- java.lang.Object
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- java.util.concurrent.atomic.AtomicReferenceArray<E>
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- Type Parameters:
E- The base class of elements held in this array
- All Implemented Interfaces:
Serializable
public class AtomicReferenceArray<E> extends Object implements Serializable
An array of object references in which elements may be updated atomically. See theVarHandlespecification for descriptions of the properties of atomic accesses.- Since:
- 1.5
- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description AtomicReferenceArray(int length)Creates a new AtomicReferenceArray of the given length, with all elements initially null.AtomicReferenceArray(E[] array)Creates a new AtomicReferenceArray with the same length as, and all elements copied from, the given array.
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description EaccumulateAndGet(int i, E x, BinaryOperator<E> accumulatorFunction)Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)) the element at indexiwith the results of applying the given function to the current and given values, returning the updated value.EcompareAndExchange(int i, E expectedValue, E newValue)Atomically sets the element at indexitonewValueif the element's current value, referred to as the witness value,== expectedValue, with memory effects as specified byVarHandle.compareAndExchange(java.lang.Object...).EcompareAndExchangeAcquire(int i, E expectedValue, E newValue)Atomically sets the element at indexitonewValueif the element's current value, referred to as the witness value,== expectedValue, with memory effects as specified byVarHandle.compareAndExchangeAcquire(java.lang.Object...).EcompareAndExchangeRelease(int i, E expectedValue, E newValue)Atomically sets the element at indexitonewValueif the element's current value, referred to as the witness value,== expectedValue, with memory effects as specified byVarHandle.compareAndExchangeRelease(java.lang.Object...).booleancompareAndSet(int i, E expectedValue, E newValue)Atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...).Eget(int i)Returns the current value of the element at indexi, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).EgetAcquire(int i)Returns the current value of the element at indexi, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...).EgetAndAccumulate(int i, E x, BinaryOperator<E> accumulatorFunction)Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)) the element at indexiwith the results of applying the given function to the current and given values, returning the previous value.EgetAndSet(int i, E newValue)Atomically sets the element at indexitonewValueand returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...).EgetAndUpdate(int i, UnaryOperator<E> updateFunction)Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)) the element at indexiwith the results of applying the given function, returning the previous value.EgetOpaque(int i)Returns the current value of the element at indexi, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...).EgetPlain(int i)Returns the current value of the element at indexi, with memory semantics of reading as if the variable was declared non-volatile.voidlazySet(int i, E newValue)Sets the element at indexitonewValue, with memory effects as specified byVarHandle.setRelease(java.lang.Object...).intlength()Returns the length of the array.voidset(int i, E newValue)Sets the element at indexitonewValue, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...).voidsetOpaque(int i, E newValue)Sets the element at indexitonewValue, with memory effects as specified byVarHandle.setOpaque(java.lang.Object...).voidsetPlain(int i, E newValue)Sets the element at indexitonewValue, with memory semantics of setting as if the variable was declared non-volatileand non-final.voidsetRelease(int i, E newValue)Sets the element at indexitonewValue, with memory effects as specified byVarHandle.setRelease(java.lang.Object...).StringtoString()Returns the String representation of the current values of array.EupdateAndGet(int i, UnaryOperator<E> updateFunction)Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)) the element at indexiwith the results of applying the given function, returning the updated value.booleanweakCompareAndSet(int i, E expectedValue, E newValue)Deprecated.This method has plain memory effects but the method name implies volatile memory effects (see methods such ascompareAndExchange(int, E, E)andcompareAndSet(int, E, E)).booleanweakCompareAndSetAcquire(int i, E expectedValue, E newValue)Possibly atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetAcquire(java.lang.Object...).booleanweakCompareAndSetPlain(int i, E expectedValue, E newValue)Possibly atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...).booleanweakCompareAndSetRelease(int i, E expectedValue, E newValue)Possibly atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetRelease(java.lang.Object...).booleanweakCompareAndSetVolatile(int i, E expectedValue, E newValue)Possibly atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSet(java.lang.Object...).
