- java.lang.Object
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- java.lang.Number
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- java.util.concurrent.atomic.AtomicInteger
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- All Implemented Interfaces:
Serializable
public class AtomicInteger extends Number implements Serializable
Anintvalue that may be updated atomically. See theVarHandlespecification for descriptions of the properties of atomic accesses. AnAtomicIntegeris used in applications such as atomically incremented counters, and cannot be used as a replacement for anInteger. However, this class does extendNumberto allow uniform access by tools and utilities that deal with numerically-based classes.- Since:
- 1.5
- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description AtomicInteger()Creates a new AtomicInteger with initial value0.AtomicInteger(int initialValue)Creates a new AtomicInteger with the given initial value.
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description 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.intaddAndGet(int delta)Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).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...).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...).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...).booleancompareAndSet(int expectedValue, int newValue)Atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...).intdecrementAndGet()Atomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).doubledoubleValue()Returns the current value of thisAtomicIntegeras adoubleafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).floatfloatValue()Returns the current value of thisAtomicIntegeras afloatafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).intget()Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).intgetAcquire()Returns the current value, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...).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.intgetAndAdd(int delta)Atomically adds the given value to the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).intgetAndDecrement()Atomically decrements the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).intgetAndIncrement()Atomically increments the current value, with memory effects as specified byVarHandle.getAndAdd(java.lang.Object...).intgetAndSet(int newValue)Atomically sets the value tonewValueand returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...).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.intgetOpaque()Returns the current value, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...).intgetPlain()Returns the current value, with memory semantics of reading as if the variable was declared non-volatile.intincrementAndGet()Atomically 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...).voidlazySet(int newValue)Sets the value tonewValue, with memory effects as specified byVarHandle.setRelease(java.lang.Object...).longlongValue()Returns the current value of thisAtomicIntegeras alongafter a widening primitive conversion, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).voidset(int newValue)Sets the value tonewValue, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...).voidsetOpaque(int newValue)Sets the value tonewValue, with memory effects as specified byVarHandle.setOpaque(java.lang.Object...).voidsetPlain(int newValue)Sets the value tonewValue, with memory semantics of setting as if the variable was declared non-volatileand non-final.voidsetRelease(int newValue)Sets the value tonewValue, with memory effects as specified byVarHandle.setRelease(java.lang.Object...).StringtoString()Returns the String representation of the current value.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.booleanweakCompareAndSet(int expectedValue, int newValue)Deprecated.This method has plain memory effects but the method name implies volatile memory effects (see methods such ascompareAndExchange(int, int)andcompareAndSet(int, int)).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...).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...).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...).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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Method Detail
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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(since="9") public final boolean weakCompareAndSet(int expectedValue, int newValue)
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:
weakCompareAndSetPlain(int, int)
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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
public 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. 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
public 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. 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
public 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. 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
public final 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. 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
public String toString()
Returns the String representation of the current value.
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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().
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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...).
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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 The Java™ Language Specification:
- 5.1.2 Widening Primitive Conversions
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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 The Java™ Language Specification:
- 5.1.2 Widening Primitive Conversions
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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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