public class AtomicMarkableReference
extends java.lang.Object
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.
Constructor and Description |
---|
AtomicMarkableReference(java.lang.Object initialRef,
boolean initialMark)
Creates a new
AtomicMarkableReference with the given
initial values. |
Modifier and Type | Method and Description |
---|---|
boolean |
attemptMark(java.lang.Object 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(java.lang.Object expectedReference,
java.lang.Object 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. |
java.lang.Object |
get(boolean[] markHolder)
Returns the current values of both the reference and the mark.
|
java.lang.Object |
getReference()
Returns the current value of the reference.
|
boolean |
isMarked()
Returns the current value of the mark.
|
void |
set(java.lang.Object newReference,
boolean newMark)
Unconditionally sets the value of both the reference and mark.
|
boolean |
weakCompareAndSet(java.lang.Object expectedReference,
java.lang.Object 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. |
public AtomicMarkableReference(java.lang.Object initialRef, boolean initialMark)
AtomicMarkableReference
with the given
initial values.initialRef
- the initial referenceinitialMark
- the initial markpublic java.lang.Object getReference()
public boolean isMarked()
public java.lang.Object get(boolean[] markHolder)
boolean[1] holder; ref = v.get(holder);
.markHolder
- an array of size of at least one. On return,
markholder[0]
will hold the value of the mark.public boolean weakCompareAndSet(java.lang.Object expectedReference, java.lang.Object newReference, boolean expectedMark, boolean newMark)
==
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
.
expectedReference
- the expected value of the referencenewReference
- the new value for the referenceexpectedMark
- the expected value of the marknewMark
- the new value for the markpublic boolean compareAndSet(java.lang.Object expectedReference, java.lang.Object newReference, boolean expectedMark, boolean newMark)
==
to the expected reference
and the current mark is equal to the expected mark.expectedReference
- the expected value of the referencenewReference
- the new value for the referenceexpectedMark
- the expected value of the marknewMark
- the new value for the markpublic void set(java.lang.Object newReference, boolean newMark)
newReference
- the new value for the referencenewMark
- the new value for the markpublic boolean attemptMark(java.lang.Object expectedReference, boolean newMark)
==
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.expectedReference
- the expected value of the referencenewMark
- the new value for the mark