Module java.base
Package 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 VarHandle specification for descriptions of the properties of atomic accesses. 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
See Also:

  • Constructor Details Link icon

    • AtomicInteger Link icon

      public AtomicInteger(int initialValue)
      Creates a new AtomicInteger with the given initial value.
      Parameters:
      initialValue - the initial value

    • AtomicInteger Link icon

      public AtomicInteger()
      Creates a new AtomicInteger with initial value 0.

  • Method Details Link icon

    • get Link icon

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

    • set Link icon

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

    • lazySet Link icon

      public final void lazySet(int 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 Link icon

      public final int getAndSet(int 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 Link icon

      public final boolean compareAndSet(int expectedValue, int 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 Link icon

      @Deprecated(since="9") public final boolean weakCompareAndSet(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) and compareAndSet(int, int)). To avoid confusion over plain or volatile memory effects it is recommended that the method weakCompareAndSetPlain(int, int) 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 Link icon

      public final boolean weakCompareAndSetPlain(int expectedValue, int 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 Link icon

      public final int 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 Link icon

      public final int 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 Link icon

      public final int getAndAdd(int 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 Link icon

      public final int 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 Link icon

      public final int 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 Link icon

      public final int addAndGet(int 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 Link icon

      public final int getAndUpdate(IntUnaryOperator 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 Link icon

      public final int updateAndGet(IntUnaryOperator 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 Link icon

      public final int getAndAccumulate(int x, IntBinaryOperator 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 Link icon

      public final int accumulateAndGet(int x, IntBinaryOperator 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 Link icon

      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 Link icon

      public int intValue()
      Returns the current value of this AtomicInteger as an int, with memory effects as specified by VarHandle.getVolatile(java.lang.Object...). Equivalent to get().
      Specified by:
      intValue in class Number
      Returns:
      the numeric value represented by this object after conversion to type int.

    • longValue Link icon

      public long longValue()
      Returns the current value of this AtomicInteger as a long after a widening primitive conversion, with memory effects as specified by VarHandle.getVolatile(java.lang.Object...).
      Specified by:
      longValue in class Number
      Returns:
      the numeric value represented by this object after conversion to type long.
      See Java Language Specification:
      5.1.2 Widening Primitive Conversion

    • floatValue Link icon

      public float floatValue()
      Returns the current value of this AtomicInteger 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 Java Language Specification:
      5.1.2 Widening Primitive Conversion

    • doubleValue Link icon

      public double doubleValue()
      Returns the current value of this AtomicInteger 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 Java Language Specification:
      5.1.2 Widening Primitive Conversion

    • getPlain Link icon

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

    • setPlain Link icon

      public final void setPlain(int 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 Link icon

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

    • setOpaque Link icon

      public final void setOpaque(int 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 Link icon

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

    • setRelease Link icon

      public final void setRelease(int 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 Link icon

      public final int compareAndExchange(int expectedValue, int 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 Link icon

      public final int compareAndExchangeAcquire(int expectedValue, int 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 Link icon

      public final int compareAndExchangeRelease(int expectedValue, int 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 Link icon

      public final boolean weakCompareAndSetVolatile(int expectedValue, int 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 Link icon

      public final boolean weakCompareAndSetAcquire(int expectedValue, int 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 Link icon

      public final boolean weakCompareAndSetRelease(int expectedValue, int 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