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 java.util.concurrent.atomic package specification for description of the properties of atomic variables. 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
Author:
Doug Lea
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 addAndGet​(long delta)
    Atomically adds the given value to the current value.
    boolean compareAndSet​(long expect, long update)
    Atomically sets the value to the given updated value if the current value == the expected value.
    long decrementAndGet()
    Atomically decrements by one the current value.
    double doubleValue()
    Returns the value of this AtomicLong as a double after a widening primitive conversion.
    float floatValue()
    Returns the value of this AtomicLong as a float after a widening primitive conversion.
    long get()
    Gets the current value.
    long getAndAdd​(long delta)
    Atomically adds the given value to the current value.
    long getAndDecrement()
    Atomically decrements by one the current value.
    long getAndIncrement()
    Atomically increments by one the current value.
    long getAndSet​(long newValue)
    Atomically sets to the given value and returns the old value.
    long incrementAndGet()
    Atomically increments by one the current value.
    int intValue()
    Returns the value of this AtomicLong as an int after a narrowing primitive conversion.
    void lazySet​(long newValue)
    Eventually sets to the given value.
    long longValue()
    Returns the value of this AtomicLong as a long.
    void set​(long newValue)
    Sets to the given value.
    String toString()
    Returns the String representation of the current value.
    boolean weakCompareAndSet​(long expect, long 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 Details

    • 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 Details

    • get

      public final long get()
      Gets the current value.
      Returns:
      the current value

    • set

      public final void set​(long newValue)
      Sets to the given value.
      Parameters:
      newValue - the new value

    • lazySet

      public final void lazySet​(long newValue)
      Eventually sets to the given value.
      Parameters:
      newValue - the new value
      Since:
      1.6

    • getAndSet

      public final long getAndSet​(long 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​(long expect, long 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​(long expect, long 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 long getAndIncrement()
      Atomically increments by one the current value.
      Returns:
      the previous value

    • getAndDecrement

      public final long getAndDecrement()
      Atomically decrements by one the current value.
      Returns:
      the previous value

    • getAndAdd

      public final long getAndAdd​(long delta)
      Atomically adds the given value to the current value.
      Parameters:
      delta - the value to add
      Returns:
      the previous value

    • incrementAndGet

      public final long incrementAndGet()
      Atomically increments by one the current value.
      Returns:
      the updated value

    • decrementAndGet

      public final long decrementAndGet()
      Atomically decrements by one the current value.
      Returns:
      the updated value

    • addAndGet

      public final long addAndGet​(long 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()
      Returns the value of this AtomicLong as an int after a narrowing primitive conversion.
      Specified by:
      intValue in class Number
      Returns:
      the primitive int value of this object.

    • longValue

      public long longValue()
      Returns the value of this AtomicLong as a long.
      Specified by:
      longValue in class Number
      Returns:
      the primitive long value of this object.

    • floatValue

      public float floatValue()
      Returns the value of this AtomicLong as a float after a widening primitive conversion.
      Specified by:
      floatValue in class Number
      Returns:
      the primitive float value of this object.

    • doubleValue

      public double doubleValue()
      Returns the value of this AtomicLong as a double after a widening primitive conversion.
      Specified by:
      doubleValue in class Number
      Returns:
      the primitive double value of this object.