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java.lang.Objectjava.lang.Number
com.google.common.util.concurrent.AtomicDouble
@Beta public class AtomicDouble
A 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
and
.
| Constructor Summary | |
|---|---|
AtomicDouble()
Creates a new AtomicDouble with initial value 0.0. |
|
AtomicDouble(double initialValue)
Creates a new AtomicDouble with the given initial value. |
|
| Method Summary | |
|---|---|
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. |
| 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 |
|---|
public AtomicDouble(double initialValue)
AtomicDouble with the given initial value.
initialValue - the initial valuepublic AtomicDouble()
AtomicDouble with initial value 0.0.
| Method Detail |
|---|
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 value
public final boolean compareAndSet(double expect,
double update)
expect - the expected valueupdate - 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 valueupdate - the new value
true if successfulpublic final double getAndAdd(double delta)
delta - the value to add
public final double addAndGet(double delta)
delta - the value to add
public String toString()
toString in class Objectpublic int intValue()
AtomicDouble as an int
after a narrowing primitive conversion.
intValue in class Numberpublic long longValue()
AtomicDouble as a long
after a narrowing primitive conversion.
longValue in class Numberpublic float floatValue()
AtomicDouble as a float
after a narrowing primitive conversion.
floatValue in class Numberpublic double doubleValue()
AtomicDouble as a double.
doubleValue in class Number
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