added in API level 1

AtomicStampedReference

public class AtomicStampedReference
extends Object

java.lang.Object
   ↳ java.util.concurrent.atomic.AtomicStampedReference<V>


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(V initialRef, int initialStamp)

Creates a new AtomicStampedReference with the given initial values.

Public methods

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.

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.

V get(int[] stampHolder)

Returns the current values of both the reference and the stamp.

V getReference()

Returns the current value of the reference.

int getStamp()

Returns the current value of the stamp.

void set(V newReference, int newStamp)

Unconditionally sets the value of both the reference and stamp.

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.

Inherited methods

Public constructors

AtomicStampedReference

added in API level 1
public AtomicStampedReference (V initialRef, 
                int initialStamp)

Creates a new AtomicStampedReference with the given initial values.

Parameters
initialRef V: the initial reference

initialStamp int: the initial stamp

Public methods

attemptStamp

added in API level 1
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.

Parameters
expectedReference V: the expected value of the reference

newStamp int: the new value for the stamp

Returns
boolean true if successful

compareAndSet

added in API level 1
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.

Parameters
expectedReference V: the expected value of the reference

newReference V: the new value for the reference

expectedStamp int: the expected value of the stamp

newStamp int: the new value for the stamp

Returns
boolean true if successful

get

added in API level 1
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); .

Parameters
stampHolder int: an array of size of at least one. On return, stampHolder[0] will hold the value of the stamp.

Returns
V the current value of the reference

getReference

added in API level 1
public V getReference ()

Returns the current value of the reference.

Returns
V the current value of the reference

getStamp

added in API level 1
public int getStamp ()

Returns the current value of the stamp.

Returns
int the current value of the stamp

set

added in API level 1
public void set (V newReference, 
                int newStamp)

Unconditionally sets the value of both the reference and stamp.

Parameters
newReference V: the new value for the reference

newStamp int: the new value for the stamp

weakCompareAndSet

added in API level 1
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.

May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to compareAndSet.

Parameters
expectedReference V: the expected value of the reference

newReference V: the new value for the reference

expectedStamp int: the expected value of the stamp

newStamp int: the new value for the stamp

Returns
boolean true if successful