1. 首页
  2. JavaAPI

Java compact1, compact2, compact3 java.util.concurrent.atomic Class AtomicLong（JDK8）

148 阅读 0 评论

Skip navigation links
Java™ Platform
Standard Ed. 8
compact1, compact2, compact3
java.util.concurrent.atomic

Class 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
    See Also:
    Serialized Form

    • Constructor Summary

      Constructors 
      Constructor and Description
      AtomicLong()
      Creates a new AtomicLong with initial value 0.
      AtomicLong(long initialValue)
      Creates a new AtomicLong with the given initial value.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method and Description
      long accumulateAndGet(long x, LongBinaryOperator accumulatorFunction)
      Atomically updates the current value with the results of applying the given function to the current and given values, returning the updated value.
      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 getAndAccumulate(long x, LongBinaryOperator accumulatorFunction)
      Atomically updates the current value with the results of applying the given function to the current and given values, returning the previous 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 getAndUpdate(LongUnaryOperator updateFunction)
      Atomically updates the current value with the results of applying the given function, returning the previous 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.
      long updateAndGet(LongUnaryOperator updateFunction)
      Atomically updates the current value with the results of applying the given function, returning the updated value.
      boolean weakCompareAndSet(long expect, long update)
      Atomically sets the value to the given updated value if the current value == the expected value.

    • 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

      • 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

      • getAndUpdate

        public final long getAndUpdate(LongUnaryOperator 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 long updateAndGet(LongUnaryOperator 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 long getAndAccumulate(long x,
                                   LongBinaryOperator 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 long accumulateAndGet(long x,
                                   LongBinaryOperator 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

      • 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 numeric value represented by this object after conversion to type int.
        See The Java™ Language Specification:
        5.1.3 Narrowing Primitive Conversions

      • longValue

        public long longValue()
        Returns the value of this AtomicLong as a long.
        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 value of this AtomicLong as a float after a widening primitive conversion.
        Specified by:
        floatValue in class Number
        Returns:
        the numeric value represented by this object after conversion to type float.
        See The Java™ Language Specification:
        5.1.2 Widening Primitive Conversions

      • 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 numeric value represented by this object after conversion to type double.
        See The Java™ Language Specification:
        5.1.2 Widening Primitive Conversions
Skip navigation links
Java™ Platform
Standard Ed. 8

Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2022, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.

微信小程序

微信扫一扫体验

微信公众账号

微信扫一扫加关注

 发表
评论 返回
顶部