com.ibm.icu.number

Class Rounder

java.lang.Object

com.ibm.icu.number.Rounder

All Implemented Interfaces:

java.lang.Cloneable

Direct Known Subclasses:

CurrencyRounder, FractionRounder

public abstract class Rounder
extends java.lang.Object
implements java.lang.Cloneable

A class that defines the rounding strategy to be used when formatting numbers in NumberFormatter.

To create a Rounder, use one of the factory methods.

See Also:

NumberFormatter

Status:

Draft ICU 60.

Method Summary

Modifier and Type	Method and Description
abstract void	apply(com.ibm.icu.impl.number.DecimalQuantity value) Deprecated. ICU 60 This API is ICU internal only.
java.lang.Object	clone() Deprecated. This API is ICU internal only.
static CurrencyRounder	currency(Currency.CurrencyUsage currencyUsage) Show numbers rounded and padded according to the rules for the currency unit.
static Rounder	fixedDigits(int minMaxSignificantDigits) Show numbers rounded if necessary to a certain number of significant digits or significant figures.
static FractionRounder	fixedFraction(int minMaxFractionPlaces) Show numbers rounded if necessary to a certain number of fraction places (numerals after the decimal separator).
static Rounder	increment(java.math.BigDecimal roundingIncrement) Show numbers rounded if necessary to the closest multiple of a certain rounding increment.
static FractionRounder	integer() Show numbers rounded if necessary to the nearest integer.
static Rounder	maxDigits(int maxSignificantDigits) Show numbers rounded if necessary to a certain number of significant digits/figures.
static FractionRounder	maxFraction(int maxFractionPlaces) Show numbers rounded if necessary to a certain number of fraction places (numerals after the decimal separator).
static Rounder	minDigits(int minSignificantDigits) Always show at least a certain number of significant digits/figures, padding with zeros if necessary.
static FractionRounder	minFraction(int minFractionPlaces) Always show at least a certain number of fraction places after the decimal separator, padding with zeros if necessary.
static Rounder	minMaxDigits(int minSignificantDigits, int maxSignificantDigits) Show numbers rounded if necessary to a certain number of significant digits/figures; in addition, always show at least a certain number of significant digits, padding with zeros if necessary.
static FractionRounder	minMaxFraction(int minFractionPlaces, int maxFractionPlaces) Show numbers rounded if necessary to a certain number of fraction places (numerals after the decimal separator); in addition, always show at least a certain number of places after the decimal separator, padding with zeros if necessary.
static Rounder	unlimited() Show all available digits to full precision.
Rounder	withMode(java.math.MathContext mathContext) Deprecated. This API is ICU internal only.
Rounder	withMode(java.math.RoundingMode roundingMode) Sets the RoundingMode to use when picking the direction to round (up or down).

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

unlimited

public static Rounder unlimited()

Show all available digits to full precision.

NOTE: When formatting a double, this method, along with minFraction(int) and minDigits(int), will trigger complex algorithm similar to Dragon4 to determine the low-order digits and the number of digits to display based on the value of the double. If the number of fraction places or significant digits can be bounded, consider using maxFraction(int) or maxDigits(int) instead to maximize performance. For more information, read the following blog post.

http://www.serpentine.com/blog/2011/06/29/here-be-dragons-advances-in-problems-you-didnt-even-know-you-had/

Returns:

A Rounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

integer

public static FractionRounder integer()

Show numbers rounded if necessary to the nearest integer.

Returns:

A FractionRounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

fixedFraction

public static FractionRounder fixedFraction(int minMaxFractionPlaces)

Show numbers rounded if necessary to a certain number of fraction places (numerals after the decimal separator). Additionally, pad with zeros to ensure that this number of places are always shown.

Example output with minMaxFractionPlaces = 3:

87,650.000
8,765.000
876.500
87.650
8.765
0.876
0.088
0.009
0.000 (zero)

This method is equivalent to minMaxFraction(int, int) with both arguments equal.

Parameters:

minMaxFractionPlaces - The minimum and maximum number of numerals to display after the decimal separator (rounding if too long or padding with zeros if too short).

Returns:

A FractionRounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

minFraction

public static FractionRounder minFraction(int minFractionPlaces)

Always show at least a certain number of fraction places after the decimal separator, padding with zeros if necessary. Do not perform rounding (display numbers to their full precision).

NOTE: If you are formatting doubles, see the performance note in unlimited().

Parameters:

minFractionPlaces - The minimum number of numerals to display after the decimal separator (padding with zeros if necessary).

Returns:

A FractionRounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

maxFraction

public static FractionRounder maxFraction(int maxFractionPlaces)

Show numbers rounded if necessary to a certain number of fraction places (numerals after the decimal separator). Unlike the other fraction rounding strategies, this strategy does not pad zeros to the end of the number.

