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Added in API level 1

AtomicMarkableReference

public class AtomicMarkableReference
extends Object

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


An AtomicMarkableReference maintains an object reference along with a mark bit, that can be updated atomically.

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

Summary

Public constructors

AtomicMarkableReference(V initialRef, boolean initialMark)

Creates a new AtomicMarkableReference with the given initial values.

Public methods

boolean attemptMark(V expectedReference, boolean newMark)

Atomically sets the value of the mark to the given update value if the current reference is == to the expected reference.

boolean compareAndSet(V expectedReference, V newReference, boolean expectedMark, boolean newMark)

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

V get(boolean[] markHolder)

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

V getReference()

Returns the current value of the reference.

boolean isMarked()

Returns the current value of the mark.

void set(V newReference, boolean newMark)

Unconditionally sets the value of both the reference and mark.

boolean weakCompareAndSet(V expectedReference, V newReference, boolean expectedMark, boolean newMark)

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

Inherited methods

From class java.lang.Object

Public constructors

AtomicMarkableReference

Added in API level 1
AtomicMarkableReference (V initialRef, 
                boolean initialMark)

Creates a new AtomicMarkableReference with the given initial values.

Parameters
initialRef V: the initial reference
initialMark boolean: the initial mark

Public methods

attemptMark

Added in API level 1
boolean attemptMark (V expectedReference, 
                boolean newMark)

Atomically sets the value of the mark 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
newMark boolean: the new value for the mark
Returns
boolean true if successful

compareAndSet

Added in API level 1
boolean compareAndSet (V expectedReference, 
                V newReference, 
                boolean expectedMark, 
                boolean newMark)

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

Parameters
expectedReference V: the expected value of the reference
newReference V: the new value for the reference
expectedMark boolean: the expected value of the mark
newMark boolean: the new value for the mark
Returns
boolean true if successful

get

Added in API level 1
V get (boolean[] markHolder)

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

Parameters
markHolder boolean: an array of size of at least one. On return, markHolder[0] will hold the value of the mark.
Returns
V the current value of the reference

getReference

Added in API level 1
V getReference ()

Returns the current value of the reference.

Returns
V the current value of the reference

isMarked

Added in API level 1
boolean isMarked ()

Returns the current value of the mark.

Returns
boolean the current value of the mark

set

Added in API level 1
void set (V newReference, 
                boolean newMark)

Unconditionally sets the value of both the reference and mark.

Parameters
newReference V: the new value for the reference
newMark boolean: the new value for the mark

weakCompareAndSet

Added in API level 1
boolean weakCompareAndSet (V expectedReference, 
                V newReference, 
                boolean expectedMark, 
                boolean newMark)

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

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
expectedMark boolean: the expected value of the mark
newMark boolean: the new value for the mark
Returns
boolean true if successful

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