java.util.concurrent.atomic
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

See Also:

Serialized Form

Constructor Summary

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

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

Method Summary

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() doubleValue returns this number as a double, may involve rounding or truncation.
float	floatValue() floatValue returns this number as a float, may involve rounding or truncation.
int	get() Gets the current 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	incrementAndGet() Atomically increments by one the current value.
int	intValue() intValue returns this number as an int, may involve rounding or truncation.
void	lazySet(int newValue) Eventually sets to the given value.
long	longValue() longValue returns this number as a long, may involve rounding or truncation.
void	set(int newValue) Sets to the given value.
String	toString() Returns the String representation of the current value.
boolean	weakCompareAndSet(int expect, int update) Atomically sets the value to the given updated value if the current value == the expected value.

Methods inherited from class java.lang.Number

byteValue, shortValue

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

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

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()

Description copied from class: Number

intValue returns this number as an int, may involve rounding or truncation.

Specified by:

intValue in class Number

Returns:

the value as an int.

longValue

public long longValue()

Description copied from class: Number

longValue returns this number as a long, may involve rounding or truncation.

Specified by:

longValue in class Number

Returns:

the value as a long.

floatValue

public float floatValue()

Description copied from class: Number

floatValue returns this number as a float, may involve rounding or truncation.

Specified by:

floatValue in class Number

Returns:

the value as a float.

doubleValue

public double doubleValue()

Description copied from class: Number

doubleValue returns this number as a double, may involve rounding or truncation.

Specified by:

doubleValue in class Number

Returns:

the value as a double.