edu.rit.pj.reduction
Class SharedDouble

java.lang.Object
  java.lang.Number
      edu.rit.pj.reduction.SharedDouble

All Implemented Interfaces:

Serializable

public class SharedDouble
extends Number

Class SharedDouble provides a reduction variable for a value of type double.

Class SharedDouble is multiple thread safe. The methods use lock-free atomic compare-and-set.

Note: Class SharedDouble is implemented using class java.util.concurrent.atomic.AtomicLong. The double value is stored as a long whose bit pattern is the same as the double value.

See Also:

Serialized Form

Constructor Summary

SharedDouble()
Construct a new double reduction variable with the initial value 0.

SharedDouble(double initialValue)
Construct a new double reduction variable with the given initial value.

Method Summary

double	addAndGet(double value) Add the given value to this reduction variable and return the new value.
boolean	compareAndSet(double expect, double update) Atomically set this reduction variable to the given updated value if the current value equals the expected value.
double	decrementAndGet() Subtract one from this reduction variable and return the new value.
double	doubleValue() Returns this reduction variable's current value converted to type double.
float	floatValue() Returns this reduction variable's current value converted to type float.
double	get() Returns this reduction variable's current value.
double	getAndAdd(double value) Add the given value to this reduction variable and return the previous value.
double	getAndDecrement() Subtract one from this reduction variable and return the previous value.
double	getAndIncrement() Add one to this reduction variable and return the previous value.
double	getAndSet(double value) Set this reduction variable to the given value and return the previous value.
double	incrementAndGet() Add one to this reduction variable and return the new value.
int	intValue() Returns this reduction variable's current value converted to type int.
long	longValue() Returns this reduction variable's current value converted to type long.
double	reduce(double value, DoubleOp op) Combine this reduction variable with the given value using the given operation.
void	set(double value) Set this reduction variable to the given value.
String	toString() Returns a string version of this reduction variable.
boolean	weakCompareAndSet(double expect, double update) Atomically set this reduction variable to the given updated value if the current value equals 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

SharedDouble

public SharedDouble()

Construct a new double reduction variable with the initial value 0.

SharedDouble

public SharedDouble(double initialValue)

Construct a new double reduction variable with the given initial value.

Parameters:

initialValue - Initial value.

Method Detail

get

public double get()

Returns this reduction variable's current value.

Returns:

Current value.

set

public void set(double value)

Set this reduction variable to the given value.

Parameters:

value - New value.

getAndSet

public double getAndSet(double value)

Set this reduction variable to the given value and return the previous value.

Parameters:

value - New value.

Returns:

Previous value.

compareAndSet

public boolean compareAndSet(double expect,
                             double update)

Atomically set this reduction variable to the given updated value if the current value equals the expected value.

Parameters:

expect - Expected value.

update - Updated value.

Returns:

True if the update happened, false otherwise.

weakCompareAndSet

public boolean weakCompareAndSet(double expect,
                                 double update)

Atomically set this reduction variable to the given updated value if the current value equals the expected value. May fail spuriously.

Parameters:

expect - Expected value.

update - Updated value.

Returns:

True if the update happened, false otherwise.

getAndIncrement

public double getAndIncrement()

Add one to this reduction variable and return the previous value.

Returns:

Previous value.

getAndDecrement

public double getAndDecrement()

Subtract one from this reduction variable and return the previous value.

Returns:

Previous value.

getAndAdd

public double getAndAdd(double value)

Add the given value to this reduction variable and return the previous value.

Parameters:

value - Value to add.

Returns:

Previous value.

incrementAndGet

public double incrementAndGet()

Add one to this reduction variable and return the new value.

Returns:

New value.

decrementAndGet

public double decrementAndGet()

Subtract one from this reduction variable and return the new value.

Returns:

New value.

addAndGet

public double addAndGet(double value)

Add the given value to this reduction variable and return the new value.

Parameters:

value - Value to add.

Returns:

New value.

reduce

public double reduce(double value,
                     DoubleOp op)

Combine this reduction variable with the given value using the given operation. The result is stored back into this reduction variable and is returned.

Parameters:

value - Value.

op - Binary operation.

Returns:

(This variable) op (value).

toString

public String toString()

Returns a string version of this reduction variable.

Overrides:

toString in class Object

Returns:

String version.

intValue

public int intValue()

Returns this reduction variable's current value converted to type int.

Specified by:

intValue in class Number

Returns:

Current value.

longValue

public long longValue()

Returns this reduction variable's current value converted to type long.

Specified by:

longValue in class Number

Returns:

Current value.

floatValue

public float floatValue()

Returns this reduction variable's current value converted to type float.

Specified by:

floatValue in class Number

Returns:

Current value.

doubleValue

public double doubleValue()

Returns this reduction variable's current value converted to type double.

Specified by:

doubleValue in class Number

Returns:

Current value.