* A list of state IDs to get. If NULL then all states will be returned.
*
* @return \Drupal\workflows\StateInterface[]
- * An array of workflow states.
+ * An array of workflow states, keyed by state IDs.
*
* @throws \InvalidArgumentException
* Thrown if $state_ids contains a state ID that does not exist.
* @param $state_id
* The state to get transitions for.
* @param string $direction
- * (optional) The direction of the transition. Defaults to 'from'. Possible
- * values are: 'from' and 'to'.
+ * (optional) The direction of the transition, defaults to
+ * TransitionInterface::DIRECTION_FROM. Possible values are:
+ * TransitionInterface::DIRECTION_FROM or TransitionInterface::DIRECTION_TO.
*
* @return array
* The transition IDs for a state for the provided direction.
+ *
+ * @see \Drupal\workflows\TransitionInterface::DIRECTION_FROM
+ * @see \Drupal\workflows\TransitionInterface::DIRECTION_TO
*/
- public function getTransitionsForState($state_id, $direction = 'from');
+ public function getTransitionsForState($state_id, $direction = TransitionInterface::DIRECTION_FROM);
/**
* Gets a transition from state to state.