java.util.concurrent.atomic

Class AtomicReference<V>

  • Type Parameters:
    V - The type of object referred to by this reference
    All Implemented Interfaces:
    Serializable 

    public class AtomicReference<V>
extends Object
implements Serializable
    An object reference that may be updated atomically. See the java.util.concurrent.atomic package specification for description of the properties of atomic variables.
    Since:
    1.5
    See Also:
    Serialized Form

    • Constructor Summary

      Constructors

      Constructor and Description
      AtomicReference()
      Creates a new AtomicReference with null initial value.
      AtomicReference(V initialValue)
      Creates a new AtomicReference with the given initial value.

    • Method Summary

      Modifier and Type Method and Description
      V accumulateAndGet(V x, BinaryOperator<V> accumulatorFunction)
      Atomically updates the current value with the results of applying the given function to the current and given values, returning the updated value.
      boolean compareAndSet(V expect, V update)
      Atomically sets the value to the given updated value if the current value == the expected value.
      V get()
      Gets the current value.
      V getAndAccumulate(V x, BinaryOperator<V> accumulatorFunction)
      Atomically updates the current value with the results of applying the given function to the current and given values, returning the previous value.
      V getAndSet(V newValue)
      Atomically sets to the given value and returns the old value.
      V getAndUpdate(UnaryOperator<V> updateFunction)
      Atomically updates the current value with the results of applying the given function, returning the previous value.
      void lazySet(V newValue)
      Eventually sets to the given value.
      void set(V newValue)
      Sets to the given value.
      String toString()
      Returns the String representation of the current value.
      V updateAndGet(UnaryOperator<V> updateFunction)
      Atomically updates the current value with the results of applying the given function, returning the updated value.
      boolean weakCompareAndSet(V expect, V update)
      Atomically sets the value to the given updated value if the current value == the expected value.

    • Constructor Detail

      • AtomicReference

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

      • AtomicReference

        public AtomicReference()
        Creates a new AtomicReference with null initial value.

    • Method Detail

      • get

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

      • set

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

      • lazySet

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

      • compareAndSet

        public final boolean compareAndSet(V expect,
                                   V 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(V expect,
                                       V 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

      • getAndSet

        public final V getAndSet(V newValue)
        Atomically sets to the given value and returns the old value.
        Parameters:
        newValue - the new value
        Returns:
        the previous value

      • getAndUpdate

        public final V getAndUpdate(UnaryOperator<V> updateFunction)
        Atomically updates 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 V updateAndGet(UnaryOperator<V> updateFunction)
        Atomically updates 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 V getAndAccumulate(V x,
                                BinaryOperator<V> accumulatorFunction)
        Atomically updates 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 V accumulateAndGet(V x,
                                BinaryOperator<V> accumulatorFunction)
        Atomically updates 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