# AtomicStampedReference

Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  
Summary:[Ctors](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#pubctors)\|[Methods](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#pubmethods)\|[Inherited Methods](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#inhmethods)  

# AtomicStampedReference

`
public


class
AtomicStampedReference
`  
`

extends `[Object](https://developer.android.com/reference/java/lang/Object)`


``


`

|---|---------------------------------------------------------|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | java.util.concurrent.atomic.AtomicStampedReference\<V\> |

<br />

*** ** * ** ***

An`AtomicStampedReference`maintains an object reference along with an integer "stamp", that can be updated atomically.

Implementation note: This implementation maintains stamped references by creating internal objects representing "boxed" \[reference, integer\] pairs.

## Summary

|                                                                                                                      ### Public constructors                                                                                                                       ||
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---|
| ` `[AtomicStampedReference](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#AtomicStampedReference(V,%20int))`(V initialRef, int initialStamp) ` Creates a new`AtomicStampedReference`with the given initial values. |

|                                                                                                                                                                                                                 ### Public methods                                                                                                                                                                                                                  ||
|------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| ` boolean` | ` `[attemptStamp](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#attemptStamp(V,%20int))`(V expectedReference, int newStamp) ` Atomically sets the value of the stamp to the given update value if the current reference is`==`to the expected reference.                                                                                                                                   |
| ` boolean` | ` `[compareAndSet](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#compareAndSet(V,%20V,%20int,%20int))`(V expectedReference, V newReference, int expectedStamp, int newStamp) ` Atomically sets the value of both the reference and stamp to the given update values if the current reference is`==`to the expected reference and the current stamp is equal to the expected stamp.         |
| ` V`       | ` `[get](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#get(int[]))`(int[] stampHolder) ` Returns the current values of both the reference and the stamp.                                                                                                                                                                                                                                   |
| ` V`       | ` `[getReference](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#getReference())`() ` Returns the current value of the reference.                                                                                                                                                                                                                                                           |
| ` int`     | ` `[getStamp](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#getStamp())`() ` Returns the current value of the stamp.                                                                                                                                                                                                                                                                       |
| ` void`    | ` `[set](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#set(V,%20int))`(V newReference, int newStamp) ` Unconditionally sets the value of both the reference and stamp.                                                                                                                                                                                                                     |
| ` boolean` | ` `[weakCompareAndSet](https://developer.android.com/reference/java/util/concurrent/atomic/AtomicStampedReference#weakCompareAndSet(V,%20V,%20int,%20int))`(V expectedReference, V newReference, int expectedStamp, int newStamp) ` Atomically sets the value of both the reference and stamp to the given update values if the current reference is`==`to the expected reference and the current stamp is equal to the expected stamp. |

| ### Inherited methods |
|-----------------------|---|
| From class` `[java.lang.Object](https://developer.android.com/reference/java/lang/Object)` ` |--------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` `[Object](https://developer.android.com/reference/java/lang/Object)          | ` `[clone](https://developer.android.com/reference/java/lang/Object#clone())`() ` Creates and returns a copy of this object.                                                                                                                                                      | | ` boolean`                                                                     | ` `[equals](https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object))`(`[Object](https://developer.android.com/reference/java/lang/Object)` obj) ` Indicates whether some other object is "equal to" this one.                                           | | ` void`                                                                        | ` `[finalize](https://developer.android.com/reference/java/lang/Object#finalize())`() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.                                                          | | ` final `[Class](https://developer.android.com/reference/java/lang/Class)`<?>` | ` `[getClass](https://developer.android.com/reference/java/lang/Object#getClass())`() ` Returns the runtime class of this`Object`.                                                                                                                                                | | ` int`                                                                         | ` `[hashCode](https://developer.android.com/reference/java/lang/Object#hashCode())`() ` Returns a hash code value for the object.                                                                                                                                                 | | ` final void`                                                                  | ` `[notify](https://developer.android.com/reference/java/lang/Object#notify())`() ` Wakes up a single thread that is waiting on this object's monitor.                                                                                                                            | | ` final void`                                                                  | ` `[notifyAll](https://developer.android.com/reference/java/lang/Object#notifyAll())`() ` Wakes up all threads that are waiting on this object's monitor.                                                                                                                         | | ` `[String](https://developer.android.com/reference/java/lang/String)          | ` `[toString](https://developer.android.com/reference/java/lang/Object#toString())`() ` Returns a string representation of the object.                                                                                                                                            | | ` final void`                                                                  | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait(long,%20int))`(long timeoutMillis, int nanos) ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*, or until a certain amount of real time has elapsed. | | ` final void`                                                                  | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait(long))`(long timeoutMillis) ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*, or until a certain amount of real time has elapsed.                   | | ` final void`                                                                  | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait())`() ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*.                                                                                             | ||

