/**
* Finds an aggregate.
*
* @param node Parse tree to search
* @return First aggregate function in parse tree, or null if not found
*/
public SqlNode findAgg(SqlNode node) {
try {
node.accept(this);
return null;
} catch (Util.FoundOne e) {
Util.swallow(e, null);
return (SqlNode) e.getNode();
}
}
/** Returns whether an array of expressions has any common sub-expressions. */
public static boolean containCommonExprs(RexNode[] exprs, boolean fail) {
final ExpressionNormalizer visitor = new ExpressionNormalizer(false);
for (int i = 0; i < exprs.length; i++) {
try {
exprs[i].accept(visitor);
} catch (ExpressionNormalizer.SubExprExistsException e) {
Util.swallow(e, null);
assert !fail;
}
}
return false;
}
/**
* Returns whether a given tree contains any {@link org.eigenbase.rex.RexFieldAccess} nodes.
*
* @param node a RexNode tree
*/
public static boolean containsFieldAccess(RexNode node) {
try {
RexVisitor<Void> visitor =
new RexVisitorImpl<Void>(true) {
public Void visitFieldAccess(RexFieldAccess fieldAccess) {
throw new Util.FoundOne(fieldAccess);
}
};
node.accept(visitor);
return false;
} catch (Util.FoundOne e) {
Util.swallow(e, null);
return true;
}
}
/**
* Returns whether a given tree contains any {link RexInputRef} nodes.
*
* @param node a RexNode tree
*/
public static boolean containsInputRef(RexNode node) {
try {
RexVisitor<Void> visitor =
new RexVisitorImpl<Void>(true) {
public Void visitInputRef(RexInputRef inputRef) {
throw new Util.FoundOne(inputRef);
}
};
node.accept(visitor);
return false;
} catch (Util.FoundOne e) {
Util.swallow(e, null);
return true;
}
}
/**
* Returns whether an array of expressions contains a forward reference. That is, if expression #i
* contains a {@link RexInputRef} referencing field i or greater.
*
* @param exprs Array of expressions
* @param inputRowType Input row type
* @param fail Whether to assert if there is a forward reference
* @return Whether there is a forward reference
*/
public static boolean containForwardRefs(
RexNode[] exprs, RelDataType inputRowType, boolean fail) {
final ForwardRefFinder visitor = new ForwardRefFinder(inputRowType);
for (int i = 0; i < exprs.length; i++) {
RexNode expr = exprs[i];
visitor.setLimit(i); // field cannot refer to self or later field
try {
expr.accept(visitor);
} catch (ForwardRefFinder.IllegalForwardRefException e) {
Util.swallow(e, null);
assert !fail : "illegal forward reference in " + expr;
return true;
}
}
return false;
}
/**
* Returns whether a given node contains a RexCall with a specified operator
*
* @param operator to look for
* @param node a RexNode tree
*/
public static RexCall findOperatorCall(final SqlOperator operator, RexNode node) {
try {
RexVisitor<Void> visitor =
new RexVisitorImpl<Void>(true) {
public Void visitCall(RexCall call) {
if (call.getOperator().equals(operator)) {
throw new Util.FoundOne(call);
}
return super.visitCall(call);
}
};
node.accept(visitor);
return null;
} catch (Util.FoundOne e) {
Util.swallow(e, null);
return (RexCall) e.getNode();
}
}