private void addResult(RexNode exp) {
// Cast of literal can't be reduced, so skip those (otherwise we'd
// go into an infinite loop as we add them back).
if (exp.getKind() == RexKind.Cast) {
RexCall cast = (RexCall) exp;
RexNode operand = cast.getOperands()[0];
if (operand instanceof RexLiteral) {
return;
}
}
constExprs.add(exp);
// In the case where the expression corresponds to a UDR argument,
// we need to preserve casts. Note that this only applies to
// the topmost argument, not expressions nested within the UDR
// call.
//
// REVIEW zfong 6/13/08 - Are there other expressions where we
// also need to preserve casts?
if (parentCallTypeStack.isEmpty()) {
addCasts.add(false);
} else {
addCasts.add(
parentCallTypeStack.get(parentCallTypeStack.size() - 1)
instanceof FarragoUserDefinedRoutine);
}
}
/**
* Returns whether a node represents the NULL value or a series of nested CAST(NULL as <TYPE>)
* calls<br>
* For Example:<br>
* isNull(CAST(CAST(NULL as INTEGER) AS VARCHAR(1))) returns true
*/
public static boolean isNull(RexNode node) {
/* Checks to see if the RexNode is null */
return RexLiteral.isNullLiteral(node)
|| ((node.getKind() == RexKind.Cast) && isNull(((RexCall) node).operands[0]));
}