AtomicIntegerArray (Java SE 26 & JDK 26)
Description: declaration: module: java.base, package: java.util.concurrent.atomic, class: AtomicIntegerArray
Keywords: java.util.concurrent.atomic.AtomicIntegerArray class

# Class AtomicIntegerArray

java.lang.Object
java.util.concurrent.atomic.AtomicIntegerArray

All Implemented Interfaces:
  `Serializable`

public class AtomicIntegerArray extends Object implements Serializable
An `int` array in which elements may be updated atomically. See the `VarHandle` specification for descriptions of the properties of atomic accesses.

Since:
  1.5
See Also:
  - Serialized Form

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `AtomicIntegerArray(int length)`
  Creates a new AtomicIntegerArray of the given length, with all elements initially zero.
  `AtomicIntegerArray(int[] array)`
  Creates a new AtomicIntegerArray with the same length as, and all elements copied from, the given array.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `final int`
  `accumulateAndGet(int i, int x, IntBinaryOperator 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 int`
  `addAndGet(int i, int delta)`
  Atomically adds the given value to the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.
  `final int`
  `compareAndExchange(int i, int expectedValue, int 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 int`
  `compareAndExchangeAcquire(int i, int expectedValue, int 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 int`
  `compareAndExchangeRelease(int i, int expectedValue, int 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, int expectedValue, int 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 int`
  `decrementAndGet(int i)`
  Atomically decrements the value of the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.
  `final int`
  `get(int i)`
  Returns the current value of the element at index `i`, with memory effects as specified by `VarHandle.getVolatile(Object...)`.
  `final int`
  `getAcquire(int i)`
  Returns the current value of the element at index `i`, with memory effects as specified by `VarHandle.getAcquire(Object...)`.
  `final int`
  `getAndAccumulate(int i, int x, IntBinaryOperator 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 int`
  `getAndAdd(int i, int delta)`
  Atomically adds the given value to the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.
  `final int`
  `getAndDecrement(int i)`
  Atomically decrements the value of the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.
  `final int`
  `getAndIncrement(int i)`
  Atomically increments the value of the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.
  `final int`
  `getAndSet(int i, int 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 int`
  `getAndUpdate(int i, IntUnaryOperator 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 int`
  `getOpaque(int i)`
  Returns the current value of the element at index `i`, with memory effects as specified by `VarHandle.getOpaque(Object...)`.
  `final int`
  `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 int`
  `incrementAndGet(int i)`
  Atomically increments the value of the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.
  `final void`
  `lazySet(int i, int 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, int newValue)`
  Sets the element at index `i` to `newValue`, with memory effects as specified by `VarHandle.setVolatile(Object...)`.
  `final void`
  `setOpaque(int i, int newValue)`
  Sets the element at index `i` to `newValue`, with memory effects as specified by `VarHandle.setOpaque(Object...)`.
  `final void`
  `setPlain(int i, int 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, int 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 int`
  `updateAndGet(int i, IntUnaryOperator 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, int expectedValue, int newValue)`
  Deprecated.
  This method has plain memory effects but the method name implies volatile memory effects (see methods such as `compareAndExchange(int, int, int)` and `compareAndSet(int, int, int)`).
  `final boolean`
  `weakCompareAndSetAcquire(int i, int expectedValue, int 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, int expectedValue, int 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, int expectedValue, int 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, int expectedValue, int 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()`
  Creates and returns a copy of this object.
  `boolean`
  `equals(Object obj)`
  Indicates whether some other object is "equal to" this one.
  `protected void`
  `finalize()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Finalization is deprecated and subject to removal in a future release.
  `final Class<?>`
  `getClass()`
  Returns the runtime class of this `Object`.
  `int`
  `hashCode()`
  Returns a hash code value for this object.
  `final void`
  `notify()`
  Wakes up a single thread that is waiting on this object's monitor.
  `final void`
  `notifyAll()`
  Wakes up all threads that are waiting on this object's monitor.
  `final void`
  `wait()`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
  `final void`
  `wait(long timeoutMillis)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
  `final void`
  `wait(long timeoutMillis, int nanos)`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

- ## Constructor Details

  - ### AtomicIntegerArray

    public AtomicIntegerArray(int length)
    Creates a new AtomicIntegerArray of the given length, with all elements initially zero.
    Parameters:
      `length` - the length of the array

  - ### AtomicIntegerArray

    public AtomicIntegerArray(int[] array)
    Creates a new AtomicIntegerArray 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 int 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, int 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, int 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 int getAndSet(int i, int 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, int expectedValue, int 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, int expectedValue, int newValue)
    Deprecated.
    This method has plain memory effects but the method name implies volatile memory effects (see methods such as `compareAndExchange(int, int, int)` and `compareAndSet(int, int, int)`). To avoid confusion over plain or volatile memory effects it is recommended that the method `weakCompareAndSetPlain(int, int, int)` 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(int, int, int)`

  - ### weakCompareAndSetPlain

    public final boolean weakCompareAndSetPlain(int i, int expectedValue, int 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

  - ### getAndIncrement

    public final int getAndIncrement(int i)
    Atomically increments the value of the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.

    Equivalent to `getAndAdd(i, 1)`.

    Parameters:
      `i` - the index
    Returns:
      the previous value

  - ### getAndDecrement

    public final int getAndDecrement(int i)
    Atomically decrements the value of the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.

    Equivalent to `getAndAdd(i, -1)`.

    Parameters:
      `i` - the index
    Returns:
      the previous value

  - ### getAndAdd

    public final int getAndAdd(int i, int delta)
    Atomically adds the given value to the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.
    Parameters:
      `i` - the index
      `delta` - the value to add
    Returns:
      the previous value

  - ### incrementAndGet

    public final int incrementAndGet(int i)
    Atomically increments the value of the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.

    Equivalent to `addAndGet(i, 1)`.

    Parameters:
      `i` - the index
    Returns:
      the updated value

  - ### decrementAndGet

    public final int decrementAndGet(int i)
    Atomically decrements the value of the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.

    Equivalent to `addAndGet(i, -1)`.

    Parameters:
      `i` - the index
    Returns:
      the updated value

  - ### addAndGet

    public final int addAndGet(int i, int delta)
    Atomically adds the given value to the element at index `i`, with memory effects as specified by `VarHandle.getAndAdd(Object...)`.
    Parameters:
      `i` - the index
      `delta` - the value to add
    Returns:
      the updated value

  - ### getAndUpdate

    public final int getAndUpdate(int i, IntUnaryOperator 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 int updateAndGet(int i, IntUnaryOperator 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 int getAndAccumulate(int i, int x, IntBinaryOperator 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 int accumulateAndGet(int i, int x, IntBinaryOperator 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 int 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, int 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 int 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, int 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 int 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, int 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 int compareAndExchange(int i, int expectedValue, int 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 int compareAndExchangeAcquire(int i, int expectedValue, int 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 int compareAndExchangeRelease(int i, int expectedValue, int 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, int expectedValue, int 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, int expectedValue, int 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, int expectedValue, int 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