java.lang.Object
java.lang.Number
java.util.concurrent.atomic.AtomicLong
- All Implemented Interfaces:
Serializable
A
long
value that may be updated atomically. See the
VarHandle
specification for descriptions of the properties
of atomic accesses. An AtomicLong
is used in applications
such as atomically incremented sequence numbers, and cannot be used
as a replacement for a Long
. 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 AtomicLong with initial value0
.AtomicLong
(long initialValue) Creates a new AtomicLong with the given initial value. -
Method Summary
Modifier and TypeMethodDescriptionfinal long
accumulateAndGet
(long x, LongBinaryOperator 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 long
addAndGet
(long delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.final long
compareAndExchange
(long expectedValue, long 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 long
compareAndExchangeAcquire
(long expectedValue, long 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 long
compareAndExchangeRelease
(long expectedValue, long 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
(long expectedValue, long newValue) Atomically sets the value tonewValue
if the current value== expectedValue
, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)
.final long
Atomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.double
Returns the current value of thisAtomicLong
as adouble
after a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.float
Returns the current value of thisAtomicLong
as afloat
after a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.final long
get()
Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.final long
Returns the current value, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...)
.final long
getAndAccumulate
(long x, LongBinaryOperator 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 long
getAndAdd
(long delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.final long
Atomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.final long
Atomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.final long
getAndSet
(long newValue) Atomically sets the value tonewValue
and returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...)
.final long
getAndUpdate
(LongUnaryOperator 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 long
Returns the current value, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...)
.final long
getPlain()
Returns the current value, with memory semantics of reading as if the variable was declared non-volatile
.final long
Atomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...)
.int
intValue()
Returns the current value of thisAtomicLong
as anint
after a narrowing primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.final void
lazySet
(long newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setRelease(java.lang.Object...)
.long
Returns the current value of thisAtomicLong
as along
, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.final void
set
(long newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...)
.final void
setOpaque
(long newValue) Sets the value tonewValue
, with memory effects as specified byVarHandle.setOpaque(java.lang.Object...)
.final void
setPlain
(long newValue) Sets the value tonewValue
, with memory semantics of setting as if the variable was declared non-volatile
and non-final
.final void
setRelease
(long 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 long
updateAndGet
(LongUnaryOperator 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
(long expectedValue, long newValue) Deprecated.final boolean
weakCompareAndSetAcquire
(long expectedValue, long 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
(long expectedValue, long 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
(long expectedValue, long 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
(long expectedValue, long 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
-
AtomicLong
public AtomicLong(long initialValue) Creates a new AtomicLong with the given initial value.- Parameters:
initialValue
- the initial value
-
AtomicLong
public AtomicLong()Creates a new AtomicLong with initial value0
.
-
-
Method Details
-
get
public final long get()Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.- Returns:
- the current value
-
set
public final void set(long 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(long 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 long getAndSet(long 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(long expectedValue, long 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(long, long)
andcompareAndSet(long, long)
). To avoid confusion over plain or volatile memory effects it is recommended that the methodweakCompareAndSetPlain(long, long)
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(long expectedValue, long 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 long 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 long 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 long getAndAdd(long 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 long 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 long 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 long addAndGet(long 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 thisAtomicLong
as anint
after a narrowing primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
.- Specified by:
intValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion
to type
int
. - See Java Language Specification:
-
5.1.3 Narrowing Primitive Conversion
-
longValue
public long longValue()Returns the current value of thisAtomicLong
as along
, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...)
. Equivalent toget()
. -
floatValue
public float floatValue()Returns the current value of thisAtomicLong
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 thisAtomicLong
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 long 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(long 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 long 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(long 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 long 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(long 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 long compareAndExchange(long expectedValue, long 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 long compareAndExchangeAcquire(long expectedValue, long 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 long compareAndExchangeRelease(long expectedValue, long 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(long expectedValue, long 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(long expectedValue, long 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(long expectedValue, long 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(long, long)
andcompareAndSet(long, long)
).