public
abstract
class
AtomicIntegerFieldUpdater
extends Object
java.lang.Object | |
↳ | java.util.concurrent.atomic.AtomicIntegerFieldUpdater<T> |
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 constructors | |
---|---|
AtomicIntegerFieldUpdater()
Protected do-nothing constructor for use by subclasses. |
Public methods | |
---|---|
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 |
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 |
Inherited methods | |
---|---|
From
class
java.lang.Object
|
AtomicIntegerFieldUpdater ()
Protected do-nothing constructor for use by subclasses.
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 |
T :
An object whose field to get and set |
x |
int :
the update value |
accumulatorFunction |
IntBinaryOperator :
a side-effect-free function of two arguments |
Returns | |
---|---|
int |
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.
Parameters | |
---|---|
obj |
T :
An object whose field to get and set |
delta |
int :
the value to add |
Returns | |
---|---|
int |
the updated value |
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 |
T :
An object whose field to conditionally set |
expect |
int :
the expected value |
update |
int :
the new value |
Returns | |
---|---|
boolean |
true if successful |
Throws | |
---|---|
ClassCastException |
if obj is not an instance
of the class possessing the field established in the constructor
|
int decrementAndGet (T obj)
Atomically decrements by one the current value of the field of the given object managed by this updater.
Parameters | |
---|---|
obj |
T :
An object whose field to get and set |
Returns | |
---|---|
int |
the updated value |
int get (T obj)
Gets the current value held in the field of the given object managed by this updater.
Parameters | |
---|---|
obj |
T :
An object whose field to get |
Returns | |
---|---|
int |
the current value |
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. 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 |
T :
An object whose field to get and set |
x |
int :
the update value |
accumulatorFunction |
IntBinaryOperator :
a side-effect-free function of two arguments |
Returns | |
---|---|
int |
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.
Parameters | |
---|---|
obj |
T :
An object whose field to get and set |
delta |
int :
the value to add |
Returns | |
---|---|
int |
the previous value |
int getAndDecrement (T obj)
Atomically decrements by one the current value of the field of the given object managed by this updater.
Parameters | |
---|---|
obj |
T :
An object whose field to get and set |
Returns | |
---|---|
int |
the previous value |
int getAndIncrement (T obj)
Atomically increments by one the current value of the field of the given object managed by this updater.
Parameters | |
---|---|
obj |
T :
An object whose field to get and set |
Returns | |
---|---|
int |
the previous value |
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.
Parameters | |
---|---|
obj |
T :
An object whose field to get and set |
newValue |
int :
the new value |
Returns | |
---|---|
int |
the previous value |
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. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads.
Parameters | |
---|---|
obj |
T :
An object whose field to get and set |
updateFunction |
IntUnaryOperator :
a side-effect-free function |
Returns | |
---|---|
int |
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.
Parameters | |
---|---|
obj |
T :
An object whose field to get and set |
Returns | |
---|---|
int |
the updated value |
void lazySet (T obj, int newValue)
Eventually sets the field of the given object managed by this updater to the given updated value.
Parameters | |
---|---|
obj |
T :
An object whose field to set |
newValue |
int :
the new value |
AtomicIntegerFieldUpdater<U> newUpdater (Class<U> tclass, String fieldName)
Creates and returns an updater for objects with the given field. The Class argument is needed to check that reflective types and generic types match.
Parameters | |
---|---|
tclass |
Class :
the class of the objects holding the field |
fieldName |
String :
the name of the field to be updated |
Returns | |
---|---|
AtomicIntegerFieldUpdater<U> |
the updater |
Throws | |
---|---|
IllegalArgumentException |
if the field is not a volatile integer type |
RuntimeException |
with a nested reflection-based exception if the class does not hold field or is the wrong type, or the field is inaccessible to the caller according to Java language access control |
void set (T obj, int newValue)
Sets the field of the given object managed by this updater to the
given updated value. This operation is guaranteed to act as a volatile
store with respect to subsequent invocations of compareAndSet
.
Parameters | |
---|---|
obj |
T :
An object whose field to set |
newValue |
int :
the new value
|
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. The function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads.
Parameters | |
---|---|
obj |
T :
An object whose field to get and set |
updateFunction |
IntUnaryOperator :
a side-effect-free function |
Returns | |
---|---|
int |
the updated value |
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. 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.
May fail
spuriously and does not provide ordering guarantees, so is
only rarely an appropriate alternative to compareAndSet
.
Parameters | |
---|---|
obj |
T :
An object whose field to conditionally set |
expect |
int :
the expected value |
update |
int :
the new value |
Returns | |
---|---|
boolean |
true if successful |
Throws | |
---|---|
ClassCastException |
if obj is not an instance
of the class possessing the field established in the constructor
|