java.util.concurrent.atomic

Class AtomicLong

Implemented Interfaces:
Serializable

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.
Since:
1.5
See Also:
Serialized Form

Constructor Summary

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

Method Summary

long
addAndGet(long delta)
Atomically adds the given value to the current value.
boolean
compareAndSet(long expect, long update)
Atomically sets the value to the given updated value if the current value == the expected value.
long
decrementAndGet()
Atomically decrements by one the current value.
double
doubleValue()
float
floatValue()
long
get()
Gets the current value.
long
getAndAdd(long delta)
Atomically adds the given value to the current value.
long
getAndDecrement()
Atomically decrements by one the current value.
long
getAndIncrement()
Atomically increments by one the current value.
long
getAndSet(long newValue)
Atomically sets to the given value and returns the old value.
long
incrementAndGet()
Atomically increments by one the current value.
int
intValue()
void
lazySet(long newValue)
Eventually sets to the given value.
long
longValue()
void
set(long newValue)
Sets to the given value.
String
toString()
Returns the String representation of the current value.
boolean
weakCompareAndSet(long expect, long 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, doubleValue, floatValue, intValue, longValue, shortValue

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

AtomicLong

public AtomicLong()
Creates a new AtomicLong with initial value 0.

AtomicLong

public AtomicLong(long initialValue)
Creates a new AtomicLong with the given initial value.
Parameters:
initialValue - the initial value

Method Details

addAndGet

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

compareAndSet

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.

decrementAndGet

public final long decrementAndGet()
Atomically decrements by one the current value.
Returns:
the updated value

doubleValue

public double doubleValue()
Overrides:
doubleValue in interface Number

floatValue

public float floatValue()
Overrides:
floatValue in interface Number

get

public final long get()
Gets the current value.
Returns:
the current value

getAndAdd

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

getAndDecrement

public final long getAndDecrement()
Atomically decrements by one the current value.
Returns:
the previous value

getAndIncrement

public final long getAndIncrement()
Atomically increments by one the current value.
Returns:
the previous value

getAndSet

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

incrementAndGet

public final long incrementAndGet()
Atomically increments by one the current value.
Returns:
the updated value

intValue

public int intValue()
Overrides:
intValue in interface Number

lazySet

public final void lazySet(long newValue)
Eventually sets to the given value.
Parameters:
newValue - the new value
Since:
1.6

longValue

public long longValue()
Overrides:
longValue in interface Number

set

public final void set(long newValue)
Sets to the given value.
Parameters:
newValue - the new value

toString

public String toString()
Returns the String representation of the current value.
Overrides:
toString in interface Object
Returns:
the String representation of the current value.

weakCompareAndSet

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.