public function getPossibleTargets()
    {
        if (is_null($this->_possibleTargets)) {
            $this->_possibleTargets = [];

            if ($this->canEndRelation()) {
                $this->_possibleTargets[] = 'end_relationship';
            }

            if ($this->canDeleteRelation()) {
                $this->_possibleTargets[] = 'delete_relationship';
            }

            if ($this->canArchiveObject()) {
                if ($this->object->archived) {
                    $this->_possibleTargets[] = 'unarchive_object';
                } else {
                    $this->_possibleTargets[] = 'archive_object';
                }
            }

            if ($this->canDeleteObject()) {
                $this->_possibleTargets[] = 'delete_object';
            }
        }

        return $this->_possibleTargets;
    }