RightsSetter::appendOne

private function appendOne(array $right)
{
	$hadOppositeRight = false;
	foreach($this->getCurrentRightsOnObject() as $currentRight)
	{
		if($this->isEqual($currentRight, $right))
		{
			return true;
		}
		if($this->isOpposite($currentRight, $right))
		{
			$hadOppositeRight = true;
			RightTable::delete($currentRight['ID']);
		}
	}
	unset($currentRight);

	return empty($right['NEGATIVE'])?
		$this->appendOnePositive($right, $hadOppositeRight) : $this->appendOneNegative($right, $hadOppositeRight);
}