public class AtomicDouble extends Number implements 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.doubleToRawLongBits(double),
which differs from both the primitive double == operator
and from Double.equals(java.lang.Object), 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 valuepublic AtomicDouble()
AtomicDouble with initial value 0.0.public final double get()
public final void set(double newValue)
newValue - the new valuepublic final void lazySet(double newValue)
newValue - the new valuepublic final double getAndSet(double newValue)
newValue - the new valuepublic final boolean compareAndSet(double expect, double update)
expect - the expected valueupdate - the new valuetrue 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 valueupdate - the new valuetrue if successfulpublic final double getAndAdd(double delta)
delta - the value to addpublic final double addAndGet(double delta)
delta - the value to addpublic 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.floatValue in class Numberpublic double doubleValue()
AtomicDouble as a double.doubleValue in class NumberCopyright © 2010-2015. All Rights Reserved.