def _add_subject_identifier (self, address):
"""Adds a subject identifier to this topic.
This method performs only the actual database operation to add
the subject identifier, and is only called after appropriate
checking in add_subject_identifier().
:param address: external form of a locator
:type address: string
"""
si = SubjectIdentifier(topic=self, address=address,
containing_topic_map=self.topic_map)
si.save()
self.subject_identifiers.add(si)
def _add_subject_identifier(self, address):
"""Adds a subject identifier to this topic.
This method performs only the actual database operation to add
the subject identifier, and is only called after appropriate
checking in add_subject_identifier().
:param address: external form of a locator
:type address: string
"""
si = SubjectIdentifier(topic=self,
address=address,
containing_topic_map=self.topic_map)
si.save()
self.subject_identifiers.add(si)
def create_topic_by_subject_identifier(self, subject_identifier):
"""Returns a `Topic` instance with the specified subject identifier.
This method returns either an existing `Topic` or creates a
new `Topic` instance with the specified subject identifier.
If a topic with the specified subject identifier exists in
this topic map, that topic is returned. If a topic with an
item identifier equal to the specified subject identifier
exists, the specified subject identifier is added to that
topic and the topic is returned. If neither a topic with the
specified subject identifier nor with an item identifier equal
to the subject identifier exists, a topic with the subject
identifier is created.
:param subject_identifier: the subject identifier the topic
should contain
:type subject_identifier: `Locator`
:rtype: `Topic`
"""
if subject_identifier is None:
raise ModelConstraintException(
self, 'The subject identifier may not be None')
reference = subject_identifier.to_external_form()
try:
topic = self.topic_constructs.get(
subject_identifiers__address=reference)
except Topic.DoesNotExist:
try:
topic = self.topic_constructs.get(
item_identifiers__address=reference)
except Topic.DoesNotExist:
topic = Topic(topic_map=self)
topic.save()
si = SubjectIdentifier(topic=topic,
address=reference,
containing_topic_map=self)
si.save()
topic.subject_identifiers.add(si)
return topic
def create_topic_by_subject_identifier (self, subject_identifier):
"""Returns a `Topic` instance with the specified subject identifier.
This method returns either an existing `Topic` or creates a
new `Topic` instance with the specified subject identifier.
If a topic with the specified subject identifier exists in
this topic map, that topic is returned. If a topic with an
item identifier equal to the specified subject identifier
exists, the specified subject identifier is added to that
topic and the topic is returned. If neither a topic with the
specified subject identifier nor with an item identifier equal
to the subject identifier exists, a topic with the subject
identifier is created.
:param subject_identifier: the subject identifier the topic
should contain
:type subject_identifier: `Locator`
:rtype: `Topic`
"""
if subject_identifier is None:
raise ModelConstraintException(
self, 'The subject identifier may not be None')
reference = subject_identifier.to_external_form()
try:
topic = self.topic_constructs.get(
subject_identifiers__address=reference)
except Topic.DoesNotExist:
try:
topic = self.topic_constructs.get(
item_identifiers__address=reference)
except Topic.DoesNotExist:
topic = Topic(topic_map=self)
topic.save()
si = SubjectIdentifier(topic=topic, address=reference,
containing_topic_map=self)
si.save()
topic.subject_identifiers.add(si)
return topic