java.util.concurrent.atomic
Class 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.
AtomicStampedReference(V initialRef, int initialStamp) - Creates a new AtomicStampedReference with the given
initial values.
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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.
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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.
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V | get(int[] stampHolder) - Returns the current values of both the reference and the stamp.
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V | getReference() - Returns the current value of the reference.
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int | getStamp() - Returns the current value of the stamp.
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void | set(V newReference, int newStamp) - Unconditionally sets the value of both the reference and stamp.
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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.
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clone , equals , extends Object> getClass , finalize , hashCode , notify , notifyAll , toString , wait , wait , wait |
AtomicStampedReference
public AtomicStampedReference(V initialRef,
int initialStamp)
Creates a new AtomicStampedReference with the given
initial values.
initialRef
- the initial referenceinitialStamp
- the initial stamp
attemptStamp
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.
expectedReference
- the expected value of the referencenewStamp
- the new value for the stamp
compareAndSet
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.
expectedReference
- the expected value of the referencenewReference
- the new value for the referenceexpectedStamp
- the expected value of the stampnewStamp
- the new value for the stamp
get
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); .
stampHolder
- an array of size of at least one. On return,
stampholder[0] will hold the value of the stamp.
- the current value of the reference
getReference
public V getReference()
Returns the current value of the reference.
- the current value of the reference
getStamp
public int getStamp()
Returns the current value of the stamp.
- the current value of the stamp
set
public void set(V newReference,
int newStamp)
Unconditionally sets the value of both the reference and stamp.
newReference
- the new value for the referencenewStamp
- the new value for the stamp
weakCompareAndSet
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.
expectedReference
- the expected value of the referencenewReference
- the new value for the referenceexpectedStamp
- the expected value of the stampnewStamp
- the new value for the stamp