Java Module java.base Package java.util.concurrent.atomic Class AtomicReferenceArray<E>（JDK11）

Constructor Detail

• 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 Detail

• 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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.Object...).

  Parameters:

  i - the index

  expectedValue - the expected value

  newValue - the new value

  Returns:

  true if successful

  See Also:

  weakCompareAndSetPlain(int, E, E)

• 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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.Object...).

  Parameters:

  i - the index

  expectedValue - the expected value

  newValue - the new value

  Returns:

  true if successful

  Since:

  9