Module java.base

Class 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
    Author:
    Doug Lea
    See Also:
    Serialized Form
    • 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

      • 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.
      • 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
        See The Java™ Language Specification:
        5.1.3 Narrowing Primitive Conversions
      • 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
        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
        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
      • 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
      • 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