DecimalFormat

public class DecimalFormat extends NumberFormat

[icu enhancement] ICU's replacement for DecimalFormat. Methods, fields, and other functionality specific to ICU are labeled '[icu]'. DecimalFormat is a concrete subclass of NumberFormat that formats decimal numbers. It has a variety of features designed to make it possible to parse and format numbers in any locale, including support for Western, Arabic, or Indic digits. It also supports different flavors of numbers, including integers ("123"), fixed-point numbers ("123.4"), scientific notation ("1.23E4"), percentages ("12%"), and currency amounts ("$123.00", "USD123.00", "123.00 US dollars"). All of these flavors can be easily localized.

To obtain a NumberFormat for a specific locale (including the default locale) call one of NumberFormat's factory methods such as getInstance(). Do not call the DecimalFormat constructors directly, unless you know what you are doing, since the NumberFormat factory methods may return subclasses other than DecimalFormat. If you need to customize the format object, do something like this:

 NumberFormat f = NumberFormat.getInstance(loc);
 if (f instanceof DecimalFormat) {
     ((DecimalFormat) f).setDecimalSeparatorAlwaysShown(true);
 }

Example Usage Print out a number using the localized number, currency, and percent format for each locale.

 Locale[] locales = NumberFormat.getAvailableLocales();
 double myNumber = -1234.56;
 NumberFormat format;
 for (int j=0; j<3; ++j) {
     System.out.println("FORMAT");
     for (int i = 0; i < locales.length; ++i) {
         if (locales[i].getCountry().length() == 0) {
            // Skip language-only locales
            continue;
         }
         System.out.print(locales[i].getDisplayName());
         switch (j) {
         case 0:
             format = NumberFormat.getInstance(locales[i]); break;
         case 1:
             format = NumberFormat.getCurrencyInstance(locales[i]); break;
         default:
             format = NumberFormat.getPercentInstance(locales[i]); break;
         }
         try {
             // Assume format is a DecimalFormat
             System.out.print(": " + ((DecimalFormat) format).toPattern()
                              + " -> " + form.format(myNumber));
         } catch (Exception e) {}
         try {
             System.out.println(" -> " + format.parse(form.format(myNumber)));
         } catch (ParseException e) {}
     }
 }

Another example use getInstance(style).
Print out a number using the localized number, currency, percent, scientific, integer, iso currency, and plural currency format for each locale.

 ULocale locale = new ULocale("en_US");
 double myNumber = 1234.56;
 for (int j=NumberFormat.NUMBERSTYLE; j<=NumberFormat.PLURALCURRENCYSTYLE; ++j) {
     NumberFormat format = NumberFormat.getInstance(locale, j);
     try {
         // Assume format is a DecimalFormat
         System.out.print(": " + ((DecimalFormat) format).toPattern()
                          + " -> " + form.format(myNumber));
     } catch (Exception e) {}
     try {
         System.out.println(" -> " + format.parse(form.format(myNumber)));
     } catch (ParseException e) {}
 }

Patterns

A DecimalFormat consists of a pattern and a set of symbols. The pattern may be set directly using applyPattern(String), or indirectly using other API methods which manipulate aspects of the pattern, such as the minimum number of integer digits. The symbols are stored in a DecimalFormatSymbols object. When using the NumberFormat factory methods, the pattern and symbols are read from ICU's locale data.

Special Pattern Characters

Many characters in a pattern are taken literally; they are matched during parsing and output unchanged during formatting. Special characters, on the other hand, stand for other characters, strings, or classes of characters. For example, the '#' character is replaced by a localized digit. Often the replacement character is the same as the pattern character; in the U.S. locale, the ',' grouping character is replaced by ','. However, the replacement is still happening, and if the symbols are modified, the grouping character changes. Some special characters affect the behavior of the formatter by their presence; for example, if the percent character is seen, then the value is multiplied by 100 before being displayed.

