Class AtomicDouble
- java.lang.Object
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- java.lang.Number
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- com.google.common.util.concurrent.AtomicDouble
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- All Implemented Interfaces:
java.io.Serializable
public class AtomicDouble extends java.lang.Number implements java.io.Serializable
Adouble
value that may be updated atomically. See thejava.util.concurrent.atomic
package specification for description of the properties of atomic variables. AnAtomicDouble
is used in applications such as atomic accumulation, and cannot be used as a replacement for aDouble
. However, this class does extendNumber
to allow uniform access by tools and utilities that deal with numerically-based classes.This class compares primitive
double
values in methods such ascompareAndSet(double, double)
by comparing their bitwise representation usingDouble.doubleToRawLongBits(double)
, which differs from both the primitive double==
operator and fromDouble.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.
- Since:
- 11.0
- Author:
- Doug Lea, Martin Buchholz
- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description AtomicDouble()
Creates a newAtomicDouble
with initial value0.0
.AtomicDouble(double initialValue)
Creates a newAtomicDouble
with the given initial value.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method 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 thisAtomicDouble
as adouble
.float
floatValue()
Returns the value of thisAtomicDouble
as afloat
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 thisAtomicDouble
as anint
after a narrowing primitive conversion.void
lazySet(double newValue)
Eventually sets to the given value.long
longValue()
Returns the value of thisAtomicDouble
as along
after a narrowing primitive conversion.void
set(double newValue)
Sets to the given value.java.lang.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.
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Constructor Detail
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AtomicDouble
public AtomicDouble(double initialValue)
Creates a newAtomicDouble
with the given initial value.- Parameters:
initialValue
- the initial value
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AtomicDouble
public AtomicDouble()
Creates a newAtomicDouble
with initial value0.0
.
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Method Detail
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get
public final double get()
Gets the current value.- Returns:
- the current value
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set
public final void set(double newValue)
Sets to the given value.- Parameters:
newValue
- the new value
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lazySet
public final void lazySet(double newValue)
Eventually sets to the given value.- Parameters:
newValue
- the new value
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getAndSet
public final double getAndSet(double newValue)
Atomically sets to the given value and returns the old value.- Parameters:
newValue
- the new value- Returns:
- the previous value
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compareAndSet
public final 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.- Parameters:
expect
- the expected valueupdate
- the new value- Returns:
true
if successful. False return indicates that the actual value was not bitwise equal to the expected value.
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weakCompareAndSet
public final 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.May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to
compareAndSet
.- Parameters:
expect
- the expected valueupdate
- the new value- Returns:
true
if successful
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getAndAdd
@CanIgnoreReturnValue public final double getAndAdd(double delta)
Atomically adds the given value to the current value.- Parameters:
delta
- the value to add- Returns:
- the previous value
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addAndGet
@CanIgnoreReturnValue public final double addAndGet(double delta)
Atomically adds the given value to the current value.- Parameters:
delta
- the value to add- Returns:
- the updated value
- Since:
- 31.1
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toString
public java.lang.String toString()
Returns the String representation of the current value.- Overrides:
toString
in classjava.lang.Object
- Returns:
- the String representation of the current value
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intValue
public int intValue()
Returns the value of thisAtomicDouble
as anint
after a narrowing primitive conversion.- Specified by:
intValue
in classjava.lang.Number
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longValue
public long longValue()
Returns the value of thisAtomicDouble
as along
after a narrowing primitive conversion.- Specified by:
longValue
in classjava.lang.Number
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floatValue
public float floatValue()
Returns the value of thisAtomicDouble
as afloat
after a narrowing primitive conversion.- Specified by:
floatValue
in classjava.lang.Number
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doubleValue
public double doubleValue()
Returns the value of thisAtomicDouble
as adouble
.- Specified by:
doubleValue
in classjava.lang.Number
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