Attribute (milky-common 1.0.13 API)

Type Parameters:

T - the type of the value it holds.
```
public interface Attribute<T>
```
An attribute which allows to store a value reference. It may be updated atomically and so is thread-safe.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`compareAndSet(T oldValue, T newValue)`	Atomically sets the value to the given updated value if the current value == the expected value.
`T`	`get()`	Returns the current value, which may be `null`
`T`	`getAndSet(T value)`	Atomically sets to the given value and returns the old value which may be `null` if non was set before.
`AttributeKey<T>`	`key()`	Returns the key of this attribute.
`void`	`set(T value)`	Sets the value
`T`	`setIfAbsent(T value)`	Atomically sets to the given value if this `Attribute`'s value is `null`.

- Method Detail
  - key
```
AttributeKey<T> key()
```
    Returns the key of this attribute.
  - get
```
T get()
```
    Returns the current value, which may be null
  - set
```
void set(T value)
```
    Sets the value
  - getAndSet
```
T getAndSet(T value)
```
    Atomically sets to the given value and returns the old value which may be null if non was set before.
  - setIfAbsent
```
T setIfAbsent(T value)
```
    Atomically sets to the given value if this Attribute's value is null. If it was not possible to set the value as it contains a value it will just return the current value.
  - compareAndSet
```
boolean compareAndSet(T oldValue,
                      T newValue)
```
    Atomically sets the value to the given updated value if the current value == the expected value. If it the set was successful it returns true otherwise false.