Attribute.OldValue (AO Lang 5.2.0 API)

java.lang.Object
- com.aoapps.lang.attribute.Attribute.OldValue

All Implemented Interfaces:

AutoCloseable

Enclosing class:

Attribute<C,T>
```
public abstract static class Attribute.OldValue
extends Object
implements AutoCloseable
```
A backup value from before attribute initialization, which must be closed to restore the old value. This is best used in try-with-resources.

Constructor Summary

Constructors
Modifier Constructor Description

protected OldValue(Object oldValue)

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`abstract void`	`close()`	Restores the old value of the attribute.
`Object`	`getOldValue()`	Gets the old value of the attribute, which will be restored on `close()`.

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

- Constructor Detail
  - OldValue
```
protected OldValue(Object oldValue)
```
- Method Detail
  - getOldValue
```
public Object getOldValue()
```
    Gets the old value of the attribute, which will be restored on close(). This can be of any type, since this is used to backup arbitrary values before new scopes.
    
    Returns:
    
    the old attribute value or null when none
  - close
```
public abstract void close()
```
    Restores the old value of the attribute.
    
    Specified by:
    
    close in interface AutoCloseable