Class AtomicLong
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:
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Constructor Summary
ConstructorsConstructorDescriptionCreates a new AtomicLong with initial value0.AtomicLong(long initialValue) Creates a new AtomicLong with the given initial value. -
Method Summary
Modifier and TypeMethodDescriptionfinal longaccumulateAndGet(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 longaddAndGet(long delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).final longcompareAndExchange(long expectedValue, long newValue) Atomically sets the value tonewValueif the current value, referred to as the witness value,== expectedValue, with memory effects as specified byVarHandle.compareAndExchange(java.lang.Object...).final longcompareAndExchangeAcquire(long expectedValue, long newValue) Atomically sets the value tonewValueif the current value, referred to as the witness value,== expectedValue, with memory effects as specified byVarHandle.compareAndExchangeAcquire(java.lang.Object...).final longcompareAndExchangeRelease(long expectedValue, long newValue) Atomically sets the value tonewValueif the current value, referred to as the witness value,== expectedValue, with memory effects as specified byVarHandle.compareAndExchangeRelease(java.lang.Object...).final booleancompareAndSet(long expectedValue, long newValue) Atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...).final longAtomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).doubleReturns the current value of thisAtomicLongas adoubleafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).floatReturns the current value of thisAtomicLongas afloatafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).final longget()Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).final longReturns the current value, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...).final longgetAndAccumulate(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 longgetAndAdd(long delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).final longAtomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).final longAtomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).final longgetAndSet(long newValue) Atomically sets the value tonewValueand returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...).final longgetAndUpdate(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 longReturns the current value, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...).final longgetPlain()Returns the current value, with memory semantics of reading as if the variable was declared non-volatile.final longAtomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).intintValue()Returns the current value of thisAtomicLongas anintafter a narrowing primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).final voidlazySet(long newValue) Sets the value tonewValue, with memory effects as specified byVarHandle.setRelease(java.lang.Object...).longReturns the current value of thisAtomicLongas along, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).final voidset(long newValue) Sets the value tonewValue, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...).final voidsetOpaque(long newValue) Sets the value tonewValue, with memory effects as specified byVarHandle.setOpaque(java.lang.Object...).final voidsetPlain(long newValue) Sets the value tonewValue, with memory semantics of setting as if the variable was declared non-volatileand non-final.final voidsetRelease(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 longupdateAndGet(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 booleanweakCompareAndSet(long expectedValue, long newValue) Deprecated.final booleanweakCompareAndSetAcquire(long expectedValue, long newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetAcquire(java.lang.Object...).final booleanweakCompareAndSetPlain(long expectedValue, long newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...).final booleanweakCompareAndSetRelease(long expectedValue, long newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetRelease(java.lang.Object...).final booleanweakCompareAndSetVolatile(long expectedValue, long newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSet(java.lang.Object...).Methods declared in class java.lang.Number
byteValue, shortValue
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Constructor Details
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AtomicLong
public AtomicLong(long initialValue) Creates a new AtomicLong with the given initial value.- Parameters:
initialValue- the initial value
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AtomicLong
public AtomicLong()Creates a new AtomicLong with initial value0.
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Method Details
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get
public final long get()Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).- Returns:
- the current value
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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
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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
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getAndSet
public final long getAndSet(long newValue) Atomically sets the value tonewValueand returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...).- Parameters:
newValue- the new value- Returns:
- the previous value
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compareAndSet
public final boolean compareAndSet(long expectedValue, long newValue) Atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...).- Parameters:
expectedValue- the expected valuenewValue- the new value- Returns:
trueif successful. False return indicates that the actual value was not equal to the expected value.
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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 tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...).- Parameters:
expectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- See Also:
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weakCompareAndSetPlain
public final boolean weakCompareAndSetPlain(long expectedValue, long newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...).- Parameters:
expectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- Since:
- 9
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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toString
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intValue
public int intValue()Returns the current value of thisAtomicLongas anintafter a narrowing primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).- Specified by:
intValuein classNumber- Returns:
- the numeric value represented by this object after conversion
to type
int. - See Java Language Specification:
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5.1.3 Narrowing Primitive Conversion
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longValue
public long longValue()Returns the current value of thisAtomicLongas along, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...). Equivalent toget(). -
floatValue
public float floatValue()Returns the current value of thisAtomicLongas afloatafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).- Specified by:
floatValuein classNumber- Returns:
- the numeric value represented by this object after conversion
to type
float. - See Java Language Specification:
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5.1.2 Widening Primitive Conversion
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doubleValue
public double doubleValue()Returns the current value of thisAtomicLongas adoubleafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).- Specified by:
doubleValuein classNumber- Returns:
- the numeric value represented by this object after conversion
to type
double. - See Java Language Specification:
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5.1.2 Widening Primitive Conversion
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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
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setPlain
public final void setPlain(long newValue) Sets the value tonewValue, with memory semantics of setting as if the variable was declared non-volatileand non-final.- Parameters:
newValue- the new value- Since:
- 9
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getOpaque
public final long getOpaque()Returns the current value, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...).- Returns:
- the value
- Since:
- 9
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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
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getAcquire
public final long getAcquire()Returns the current value, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...).- Returns:
- the value
- Since:
- 9
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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
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compareAndExchange
public final long compareAndExchange(long expectedValue, long newValue) Atomically sets the value tonewValueif 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
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compareAndExchangeAcquire
public final long compareAndExchangeAcquire(long expectedValue, long newValue) Atomically sets the value tonewValueif 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
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compareAndExchangeRelease
public final long compareAndExchangeRelease(long expectedValue, long newValue) Atomically sets the value tonewValueif 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
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weakCompareAndSetVolatile
public final boolean weakCompareAndSetVolatile(long expectedValue, long newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSet(java.lang.Object...).- Parameters:
expectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- Since:
- 9
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weakCompareAndSetAcquire
public final boolean weakCompareAndSetAcquire(long expectedValue, long newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetAcquire(java.lang.Object...).- Parameters:
expectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- Since:
- 9
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weakCompareAndSetRelease
public final boolean weakCompareAndSetRelease(long expectedValue, long newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetRelease(java.lang.Object...).- Parameters:
expectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- Since:
- 9
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compareAndExchange(long, long)andcompareAndSet(long, long)).