RelVisitor (Apache Calcite API)

java.lang.Object
- org.apache.calcite.rel.RelVisitor

Direct Known Subclasses:

Interpreter.CompilerImpl, RelOptUtil.VariableSetVisitor, RelStructuredTypeFlattener.RewriteRelVisitor, RelTraitPropagationVisitor, TableAccessMap.TableRelVisitor
```
public abstract class RelVisitor
extends java.lang.Object
```
A RelVisitor is a Visitor role in the visitor pattern and visits RelNode objects as the role of Element. Other components in the pattern: RelNode.childrenAccept(RelVisitor).

Field Summary

Fields
Modifier and Type Field Description

private RelNode root

Constructor Summary

Constructors
Constructor Description

RelVisitor()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`RelNode`	`go(RelNode p)`	Starts an iteration.
`void`	`replaceRoot(RelNode node)`	Replaces the root node of this traversal.
`void`	`visit(RelNode node, int ordinal, RelNode parent)`	Visits a node during a traversal.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - root
```
private RelNode root
```
- Constructor Detail
  - RelVisitor
```
public RelVisitor()
```
- Method Detail
  - visit
```
public void visit(RelNode node,
                  int ordinal,
                  RelNode parent)
```
    Visits a node during a traversal.
    
    Parameters:
    
    node - Node to visit
    
    ordinal - Ordinal of node within its parent
    
    parent - Parent of the node, or null if it is the root of the traversal
  - replaceRoot
```
public void replaceRoot(RelNode node)
```
    Replaces the root node of this traversal.
    
    Parameters:
    
    node - The new root node
  - go
```
public RelNode go(RelNode p)
```
    Starts an iteration.