/**
* Builds filter expression
*
* @param Filter $filter The filter object
* @param string &$e The filter expression
*
* @return string
*/
private function _buildFilterExpressionRec($filter, &$e)
{
if (is_null($filter)) {
return;
}
if ($filter instanceof PropertyNameFilter) {
$e .= $filter->getPropertyName();
} else {
if ($filter instanceof ConstantFilter) {
$value = $filter->getValue();
// If the value is null we just append null regardless of the edmType.
if (is_null($value)) {
$e .= 'null';
} else {
$type = $filter->getEdmType();
$e .= EdmType::serializeQueryValue($type, $value);
}
} else {
if ($filter instanceof UnaryFilter) {
$e .= $filter->getOperator();
$e .= '(';
$this->_buildFilterExpressionRec($filter->getOperand(), $e);
$e .= ')';
} else {
if ($filter instanceof Filters\BinaryFilter) {
$e .= '(';
$this->_buildFilterExpressionRec($filter->getLeft(), $e);
$e .= ' ';
$e .= $filter->getOperator();
$e .= ' ';
$this->_buildFilterExpressionRec($filter->getRight(), $e);
$e .= ')';
} else {
if ($filter instanceof QueryStringFilter) {
$e .= $filter->getQueryString();
}
}
}
}
}
return $e;
}
