org.decimal4j.util

Class DoubleRounder

java.lang.Object

org.decimal4j.util.DoubleRounder

public final class DoubleRounder
extends Object

Utility class to round double values to an arbitrary decimal precision between 0 and 18. The rounding is efficient and garbage free.

Constructor Summary

Constructors

Constructor and Description
DoubleRounder(int precision) Creates a rounder for the given decimal precision.
DoubleRounder(ScaleMetrics scaleMetrics) Creates a rounder with the given scale metrics defining the decimal precision.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object obj) Returns true if obj is a DoubleRounder with the same precision as this rounder instance.
int	getPrecision() Returns the precision of this rounder, a value between zero and 18.
int	hashCode() Returns a hash code for this DoubleRounder instance.
double	round(double value) Rounds the given double value to the decimal precision of this rounder using HALF_UP rounding.
static double	round(double value, int precision) Rounds the given double value to the specified decimal precision using HALF_UP rounding.
static double	round(double value, int precision, RoundingMode roundingMode) Rounds the given double value to the specified decimal precision using the specified rounding mode.
double	round(double value, RoundingMode roundingMode) Rounds the given double value to the decimal precision of this rounder using the specified rounding mode.
String	toString() Returns a string consisting of the simple class name and the precision.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

DoubleRounder

public DoubleRounder(int precision)

Creates a rounder for the given decimal precision.

Parameters:

precision - the decimal rounding precision, must be in [0,18]

Throws:

IllegalArgumentException - if precision is negative or larger than 18

DoubleRounder

public DoubleRounder(ScaleMetrics scaleMetrics)

Creates a rounder with the given scale metrics defining the decimal precision.

Parameters:

scaleMetrics - the scale metrics determining the rounding precision

Throws:

NullPointerException - if scale metrics is null

Method Detail

getPrecision

public int getPrecision()

Returns the precision of this rounder, a value between zero and 18.

Returns:

this rounder's decimal precision

round

public double round(double value)

Rounds the given double value to the decimal precision of this rounder using HALF_UP rounding.

Parameters:

value - the value to round

Returns:

the rounded value

See Also:

getPrecision()

round

public double round(double value,
           RoundingMode roundingMode)

Rounds the given double value to the decimal precision of this rounder using the specified rounding mode.

Parameters:

value - the value to round

roundingMode - the rounding mode indicating how the least significant returned decimal digit of the result is to be calculated

Returns:

the rounded value

See Also:

getPrecision()

hashCode

public int hashCode()

Returns a hash code for this DoubleRounder instance.

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

equals

public boolean equals(Object obj)

Returns true if obj is a DoubleRounder with the same precision as this rounder instance.

Overrides:

equals in class Object

Parameters:

obj - the reference object with which to compare

Returns:

true for a double rounder with the same precision as this instance

toString

public String toString()

Returns a string consisting of the simple class name and the precision.

Overrides:

toString in class Object

Returns:

a string like "DoubleRounder[precision=7]"

round

public static final double round(double value,
           int precision)

Rounds the given double value to the specified decimal precision using HALF_UP rounding.

Parameters:

value - the value to round

precision - the decimal precision to round to (aka decimal places)

Returns:

the rounded value

round

public static final double round(double value,
           int precision,
           RoundingMode roundingMode)

Rounds the given double value to the specified decimal precision using the specified rounding mode.

Parameters:

value - the value to round

precision - the decimal precision to round to (aka decimal places)

roundingMode - the rounding mode indicating how the least significant returned decimal digit of the result is to be calculated

Returns:

the rounded value