AtomicInteger

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.

Public Constructor Summary

AtomicInteger(int initialValue)
Creates a new AtomicInteger with the given initial value.
AtomicInteger()
Creates a new AtomicInteger with initial value 0.

Public Method Summary

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

Inherited Method Summary

Public Constructors

public AtomicInteger (int initialValue)

Creates a new AtomicInteger with the given initial value.

Parameters
initialValue the initial value

public AtomicInteger ()

Creates a new AtomicInteger with initial value 0.

Public Methods

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

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

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.

public final int decrementAndGet ()

Atomically decrements by one the current value.

Returns
  • the updated value

public double doubleValue ()

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

public float floatValue ()

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

public final int get ()

Gets the current value.

Returns
  • the current value

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

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

public final int getAndDecrement ()

Atomically decrements by one the current value.

Returns
  • the previous value

public final int getAndIncrement ()

Atomically increments by one the current value.

Returns
  • the previous value

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

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

public final int incrementAndGet ()

Atomically increments by one the current value.

Returns
  • the updated value

public int intValue ()

Returns the value of this AtomicInteger as an int. Equivalent to get().

public final void lazySet (int newValue)

Eventually sets to the given value.

Parameters
newValue the new value

public long longValue ()

Returns the value of this AtomicInteger as a long after a widening primitive conversion.

public final void set (int 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 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

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