def add_attribute_lookup(self, key):
"""Adds a fast-lookup index for the component/attribute key path.
This also causes the newly-created lookup table to rebuild its index.
Depending on how many entities already exist, building the index could
take a couple of seconds.
"""
# Don't add the same one twice.
if self.lookup_tables.get(key, None):
return
attribute = entity_module.Entity.reflect_attribute(key)
if not isinstance(attribute, entity_component.Field):
logging.info(
("Can't create a lookup for %s, because it's not a simple "
"field."), attribute)
return
logging.debug("Creating a lookup table for %s", key)
component, _ = key.split("/")
lookup_table = entity_lookup.AttributeLookupTable(attribute=key,
entity_manager=self)
# Only use the entities that actually have the component to build the
# index.
lookup_table.update_index(
self.find(expression.ComponentLiteral(component), complete=False))
self.lookup_tables[key] = lookup_table
def find_by_component(self, component, complete=True):
"""Finds all entities that have the component.
Arguments:
complete: If True, will attempt to collect the component.
"""
query = entity_query.Query(expression.ComponentLiteral(component))
if complete:
self.collect_for(query)
return list(self.lookup_tables["components"].lookup(component))
def testHasComponent(self):
query = "has component Process"
expected = expression.ComponentLiteral("Process")
self.assertQueryMatches(query, expected)
def FlattenComponentLiteral(*args, **kwargs):
if not isinstance(args[0], expression.Binding):
raise ValueError(
"'has component' must be followed by a component. Got %s." %
(args[0]))
return expression.ComponentLiteral(args[0].value, **kwargs)