AtomicIntegerFieldUpdater

public abstract class AtomicIntegerFieldUpdater extends Object

A reflection-based utility that enables atomic updates to designated volatile int fields of designated classes. This class is designed for use in atomic data structures in which several fields of the same node are independently subject to atomic updates.

Note that the guarantees of the compareAndSet method in this class are weaker than in other atomic classes. Because this class cannot ensure that all uses of the field are appropriate for purposes of atomic access, it can guarantee atomicity only with respect to other invocations of compareAndSet and set on the same updater.

Protected Constructor Summary

AtomicIntegerFieldUpdater()
Protected do-nothing constructor for use by subclasses.

Public Method Summary

final int
accumulateAndGet(T obj, int x, IntBinaryOperator accumulatorFunction)
Atomically updates the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the updated value.
int
addAndGet(T obj, int delta)
Atomically adds the given value to the current value of the field of the given object managed by this updater.
abstract boolean
compareAndSet(T obj, int expect, int update)
Atomically sets the field of the given object managed by this updater to the given updated value if the current value == the expected value.
int
decrementAndGet(T obj)
Atomically decrements by one the current value of the field of the given object managed by this updater.
abstract int
get(T obj)
Gets the current value held in the field of the given object managed by this updater.
final int
getAndAccumulate(T obj, int x, IntBinaryOperator accumulatorFunction)
Atomically updates the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the previous value.
int
getAndAdd(T obj, int delta)
Atomically adds the given value to the current value of the field of the given object managed by this updater.
int
getAndDecrement(T obj)
Atomically decrements by one the current value of the field of the given object managed by this updater.
int
getAndIncrement(T obj)
Atomically increments by one the current value of the field of the given object managed by this updater.
int
getAndSet(T obj, int newValue)
Atomically sets the field of the given object managed by this updater to the given value and returns the old value.
final int
getAndUpdate(T obj, IntUnaryOperator updateFunction)
Atomically updates the field of the given object managed by this updater with the results of applying the given function, returning the previous value.
int
incrementAndGet(T obj)
Atomically increments by one the current value of the field of the given object managed by this updater.
abstract void
lazySet(T obj, int newValue)
Eventually sets the field of the given object managed by this updater to the given updated value.
static <U> AtomicIntegerFieldUpdater<U>
newUpdater(Class<U> tclass, String fieldName)
Creates and returns an updater for objects with the given field.
abstract void
set(T obj, int newValue)
Sets the field of the given object managed by this updater to the given updated value.
final int
updateAndGet(T obj, IntUnaryOperator updateFunction)
Atomically updates the field of the given object managed by this updater with the results of applying the given function, returning the updated value.
abstract boolean
weakCompareAndSet(T obj, int expect, int update)
Atomically sets the field of the given object managed by this updater to the given updated value if the current value == the expected value.

Inherited Method Summary

Protected Constructors

protected AtomicIntegerFieldUpdater ()

Protected do-nothing constructor for use by subclasses.

Public Methods

public final int accumulateAndGet (T obj, int x, IntBinaryOperator accumulatorFunction)

Atomically updates the field of the given object managed by this updater with the results of applying the given function to the current and given values, returning the updated value. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. The function is applied with the current value as its first argument, and the given update as the second argument.

Parameters
obj An object whose field to get and set
x the update value
accumulatorFunction a side-effect-free function of two arguments
Returns
  • the updated value

public int addAndGet (T obj, int delta)

Atomically adds the given value to the current value of the field of the given object managed by this updater.

Parameters
obj An object whose field to get and set
delta the value to add
Returns
  • the updated value

public abstract boolean compareAndSet (T obj, int expect, int update)

Atomically sets the field of the given object managed by this updater to the given updated value if the current value == the expected value. This method is guaranteed to be atomic with respect to other calls to compareAndSet and set, but not necessarily with respect to other changes in the field.

Parameters
obj An object whose field to conditionally set
expect the expected value
update the new value
Returns
  • true if successful
Throws
ClassCastException if obj is not an instance of the class possessing the field established in the constructor

public