def ClassInstances(cls):
"""return a generator for instances of this rdf:type
you can look in MyClass.rdf_type to see the predicate being used"""
# Start with all things of "my" type in the db
beenthere = set([])
for i in cls.db.subjects(RDF.type, cls.rdf_type):
if not i in beenthere:
yield cls(i)
beenthere.add(i)
# for all subclasses of me in python do the same (recursivly)
pySubClasses = allsub(cls)
for sub in pySubClasses:
for i in sub.ClassInstances():
if not i in beenthere:
yield i
beenthere.add(i)
# not done yet, for all db subclasses that I have not processed
# already...get them too
dbSubClasses = rdfsClass(cls.rdf_type).transitive_subClasses
moreSubClasses = [
dbsub.resUri for dbsub in dbSubClasses
if dbsub.resUri not in [
pysub.rdf_type for pysub in pySubClasses]]
for sub in moreSubClasses:
for i in cls.db.subjects(RDF.type, sub):
if '' and not i in beenthere:
yield i
beenthere.add(i)
def ClassInstances(cls):
"""return a generator for instances of this rdf:type
you can look in MyClass.rdf_type to see the predicate being used"""
# Start with all things of "my" type in the db
beenthere = set([])
for i in cls.db.subjects(RDF.type, cls.rdf_type):
if not i in beenthere:
yield cls(i)
beenthere.add(i)
# for all subclasses of me in python do the same (recursivly)
pySubClasses = allsub(cls)
for sub in pySubClasses:
for i in sub.ClassInstances():
if not i in beenthere:
yield i
beenthere.add(i)
# not done yet, for all db subclasses that I have not processed
# already...get them too
dbSubClasses = rdfsClass(cls.rdf_type).transitive_subClasses
moreSubClasses = [
dbsub.resUri for dbsub in dbSubClasses
if dbsub.resUri not in [
pysub.rdf_type for pysub in pySubClasses]]
for sub in moreSubClasses:
for i in cls.db.subjects(RDF.type, sub):
if '' and not i in beenthere:
yield i
beenthere.add(i)
def __new__(cls, resUri=None, schemaGraph=None, *args, **kwargs):
# create a bnode
if not resUri or isinstance(resUri, BNode) or issubclass(cls, BNode):
obj = BNode.__new__(cls, resUri)
obj._nodetype = BNode
# user the identifier passed in
elif isinstance(resUri, URIRef) or issubclass(cls, URIRef):
obj = URIRef.__new__(cls, resUri)
obj._nodetype = URIRef
# use the resUri of the subject passed in
elif isinstance(resUri, rdfSubject):
obj = type(resUri.resUri).__new__(cls, resUri.resUri)
obj._nodetype = type(resUri.resUri)
# create one from a <uri> or _:bnode string
elif isinstance(resUri, (str, unicode)):
if resUri[0] == "<" and resUri[-1] == ">":
obj = URIRef.__new__(cls, resUri[1:-1])
obj._nodetype = URIRef
elif resUri.startswith("_:"):
obj = BNode.__new__(cls, resUri[2:])
obj._nodetype = BNode
else:
raise AttributeError(
"cannot construct rdfSubject from %s" % (str(resUri)))
# At this point we have an obj to return...but we might want to look
# deeper if there is an RDF:type entry on the Graph, find the mapped
# subclass and return an object of that new type
if resUri:
rdf_type = obj[RDF.type]
if rdf_type:
class_dict = dict(
[(str(cl.rdf_type), cl)
for cl in allsub(cls) if cl.rdf_type])
subclass = class_dict.get(str(rdf_type.resUri), cls)
else:
subclass = cls
else:
subclass = cls
# improve this do do some kind of hash with classname??
# this uses _weakrefs to allow us to return an existing object
# rather than copies
md5id = obj.md5_term_hash()
newobj = rdfsSubject._weakrefs.get(md5id, None)
log.debug("looking for weakref %s found %s" % (md5id, newobj))
if newobj:
return newobj
newobj = super(rdfSubject, obj).__new__(subclass, obj.resUri)
log.debug("add a weakref %s", newobj)
newobj._nodetype = obj._nodetype
rdfsSubject._weakrefs[newobj.md5_term_hash()] = newobj
return newobj
def __new__(cls, resUri=None, schemaGraph=None, *args, **kwargs):
# create a bnode
if not resUri or isinstance(resUri, BNode) or issubclass(cls, BNode):
obj = BNode.__new__(cls, resUri)
obj._nodetype = BNode
# user the identifier passed in
elif isinstance(resUri, URIRef) or issubclass(cls, URIRef):
obj = URIRef.__new__(cls, resUri)
obj._nodetype = URIRef
# use the resUri of the subject passed in
elif isinstance(resUri, rdfSubject):
obj = type(resUri.resUri).__new__(cls, resUri.resUri)
obj._nodetype = type(resUri.resUri)
# create one from a <uri> or _:bnode string
elif isinstance(resUri, (str, unicode)):
if resUri[0] == "<" and resUri[-1] == ">":
obj = URIRef.__new__(cls, resUri[1:-1])
obj._nodetype = URIRef
elif resUri.startswith("_:"):
obj = BNode.__new__(cls, resUri[2:])
obj._nodetype = BNode
else:
raise AttributeError(
"cannot construct rdfSubject from %s" % (str(resUri)))
# At this point we have an obj to return...but we might want to look
# deeper if there is an RDF:type entry on the Graph, find the mapped
# subclass and return an object of that new type
if resUri:
rdf_type = obj[RDF.type]
if rdf_type:
class_dict = dict(
[(str(cl.rdf_type), cl)
for cl in allsub(cls) if cl.rdf_type])
subclass = class_dict.get(str(rdf_type.resUri), cls)
else:
subclass = cls
else:
subclass = cls
# improve this do do some kind of hash with classname??
# this uses _weakrefs to allow us to return an existing object
# rather than copies
md5id = obj.n3()
newobj = rdfsSubject._weakrefs.get(md5id, None)
log.debug("looking for weakref %s found %s" % (md5id, newobj))
if newobj:
return newobj
newobj = super(rdfSubject, obj).__new__(subclass, obj.resUri)
log.debug("add a weakref %s", newobj)
newobj._nodetype = obj._nodetype
rdfsSubject._weakrefs[newobj.n3()] = newobj
return newobj
def initRDFDatabase(graph=None):
"""
Initialize the database of every mapped RDF class. Returns the prior
value of rdfSubject.db
"""
mapper()
old = getattr(rdfSubject, 'db', None)
# recursively purge class-bound 'db' attributes, which might be
# polluted by other rdfalchemy code. Instance-bound attributes should not
# be a problem since we'll be fetching new instances.
for sub in allsub(rdfSubject):
if 'db' in sub.__dict__: # hasattr returns true for superclasses, must
# check the subclass's own __dict__
del sub.db
rdfSubject.db = graph
return old
