Class AtomicInteger

• java.lang.Object
• • java.lang.Number
  • • java.util.concurrent.atomic.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

Constructors

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.

Methods

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)

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.

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.

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.