def _add_item_identifier(self, address):
"""Adds an item identifier to this topic.
This method performs only the actual database operation to add
the item identifier, and is only called after appropriate
checking in add_item_identifier().
:param address: external form of a locator
:type address: string
"""
ii = ItemIdentifier(address=address,
containing_topic_map=self.topic_map)
ii.save()
self.item_identifiers.add(ii)
def _add_item_identifier (self, address):
"""Adds an item identifier to this topic.
This method performs only the actual database operation to add
the item identifier, and is only called after appropriate
checking in add_item_identifier().
:param address: external form of a locator
:type address: string
"""
ii = ItemIdentifier(address=address,
containing_topic_map=self.topic_map)
ii.save()
self.item_identifiers.add(ii)
def add_item_identifier(self, item_identifier):
"""Adds an item identifier.
It is not allowed to have two `Construct`s in the same
`TopicMap` with the same item identifier. If the two objects
are `Topic`s, then they must be merged. If at least one of the
two objects is not a `Topic`, an `IdentityConstraintException`
must be reported.
:param item_identifier: the item identifier to be added
:type item_identifier: `Locator`
:raises `IdentityConstraintException`: if another construct
has an item identifier which is equal to `item_identifier`
"""
if item_identifier is None:
raise ModelConstraintException(
self, 'The item identifier may not be None')
address = item_identifier.to_external_form()
topic_map = self.get_topic_map()
try:
ii = ItemIdentifier.objects.get(address=address,
containing_topic_map=topic_map)
construct = ii.get_construct()
if construct == self:
return
# While an ItemIdentifier may legitimately (in the
# database's terms) exist while not being associated with
# any constructs, the only valid ways to remove an item
# identifier from a construct (remove_item_identifier()
# and remove()) delete the item identifier. Therefore,
# raise an exception without checking that construct is
# not None.
raise IdentityConstraintException(
self, ii.get_construct(), item_identifier,
'This item identifier is already associated with another construct'
)
except ItemIdentifier.DoesNotExist:
ii = ItemIdentifier(address=address,
containing_topic_map=topic_map)
ii.save()
self.item_identifiers.add(ii)
def create_topic_by_item_identifier (self, item_identifier):
"""Returns a `Topic` instance with the specified item identifier.
This method returns either an existing `Topic` or creates a
new `Topic` instance with the specified item identifier.
If a topic with the specified item identifier exists in the
topic map, that topic is returned. If a topic with a subject
identifier equal to the specified item identifier exists, the
specified item identifier is added to that topic and the topic
is returned. If neither a topic with the specified item
identifier nor with a subject identifier equal to the subject
identifier exists, a topic with the item identifier is
created.
:param item_identifier: the item identifier the topic should contain
:type item_identifier: `Locator`
:rtype: `Topic`
"""
if item_identifier is None:
raise ModelConstraintException(
self, 'The item identifier may not be None')
reference = item_identifier.to_external_form()
try:
topic = self.topic_constructs.get(
item_identifiers__address=reference)
except Topic.DoesNotExist:
try:
topic = self.topic_constructs.get(
subject_identifiers__address=reference)
except Topic.DoesNotExist:
topic = Topic(topic_map=self)
topic.save()
ii = ItemIdentifier(address=reference, containing_topic_map=self)
ii.save()
topic.item_identifiers.add(ii)
return topic
def create_topic_by_item_identifier(self, item_identifier):
"""Returns a `Topic` instance with the specified item identifier.
This method returns either an existing `Topic` or creates a
new `Topic` instance with the specified item identifier.
If a topic with the specified item identifier exists in the
topic map, that topic is returned. If a topic with a subject
identifier equal to the specified item identifier exists, the
specified item identifier is added to that topic and the topic
is returned. If neither a topic with the specified item
identifier nor with a subject identifier equal to the subject
identifier exists, a topic with the item identifier is
created.
:param item_identifier: the item identifier the topic should contain
:type item_identifier: `Locator`
:rtype: `Topic`
"""
if item_identifier is None:
raise ModelConstraintException(
self, 'The item identifier may not be None')
reference = item_identifier.to_external_form()
try:
topic = self.topic_constructs.get(
item_identifiers__address=reference)
except Topic.DoesNotExist:
try:
topic = self.topic_constructs.get(
subject_identifiers__address=reference)
except Topic.DoesNotExist:
topic = Topic(topic_map=self)
topic.save()
ii = ItemIdentifier(address=reference, containing_topic_map=self)
ii.save()
topic.item_identifiers.add(ii)
return topic
def create_topic (self, proxy=Topic):
"""Returns a `Topic` instance with an automatically generated
item identifier.
This method never returns an existing `Topic` but creates a
new one with an automatically generated item identifier.
Returns the newly created `Topic` instance with an automatically
generated item identifier.
:param proxy: Django proxy model class
:type proxy: class
:rtype: `Topic`
"""
topic = proxy(topic_map=self)
topic.save()
address = 'http://%s/tmapi/iid/auto/%d' % \
(Site.objects.get_current().domain, topic.id)
ii = ItemIdentifier(address=address, containing_topic_map=self)
ii.save()
topic.item_identifiers.add(ii)
return topic
def create_topic(self, proxy=Topic):
"""Returns a `Topic` instance with an automatically generated
item identifier.
This method never returns an existing `Topic` but creates a
new one with an automatically generated item identifier.
Returns the newly created `Topic` instance with an automatically
generated item identifier.
:param proxy: Django proxy model class
:type proxy: class
:rtype: `Topic`
"""
topic = proxy(topic_map=self)
topic.save()
address = 'http://%s/tmapi/iid/auto/%d' % \
(Site.objects.get_current().domain, topic.id)
ii = ItemIdentifier(address=address, containing_topic_map=self)
ii.save()
topic.item_identifiers.add(ii)
return topic