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 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()
      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 Java Language Specification:
      5.1.3 Narrowing Primitive Conversion

    • 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 Java Language Specification:
      5.1.2 Widening Primitive Conversion

    • 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 Java Language Specification:
      5.1.2 Widening Primitive Conversion

    • 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