ExpressionFactory.NullExpression (JOSM)

java.lang.Object
- org.openstreetmap.josm.gui.mappaint.mapcss.ExpressionFactory.NullExpression

All Implemented Interfaces:

Expression

Enclosing class:

ExpressionFactory
```
public static class ExpressionFactory.NullExpression
extends java.lang.Object
implements Expression
```
Expression that always evaluates to null.

- Field Summary
  
  Fields
  Modifier and Type Field Description
  
  static ExpressionFactory.NullExpression INSTANCE
  The unique instance.
- Constructor Summary
  
  Constructors
  Constructor Description
  
  NullExpression()
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  java.lang.Object evaluate(Environment env)
  Evaluate this expression.
  - Methods inherited from class java.lang.Object
    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - INSTANCE
```
public static final ExpressionFactory.NullExpression INSTANCE
```
    The unique instance.
- Constructor Detail
  - NullExpression
```
public NullExpression()
```
- Method Detail
  - evaluate
```
public java.lang.Object evaluate(Environment env)
```
    Description copied from interface: Expression
    
    Evaluate this expression.
    
    Specified by:
    
    evaluate in interface Expression
    
    Parameters:
    
    env - The environment
    
    Returns:
    
    the result of the evaluation, can be a List, String or any primitive type or wrapper classes of a primitive type.