java.lang.Object
- org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractStateObject
- - org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractEncapsulatedExpressionStateObject
  - - org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractDoubleEncapsulatedExpressionStateObject
    - - org.eclipse.persistence.jpa.jpql.tools.model.query.NullIfExpressionStateObject

All Implemented Interfaces:

StateObject
```
public class NullIfExpressionStateObject
extends AbstractDoubleEncapsulatedExpressionStateObject
```
NULLIF returns the first expression if the two expressions are not equal. If the expressions are equal, NULLIF returns a null value of the type of the first expression.
NULLIF is equivalent to a searched CASE expression in which the two expressions are equal and the resulting expression is NULL.
Returns the same type as the first expression.
BNF: nullif_expression::= NULLIF(scalar_expression, scalar_expression)

Since:

2.4

Version:

2.4

Author:

Pascal Filion

See Also:

NullIfExpression

Field Summary
- Fields inherited from class org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractDoubleEncapsulatedExpressionStateObject
  FIRST_STATE_OBJECT_PROPERTY, SECOND_STATE_OBJECT_PROPERTY

Constructor Summary

Constructors
Constructor	Description
`NullIfExpressionStateObject(StateObject parent)`	Creates a new `NullIfExpressionStateObject`.
`NullIfExpressionStateObject(StateObject parent, String firstJpqlFragment, String secondJpqlFragment)`	Creates a new `NullIfExpressionStateObject`.
`NullIfExpressionStateObject(StateObject parent, StateObject firstStateObject, StateObject secondStateObject)`	Creates a new `NullIfExpressionStateObject`.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`accept(StateObjectVisitor visitor)`	Visits this `StateObject` by the given `visitor`.
`NullIfExpression`	`getExpression()`	Returns the actual parsed object if this `StateObject` representation of the JPQL query was created by parsing an existing JPQL query.
`String`	`getIdentifier()`	Returns the JPQL identifier of the expression represented by this `AbstractSingleEncapsulatedExpressionStateObject`.
`void`	`setExpression(NullIfExpression expression)`	Keeps a reference of the `parsed object` object, which should only be done when this object is instantiated during the conversion of a parsed JPQL query into `StateObjects`.

Methods inherited from class org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractDoubleEncapsulatedExpressionStateObject
getFirst, getSecond, hasFirst, hasSecond, isEquivalent, parseFirst, parseSecond, setFirst, setSecond

Methods inherited from class org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractStateObject
addPropertyChangeListener, children, decorate, equals, findIdentificationVariable, getDeclaration, getDecorator, getGrammar, getManagedTypeProvider, getParent, getQueryBuilder, getRoot, getType, getType, getTypeHelper, getTypeRepository, hashCode, isDecorated, removePropertyChangeListener, setExpression, setParent, toString, toString, toText

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

- Constructor Detail
  - NullIfExpressionStateObject
```
public NullIfExpressionStateObject(StateObject parent)
```
    Creates a new NullIfExpressionStateObject.
    
    Parameters:
    
    parent - The parent of this state object, which cannot be null
    
    Throws:
    
    NullPointerException - The given parent cannot be null
  - NullIfExpressionStateObject
```
public NullIfExpressionStateObject(StateObject parent,
                                   StateObject firstStateObject,
                                   StateObject secondStateObject)
```
    Creates a new NullIfExpressionStateObject.
    
    Parameters:
    
    parent - The parent of this state object, which cannot be null
    
    firstStateObject - The StateObject representing the first expression
    
    secondStateObject - The StateObject representing the second expression
    
    Throws:
    
    NullPointerException - The given parent cannot be null
  - NullIfExpressionStateObject
```
public NullIfExpressionStateObject(StateObject parent,
                                   String firstJpqlFragment,
                                   String secondJpqlFragment)
```
    Creates a new NullIfExpressionStateObject.
    
    Parameters:
    
    parent - The parent of this state object, which cannot be null
    
    firstJpqlFragment - The string representation of the first encapsulated expression to parse and to convert into a StateObject representation
    
    secondJpqlFragment - The string representation of the second encapsulated expression to parse and to convert into a StateObject representation
    
    Throws:
    
    NullPointerException - The given parent cannot be null
- Method Detail
  - accept
```
public void accept(StateObjectVisitor visitor)
```
    Visits this StateObject by the given visitor.
    
    Parameters:
    
    visitor - The visitor to visit this object
  - getExpression
```
public NullIfExpression getExpression()
```
    Returns the actual parsed object if this StateObject representation of the JPQL query was created by parsing an existing JPQL query.
    
    Specified by:
    
    getExpression in interface StateObject
    
    Overrides:
    
    getExpression in class AbstractDoubleEncapsulatedExpressionStateObject
    
    Returns:
    
    The parsed object when a JPQL query is parsed and converted into a StateObject or null when the JPQL query is manually created (i.e. not from a string)
  - getIdentifier
```
public String getIdentifier()
```
    Returns the JPQL identifier of the expression represented by this AbstractSingleEncapsulatedExpressionStateObject.
    
    Specified by:
    
    getIdentifier in class AbstractEncapsulatedExpressionStateObject
    
    Returns:
    
    The JPQL identifier that is shown before the left parenthesis
  - setExpression
```
public void setExpression(NullIfExpression expression)
```
    Keeps a reference of the parsed object object, which should only be done when this object is instantiated during the conversion of a parsed JPQL query into StateObjects.
    
    Parameters:
    
    expression - The parsed object representing a NULLIF expression

Class NullIfExpressionStateObject

Field Summary

Fields inherited from class org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractDoubleEncapsulatedExpressionStateObject

Constructor Summary

Method Summary

Methods inherited from class org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractDoubleEncapsulatedExpressionStateObject

Methods inherited from class org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractStateObject

Methods inherited from class java.lang.Object

Constructor Detail

NullIfExpressionStateObject

NullIfExpressionStateObject

NullIfExpressionStateObject

Method Detail

accept

getExpression

getIdentifier

setExpression