Class AtomicReferenceArray<E>

java.lang.Object
java.util.concurrent.atomic.AtomicReferenceArray<E>
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 the VarHandle specification for descriptions of the properties of atomic accesses.
Since:
1.5
See Also:

  • 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.

  • Method Summary

    Modifier and Type
    Method
    Description
    final E
    accumulateAndGet(int i, E x, BinaryOperator<E> accumulatorFunction)
    Atomically updates (with memory effects as specified by VarHandle.compareAndSet(Object...)) the element at index i with the results of applying the given function to the current and given values, returning the updated value.
    final E
    compareAndExchange(int i, E expectedValue, E newValue)
    Atomically sets the element at index i to newValue if the element's current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchange(Object...).
    final E
    compareAndExchangeAcquire(int i, E expectedValue, E newValue)
    Atomically sets the element at index i to newValue if the element's current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchangeAcquire(Object...).
    final E
    compareAndExchangeRelease(int i, E expectedValue, E newValue)
    Atomically sets the element at index i to newValue if the element's current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchangeRelease(Object...).
    final boolean
    compareAndSet(int i, E expectedValue, E newValue)
    Atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.compareAndSet(Object...).
    final E
    get(int i)
    Returns the current value of the element at index i, with memory effects as specified by VarHandle.getVolatile(Object...).
    final E
    getAcquire(int i)
    Returns the current value of the element at index i, with memory effects as specified by VarHandle.getAcquire(Object...).
    final E
    getAndAccumulate(int i, E x, BinaryOperator<E> accumulatorFunction)
    Atomically updates (with memory effects as specified by VarHandle.compareAndSet(Object...)) the element at index i with the results of applying the given function to the current and given values, returning the previous value.
    final E
    getAndSet(int i, E newValue)
    Atomically sets the element at index i to newValue and returns the old value, with memory effects as specified by VarHandle.getAndSet(Object...).
    final E
    getAndUpdate(int i, UnaryOperator<E> updateFunction)
    Atomically updates (with memory effects as specified by VarHandle.compareAndSet(Object...)) the element at index i with the results of applying the given function, returning the previous value.
    final E
    getOpaque(int i)
    Returns the current value of the element at index i, with memory effects as specified by VarHandle.getOpaque(Object...).
    final E
    getPlain(int i)
    Returns the current value of the element at index i, with memory semantics of reading as if the variable was declared non-volatile.
    final void
    lazySet(int i, E newValue)
    Sets the element at index i to newValue, with memory effects as specified by VarHandle.setRelease(Object...).
    final int
    length()
    Returns the length of the array.
    final void
    set(int i, E newValue)
    Sets the element at index i to newValue, with memory effects as specified by VarHandle.setVolatile(Object...).
    final void
    setOpaque(int i, E newValue)
    Sets the element at index i to newValue, with memory effects as specified by VarHandle.setOpaque(Object...).
    final void
    setPlain(int i, E newValue)
    Sets the element at index i to newValue, with memory semantics of setting as if the variable was declared non-volatile and non-final.
    final void
    setRelease(int i, E newValue)
    Sets the element at index i to newValue, with memory effects as specified by VarHandle.setRelease(Object...).
    String
    toString()
    Returns the String representation of the current values of array.
    final E
    updateAndGet(int i, UnaryOperator<E> updateFunction)
    Atomically updates (with memory effects as specified by VarHandle.compareAndSet(Object...)) the element at index i with the results of applying the given function, returning the updated value.
    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 as compareAndExchange(int, E, E) and compareAndSet(int, E, E)).
    final boolean
    weakCompareAndSetAcquire(int i, E expectedValue, E newValue)
    Possibly atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetAcquire(Object...).
    final boolean
    weakCompareAndSetPlain(int i, E expectedValue, E newValue)
    Possibly atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetPlain(Object...).
    final boolean
    weakCompareAndSetRelease(int i, E expectedValue, E newValue)
    Possibly atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetRelease(Object...).
    final boolean
    weakCompareAndSetVolatile(int i, E expectedValue, E newValue)
    Possibly atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSet(Object...).

