|Constructor and Description|
|Modifier and Type||Method and Description|
This is the default visit operation on a QueryTreeNode.
getNumSubstitutions, getSource, skipChildren, stopTraversal, visitChildrenFirst
public Visitable visit(Visitable node, QueryTreeNode parent) throws StandardException
Visitors will overload this method by implementing a version with a signature that matches a specific type of node. For example, if I want to do something special with aggregate nodes, then that Visitor will implement a visit(AggregateNode node) method which does the aggregate specific processing.
node- the node to process
parent- the parent of the node being visited, or, more generally, the node that contains a reference to the node being visited.
StandardException- may be throw an error as needed by the visitor (i.e. may be a normal error if a particular node is found, e.g. if checking a group by, we don't expect to find any ColumnReferences that aren't under an AggregateNode -- the easiest thing to do is just throw an error when we find the questionable node).