Module java.base
Package java.util.concurrent.atomic

## Class AtomicLong

- java.lang.Object
- - java.lang.Number
  - - java.util.concurrent.atomic.AtomicLong

- All Implemented Interfaces:
    `Serializable`

      public class AtomicLong
      extends Number
      implements Serializable

  A `long` value that may be updated atomically. See the `VarHandle` specification for descriptions of the properties of atomic accesses. An `AtomicLong` is used in applications such as atomically incremented sequence numbers, and cannot be used as a replacement for a `Long`. However, this class does extend `Number` to allow uniform access by tools and utilities that deal with numerically-based classes.
  Since:
    1.5
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `AtomicLong()` | Creates a new AtomicLong with initial value `0`.
    `AtomicLong​(long initialValue)` | Creates a new AtomicLong with the given initial value.

  - ### Method Summary

    Modifier and Type | Method | Description
    --- | --- | ---
    `long` | `accumulateAndGet​(long x, LongBinaryOperator accumulatorFunction)` | Atomically updates (with memory effects as specified by `VarHandle.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.
    `long` | `addAndGet​(long delta)` | Atomically adds the given value to the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.
    `long` | `compareAndExchange​(long expectedValue, long newValue)` | Atomically sets the value to `newValue` if the current value, referred to as the witness value, `== expectedValue`, with memory effects as specified by `VarHandle.compareAndExchange(java.lang.Object...)`.
    `long` | `compareAndExchangeAcquire​(long expectedValue, long newValue)` | Atomically sets the value to `newValue` if the current value, referred to as the witness value, `== expectedValue`, with memory effects as specified by `VarHandle.compareAndExchangeAcquire(java.lang.Object...)`.
    `long` | `compareAndExchangeRelease​(long expectedValue, long newValue)` | Atomically sets the value to `newValue` if the current value, referred to as the witness value, `== expectedValue`, with memory effects as specified by `VarHandle.compareAndExchangeRelease(java.lang.Object...)`.
    `boolean` | `compareAndSet​(long expectedValue, long newValue)` | Atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.compareAndSet(java.lang.Object...)`.
    `long` | `decrementAndGet()` | Atomically decrements the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.
    `double` | `doubleValue()` | Returns the current value of this `AtomicLong` as a `double` after a widening primitive conversion, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`.
    `float` | `floatValue()` | Returns the current value of this `AtomicLong` as a `float` after a widening primitive conversion, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`.
    `long` | `get()` | Returns the current value, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`.
    `long` | `getAcquire()` | Returns the current value, with memory effects as specified by `VarHandle.getAcquire(java.lang.Object...)`.
    `long` | `getAndAccumulate​(long x, LongBinaryOperator accumulatorFunction)` | Atomically updates (with memory effects as specified by `VarHandle.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.
    `long` | `getAndAdd​(long delta)` | Atomically adds the given value to the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.
    `long` | `getAndDecrement()` | Atomically decrements the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.
    `long` | `getAndIncrement()` | Atomically increments the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.
    `long` | `getAndSet​(long newValue)` | Atomically sets the value to `newValue` and returns the old value, with memory effects as specified by `VarHandle.getAndSet(java.lang.Object...)`.
    `long` | `getAndUpdate​(LongUnaryOperator updateFunction)` | Atomically updates (with memory effects as specified by `VarHandle.compareAndSet(java.lang.Object...)`) the current value with the results of applying the given function, returning the previous value.
    `long` | `getOpaque()` | Returns the current value, with memory effects as specified by `VarHandle.getOpaque(java.lang.Object...)`.
    `long` | `getPlain()` | Returns the current value, with memory semantics of reading as if the variable was declared non-`volatile`.
    `long` | `incrementAndGet()` | Atomically increments the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.
    `int` | `intValue()` | Returns the current value of this `AtomicLong` as an `int` after a narrowing primitive conversion, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`.
    `void` | `lazySet​(long newValue)` | Sets the value to `newValue`, with memory effects as specified by `VarHandle.setRelease(java.lang.Object...)`.
    `long` | `longValue()` | Returns the current value of this `AtomicLong` as a `long`, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`.
    `void` | `set​(long newValue)` | Sets the value to `newValue`, with memory effects as specified by `VarHandle.setVolatile(java.lang.Object...)`.
    `void` | `setOpaque​(long newValue)` | Sets the value to `newValue`, with memory effects as specified by `VarHandle.setOpaque(java.lang.Object...)`.
    `void` | `setPlain​(long newValue)` | Sets the value to `newValue`, with memory semantics of setting as if the variable was declared non-`volatile` and non-`final`.
    `void` | `setRelease​(long newValue)` | Sets the value to `newValue`, with memory effects as specified by `VarHandle.setRelease(java.lang.Object...)`.
    `String` | `toString()` | Returns the String representation of the current value.
    `long` | `updateAndGet​(LongUnaryOperator updateFunction)` | Atomically updates (with memory effects as specified by `VarHandle.compareAndSet(java.lang.Object...)`) the current value with the results of applying the given function, returning the updated value.
    `boolean` | `weakCompareAndSet​(long expectedValue, long newValue)` | Deprecated. This method has plain memory effects but the method name implies volatile memory effects (see methods such as `compareAndExchange(long, long)` and `compareAndSet(long, long)`).
    `boolean` | `weakCompareAndSetAcquire​(long expectedValue, long newValue)` | Possibly atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.weakCompareAndSetAcquire(java.lang.Object...)`.
    `boolean` | `weakCompareAndSetPlain​(long expectedValue, long newValue)` | Possibly atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.weakCompareAndSetPlain(java.lang.Object...)`.
    `boolean` | `weakCompareAndSetRelease​(long expectedValue, long newValue)` | Possibly atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.weakCompareAndSetRelease(java.lang.Object...)`.
    `boolean` | `weakCompareAndSetVolatile​(long expectedValue, long newValue)` | Possibly atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.weakCompareAndSet(java.lang.Object...)`.

