Java Module java.base Package java.util.concurrent.atomic Class AtomicLong（JDK11）

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()

  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 The Java™ Language Specification:

  5.1.3 Narrowing Primitive Conversions

• 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 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

  Returns:

  the numeric value represented by this object after conversion to type double.

  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

• 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