AtomicLong

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.

Public Constructor Summary

AtomicLong(long initialValue)
Creates a new AtomicLong with the given initial value.
AtomicLong()
Creates a new AtomicLong with initial value 0.

Public Method Summary

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.
final long
addAndGet(long delta)
Atomically adds the given value to the current value.
final boolean
compareAndSet(long expect, long update)
Atomically sets the value to the given updated value if the current value == the expected value.
final 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.
final long
get()
Gets the current value.
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.
final long
getAndAdd(long delta)
Atomically adds the given value to the current value.
final long
getAndDecrement()
Atomically decrements by one the current value.
final long
getAndIncrement()
Atomically increments by one the current value.
final long
getAndSet(long newValue)
Atomically sets to the given value and returns the old value.
final long
getAndUpdate(LongUnaryOperator updateFunction)
Atomically updates the current value with the results of applying the given function, returning the previous value.
final 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.
final void
lazySet(long newValue)
Eventually sets to the given value.
long
longValue()
Returns the value of this AtomicLong as a long.
final void
set(long newValue)
Sets to the given value.
String
toString()
Returns the String representation of the current value.
final long
updateAndGet(LongUnaryOperator updateFunction)
Atomically updates the current value with the results of applying the given function, returning the updated value.
final boolean
weakCompareAndSet(long expect, long update)
Atomically sets the value to the given updated value if the current value == the expected value.

Inherited Method Summary

Public Constructors

public AtomicLong (long initialValue)

Creates a new AtomicLong with the given initial value.

Parameters
initialValue the initial value

public AtomicLong ()

Creates a new AtomicLong with initial value 0.

Public Methods

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

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

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.

public final long decrementAndGet ()

Atomically decrements by one the current value.

Returns
  • the updated value

public double doubleValue ()

Returns the value of this AtomicLong as a double after a widening primitive conversion.

public float floatValue ()

Returns the value of this AtomicLong as a float after a widening primitive conversion.

public final long get ()

Gets the current value.

Returns
  • the current value

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

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

public final long getAndDecrement ()

Atomically decrements by one the current value.

Returns
  • the previous value

public final long getAndIncrement ()

Atomically increments by one the current value.

Returns
  • the previous value

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

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

public final long incrementAndGet ()

Atomically increments by one the current value.

Returns
  • the updated value

public int intValue ()

Returns the value of this AtomicLong as an int after a narrowing primitive conversion.

public final void lazySet (long newValue)

Eventually sets to the given value.

Parameters
newValue the new value

public long longValue ()

Returns the value of this AtomicLong as a long. Equivalent to get().

public final void set (long newValue)

Sets to the given value.

Parameters
newValue the new value

public String toString ()

Returns the String representation of the current value.

Returns
  • the String representation of the current value

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

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