public class AtomicDouble extends Numberimplements Serializable
double value that may be updated atomically. See the
java.util.concurrent.atomic package specification for description of the properties of atomic variables. An
AtomicDouble is used in applications such as atomic accumulation, and cannot be used as a replacement for a
Double. However, this class does extend
Number to allow uniform access by tools and utilities that deal with numerically-based classes.
This class compares primitive double values in methods such as compareAndSet(double, double) by comparing their bitwise representation using Double, which differs from both the primitive double == operator and from Double, as if implemented by:
static boolean bitEquals(double x, double y) { long xBits = Double.doubleToRawLongBits(x); long yBits = Double.doubleToRawLongBits(y); return xBits == yBits; }
It is possible to write a more scalable updater, at the cost of giving up strict atomicity. See for example DoubleAdder and DoubleMaxUpdater.
| Constructor and Description |
|---|
AtomicDouble()
Creates a new
AtomicDouble with initial value
0.0.
|
AtomicDouble(double initialValue)
Creates a new
AtomicDouble with the given initial value.
|
| Modifier and Type | Method and Description |
|---|---|
double |
addAndGet(double delta)
Atomically adds the given value to the current value.
|
boolean |
compareAndSet(double expect, double update)
Atomically sets the value to the given updated value if the current value is
bitwise equal to the expected value.
|
double |
doubleValue()
Returns the value of this
AtomicDouble as a
double.
|
float |
floatValue()
Returns the value of this
AtomicDouble as a
float after a narrowing primitive conversion.
|
double |
get()
Gets the current value.
|
double |
getAndAdd(double delta)
Atomically adds the given value to the current value.
|
double |
getAndSet(double newValue)
Atomically sets to the given value and returns the old value.
|
int |
intValue()
Returns the value of this
AtomicDouble as an
int after a narrowing primitive conversion.
|
void |
lazySet(double newValue)
Eventually sets to the given value.
|
long |
longValue()
Returns the value of this
AtomicDouble as a
long after a narrowing primitive conversion.
|
void |
set(double newValue)
Sets to the given value.
|
String |
toString()
Returns the String representation of the current value.
|
boolean |
weakCompareAndSet(double expect, double update)
Atomically sets the value to the given updated value if the current value is
bitwise equal to the expected value.
|
byteValue, shortValuepublic AtomicDouble(double initialValue)
AtomicDouble with the given initial value.
initialValue - the initial value
public AtomicDouble()
AtomicDouble with initial value
0.0.
public final double get()
public final void set(double newValue)
newValue - the new value
public final void lazySet(double newValue)
newValue - the new value
public final double getAndSet(double newValue)
newValue - the new value
public final boolean compareAndSet(double expect,
double update)
expect - the expected value
update - the new value
true if successful. False return indicates that the actual value was not bitwise equal to the expected value.
public final boolean weakCompareAndSet(double expect,
double update)
May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to compareAndSet.
expect - the expected value
update - the new value
true if successful
public final double getAndAdd(double delta)
delta - the value to add
public final double addAndGet(double delta)
delta - the value to add
public StringtoString()
public int intValue()
AtomicDouble as an
int after a narrowing primitive conversion.
public long longValue()
AtomicDouble as a
long after a narrowing primitive conversion.
public float floatValue()
AtomicDouble as a
float after a narrowing primitive conversion.
public double doubleValue()
AtomicDouble as a
double.