    Methods declared in class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    Modifier and Type
    Method
    Description
    protected Object
    clone()
    Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
    boolean
    equals(Object o)
    Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
    protected void
    finalize()
    Deprecated, for removal: This API element is subject to removal in a future version.
    May cause performance issues, deadlocks and hangs.
    final Class<? extends Object>
    getClass()
    Answers the unique instance of java.lang.Class which represents the class of the receiver.
    int
    hashCode()
    Answers an integer hash code for the receiver.
    final void
    notify()
    Causes one thread which is waiting on the receiver to be made ready to run.
    final void
    notifyAll()
    Causes all threads which are waiting on the receiver to be made ready to run.
    final void
    wait()
    Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
    final void
    wait(long time)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
    final void
    wait(long time, int frac)
    Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

  • Constructor Details

    • 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

    • 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

  • Method Details

    • length

      public final int length()
      Returns the length of the array.
      Returns:
      the length of the array

    • get

      public final E get(int i)
      Returns the current value of the element at index i, with memory effects as specified by VarHandle.getVolatile(Object...).
      Parameters:
      i - the index
      Returns:
      the current value

    • set

      public final void set(int i, E newValue)
      Sets the element at index i to newValue, with memory effects as specified by VarHandle.setVolatile(Object...).
      Parameters:
      i - the index
      newValue - the new value

    • lazySet

      public final void lazySet(int i, E newValue)
      Sets the element at index i to newValue, with memory effects as specified by VarHandle.setRelease(Object...).
      Parameters:
      i - the index
      newValue - the new value
      Since:
      1.6

    • getAndSet

      public final E getAndSet(int i, E newValue)
      Atomically sets the element at index i to newValue and returns the old value, with memory effects as specified by VarHandle.getAndSet(Object...).
      Parameters:
      i - the index
      newValue - the new value
      Returns:
      the previous value

    • compareAndSet

      public final boolean compareAndSet(int i, E expectedValue, E newValue)
      Atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.compareAndSet(Object...).
      Parameters:
      i - the index
      expectedValue - the expected value
      newValue - the new value
      Returns:
      true if successful. False return indicates that the actual value was not equal to the expected value.

    • 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 as compareAndExchange(int, E, E) and compareAndSet(int, E, E)). To avoid confusion over plain or volatile memory effects it is recommended that the method weakCompareAndSetPlain(int, E, E) be used instead.
      Possibly atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetPlain(Object...).
      Parameters:
      i - the index
      expectedValue - the expected value
      newValue - the new value
      Returns:
      true if successful
      See Also:

    • weakCompareAndSetPlain

      public final boolean weakCompareAndSetPlain(int i, E expectedValue, E newValue)
      Possibly atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetPlain(Object...).
      Parameters:
      i - the index
      expectedValue - the expected value
      newValue - the new value
      Returns:
      true if successful
      Since:
      9

    • getAndUpdate

      public final E getAndUpdate(int i, UnaryOperator<E> updateFunction)
      Atomically updates (with memory effects as specified by VarHandle.compareAndSet(Object...)) the element at index i 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:
      i - the index
      updateFunction - a side-effect-free function
      Returns:
      the previous value
      Since:
      1.8

    • updateAndGet

      public final E updateAndGet(int i, UnaryOperator<E> updateFunction)
      Atomically updates (with memory effects as specified by VarHandle.compareAndSet(Object...)) the element at index i 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:
      i - the index
      updateFunction - a side-effect-free function
      Returns:
      the updated value
      Since:
      1.8

    • getAndAccumulate

      public final E getAndAccumulate(int i, E x, BinaryOperator<E> accumulatorFunction)
      Atomically updates (with memory effects as specified by VarHandle.compareAndSet(Object...)) the element at index i 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 of the element at index i as its first argument, and the given update as the second argument.
      Parameters:
      i - the index
      x - the update value
      accumulatorFunction - a side-effect-free function of two arguments
      Returns:
      the previous value
      Since:
      1.8