    - ### Methods declared in class java.lang.Number

      `byteValue, shortValue`

    - ### Methods declared in class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### AtomicLong

          public AtomicLong​(long initialValue)

      Creates a new AtomicLong with the given initial value.
      Parameters:
        `initialValue` - the initial value

    - #### AtomicLong

          public AtomicLong()

      Creates a new AtomicLong with initial value `0`.

  - ### Method Detail

    - #### get

          public final long get()

      Returns the current value, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`.
      Returns:
        the current value

    - #### set

          public final void set​(long newValue)

      Sets the value to `newValue`, with memory effects as specified by `VarHandle.setVolatile(java.lang.Object...)`.
      Parameters:
        `newValue` - the new value

    - #### lazySet

          public final void lazySet​(long newValue)

      Sets the value to `newValue`, with memory effects as specified by `VarHandle.setRelease(java.lang.Object...)`.
      Parameters:
        `newValue` - the new value
      Since:
        1.6

    - #### getAndSet

          public final long getAndSet​(long newValue)

      Atomically sets the value to `newValue` and returns the old value, with memory effects as specified by `VarHandle.getAndSet(java.lang.Object...)`.
      Parameters:
        `newValue` - the new value
      Returns:
        the previous value

    - #### compareAndSet

          public final boolean compareAndSet​(long expectedValue,
                                             long newValue)

      Atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.compareAndSet(java.lang.Object...)`.
      Parameters:
        `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​(long expectedValue,
                                                 long newValue)

      Deprecated.
      This method has plain memory effects but the method name implies volatile memory effects (see methods such as `compareAndExchange(long, long)` and `compareAndSet(long, long)`). To avoid confusion over plain or volatile memory effects it is recommended that the method `weakCompareAndSetPlain(long, long)` be used instead.
      Possibly atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.weakCompareAndSetPlain(java.lang.Object...)`.
      Parameters:
        `expectedValue` - the expected value
        `newValue` - the new value
      Returns:
        `true` if successful
      See Also:
        `weakCompareAndSetPlain(long, long)`

    - #### weakCompareAndSetPlain

          public final boolean weakCompareAndSetPlain​(long expectedValue,
                                                      long newValue)

      Possibly atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.weakCompareAndSetPlain(java.lang.Object...)`.
      Parameters:
        `expectedValue` - the expected value
        `newValue` - the new value
      Returns:
        `true` if successful
      Since:
        9

    - #### getAndIncrement

          public final long getAndIncrement()

      Atomically increments the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.

      Equivalent to `getAndAdd(1)`.

      Returns:
        the previous value

    - #### getAndDecrement

          public final long getAndDecrement()

      Atomically decrements the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.

      Equivalent to `getAndAdd(-1)`.

      Returns:
        the previous value

    - #### getAndAdd

          public final long getAndAdd​(long delta)

      Atomically adds the given value to the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.
      Parameters:
        `delta` - the value to add
      Returns:
        the previous value

    - #### incrementAndGet

          public final long incrementAndGet()

      Atomically increments the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.

      Equivalent to `addAndGet(1)`.

      Returns:
        the updated value

    - #### decrementAndGet

          public final long decrementAndGet()

      Atomically decrements the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.

      Equivalent to `addAndGet(-1)`.

      Returns:
        the updated value

    - #### addAndGet

          public final long addAndGet​(long delta)

      Atomically adds the given value to the current value, with memory effects as specified by `VarHandle.getAndAdd(java.lang.Object...)`.
      Parameters:
        `delta` - the value to add
      Returns:
        the updated value

    - #### getAndUpdate

          public final long getAndUpdate​(LongUnaryOperator updateFunction)

      Atomically updates (with memory effects as specified by `VarHandle.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

    - #### updateAndGet

          public final long updateAndGet​(LongUnaryOperator updateFunction)

      Atomically updates (with memory effects as specified by `VarHandle.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

    - #### getAndAccumulate

          public final long getAndAccumulate​(long x,
                                             LongBinaryOperator accumulatorFunction)

      Atomically updates (with memory effects as specified by `VarHandle.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 value
        `accumulatorFunction` - a side-effect-free function of two arguments
      Returns:
        the previous value
      Since:
        1.8

    - #### accumulateAndGet

          public final long accumulateAndGet​(long x,
                                             LongBinaryOperator accumulatorFunction)

      Atomically updates (with memory effects as specified by `VarHandle.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 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 value.
      Overrides:
        `toString` in class `Object`
      Returns:
        the String representation of the current value

    - #### intValue

          public int intValue()

      Returns the current value of this `AtomicLong` as an `int` after a narrowing primitive conversion, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`.
      Specified by:
        `intValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `int`.
      See The Java™ Language Specification:
        5.1.3 Narrowing Primitive Conversions

    - #### longValue

          public long longValue()

      Returns the current value of this `AtomicLong` as a `long`, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`. Equivalent to `get()`.
      Specified by:
        `longValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `long`.

    - #### floatValue

          public float floatValue()

      Returns the current value of this `AtomicLong` as a `float` after a widening primitive conversion, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`.
      Specified by:
        `floatValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `float`.
      See The Java™ Language Specification:
        5.1.2 Widening Primitive Conversions

    - #### doubleValue

          public double doubleValue()

      Returns the current value of this `AtomicLong` as a `double` after a widening primitive conversion, with memory effects as specified by `VarHandle.getVolatile(java.lang.Object...)`.
      Specified by:
        `doubleValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `double`.
      See The Java™ Language Specification:
        5.1.2 Widening Primitive Conversions

    - #### getPlain

          public final long getPlain()

      Returns the current value, with memory semantics of reading as if the variable was declared non-`volatile`.
      Returns:
        the value
      Since:
        9

    - #### setPlain

          public final void setPlain​(long newValue)

      Sets the value to `newValue`, with memory semantics of setting as if the variable was declared non-`volatile` and non-`final`.
      Parameters:
        `newValue` - the new value
      Since:
        9

    - #### getOpaque

          public final long getOpaque()

      Returns the current value, with memory effects as specified by `VarHandle.getOpaque(java.lang.Object...)`.
      Returns:
        the value
      Since:
        9

    - #### setOpaque

          public final void setOpaque​(long newValue)

      Sets the value to `newValue`, with memory effects as specified by `VarHandle.setOpaque(java.lang.Object...)`.
      Parameters:
        `newValue` - the new value
      Since:
        9

    - #### getAcquire

          public final long getAcquire()

      Returns the current value, with memory effects as specified by `VarHandle.getAcquire(java.lang.Object...)`.
      Returns:
        the value
      Since:
        9

    - #### setRelease

          public final void setRelease​(long newValue)

      Sets the value to `newValue`, with memory effects as specified by `VarHandle.setRelease(java.lang.Object...)`.
      Parameters:
        `newValue` - the new value
      Since:
        9

    - #### compareAndExchange

          public final long compareAndExchange​(long expectedValue,
                                               long newValue)

      Atomically sets the value to `newValue` if the current value, referred to as the witness value, `== expectedValue`, with memory effects as specified by `VarHandle.compareAndExchange(java.lang.Object...)`.
      Parameters:
        `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 long compareAndExchangeAcquire​(long expectedValue,
                                                      long newValue)

      Atomically sets the value to `newValue` if the current value, referred to as the witness value, `== expectedValue`, with memory effects as specified by `VarHandle.compareAndExchangeAcquire(java.lang.Object...)`.
      Parameters:
        `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 long compareAndExchangeRelease​(long expectedValue,
                                                      long newValue)

      Atomically sets the value to `newValue` if the current value, referred to as the witness value, `== expectedValue`, with memory effects as specified by `VarHandle.compareAndExchangeRelease(java.lang.Object...)`.
      Parameters:
        `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​(long expectedValue,
                                                         long newValue)

      Possibly atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.weakCompareAndSet(java.lang.Object...)`.
      Parameters:
        `expectedValue` - the expected value
        `newValue` - the new value
      Returns:
        `true` if successful
      Since:
        9

    - #### weakCompareAndSetAcquire

          public final boolean weakCompareAndSetAcquire​(long expectedValue,
                                                        long newValue)

      Possibly atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.weakCompareAndSetAcquire(java.lang.Object...)`.
      Parameters:
        `expectedValue` - the expected value
        `newValue` - the new value
      Returns:
        `true` if successful
      Since:
        9

    - #### weakCompareAndSetRelease

          public final boolean weakCompareAndSetRelease​(long expectedValue,
                                                        long newValue)

      Possibly atomically sets the value to `newValue` if the current value `== expectedValue`, with memory effects as specified by `VarHandle.weakCompareAndSetRelease(java.lang.Object...)`.
      Parameters:
        `expectedValue` - the expected value
        `newValue` - the new value
      Returns:
        `true` if successful
      Since:
        9