class(mo:'MusicGroup').
Daniel@0: 
Daniel@0: current_periodical(Interval,Goal,Id) :- current_alarm(_,periodically(Interval,Goal),Id,_).
Daniel@0: remove_periodical(Id) :- remove_alarm(Id).
Daniel@0: 
Daniel@0: periodically(Interval,Goal) :-
Daniel@0:    memo:reify(Goal,Status),
Daniel@0:    (Status=ok -> true; debug(cron,'Periodic goal ~q failed with ~q',[Goal,Status])),
Daniel@0:    alarm(Interval,periodically(Interval,Goal),_,[remove(true)]).
Daniel@0: