CommonRelSubExprRule (Apache Calcite API)

java.lang.Object
- org.apache.calcite.plan.RelOptRule
- - org.apache.calcite.plan.CommonRelSubExprRule

```
public abstract class CommonRelSubExprRule
extends RelOptRule
```
A CommonRelSubExprRule is an abstract base class for rules that are fired only on relational expressions that appear more than once in a query tree.

- Field Summary
  - Fields inherited from class org.apache.calcite.plan.RelOptRule
    description, operands, relBuilderFactory
- Constructor Summary
  
  Constructors
  Constructor Description
  
  CommonRelSubExprRule(RelOptRuleOperand operand)
  Creates a CommonRelSubExprRule.
- Method Summary
  - Methods inherited from class org.apache.calcite.plan.RelOptRule
    any, convert, convert, convertList, convertOperand, convertOperand, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, guessDescription, hashCode, matches, none, onMatch, operand, operand, operand, operand, operand, operandJ, operandJ, some, toString, unordered
  - Methods inherited from class java.lang.Object
    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - CommonRelSubExprRule
```
public CommonRelSubExprRule(RelOptRuleOperand operand)
```
    Creates a CommonRelSubExprRule.
    
    Parameters:
    
    operand - root operand, must not be null