def __init__(self, configuration=None, identifier=None):
IOMemory.__init__(self, configuration, identifier)
self.__namespace = OrderedDict() #{}
self.__prefix = OrderedDict() #{}
# Mappings for encoding RDF nodes using integer keys, to save memory
# in the indexes Note that None is always mapped to itself, to make
# it easy to test for it in either encoded or unencoded form.
#self.__int2obj = {None: None} # maps integer keys to objects
#self.__obj2int = {None: None} # maps objects to integer keys
self.__int2obj = OrderedDict()
self.__int2obj[None] = None
self.__obj2int = OrderedDict()
self.__obj2int[None] = None
# Indexes for each triple part, and a list of contexts for each triple
self.__subjectIndex = OrderedDict() #{} # key: sid val: set(enctriples)
self.__predicateIndex = OrderedDict() #{} # key: pid val: set(enctriples)
self.__objectIndex = OrderedDict() #{} # key: oid val: set(enctriples)
self.__tripleContexts = OrderedDict() #{} # key: enctriple val: {cid1: quoted, cid2: quoted ...}
#self.__contextTriples = {None: set()} # key: cid val: set(enctriples)
self.__contextTriples = OrderedDict()
self.__contextTriples[None] = OrderedSet()
# all contexts used in store (unencoded)
self.__all_contexts = OrderedSet() #set()
# default context information for triples
self.__defaultContexts = None