To insert a special character in a pattern as a literal, that is, without any special meaning, the character must be quoted. There are some exceptions to this which are noted below.

The characters listed here are used in non-localized patterns. Localized patterns use the corresponding characters taken from this formatter's DecimalFormatSymbols object instead, and these characters lose their special status. Two exceptions are the currency sign and quote, which are not localized.

Symbol Location Localized? Meaning
0 Number Yes Digit
1-9 Number Yes '1' through '9' indicate rounding.
@ Number No Significant digit
# Number Yes Digit, zero shows as absent
. Number Yes Decimal separator or monetary decimal separator
- Number Yes Minus sign
, Number Yes Grouping separator
E Number Yes Separates mantissa and exponent in scientific notation. Need not be quoted in prefix or suffix.
+ Exponent Yes Prefix positive exponents with localized plus sign. Need not be quoted in prefix or suffix.
; Subpattern boundary Yes Separates positive and negative subpatterns
% Prefix or suffix Yes Multiply by 100 and show as percentage
\u2030 Prefix or suffix Yes Multiply by 1000 and show as per mille
¤ (\u00A4) Prefix or suffix No Currency sign, replaced by currency symbol. If doubled, replaced by international currency symbol. If tripled, replaced by currency plural names, for example, "US dollar" or "US dollars" for America. If present in a pattern, the monetary decimal separator is used instead of the decimal separator.
' Prefix or suffix No Used to quote special characters in a prefix or suffix, for example, "'#'#" formats 123 to "#123". To create a single quote itself, use two in a row: "# o''clock".
* Prefix or suffix boundary Yes Pad escape, precedes pad character

A DecimalFormat pattern contains a postive and negative subpattern, for example, "#,##0.00;(#,##0.00)". Each subpattern has a prefix, a numeric part, and a suffix. If there is no explicit negative subpattern, the negative subpattern is the localized minus sign prefixed to the positive subpattern. That is, "0.00" alone is equivalent to "0.00;-0.00". If there is an explicit negative subpattern, it serves only to specify the negative prefix and suffix; the number of digits, minimal digits, and other characteristics are ignored in the negative subpattern. That means that "#,##0.0#;(#)" has precisely the same result as "#,##0.0#;(#,##0.0#)".

The prefixes, suffixes, and various symbols used for infinity, digits, thousands separators, decimal separators, etc. may be set to arbitrary values, and they will appear properly during formatting. However, care must be taken that the symbols and strings do not conflict, or parsing will be unreliable. For example, either the positive and negative prefixes or the suffixes must be distinct for parse(String) to be able to distinguish positive from negative values. Another example is that the decimal separator and thousands separator should be distinct characters, or parsing will be impossible.

The grouping separator is a character that separates clusters of integer digits to make large numbers more legible. It commonly used for thousands, but in some locales it separates ten-thousands. The grouping size is the number of digits between the grouping separators, such as 3 for "100,000,000" or 4 for "1 0000 0000". There are actually two different grouping sizes: One used for the least significant integer digits, the primary grouping size, and one used for all others, the secondary grouping size. In most locales these are the same, but sometimes they are different. For example, if the primary grouping interval is 3, and the secondary is 2, then this corresponds to the pattern "#,##,##0", and the number 123456789 is formatted as "12,34,56,789". If a pattern contains multiple grouping separators, the interval between the last one and the end of the integer defines the primary grouping size, and the interval between the last two defines the secondary grouping size. All others are ignored, so "#,##,###,####" == "###,###,####" == "##,#,###,####".

Illegal patterns, such as "#.#.#" or "#.###,###", will cause DecimalFormat to throw an IllegalArgumentException with a message that describes the problem.

