public function activate(ezcWorkflowExecution $execution, ezcWorkflowNode $activatedFrom = null, $threadId = 0)
{
$parentThreadId = $execution->getParentThreadId($threadId);
if (empty($this->state['threads'])) {
$this->state['threads'][] = $threadId;
parent::activate($execution, $activatedFrom, $parentThreadId);
}
}