java.lang.Object
java.lang.Number
java.util.concurrent.atomic.AtomicInteger
- All Implemented Interfaces:
Serializable
An
int
value that may be updated atomically. See the
VarHandle
specification for descriptions of the properties
of atomic accesses. An AtomicInteger
is used in
applications such as atomically incremented counters, and cannot be
used as a replacement for an Integer
. However,
this class does extend Number
to allow uniform access by
tools and utilities that deal with numerically-based classes.- Since:
- 1.5
- See Also:
-
Constructor Summary
ConstructorDescriptionCreates a new AtomicInteger with initial value0
.AtomicInteger
(int initialValue) Creates a new AtomicInteger with the given initial value. -
Method Summary
Modifier and TypeMethodDescriptionfinal int
accumulateAndGet
(int x, IntBinaryOperator accumulatorFunction) Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
) the current value with the results of applying the given function to the current and given values, returning the updated value.final int
addAndGet
(int delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.final int
compareAndExchange
(int expectedValue, int newValue) Atomically sets the value tonewValue
if the current value, referred to as the witness value,== expectedValue
, with memory effects as specified byVarHandle.compareAndExchange(java.lang.Object...)
.final int
compareAndExchangeAcquire
(int expectedValue, int newValue) Atomically sets the value tonewValue
if the current value, referred to as the witness value,== expectedValue
, with memory effects as specified byVarHandle.compareAndExchangeAcquire(java.lang.Object...)
.final int
compareAndExchangeRelease
(int expectedValue, int newValue) Atomically sets the value tonewValue
if the current value, referred to as the witness value,== expectedValue
, with memory effects as specified byVarHandle.compareAndExchangeRelease(java.lang.Object...)
.final boolean
compareAndSet
(int expectedValue, int newValue) Atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
.final int
Atomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.double
Returns the current value of thisAtomicInteger
as adouble
after a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.float
Returns the current value of thisAtomicInteger
as afloat
after a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.final int
get()
Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.final int
Returns the current value, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...)
.final int
getAndAccumulate
(int x, IntBinaryOperator accumulatorFunction) Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
) the current value with the results of applying the given function to the current and given values, returning the previous value.final int
getAndAdd
(int delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.final int
Atomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.final int
Atomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.final int
getAndSet
(int newValue) Atomically sets the value tonewValue
and returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...)
.final int
getAndUpdate
(IntUnaryOperator updateFunction) Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
) the current value with the results of applying the given function, returning the previous value.final int
Returns the current value, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...)
.final int
getPlain()
Returns the current value, with memory semantics of reading as if the variable was declared non-volatile
.final int
Atomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.int
intValue()
Returns the current value of thisAtomicInteger
as anint
, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.final void
lazySet
(int newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setRelease(java.lang.Object...)
.long
Returns the current value of thisAtomicInteger
as along
after a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.final void
set
(int newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...)
.final void
setOpaque
(int newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setOpaque(java.lang.Object...)
.final void
setPlain
(int newValue) Sets the value tonewValue
, with memory semantics of setting as if the variable was declared non-volatile
and non-final
.final void
setRelease
(int newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setRelease(java.lang.Object...)
.toString()
Returns the String representation of the current value.final int
updateAndGet
(IntUnaryOperator updateFunction) Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
) the current value with the results of applying the given function, returning the updated value.final boolean
weakCompareAndSet
(int expectedValue, int newValue) Deprecated.final boolean
weakCompareAndSetAcquire
(int expectedValue, int newValue) Possibly atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.weakCompareAndSetAcquire(java.lang.Object...)
.final boolean
weakCompareAndSetPlain
(int expectedValue, int newValue) Possibly atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...)
.final boolean
weakCompareAndSetRelease
(int expectedValue, int newValue) Possibly atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.weakCompareAndSetRelease(java.lang.Object...)
.final boolean
weakCompareAndSetVolatile
(int expectedValue, int newValue) Possibly atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.weakCompareAndSet(java.lang.Object...)
.Methods declared in class java.lang.Number
byteValue, shortValue
-
Constructor Details
-
AtomicInteger
public AtomicInteger(int initialValue) Creates a new AtomicInteger with the given initial value.- Parameters:
initialValue
- the initial value
-
AtomicInteger
public AtomicInteger()Creates a new AtomicInteger with initial value0
.
-
-
Method Details
-
get
public final int get()Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.- Returns:
- the current value
-
set
public final void set(int newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...)
.- Parameters:
newValue
- the new value
-
lazySet
public final void lazySet(int newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setRelease(java.lang.Object...)
.- Parameters:
newValue
- the new value- Since:
- 1.6
-
getAndSet
public final int getAndSet(int newValue) Atomically sets the value tonewValue
and returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...)
.- Parameters:
newValue
- the new value- Returns:
- the previous value
-
compareAndSet
public final boolean compareAndSet(int expectedValue, int newValue) Atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
.- Parameters:
expectedValue
- the expected valuenewValue
- the new value- Returns:
true
if successful. False return indicates that the actual value was not equal to the expected value.
-
weakCompareAndSet
Deprecated.This method has plain memory effects but the method name implies volatile memory effects (see methods such ascompareAndExchange(int, int)
andcompareAndSet(int, int)
). To avoid confusion over plain or volatile memory effects it is recommended that the methodweakCompareAndSetPlain(int, int)
be used instead.Possibly atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...)
.- Parameters:
expectedValue
- the expected valuenewValue
- the new value- Returns:
true
if successful- See Also:
-
weakCompareAndSetPlain
public final boolean weakCompareAndSetPlain(int expectedValue, int newValue) Possibly atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...)