    • accumulateAndGet

      public final E accumulateAndGet(int i, E x, BinaryOperator<E> accumulatorFunction)
      Atomically updates (with memory effects as specified by VarHandle.compareAndSet(Object...)) the element at index i 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 of the element at index i as its first argument, and the given update as the second argument.
      Parameters:
      i - the index
      x - the update value
      accumulatorFunction - a side-effect-free function of two arguments
      Returns:
      the updated value
      Since:
      1.8

    • toString

      public String toString()
      Returns the String representation of the current values of array.
      Overrides:
      toString in class Object
      Returns:
      the String representation of the current values of array

    • getPlain

      public final E getPlain(int i)
      Returns the current value of the element at index i, with memory semantics of reading as if the variable was declared non-volatile.
      Parameters:
      i - the index
      Returns:
      the value
      Since:
      9

    • setPlain

      public final void setPlain(int i, E newValue)
      Sets the element at index i to newValue, with memory semantics of setting as if the variable was declared non-volatile and non-final.
      Parameters:
      i - the index
      newValue - the new value
      Since:
      9

    • getOpaque

      public final E getOpaque(int i)
      Returns the current value of the element at index i, with memory effects as specified by VarHandle.getOpaque(Object...).
      Parameters:
      i - the index
      Returns:
      the value
      Since:
      9

    • setOpaque

      public final void setOpaque(int i, E newValue)
      Sets the element at index i to newValue, with memory effects as specified by VarHandle.setOpaque(Object...).
      Parameters:
      i - the index
      newValue - the new value
      Since:
      9

    • getAcquire

      public final E getAcquire(int i)
      Returns the current value of the element at index i, with memory effects as specified by VarHandle.getAcquire(Object...).
      Parameters:
      i - the index
      Returns:
      the value
      Since:
      9

    • setRelease

      public final void setRelease(int i, E newValue)
      Sets the element at index i to newValue, with memory effects as specified by VarHandle.setRelease(Object...).
      Parameters:
      i - the index
      newValue - the new value
      Since:
      9

    • compareAndExchange

      public final E compareAndExchange(int i, E expectedValue, E newValue)
      Atomically sets the element at index i to newValue if the element's current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchange(Object...).
      Parameters:
      i - the index
      expectedValue - the expected value
      newValue - the new value
      Returns:
      the witness value, which will be the same as the expected value if successful
      Since:
      9

    • compareAndExchangeAcquire

      public final E compareAndExchangeAcquire(int i, E expectedValue, E newValue)
      Atomically sets the element at index i to newValue if the element's current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchangeAcquire(Object...).
      Parameters:
      i - the index
      expectedValue - the expected value
      newValue - the new value
      Returns:
      the witness value, which will be the same as the expected value if successful
      Since:
      9

    • compareAndExchangeRelease

      public final E compareAndExchangeRelease(int i, E expectedValue, E newValue)
      Atomically sets the element at index i to newValue if the element's current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchangeRelease(Object...).
      Parameters:
      i - the index
      expectedValue - the expected value
      newValue - the new value
      Returns:
      the witness value, which will be the same as the expected value if successful
      Since:
      9

    • weakCompareAndSetVolatile

      public final boolean weakCompareAndSetVolatile(int i, E expectedValue, E newValue)
      Possibly atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSet(Object...).
      Parameters:
      i - the index
      expectedValue - the expected value
      newValue - the new value
      Returns:
      true if successful
      Since:
      9

    • weakCompareAndSetAcquire

      public final boolean weakCompareAndSetAcquire(int i, E expectedValue, E newValue)
      Possibly atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetAcquire(Object...).
      Parameters:
      i - the index
      expectedValue - the expected value
      newValue - the new value
      Returns:
      true if successful
      Since:
      9

    • weakCompareAndSetRelease

      public final boolean weakCompareAndSetRelease(int i, E expectedValue, E newValue)
      Possibly atomically sets the element at index i to newValue if the element's current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetRelease(Object...).
      Parameters:
      i - the index
      expectedValue - the expected value
      newValue - the new value
      Returns:
      true if successful
      Since:
      9