private function _addInstanceDefinition(__InstanceDefinition &$instance_definition) { if ($instance_definition->validate()) { $instance_id = $instance_definition->getId(); if (!key_exists($instance_id, $this->_instance_definitions)) { $this->_instance_definitions[__InstanceDefinition::SCOPE_ALL][$instance_id] =& $instance_definition; $this->_instance_definitions[$instance_definition->getScope()][$instance_id] =& $instance_definition; } else { throw new __ConfigurationException('Double definition of instance "' . $instance_id . '"'); } } }