Adds validation and save callbacks for the association as specified by the
reflection.
For performance reasons, we don’t check whether to validate at
runtime. However the validation and callback methods are lazy and those
methods get created when they are invoked for the very first time. However,
this can change, for instance, when using nested attributes, which is
called after the association has been defined. Since we
don’t want the callbacks to get defined multiple times, there are
guards that check if the save or validation methods have already been
defined before actually defining them.
# File activerecord/lib/active_record/autosave_association.rb, line 155
def add_autosave_association_callbacks(reflection)
save_method = "autosave_associated_records_for_#{reflection.name}""autosave_associated_records_for_#{reflection.name}"
validation_method = "validate_associated_records_for_#{reflection.name}""validate_associated_records_for_#{reflection.name}"
collection = reflection.collection?
unless method_defined?(save_method)
if collection
before_save :before_save_collection_association
define_method(save_method) { save_collection_association(reflection) }
# Doesn't use after_save as that would save associations added in after_create/after_update twice
after_create save_method
after_update save_method
else
if reflection.macro == :has_one
define_method(save_method) { save_has_one_association(reflection) }
after_save save_method
else
define_method(save_method) { save_belongs_to_association(reflection) }
before_save save_method
end
end
end
if reflection.validate? && !method_defined?(validation_method)
method = (collection ? :validate_collection_association : :validate_single_association)
define_method(validation_method) { send(method, reflection) }
validate validation_method
end
end
