Base::getFilterValue

public function getFilterValue($key, $acceptedListModificators = '=<>!@%')
{
	$filter = $this->getFilter();

	$value = null;
	foreach ($filter as $keyId => $val)
	{
		$testKey = trim($keyId, $acceptedListModificators);
		if ($testKey == $key)
		{
			$value = $val;
			break;
		}
	}

	return $value;
}