public class

AtomicStampedReference

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

Class Overview

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.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public AtomicStampedReference (V initialRef, int initialStamp)

Since: API Level 1

Creates a new AtomicStampedReference with the given initial values.

Parameters
initialRef the initial reference
initialStamp the initial stamp

Public Methods

public boolean attemptStamp (V expectedReference, int newStamp)

Since: API Level 1

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 the expected value of the reference
newStamp the new value for the stamp
Returns
  • true if successful

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

Since: API Level 1

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 the expected value of the reference
newReference the new value for the reference
expectedStamp the expected value of the stamp
newStamp the new value for the stamp
Returns
  • true if successful

public V get (int[] stampHolder)

Since: API Level 1

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

Parameters
stampHolder an array of size of at least one. On return, stampholder[0] will hold the value of the stamp.
Returns
  • the current value of the reference

public V getReference ()

Since: API Level 1

Returns the current value of the reference.

Returns
  • the current value of the reference

public int getStamp ()

Since: API Level 1

Returns the current value of the stamp.

Returns
  • the current value of the stamp

public void set (V newReference, int newStamp)

Since: API Level 1

Unconditionally sets the value of both the reference and stamp.

Parameters
newReference the new value for the reference
newStamp the new value for the stamp

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

Since: API Level 1

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 the expected value of the reference
newReference the new value for the reference
expectedStamp the expected value of the stamp
newStamp the new value for the stamp
Returns
  • true if successful