.- Parameters:
expectedValue
- the expected valuenewValue
- the new value- Returns:
true
if successful- Since:
- 9
-
getAndIncrement
public final int getAndIncrement()Atomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.Equivalent to
getAndAdd(1)
.- Returns:
- the previous value
-
getAndDecrement
public final int getAndDecrement()Atomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.Equivalent to
getAndAdd(-1)
.- Returns:
- the previous value
-
getAndAdd
public final int getAndAdd(int delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.- Parameters:
delta
- the value to add- Returns:
- the previous value
-
incrementAndGet
public final int incrementAndGet()Atomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.Equivalent to
addAndGet(1)
.- Returns:
- the updated value
-
decrementAndGet
public final int decrementAndGet()Atomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.Equivalent to
addAndGet(-1)
.- Returns:
- the updated value
-
addAndGet
public final int addAndGet(int delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.- Parameters:
delta
- the value to add- Returns:
- the updated value
-
getAndUpdate
Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
) the current value 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:
updateFunction
- a side-effect-free function- Returns:
- the previous value
- Since:
- 1.8
-
updateAndGet
Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
) the current value 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:
updateFunction
- a side-effect-free function- Returns:
- the updated value
- Since:
- 1.8
-
getAndAccumulate
Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
) the current value 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:
x
- the update valueaccumulatorFunction
- a side-effect-free function of two arguments- Returns:
- the previous value
- Since:
- 1.8
-
accumulateAndGet
Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
) the current value 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:
x
- the update valueaccumulatorFunction
- a side-effect-free function of two arguments- Returns:
- the updated value
- Since:
- 1.8
-
toString
-
intValue
public int intValue()Returns the current value of thisAtomicInteger
as anint
, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
. Equivalent toget()
. -
longValue
public long longValue()Returns the current value of thisAtomicInteger
as along
after a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.- Specified by:
longValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion
to type
long
. - See Java Language Specification:
-
5.1.2 Widening Primitive Conversion
-
floatValue
public float floatValue()Returns the current value of thisAtomicInteger
as afloat
after a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.- Specified by:
floatValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion
to type
float
. - See Java Language Specification:
-
5.1.2 Widening Primitive Conversion
-
doubleValue
public double doubleValue()Returns the current value of thisAtomicInteger
as adouble
after a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.- Specified by:
doubleValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion
to type
double
. - See Java Language Specification:
-
5.1.2 Widening Primitive Conversion
-
getPlain
public final int getPlain()Returns the current value, with memory semantics of reading as if the variable was declared non-volatile
.- Returns:
- the value
- Since:
- 9
-
setPlain
public final void setPlain(int newValue) Sets the value tonewValue
, with memory semantics of setting as if the variable was declared non-volatile
and non-final
.- Parameters:
newValue
- the new value- Since:
- 9
-
getOpaque
public final int getOpaque()Returns the current value, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...)
.- Returns:
- the value
- Since:
- 9
-
setOpaque
public final void setOpaque(int newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setOpaque(java.lang.Object...)
.- Parameters:
newValue
- the new value- Since:
- 9
-
getAcquire
public final int getAcquire()Returns the current value, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...)
.- Returns:
- the value
- Since:
- 9
-
setRelease
public final void setRelease(int newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setRelease(java.lang.Object...)
.- Parameters:
newValue
- the new value- Since:
- 9
-
compareAndExchange
public final int compareAndExchange(int expectedValue, int newValue) Atomically sets the value tonewValue
if the current value, referred to as the witness value,== expectedValue
, with memory effects as specified byVarHandle.compareAndExchange(java.lang.Object...)
.- Parameters:
expectedValue
- the expected valuenewValue
- the new value- Returns:
- the witness value, which will be the same as the expected value if successful
- Since:
- 9
-
compareAndExchangeAcquire
public final int compareAndExchangeAcquire(int expectedValue, int newValue) Atomically sets the value tonewValue
if the current value, referred to as the witness value,== expectedValue
, with memory effects as specified byVarHandle.compareAndExchangeAcquire(java.lang.Object...)
.- Parameters:
expectedValue
- the expected valuenewValue
- the new value- Returns:
- the witness value, which will be the same as the expected value if successful
- Since:
- 9
-
compareAndExchangeRelease
public final int compareAndExchangeRelease(int expectedValue, int newValue) Atomically sets the value tonewValue
if the current value, referred to as the witness value,== expectedValue
, with memory effects as specified byVarHandle.compareAndExchangeRelease(java.lang.Object...)
.- Parameters:
expectedValue
- the expected valuenewValue
- the new value- Returns:
- the witness value, which will be the same as the expected value if successful
- Since:
- 9
-
weakCompareAndSetVolatile
public final boolean weakCompareAndSetVolatile(int expectedValue, int newValue) Possibly atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.weakCompareAndSet(java.lang.Object...)
.- Parameters:
expectedValue
- the expected valuenewValue
- the new value- Returns:
true
if successful- Since:
- 9
-
weakCompareAndSetAcquire
public final boolean weakCompareAndSetAcquire(int expectedValue, int newValue) Possibly atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.weakCompareAndSetAcquire(java.lang.Object...)
.- Parameters:
expectedValue
- the expected valuenewValue
- the new value- Returns:
true
if successful- Since:
- 9
-
weakCompareAndSetRelease
public final boolean weakCompareAndSetRelease(int expectedValue, int newValue) Possibly atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.weakCompareAndSetRelease(java.lang.Object...)
.- Parameters:
expectedValue
- the expected valuenewValue
- the new value- Returns:
true
if successful- Since:
- 9
-
compareAndExchange(int, int)
andcompareAndSet(int, int)
).