## Public constructors

### AtomicStampedReference

Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public AtomicStampedReference (V initialRef, 
                int initialStamp)
```

Creates a new`AtomicStampedReference`with the given initial values.

<br />

|                    Parameters                     ||
|----------------|-----------------------------------|
| `initialRef`   | `V`: the initial reference <br /> |
| `initialStamp` | `int`: the initial stamp <br />   |

## Public methods

### attemptStamp

Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public boolean attemptStamp (V expectedReference, 
                int newStamp)
```

Atomically sets the value of the stamp to the given update value if the current reference is`==`to the expected reference. Any given invocation of this operation may fail (return`false`) spuriously, but repeated invocation when the current value holds the expected value and no other thread is also attempting to set the value will eventually succeed.

<br />

|                              Parameters                              ||
|---------------------|-------------------------------------------------|
| `expectedReference` | `V`: the expected value of the reference <br /> |
| `newStamp`          | `int`: the new value for the stamp <br />       |

|                Returns                ||
|-----------|----------------------------|
| `boolean` | `true`if successful <br /> |

### compareAndSet

Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public boolean compareAndSet (V expectedReference, 
                V newReference, 
                int expectedStamp, 
                int newStamp)
```

Atomically sets the value of both the reference and stamp to the given update values if the current reference is`==`to the expected reference and the current stamp is equal to the expected stamp.

<br />

|                              Parameters                              ||
|---------------------|-------------------------------------------------|
| `expectedReference` | `V`: the expected value of the reference <br /> |
| `newReference`      | `V`: the new value for the reference <br />     |
| `expectedStamp`     | `int`: the expected value of the stamp <br />   |
| `newStamp`          | `int`: the new value for the stamp <br />       |

|                Returns                ||
|-----------|----------------------------|
| `boolean` | `true`if successful <br /> |

### get

Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public V get (int[] stampHolder)
```

Returns the current values of both the reference and the stamp. Typical usage is`int[1] holder; ref = v.get(holder); `.

<br />

|                                                         Parameters                                                         ||
|---------------|-------------------------------------------------------------------------------------------------------------|
| `stampHolder` | `int`: an array of size of at least one. On return,`stampHolder[0]`will hold the value of the stamp. <br /> |

|                    Returns                     ||
|-----|-------------------------------------------|
| `V` | the current value of the reference <br /> |

### getReference

Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public V getReference ()
```

Returns the current value of the reference.

<br />

|                    Returns                     ||
|-----|-------------------------------------------|
| `V` | the current value of the reference <br /> |

### getStamp

Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public int getStamp ()
```

Returns the current value of the stamp.

<br />

|                   Returns                    ||
|-------|---------------------------------------|
| `int` | the current value of the stamp <br /> |

### set

Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public void set (V newReference, 
                int newStamp)
```

Unconditionally sets the value of both the reference and stamp.

<br />

|                         Parameters                          ||
|----------------|---------------------------------------------|
| `newReference` | `V`: the new value for the reference <br /> |
| `newStamp`     | `int`: the new value for the stamp <br />   |

### weakCompareAndSet

Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  

```
public boolean weakCompareAndSet (V expectedReference, 
                V newReference, 
                int expectedStamp, 
                int newStamp)
```

Atomically sets the value of both the reference and stamp to the given update values if the current reference is`==`to the expected reference and the current stamp is equal to the expected stamp. This operation may fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to`compareAndSet`.

<br />

|                              Parameters                              ||
|---------------------|-------------------------------------------------|
| `expectedReference` | `V`: the expected value of the reference <br /> |
| `newReference`      | `V`: the new value for the reference <br />     |
| `expectedStamp`     | `int`: the expected value of the stamp <br />   |
| `newStamp`          | `int`: the new value for the stamp <br />       |

|                Returns                ||
|-----------|----------------------------|
| `boolean` | `true`if successful <br /> |