Parameters:

maxFractionPlaces - The maximum number of numerals to display after the decimal mark (rounding if necessary).

Returns:

A FractionRounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

minMaxFraction

public static FractionRounder minMaxFraction(int minFractionPlaces,
                                             int maxFractionPlaces)

Show numbers rounded if necessary to a certain number of fraction places (numerals after the decimal separator); in addition, always show at least a certain number of places after the decimal separator, padding with zeros if necessary.

Parameters:

minFractionPlaces - The minimum number of numerals to display after the decimal separator (padding with zeros if necessary).

maxFractionPlaces - The maximum number of numerals to display after the decimal separator (rounding if necessary).

Returns:

A FractionRounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

fixedDigits

public static Rounder fixedDigits(int minMaxSignificantDigits)

Show numbers rounded if necessary to a certain number of significant digits or significant figures. Additionally, pad with zeros to ensure that this number of significant digits/figures are always shown.

This method is equivalent to minMaxDigits(int, int) with both arguments equal.

Parameters:

minMaxSignificantDigits - The minimum and maximum number of significant digits to display (rounding if too long or padding with zeros if too short).

Returns:

A Rounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

minDigits

public static Rounder minDigits(int minSignificantDigits)

Always show at least a certain number of significant digits/figures, padding with zeros if necessary. Do not perform rounding (display numbers to their full precision).

NOTE: If you are formatting doubles, see the performance note in unlimited().

Parameters:

minSignificantDigits - The minimum number of significant digits to display (padding with zeros if too short).

Returns:

A Rounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

maxDigits

public static Rounder maxDigits(int maxSignificantDigits)

Show numbers rounded if necessary to a certain number of significant digits/figures.

Parameters:

maxSignificantDigits - The maximum number of significant digits to display (rounding if too long).

Returns:

A Rounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

minMaxDigits

public static Rounder minMaxDigits(int minSignificantDigits,
                                   int maxSignificantDigits)

Show numbers rounded if necessary to a certain number of significant digits/figures; in addition, always show at least a certain number of significant digits, padding with zeros if necessary.

Parameters:

minSignificantDigits - The minimum number of significant digits to display (padding with zeros if necessary).

maxSignificantDigits - The maximum number of significant digits to display (rounding if necessary).

Returns:

A Rounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

increment

public static Rounder increment(java.math.BigDecimal roundingIncrement)

Show numbers rounded if necessary to the closest multiple of a certain rounding increment. For example, if the rounding increment is 0.5, then round 1.2 to 1 and round 1.3 to 1.5.

In order to ensure that numbers are padded to the appropriate number of fraction places, set the scale on the rounding increment BigDecimal. For example, to round to the nearest 0.5 and always display 2 numerals after the decimal separator (to display 1.2 as "1.00" and 1.3 as "1.50"), you can run:

 Rounder.increment(new BigDecimal("0.50"))
 

For more information on the scale of Java BigDecimal, see BigDecimal.scale().

Parameters:

roundingIncrement - The increment to which to round numbers.

Returns:

A Rounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

currency

public static CurrencyRounder currency(Currency.CurrencyUsage currencyUsage)

Show numbers rounded and padded according to the rules for the currency unit. The most common rounding settings for currencies include Rounder.fixedFraction(2), Rounder.integer(), and Rounder.increment(0.05) for cash transactions ("nickel rounding").

The exact rounding details will be resolved at runtime based on the currency unit specified in the NumberFormatter chain. To round according to the rules for one currency while displaying the symbol for another currency, the withCurrency() method can be called on the return value of this method.

Parameters:

currencyUsage - Either STANDARD (for digital transactions) or CASH (for transactions where the rounding increment may be limited by the available denominations of cash or coins).

Returns:

A CurrencyRounder for chaining or passing to the NumberFormatter rounding() setter.

See Also:

NumberFormatter

Status:

Draft ICU 60.

withMode

public Rounder withMode(java.math.RoundingMode roundingMode)

Sets the RoundingMode to use when picking the direction to round (up or down). Common values include HALF_EVEN, HALF_UP, and FLOOR. The default is HALF_EVEN.

Parameters:

roundingMode - The RoundingMode to use.

Returns:

A Rounder for chaining.

See Also:

NumberFormatter

Status:

Draft ICU 60.

withMode

@Deprecated
public Rounder withMode(java.math.MathContext mathContext)

Deprecated. This API is ICU internal only.

Sets a MathContext directly instead of RoundingMode.

Status:

Internal. This API is ICU internal only.

clone

@Deprecated
public java.lang.Object clone()

Deprecated. This API is ICU internal only.

Overrides:

clone in class java.lang.Object

Status:

Internal. This API is ICU internal only.

apply

@Deprecated
public abstract void apply(com.ibm.icu.impl.number.DecimalQuantity value)

Deprecated. ICU 60 This API is ICU internal only.

Status:

Internal. This API is ICU internal only.