Pattern BNF

 pattern    := subpattern (';' subpattern)?
 subpattern := prefix? number exponent? suffix?
 number     := (integer ('.' fraction)?) | sigDigits
 prefix     := '\u0000'..'\uFFFD' - specialCharacters
 suffix     := '\u0000'..'\uFFFD' - specialCharacters
 integer    := '#'* '0'* '0'
 fraction   := '0'* '#'*
 sigDigits  := '#'* '@' '@'* '#'*
 exponent   := 'E' '+'? '0'* '0'
 padSpec    := '*' padChar
 padChar    := '\u0000'..'\uFFFD' - quote
  
 Notation:
   X*       0 or more instances of X
   X?       0 or 1 instances of X
   X|Y      either X or Y
   C..D     any character from C up to D, inclusive
   S-T      characters in S, except those in T
 
The first subpattern is for positive numbers. The second (optional) subpattern is for negative numbers.

Not indicated in the BNF syntax above:

  • The grouping separator ',' can occur inside the integer and sigDigits elements, between any two pattern characters of that element, as long as the integer or sigDigits element is not followed by the exponent element.
  • Two grouping intervals are recognized: That between the decimal point and the first grouping symbol, and that between the first and second grouping symbols. These intervals are identical in most locales, but in some locales they differ. For example, the pattern "#,##,###" formats the number 123456789 as "12,34,56,789".
  • The pad specifier padSpec may appear before the prefix, after the prefix, before the suffix, after the suffix, or not at all.
  • In place of '0', the digits '1' through '9' may be used to indicate a rounding increment.

Parsing

DecimalFormat parses all Unicode characters that represent decimal digits, as defined by digit(int). In addition, DecimalFormat also recognizes as digits the ten consecutive characters starting with the localized zero digit defined in the DecimalFormatSymbols object. During formatting, the DecimalFormatSymbols-based digits are output.

During parsing, grouping separators are ignored.

For currency parsing, the formatter is able to parse every currency style formats no matter which style the formatter is constructed with. For example, a formatter instance gotten from NumberFormat.getInstance(ULocale, NumberFormat.CURRENCYSTYLE) can parse formats such as "USD1.00" and "3.00 US dollars".

If parse(String, ParsePosition) fails to parse a string, it returns null and leaves the parse position unchanged. The convenience method parse(String) indicates parse failure by throwing a ParseException.

Parsing an extremely large or small absolute value (such as 1.0E10000 or 1.0E-10000) requires huge memory allocation for representing the parsed number. Such input may expose a risk of DoS attacks. To prevent huge memory allocation triggered by such inputs, DecimalFormat internally limits of maximum decimal digits to be 1000. Thus, an input string resulting more than 1000 digits in plain decimal representation (non-exponent) will be treated as either overflow (positive/negative infinite) or underflow (+0.0/-0.0).

Formatting

Formatting is guided by several parameters, all of which can be specified either using a pattern or using the API. The following description applies to formats that do not use scientific notation or significant digits.

  • If the number of actual integer digits exceeds the maximum integer digits, then only the least significant digits are shown. For example, 1997 is formatted as "97" if the maximum integer digits is set to 2.
  • If the number of actual integer digits is less than the minimum integer digits, then leading zeros are added. For example, 1997 is formatted as "01997" if the minimum integer digits is set to 5.
  • If the number of actual fraction digits exceeds the maximum fraction digits, then half-even rounding it performed to the maximum fraction digits. For example, 0.125 is formatted as "0.12" if the maximum fraction digits is 2. This behavior can be changed by specifying a rounding increment and a rounding mode.
  • If the number of actual fraction digits is less than the minimum fraction digits, then trailing zeros are added. For example, 0.125 is formatted as "0.1250" if the mimimum fraction digits is set to 4.
  • Trailing fractional zeros are not displayed if they occur j positions after the decimal, where j is less than the maximum fraction digits. For example, 0.10004 is formatted as "0.1" if the maximum fraction digits is four or less.

Special Values

NaN is represented as a single character, typically \uFFFD. This character is determined by the DecimalFormatSymbols object. This is the only value for which the prefixes and suffixes are not used.

Infinity is represented as a single character, typically \u221E, with the positive or negative prefixes and suffixes applied. The infinity character is determined by the DecimalFormatSymbols object.

Scientific Notation

Numbers in scientific notation are expressed as the product of a mantissa and a power of ten, for example, 1234 can be expressed as 1.234 x 103. The mantissa is typically in the half-open interval [1.0, 10.0) or sometimes [0.0, 1.0), but it need not be. DecimalFormat supports arbitrary mantissas. DecimalFormat can be instructed to use scientific notation through the API or through the pattern. In a pattern, the exponent character immediately followed by one or more digit characters indicates scientific notation. Example: "0.###E0" formats the number 1234 as "1.234E3".

  • The number of digit characters after the exponent character gives the minimum exponent digit count. There is no maximum. Negative exponents are formatted using the localized minus sign, not the prefix and suffix from the pattern. This allows patterns such as "0.###E0 m/s". To prefix positive exponents with a localized plus sign, specify '+' between the exponent and the digits: "0.###E+0" will produce formats "1E+1", "1E+0", "1E-1", etc. (In localized patterns, use the localized plus sign rather than '+'.)
  • The minimum number of integer digits is achieved by adjusting the exponent. Example: 0.00123 formatted with "00.###E0" yields "12.3E-4". This only happens if there is no maximum number of integer digits. If there is a maximum, then the minimum number of integer digits is fixed at one.
  • The maximum number of integer digits, if present, specifies the exponent grouping. The most common use of this is to generate engineering notation, in which the exponent is a multiple of three, e.g., "##0.###E0". The number 12345 is formatted using "##0.####E0" as "12.345E3".
  • When using scientific notation, the formatter controls the digit counts using significant digits logic. The maximum number of significant digits limits the total number of integer and fraction digits that will be shown in the mantissa; it does not affect parsing. For example, 12345 formatted with "##0.##E0" is "12.3E3". See the section on significant digits for more details.
  • The number of significant digits shown is determined as follows: If areSignificantDigitsUsed() returns false, then the minimum number of significant digits shown is one, and the maximum number of significant digits shown is the sum of the minimum integer and maximum fraction digits, and is unaffected by the maximum integer digits. If this sum is zero, then all significant digits are shown. If areSignificantDigitsUsed() returns true, then the significant digit counts are specified by getMinimumSignificantDigits() and getMaximumSignificantDigits(). In this case, the number of integer digits is fixed at one, and there is no exponent grouping.
  • Exponential patterns may not contain grouping separators.

Significant Digits

DecimalFormat has two ways of controlling how many digits are shows: (a) significant digits counts, or (b) integer and fraction digit counts. Integer and fraction digit counts are described above. When a formatter is using significant digits counts, the number of integer and fraction digits is not specified directly, and the formatter settings for these counts are ignored. Instead, the formatter uses however many integer and fraction digits are required to display the specified number of significant digits. Examples:
Pattern Minimum significant digits Maximum significant digits Number Output of format()
@@@ 3 3 12345 12300
@@@ 3 3 0.12345 0.123
@@## 2 4 3.14159 3.142
@@## 2 4 1.23004 1.23
  • Significant digit counts may be expressed using patterns that specify a minimum and maximum number of significant digits. These are indicated by the '@' and '#' characters. The minimum number of significant digits is the number of '@' characters. The maximum number of significant digits is the number of '@' characters plus the number of '#' characters following on the right. For example, the pattern "@@@" indicates exactly 3 significant digits. The pattern "@##" indicates from 1 to 3 significant digits. Trailing zero digits to the right of the decimal separator are suppressed after the minimum number of significant digits have been shown. For example, the pattern "@##" formats the number 0.1203 as "0.12".
  • If a pattern uses significant digits, it may not contain a decimal separator, nor the '0' pattern character. Patterns such as "@00" or "@.###" are disallowed.
  • Any number of '#' characters may be prepended to the left of the leftmost '@' character. These have no effect on the minimum and maximum significant digits counts, but may be used to position grouping separators. For example, "#,#@#" indicates a minimum of one significant digits, a maximum of two significant digits, and a grouping size of three.
  • In order to enable significant digits formatting, use a pattern containing the '@' pattern character. Alternatively, call setSignificantDigitsUsed(true).
  • In order to disable significant digits formatting, use a pattern that does not contain the '@' pattern character. Alternatively, call setSignificantDigitsUsed(false).
  • The number of significant digits has no effect on parsing.
  • Significant digits may be used together with exponential notation. Such patterns are equivalent to a normal exponential pattern with a minimum and maximum integer digit count of one, a minimum fraction digit count of getMinimumSignificantDigits() - 1, and a maximum fraction digit count of getMaximumSignificantDigits() - 1. For example, the pattern "@@###E0" is equivalent to "0.0###E0".
  • If signficant digits are in use, then the integer and fraction digit counts, as set via the API, are ignored. If significant digits are not in use, then the signficant digit counts, as set via the API, are ignored.

Padding

DecimalFormat supports padding the result of format(BigDecimal) to a specific width. Padding may be specified either through the API or through the pattern syntax. In a pattern the pad escape character, followed by a single pad character, causes padding to be parsed and formatted. The pad escape character is '*' in unlocalized patterns, and can be localized using setPadEscape(char). For example, "$*x#,##0.00" formats 123 to "$xx123.00", and 1234 to "$1,234.00".

  • When padding is in effect, the width of the positive subpattern, including prefix and suffix, determines the format width. For example, in the pattern "* #0 o''clock", the format width is 10.
  • The width is counted in 16-bit code units (Java chars).
  • Some parameters which usually do not matter have meaning when padding is used, because the pattern width is significant with padding. In the pattern "* ##,##,#,##0.##", the format width is 14. The initial characters "##,##," do not affect the grouping size or maximum integer digits, but they do affect the format width.
  • Padding may be inserted at one of four locations: before the prefix, after the prefix, before the suffix, or after the suffix. If padding is specified in any other location, applyPattern(String) throws an IllegalArgumentException. If there is no prefix, before the prefix and after the prefix are equivalent, likewise for the suffix.
  • When specified in a pattern, the 16-bit char immediately following the pad escape is the pad character. This may be any character, including a special pattern character. That is, the pad escape escapes the following character. If there is no character after the pad escape, then the pattern is illegal.

Rounding

DecimalFormat supports rounding to a specific increment. For example, 1230 rounded to the nearest 50 is 1250. 1.234 rounded to the nearest 0.65 is 1.3. The rounding increment may be specified through the API or in a pattern. To specify a rounding increment in a pattern, include the increment in the pattern itself. "#,#50" specifies a rounding increment of 50. "#,##0.05" specifies a rounding increment of 0.05.

  • Rounding only affects the string produced by formatting. It does not affect parsing or change any numerical values.
  • A rounding mode determines how values are rounded; see the BigDecimal documentation for a description of the modes. Rounding increments specified in patterns use the default mode, ROUND_HALF_EVEN.
  • Some locales use rounding in their currency formats to reflect the smallest currency denomination.
  • In a pattern, digits '1' through '9' specify rounding, but otherwise behave identically to digit '0'.

Synchronization

DecimalFormat objects are not synchronized. Multiple threads should not access one formatter concurrently.

Constant Summary

int PAD_AFTER_PREFIX [icu] Constant for getPadPosition() and setPadPosition(int) to specify pad characters inserted after the prefix.
int PAD_AFTER_SUFFIX [icu] Constant for getPadPosition() and setPadPosition(int) to specify pad characters inserted after the suffix.
int PAD_BEFORE_PREFIX [icu] Constant for getPadPosition() and setPadPosition(int) to specify pad characters inserted before the prefix.
int PAD_BEFORE_SUFFIX [icu] Constant for getPadPosition() and setPadPosition(int) to specify pad characters inserted before the suffix.

Inherited Constant Summary

Public Constructor Summary

DecimalFormat()
Creates a DecimalFormat using the default pattern and symbols for the default FORMAT locale.
DecimalFormat(String pattern)
Creates a DecimalFormat from the given pattern and the symbols for the default FORMAT locale.
DecimalFormat(String pattern, DecimalFormatSymbols symbols)
Creates a DecimalFormat from the given pattern and symbols.
DecimalFormat(String pattern, DecimalFormatSymbols symbols, CurrencyPluralInfo infoInput, int style)
Creates a DecimalFormat from the given pattern, symbols, information used for currency plural format, and format style.

Public Method Summary

void
applyLocalizedPattern(String pattern)
Applies the given pattern to this Format object.
void
applyPattern(String pattern)
Applies the given pattern to this Format object.
boolean
areSignificantDigitsUsed()
[icu] Returns true if significant digits are in use or false if integer and fraction digit counts are in use.
Object
clone()
Overrides clone.
boolean
equals(Object obj)
Overrides equals.
StringBuffer
format(BigInteger number, StringBuffer result, FieldPosition fieldPosition)
Formats a BigInteger number.
StringBuffer
format(BigDecimal number, StringBuffer result, FieldPosition fieldPosition)
Formats a BigDecimal number.
StringBuffer
format(double number, StringBuffer result, FieldPosition fieldPosition)
Specialization of format.
StringBuffer
format(BigDecimal number, StringBuffer result, FieldPosition fieldPosition)
Formats a BigDecimal number.
StringBuffer
format(long number, StringBuffer result, FieldPosition fieldPosition)
Specialization of format.
AttributedCharacterIterator
formatToCharacterIterator(Object obj)
Formats the object to an attributed string, and return the corresponding iterator.
CurrencyPluralInfo
getCurrencyPluralInfo()
[icu] Returns a copy of the CurrencyPluralInfo used by this format.
Currency.CurrencyUsage
getCurrencyUsage()
Returns the Currency Usage object used to display currency
DecimalFormatSymbols
getDecimalFormatSymbols()
Returns a copy of the decimal format symbols used by this format.
int
getFormatWidth()
Returns the width to which the output of format() is padded.
int
getGroupingSize()
Returns the grouping size.
MathContext
getMathContext()
[icu] Returns the MathContext used by this format.
MathContext
getMathContextICU()
[icu] Returns the MathContext used by this format.
int
getMaximumSignificantDigits()
[icu] Returns the maximum number of significant digits that will be displayed.
byte
getMinimumExponentDigits()
[icu] Returns the minimum exponent digits that will be shown.
int
getMinimumSignificantDigits()
[icu] Returns the minimum number of significant digits that will be displayed.
int
getMultiplier()
Returns the multiplier for use in percent, permill, etc.
String
getNegativePrefix()
Returns the negative prefix.
String
getNegativeSuffix()
Returns the negative suffix.
char
getPadCharacter()
[icu] Returns the character used to pad to the format width.
int
getPadPosition()
[icu] Returns the position at which padding will take place.
int
getParseMaxDigits()
Get the current maximum number of exponent digits when parsing a number.
String
getPositivePrefix()
Returns the positive prefix.
String
getPositiveSuffix()
Returns the positive suffix.
BigDecimal
getRoundingIncrement()
[icu] Returns the rounding increment.
int
getRoundingMode()
Returns the rounding mode.
int
getSecondaryGroupingSize()
[icu] Returns the secondary grouping size.
int
hashCode()
Overrides hashCode.
boolean
isDecimalPatternMatchRequired()
[icu] Returns whether the input to parsing must contain a decimal mark if there is a decimal mark in the pattern.
boolean
isDecimalSeparatorAlwaysShown()
Returns the behavior of the decimal separator with integers.
boolean
isExponentSignAlwaysShown()
[icu] Returns whether the exponent sign is always shown.
boolean
isParseBigDecimal()
Returns whether parse(String, ParsePosition) returns BigDecimal.
boolean
