Class AtomicReference<V>
java.lang.Object
java.util.concurrent.atomic.AtomicReference<V>
- Type Parameters:
V- The type of object referred to by this reference
- All Implemented Interfaces:
Serializable
An object reference that may be updated atomically. See the
VarHandle specification for descriptions of the properties of
atomic accesses.- Since:
- 1.5
- See Also:
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Constructor Summary
ConstructorsConstructorDescriptionCreates a new AtomicReference with null initial value.AtomicReference(V initialValue) Creates a new AtomicReference with the given initial value. -
Method Summary
Modifier and TypeMethodDescriptionfinal VaccumulateAndGet(V x, BinaryOperator<V> 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 VcompareAndExchange(V expectedValue, V 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 VcompareAndExchangeAcquire(V expectedValue, V 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 VcompareAndExchangeRelease(V expectedValue, V 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(V expectedValue, V newValue) Atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...).final Vget()Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).final VReturns the current value, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...).final VgetAndAccumulate(V x, BinaryOperator<V> 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 VAtomically sets the value tonewValueand returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...).final VgetAndUpdate(UnaryOperator<V> 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 VReturns the current value, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...).final VgetPlain()Returns the current value, with memory semantics of reading as if the variable was declared non-volatile.final voidSets the value tonewValue, with memory effects as specified byVarHandle.setRelease(java.lang.Object...).final voidSets the value tonewValue, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...).final voidSets the value tonewValue, with memory effects as specified byVarHandle.setOpaque(java.lang.Object...).final voidSets the value tonewValue, with memory semantics of setting as if the variable was declared non-volatileand non-final.final voidsetRelease(V 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 VupdateAndGet(UnaryOperator<V> 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(V expectedValue, V newValue) Deprecated.final booleanweakCompareAndSetAcquire(V expectedValue, V newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetAcquire(java.lang.Object...).final booleanweakCompareAndSetPlain(V expectedValue, V newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...).final booleanweakCompareAndSetRelease(V expectedValue, V newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetRelease(java.lang.Object...).final booleanweakCompareAndSetVolatile(V expectedValue, V newValue) Possibly atomically sets the value tonewValueif the current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSet(java.lang.Object...).
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Constructor Details
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AtomicReference
Creates a new AtomicReference with the given initial value.- Parameters:
initialValue- the initial value
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AtomicReference
public AtomicReference()Creates a new AtomicReference with null initial value.
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Method Details
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get
Returns the current value, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).- Returns:
- the current value
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set
Sets the value tonewValue, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...).- Parameters:
newValue- the new value
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lazySet
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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compareAndSet
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(V, V)andcompareAndSet(V, V)). To avoid confusion over plain or volatile memory effects it is recommended that the methodweakCompareAndSetPlain(V, V)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
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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getAndSet
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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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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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
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
Returns the current value, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...).- Returns:
- the value
- Since:
- 9
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setOpaque
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
Returns the current value, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...).- Returns:
- the value
- Since:
- 9
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setRelease
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
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
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
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
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
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
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(V, V)andcompareAndSet(V, V)).