IsNullExpNode (LinuxForHealth FHIR Server)

java.lang.Object
- org.linuxforhealth.fhir.database.utils.query.node.OperatorNode
- - org.linuxforhealth.fhir.database.utils.query.node.UnaryExpNode
  - - org.linuxforhealth.fhir.database.utils.query.node.IsNullExpNode

All Implemented Interfaces:

ExpNode
```
public class IsNullExpNode
extends UnaryExpNode
```
Represents IS NULL in a SQL expression

Constructor Summary

Constructors
Constructor Description

IsNullExpNode()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`precedence()`	Precedence of this expression node.
`<T> T`	`visit(ExpNodeVisitor<T> visitor)`	Generic evaluation visitor

Methods inherited from class org.linuxforhealth.fhir.database.utils.query.node.UnaryExpNode
getExpr, popOperands, setExpr, toString

Methods inherited from class org.linuxforhealth.fhir.database.utils.query.node.OperatorNode
isOperator

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

Methods inherited from interface org.linuxforhealth.fhir.database.utils.query.node.ExpNode
isLeftParen, isOperand, isRightParen

- Constructor Detail
  - IsNullExpNode
```
public IsNullExpNode()
```
- Method Detail
  - visit
```
public <T> T visit(ExpNodeVisitor<T> visitor)
```
    Description copied from interface: ExpNode
    
    Generic evaluation visitor
    
    Returns:
  - precedence
```
public int precedence()
```
    Description copied from interface: ExpNode
    
    Precedence of this expression node. Used to parse the expression into the correct tree. We use 0 to represent the highest precedence
    
    Returns: