java.util.concurrent.atomic

## Class AtomicInteger

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

- All Implemented Interfaces:
    Serializable

      public class AtomicInteger
      extends Number
      implements Serializable

  An `int` value that may be updated atomically. See the `java.util.concurrent.atomic` package specification for description of the properties of atomic variables. An `AtomicInteger` is used in applications such as atomically incremented counters, and cannot be used as a replacement for an `Integer`. However, this class does extend `Number` to allow uniform access by tools and utilities that deal with numerically-based classes.
  Since:
    1.5
  Author:
    Doug Lea
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `AtomicInteger()` Creates a new AtomicInteger with initial value `0`.
    `AtomicInteger(int initialValue)` Creates a new AtomicInteger with the given initial value.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `addAndGet(int delta)` Atomically adds the given value to the current value.
    `boolean` | `compareAndSet(int expect, int update)` Atomically sets the value to the given updated value if the current value `==` the expected value.
    `int` | `decrementAndGet()` Atomically decrements by one the current value.
    `double` | `doubleValue()` Returns the value of the specified number as a `double`.
    `float` | `floatValue()` Returns the value of the specified number as a `float`.
    `int` | `get()` Gets the current value.
    `int` | `getAndAdd(int delta)` Atomically adds the given value to the current value.
    `int` | `getAndDecrement()` Atomically decrements by one the current value.
    `int` | `getAndIncrement()` Atomically increments by one the current value.
    `int` | `getAndSet(int newValue)` Atomically sets to the given value and returns the old value.
    `int` | `incrementAndGet()` Atomically increments by one the current value.
    `int` | `intValue()` Returns the value of the specified number as an `int`.
    `void` | `lazySet(int newValue)` Eventually sets to the given value.
    `long` | `longValue()` Returns the value of the specified number as a `long`.
    `void` | `set(int newValue)` Sets to the given value.
    `String` | `toString()` Returns the String representation of the current value.
    `boolean` | `weakCompareAndSet(int expect, int update)` Atomically sets the value to the given updated value if the current value `==` the expected value.

    - ### Methods inherited from class java.lang.Number

      `byteValue, shortValue`

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### AtomicInteger

          public AtomicInteger(int initialValue)

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

    - #### AtomicInteger

          public AtomicInteger()

      Creates a new AtomicInteger with initial value `0`.

  - ### Method Detail

    - #### get

          public final int get()

      Gets the current value.
      Returns:
        the current value

    - #### set

          public final void set(int newValue)

      Sets to the given value.
      Parameters:
        `newValue` - the new value

    - #### lazySet

          public final void lazySet(int newValue)

      Eventually sets to the given value.
      Parameters:
        `newValue` - the new value
      Since:
        1.6

    - #### getAndSet

          public final int getAndSet(int newValue)

      Atomically sets to the given value and returns the old value.
      Parameters:
        `newValue` - the new value
      Returns:
        the previous value

    - #### compareAndSet

          public final boolean compareAndSet(int expect,
                                             int update)

      Atomically sets the value to the given updated value if the current value `==` the expected value.
      Parameters:
        `expect` - the expected value
        `update` - the new value
      Returns:
        true if successful. False return indicates that the actual value was not equal to the expected value.

    - #### weakCompareAndSet

          public final boolean weakCompareAndSet(int expect,
                                                 int update)

      Atomically sets the value to the given updated value if the current value `==` the expected value.

      May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to `compareAndSet`.

      Parameters:
        `expect` - the expected value
        `update` - the new value
      Returns:
        true if successful.

    - #### getAndIncrement

          public final int getAndIncrement()

      Atomically increments by one the current value.
      Returns:
        the previous value

    - #### getAndDecrement

          public final int getAndDecrement()

      Atomically decrements by one the current value.
      Returns:
        the previous value

    - #### getAndAdd

          public final int getAndAdd(int delta)

      Atomically adds the given value to the current value.
      Parameters:
        `delta` - the value to add
      Returns:
        the previous value

    - #### incrementAndGet

          public final int incrementAndGet()

      Atomically increments by one the current value.
      Returns:
        the updated value

    - #### decrementAndGet

          public final int decrementAndGet()

      Atomically decrements by one the current value.
      Returns:
        the updated value

    - #### addAndGet

          public final int addAndGet(int delta)

      Atomically adds the given value to the current value.
      Parameters:
        `delta` - the value to add
      Returns:
        the updated value

    - #### 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()

      Description copied from class: `Number`
      Returns the value of the specified number as an `int`. This may involve rounding or truncation.
      Specified by:
        `intValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `int`.

    - #### longValue

          public long longValue()

      Description copied from class: `Number`
      Returns the value of the specified number as a `long`. This may involve rounding or truncation.
      Specified by:
        `longValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `long`.

    - #### floatValue

          public float floatValue()

      Description copied from class: `Number`
      Returns the value of the specified number as a `float`. This may involve rounding.
      Specified by:
        `floatValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `float`.

    - #### doubleValue

          public double doubleValue()

      Description copied from class: `Number`
      Returns the value of the specified number as a `double`. This may involve rounding.
      Specified by:
        `doubleValue` in class `Number`
      Returns:
        the numeric value represented by this object after conversion to type `double`.

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