isScientificNotation()
[icu] Returns whether or not scientific notation is used.
Number
parse(String text, ParsePosition parsePosition)
Parses the given string, returning a Number object to represent the parsed value.
CurrencyAmount
parseCurrency(CharSequence text, ParsePosition pos)
Parses text from the given string as a CurrencyAmount.
void
setCurrency(Currency theCurrency)
Sets the Currency object used to display currency amounts.
void
setCurrencyPluralInfo(CurrencyPluralInfo newInfo)
[icu] Sets the CurrencyPluralInfo used by this format.
void
setCurrencyUsage(Currency.CurrencyUsage newUsage)
Sets the Currency Usage object used to display currency.
void
setDecimalFormatSymbols(DecimalFormatSymbols newSymbols)
Sets the decimal format symbols used by this format.
void
setDecimalPatternMatchRequired(boolean value)
When decimal match is not required, the input does not have to contain a decimal mark when there is a decimal mark specified in the pattern.
void
setDecimalSeparatorAlwaysShown(boolean newValue)
Sets the behavior of the decimal separator with integers.
void
setExponentSignAlwaysShown(boolean expSignAlways)
[icu] Sets whether the exponent sign is always shown.
void
setFormatWidth(int width)
Sets the width to which the output of format() is padded.
void
setGroupingSize(int newValue)
Sets the grouping size.
void
setMathContext(MathContext newValue)
[icu] Sets the MathContext used by this format.
void
setMathContextICU(MathContext newValue)
[icu] Sets the MathContext used by this format.
void
setMaximumFractionDigits(int newValue)
Sets the maximum number of digits allowed in the fraction portion of a number.
void
setMaximumIntegerDigits(int newValue)
Sets the maximum number of digits allowed in the integer portion of a number.
void
setMaximumSignificantDigits(int max)
[icu] Sets the maximum number of significant digits that will be displayed.
void
setMinimumExponentDigits(byte minExpDig)
[icu] Sets the minimum exponent digits that will be shown.
void
setMinimumFractionDigits(int newValue)
Sets the minimum number of digits allowed in the fraction portion of a number.
void
setMinimumIntegerDigits(int newValue)
Sets the minimum number of digits allowed in the integer portion of a number.
void
setMinimumSignificantDigits(int min)
[icu] Sets the minimum number of significant digits that will be displayed.
void
setMultiplier(int newValue)
Sets the multiplier for use in percent, permill, etc.
void
setNegativePrefix(String newValue)
Sets the negative prefix.
void
setNegativeSuffix(String newValue)
Sets the positive suffix.
void
setPadCharacter(char padChar)
[icu] Sets the character used to pad to the format width.
void
setPadPosition(int padPos)
[icu] Sets the position at which padding will take place.
void
setParseBigDecimal(boolean value)
Sets whether parse(String, ParsePosition) returns BigDecimal.
void
setParseMaxDigits(int newValue)
Set the maximum number of exponent digits when parsing a number.
void
setPositivePrefix(String newValue)
Sets the positive prefix.
void
setPositiveSuffix(String newValue)
Sets the positive suffix.
void
setRoundingIncrement(BigDecimal newValue)
[icu] Sets the rounding increment.
void
setRoundingIncrement(BigDecimal newValue)
[icu] Sets the rounding increment.
void
setRoundingIncrement(double newValue)
[icu] Sets the rounding increment.
void
setRoundingMode(int roundingMode)
Sets the rounding mode.
void
setScientificNotation(boolean useScientific)
[icu] Sets whether or not scientific notation is used.
void
setSecondaryGroupingSize(int newValue)
[icu] Sets the secondary grouping size.
void
setSignificantDigitsUsed(boolean useSignificantDigits)
[icu] Sets whether significant digits are in use, or integer and fraction digit counts are in use.
String
toLocalizedPattern()
Synthesizes a localized pattern string that represents the current state of this Format object.
String
toPattern()
Synthesizes a pattern string that represents the current state of this Format object.