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Constructor Detail
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AtomicReferenceArray
public AtomicReferenceArray(int length)
Creates a new AtomicReferenceArray of the given length, with all elements initially null.- Parameters:
length- the length of the array
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AtomicReferenceArray
public AtomicReferenceArray(E[] array)
Creates a new AtomicReferenceArray with the same length as, and all elements copied from, the given array.- Parameters:
array- the array to copy elements from- Throws:
NullPointerException- if array is null
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Method Detail
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length
public final int length()
Returns the length of the array.- Returns:
- the length of the array
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get
public final E get(int i)
Returns the current value of the element at indexi, with memory effects as specified byVarHandle.getVolatile(java.lang.Object...).- Parameters:
i- the index- Returns:
- the current value
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set
public final void set(int i, E newValue)Sets the element at indexitonewValue, with memory effects as specified byVarHandle.setVolatile(java.lang.Object...).- Parameters:
i- the indexnewValue- the new value
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lazySet
public final void lazySet(int i, E newValue)Sets the element at indexitonewValue, with memory effects as specified byVarHandle.setRelease(java.lang.Object...).- Parameters:
i- the indexnewValue- the new value- Since:
- 1.6
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getAndSet
public final E getAndSet(int i, E newValue)
Atomically sets the element at indexitonewValueand returns the old value, with memory effects as specified byVarHandle.getAndSet(java.lang.Object...).- Parameters:
i- the indexnewValue- the new value- Returns:
- the previous value
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compareAndSet
public final boolean compareAndSet(int i, E expectedValue, E newValue)Atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...).- Parameters:
i- the indexexpectedValue- 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 i, E expectedValue, E newValue)
Deprecated.This method has plain memory effects but the method name implies volatile memory effects (see methods such ascompareAndExchange(int, E, E)andcompareAndSet(int, E, E)). To avoid confusion over plain or volatile memory effects it is recommended that the methodweakCompareAndSetPlain(int, E, E)be used instead.Possibly atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...).- Parameters:
i- the indexexpectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- See Also:
weakCompareAndSetPlain(int, E, E)
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weakCompareAndSetPlain
public final boolean weakCompareAndSetPlain(int i, E expectedValue, E newValue)Possibly atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetPlain(java.lang.Object...).- Parameters:
i- the indexexpectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- Since:
- 9
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getAndUpdate
public final E getAndUpdate(int i, UnaryOperator<E> updateFunction)
Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)) the element at indexiwith 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:
i- the indexupdateFunction- a side-effect-free function- Returns:
- the previous value
- Since:
- 1.8
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updateAndGet
public final E updateAndGet(int i, UnaryOperator<E> updateFunction)
Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)) the element at indexiwith 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:
i- the indexupdateFunction- a side-effect-free function- Returns:
- the updated value
- Since:
- 1.8
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getAndAccumulate
public final E getAndAccumulate(int i, E x, BinaryOperator<E> accumulatorFunction)
Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)) the element at indexiwith 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 of the element at indexias its first argument, and the given update as the second argument.- Parameters:
i- the indexx- 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 E accumulateAndGet(int i, E x, BinaryOperator<E> accumulatorFunction)
Atomically updates (with memory effects as specified byVarHandle.compareAndSet(java.lang.Object...)) the element at indexiwith 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 of the element at indexias its first argument, and the given update as the second argument.- Parameters:
i- the indexx- 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 values of array.
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getPlain
public final E getPlain(int i)
Returns the current value of the element at indexi, with memory semantics of reading as if the variable was declared non-volatile.- Parameters:
i- the index- Returns:
- the value
- Since:
- 9
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setPlain
public final void setPlain(int i, E newValue)Sets the element at indexitonewValue, with memory semantics of setting as if the variable was declared non-volatileand non-final.- Parameters:
i- the indexnewValue- the new value- Since:
- 9
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getOpaque
public final E getOpaque(int i)
Returns the current value of the element at indexi, with memory effects as specified byVarHandle.getOpaque(java.lang.Object...).- Parameters:
i- the index- Returns:
- the value
- Since:
- 9
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setOpaque
public final void setOpaque(int i, E newValue)Sets the element at indexitonewValue, with memory effects as specified byVarHandle.setOpaque(java.lang.Object...).- Parameters:
i- the indexnewValue- the new value- Since:
- 9
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getAcquire
public final E getAcquire(int i)
Returns the current value of the element at indexi, with memory effects as specified byVarHandle.getAcquire(java.lang.Object...).- Parameters:
i- the index- Returns:
- the value
- Since:
- 9
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setRelease
public final void setRelease(int i, E newValue)Sets the element at indexitonewValue, with memory effects as specified byVarHandle.setRelease(java.lang.Object...).- Parameters:
i- the indexnewValue- the new value- Since:
- 9
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compareAndExchange
public final E compareAndExchange(int i, E expectedValue, E newValue)
Atomically sets the element at indexitonewValueif the element's current value, referred to as the witness value,== expectedValue, with memory effects as specified byVarHandle.compareAndExchange(java.lang.Object...).- Parameters:
i- the indexexpectedValue- 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 E compareAndExchangeAcquire(int i, E expectedValue, E newValue)
Atomically sets the element at indexitonewValueif the element's current value, referred to as the witness value,== expectedValue, with memory effects as specified byVarHandle.compareAndExchangeAcquire(java.lang.Object...).- Parameters:
i- the indexexpectedValue- 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 E compareAndExchangeRelease(int i, E expectedValue, E newValue)
Atomically sets the element at indexitonewValueif the element's current value, referred to as the witness value,== expectedValue, with memory effects as specified byVarHandle.compareAndExchangeRelease(java.lang.Object...).- Parameters:
i- the indexexpectedValue- 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 i, E expectedValue, E newValue)Possibly atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSet(java.lang.Object...).- Parameters:
i- the indexexpectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- Since:
- 9
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weakCompareAndSetAcquire
public final boolean weakCompareAndSetAcquire(int i, E expectedValue, E newValue)Possibly atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetAcquire(java.lang.Object...).- Parameters:
i- the indexexpectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- Since:
- 9
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weakCompareAndSetRelease
public final boolean weakCompareAndSetRelease(int i, E expectedValue, E newValue)Possibly atomically sets the element at indexitonewValueif the element's current value== expectedValue, with memory effects as specified byVarHandle.weakCompareAndSetRelease(java.lang.Object...).- Parameters:
i- the indexexpectedValue- the expected valuenewValue- the new value- Returns:
trueif successful- Since:
- 9
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