Java™ Platform
Standard Ed. 6

java.util.concurrent.atomic
Class AtomicInteger

java.lang.Object
  extended by java.lang.Number
      extended by 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()
          Returns the value of the specified number as a double.
 float floatValue()
          Returns the value of the specified number as a float.
 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()
          Returns the value of the specified number as an int.
 void lazySet(int newValue)
          Eventually sets to the given value.
 long longValue()
          Returns the value of the specified number as a long.
 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
Returns the value of the specified number as an int. This may involve rounding or truncation.

Specified by:
intValue in class Number
Returns:
the numeric value represented by this object after conversion to type int.

longValue

public long longValue()
Description copied from class: Number
Returns the value of the specified number as a long. This may involve rounding or truncation.

Specified by:
longValue in class Number
Returns:
the numeric value represented by this object after conversion to type long.

floatValue

public float floatValue()
Description copied from class: Number
Returns the value of the specified number as a float. This may involve rounding.

Specified by:
floatValue in class Number
Returns:
the numeric value represented by this object after conversion to type float.

doubleValue

public double doubleValue()
Description copied from class: Number
Returns the value of the specified number as a double. This may involve rounding.

Specified by:
doubleValue in class Number
Returns:
the numeric value represented by this object after conversion to type double.

Java™ Platform
Standard Ed. 6

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