StateVar (nflow-engine 8.0.0 API)

```
@Retention(RUNTIME)
@Target(PARAMETER)
public @interface StateVar
```
Used for state handler method parameters. Annotated parameters are automatically populated from the workflow instance variables and persisted after processing the state handler method.

Required Element Summary

Required Elements
Modifier and Type Required Element Description

String value
The name of the workflow instance variable.

Optional Element Summary

Optional Elements
Modifier and Type	Optional Element	Description
`boolean`	`instantiateIfNotExists`	Initializes the variable using default constructor (or zero value for primitive types) if the variable does not exist.
`boolean`	`readOnly`	Makes the variable readonly in the state handler method.

- Element Detail
  - value
```
String value
```
    The name of the workflow instance variable.
    
    Returns:
    
    The name of the variable.
- - readOnly
```
boolean readOnly
```
    Makes the variable readonly in the state handler method.
    
    Returns:
    
    True when variable should not be modified, false otherwise.
    
    Default:
    
    false
- - instantiateIfNotExists
```
boolean instantiateIfNotExists
```
    Initializes the variable using default constructor (or zero value for primitive types) if the variable does not exist. Used to ensure that the variable value is never null.
    
    Returns:
    
    True if non-existing variables should be initialized, false otherwise.
    
    Default:
    
    false