/*
* returns true if an expression was found in tupleSchema true means no need
* to call parent, somthing added to stack It has side effects - putting on
* exprStack
*/
private <T extends Expression> boolean isRecognized(T expr) {
// expr is changed in place, so that it does not contain synonims
final int position = _nt.indexOf(_tupleSchema, expr);
if (position != ParserUtil.NOT_FOUND) {
// we found an expression already in the tuple schema
final Type tc = _nt.getType(_tupleSchema, expr);
final ValueExpression ve = new ColumnReference(tc, position, ParserUtil.getStringExpr(expr));
pushToExprStack(ve);
return true;
} else return false;
}
/*
* only getColumnIndex method invocation is different than in parent
*/
@Override
public void visit(Column column) {
// extract the position (index) of the required column
// column might be changed, due to the synonym effect
final int position = _nt.getColumnIndex(_tupleSchema, column);
// extract type for the column
// TypeConversion tc = _nt.getType(_tupleSchema, column);
// TODO: Due to the fact that Project prepares columns for FinalAgg on
// the last component
// and that for SUM or COUNT this method is not invoked (recognize is
// true),
// but only for GroupByProjections as the top level method.
// That is, we can safely assume StringConversion method.
// Permanent fix is to create StringConversion over overallAggregation.
final Type tc = _sc;
final ValueExpression ve = new ColumnReference(tc, position, ParserUtil.getStringExpr(column));
pushToExprStack(ve);
}