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

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

Class AtomicInteger

  • All Implemented Interfaces:
    Serializable 

    public class AtomicInteger
extends Number
implements Serializable
    An int value that may be updated atomically. See the java.util.concurrent.atomic package specification for description of the properties of atomic variables. An AtomicInteger is used in applications such as atomically incremented counters, and cannot be used as a replacement for an Integer. 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
      AtomicInteger()
      Creates a new AtomicInteger with initial value 0.
      AtomicInteger(int initialValue)
      Creates a new AtomicInteger with the given initial value.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method and Description
      int accumulateAndGet(int x, IntBinaryOperator accumulatorFunction)
      Atomically updates the current value with the results of applying the given function to the current and given values, returning the updated value.
      int addAndGet(int delta)
      Atomically adds the given value to the current value.
      boolean compareAndSet(int expect, int update)
      Atomically sets the value to the given updated value if the current value == the expected value.
      int decrementAndGet()
      Atomically decrements by one the current value.
      double doubleValue()
      Returns the value of this AtomicInteger as a double after a widening primitive conversion.
      float floatValue()
      Returns the value of this AtomicInteger as a float after a widening primitive conversion.
      int get()
      Gets the current value.
      int getAndAccumulate(int x, IntBinaryOperator accumulatorFunction)
      Atomically updates the current value with the results of applying the given function to the current and given values, returning the previous value.
      int getAndAdd(int delta)
      Atomically adds the given value to the current value.
      int getAndDecrement()
      Atomically decrements by one the current value.
      int getAndIncrement()
      Atomically increments by one the current value.
      int getAndSet(int newValue)
      Atomically sets to the given value and returns the old value.
      int getAndUpdate(IntUnaryOperator updateFunction)
      Atomically updates the current value with the results of applying the given function, returning the previous value.
      int incrementAndGet()
      Atomically increments by one the current value.
      int intValue()
      Returns the value of this AtomicInteger as an int.
      void lazySet(int newValue)
      Eventually sets to the given value.
      long longValue()
      Returns the value of this AtomicInteger as a long after a widening primitive conversion.
      void set(int newValue)
      Sets to the given value.
      String toString()
      Returns the String representation of the current value.
      int updateAndGet(IntUnaryOperator updateFunction)
      Atomically updates the current value with the results of applying the given function, returning the updated value.
      boolean weakCompareAndSet(int expect, int update)
      Atomically sets the value to the given updated value if the current value == the expected value.

    • Constructor Detail

      • AtomicInteger

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

      • AtomicInteger

        public AtomicInteger()
        Creates a new AtomicInteger with initial value 0.

    • Method Detail

      • get

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

      • set

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

      • lazySet

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

      • getAndSet

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

      • getAndDecrement

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

      • getAndAdd

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

      • incrementAndGet

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

      • decrementAndGet

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

      • addAndGet

        public final int addAndGet(int delta)
        Atomically adds the given value to the current value.
        Parameters:
        delta - the value to add
        Returns:
        the updated value

      • getAndUpdate

        public final int getAndUpdate(IntUnaryOperator 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 int updateAndGet(IntUnaryOperator 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 int getAndAccumulate(int x,
                                  IntBinaryOperator 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 int accumulateAndGet(int x,
                                  IntBinaryOperator 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 AtomicInteger as an int.
        Specified by:
        intValue in class Number
        Returns:
        the numeric value represented by this object after conversion to type int.

      • longValue

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

      • floatValue

        public float floatValue()
        Returns the value of this AtomicInteger 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 AtomicInteger 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
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Java™ Platform
Standard Ed. 8

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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.
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