Class AtomicInteger
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:
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Constructor Summary
ConstructorsConstructorDescriptionCreates a new AtomicInteger with initial value0.AtomicInteger(int initialValue) Creates a new AtomicInteger with the given initial value. -
Method Summary
Modifier and TypeMethodDescriptionfinal intaccumulateAndGet(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 intaddAndGet(int delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).final intcompareAndExchange(int expectedValue, int 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 intcompareAndExchangeAcquire(int expectedValue, int 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 intcompareAndExchangeRelease(int expectedValue, int 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(int expectedValue, int newValue) Atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...).final intAtomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).doubleReturns the current value of thisAtomicIntegeras adoubleafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).floatReturns the current value of thisAtomicIntegeras afloatafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).final intget()Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).final intReturns the current value, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...).final intgetAndAccumulate(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 intgetAndAdd(int delta) Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).final intAtomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).final intAtomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).final intgetAndSet(int newValue) Atomically sets the value tonewValueand returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...).final intgetAndUpdate(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 intReturns the current value, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...).final intgetPlain()Returns the current value, with memory semantics of reading as if the variable was declared non-volatile.final intAtomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).intintValue()Returns the current value of thisAtomicIntegeras anint, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).final voidlazySet(int newValue) Sets the value tonewValue, with memory effects as specified byVarHandle.setRelease(java.lang.Object...).longReturns the current value of thisAtomicIntegeras alongafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).final voidset(int newValue) Sets the value tonewValue, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...).final voidsetOpaque(int newValue) Sets the value tonewValue, with memory effects as specified byVarHandle.setOpaque(java.lang.Object...).final voidsetPlain(int newValue) Sets the value tonewValue, with memory semantics of setting as if the variable was declared non-volatileand non-final.final voidsetRelease(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 intupdateAndGet(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 booleanweakCompareAndSet(int expectedValue, int newValue) Deprecated.final booleanweakCompareAndSetAcquire(int expectedValue, int newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetAcquire(java.lang.Object...).final booleanweakCompareAndSetPlain(int expectedValue, int newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...).final booleanweakCompareAndSetRelease(int expectedValue, int newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetRelease(java.lang.Object...).final booleanweakCompareAndSetVolatile(int expectedValue, int 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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AtomicInteger
public AtomicInteger(int initialValue) Creates a new AtomicInteger with the given initial value.- Parameters:
initialValue- the initial value
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AtomicInteger
public AtomicInteger()Creates a new AtomicInteger with initial value0.
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Method Details
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get
public final int 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(int 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(int 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 int getAndSet(int 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(int expectedValue, int 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(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 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(int expectedValue, int 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 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
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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
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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
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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
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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
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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
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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 thisAtomicIntegeras anint, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...). Equivalent toget(). -
longValue
public long longValue()Returns the current value of thisAtomicIntegeras alongafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).- Specified by:
longValuein classNumber- Returns:
- the numeric value represented by this object after conversion
to type
long. - See Java Language Specification:
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5.1.2 Widening Primitive Conversion
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floatValue
public float floatValue()Returns the current value of thisAtomicIntegeras 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 thisAtomicIntegeras 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 int 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(int 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 int 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(int 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 int 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(int 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 int compareAndExchange(int expectedValue, int 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 int compareAndExchangeAcquire(int expectedValue, int 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 int compareAndExchangeRelease(int expectedValue, int 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(int expectedValue, int 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(int expectedValue, int 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(int expectedValue, int 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(int, int)andcompareAndSet(int, int)).