class RDFClassManager(object):
"""A container like object which represents a SPARQL query and returns
RDFClass objects.
"""
def __init__(self, cls, query=None):
self.cls = cls
if query:
self.query = query
else:
self.query = SelectQuery().select("?resource").where("?resource", a,
cls.class_uri)
def run_query(self):
"""Return a list of URIs representing each of the objects matched by the
query.
"""
return self.cls.endpoint.simple_query(str(self.query))
def __iter__(self):
"""Return a generator which yields objects of the type passed to the
constructor.
"""
return (self.cls(uri) for uri in self.run_query())
def __getitem__(self, k):
"""Return a single object of type cls if k is a long or an int, return
an iterator over a sequence of objects of type cls is k is a slice.
"""
results = self.run_query()[k]
if isinstance(k, (int, long)):
return self.cls(results)
elif isinstance(k, slice):
return (self.cls(uri) for uri in results)
def where(self, predicate, object):
"""Automatically insert current resource as subject for where query."""
new_query = self.query.where(u"?resource", predicate, object)
return RDFClassManager(self.cls, new_query)
def optional(self, predicate, object):
"""Automatically insert current resource as subject for optional query."""
new_query = self.query.optional(u"?resource", predicate, object)
return RDFClassManager(self.cls, new_query)
def __getattr__(self, name, *args, **kwargs):
attr = getattr(self.query, name)
new_query = attr(*args, **kwargs)
return RDFClassManager(self.cls, new_query)
def __init__(self, cls, query=None):
self.cls = cls
if query:
self.query = query
else:
self.query = SelectQuery().select("?resource").where("?resource", a,
cls.class_uri)