Inherited Method Summary

Constants

public static final int PAD_AFTER_PREFIX

[icu] Constant for getPadPosition() and setPadPosition(int) to specify pad characters inserted after the prefix.

Constant Value: 1

public static final int PAD_AFTER_SUFFIX

[icu] Constant for getPadPosition() and setPadPosition(int) to specify pad characters inserted after the suffix.

Constant Value: 3

public static final int PAD_BEFORE_PREFIX

[icu] Constant for getPadPosition() and setPadPosition(int) to specify pad characters inserted before the prefix.

Constant Value: 0

public static final int PAD_BEFORE_SUFFIX

[icu] Constant for getPadPosition() and setPadPosition(int) to specify pad characters inserted before the suffix.

Constant Value: 2

Public Constructors

public DecimalFormat ()

Creates a DecimalFormat using the default pattern and symbols for the default FORMAT locale. This is a convenient way to obtain a DecimalFormat when internationalization is not the main concern.

To obtain standard formats for a given locale, use the factory methods on NumberFormat such as getNumberInstance. These factories will return the most appropriate sub-class of NumberFormat for a given locale.

public DecimalFormat (String pattern)

Creates a DecimalFormat from the given pattern and the symbols for the default FORMAT locale. This is a convenient way to obtain a DecimalFormat when internationalization is not the main concern.

To obtain standard formats for a given locale, use the factory methods on NumberFormat such as getNumberInstance. These factories will return the most appropriate sub-class of NumberFormat for a given locale.

Parameters
pattern A non-localized pattern string.
Throws
IllegalArgumentException if the given pattern is invalid.

public DecimalFormat (String pattern, DecimalFormatSymbols symbols)

Creates a DecimalFormat from the given pattern and symbols. Use this constructor when you need to completely customize the behavior of the format.

To obtain standard formats for a given locale, use the factory methods on NumberFormat such as getInstance or getCurrencyInstance. If you need only minor adjustments to a standard format, you can modify the format returned by a NumberFormat factory method.

Parameters
pattern a non-localized pattern string
symbols the set of symbols to be used
Throws
IllegalArgumentException if the given pattern is invalid

public DecimalFormat (String pattern, DecimalFormatSymbols symbols, CurrencyPluralInfo infoInput, int style)

Creates a DecimalFormat from the given pattern, symbols, information used for currency plural format, and format style. Use this constructor when you need to completely customize the behavior of the format.

To obtain standard formats for a given locale, use the factory methods on NumberFormat such as getInstance or getCurrencyInstance.

If you need only minor adjustments to a standard format, you can modify the format returned by a NumberFormat factory method using the setters.

If you want to completely customize a decimal format, using your own DecimalFormatSymbols (such as group separators) and your own information for currency plural formatting (such as plural rule and currency plural patterns), you can use this constructor.

Parameters
pattern a non-localized pattern string
symbols the set of symbols to be used
infoInput the information used for currency plural format, including currency plural patterns and plural rules.
style the decimal formatting style, it is one of the following values: NumberFormat.NUMBERSTYLE; NumberFormat.CURRENCYSTYLE; NumberFormat.PERCENTSTYLE; NumberFormat.SCIENTIFICSTYLE; NumberFormat.INTEGERSTYLE; NumberFormat.ISOCURRENCYSTYLE; NumberFormat.PLURALCURRENCYSTYLE;

Public Methods

public void applyLocalizedPattern (String pattern)

Applies the given pattern to this Format object. The pattern is assumed to be in a localized notation. A pattern is a short-hand specification for the various formatting properties. These properties can also be changed individually through the various setter methods.

There is no limit to integer digits are set by this routine, since that is the typical end-user desire; use setMaximumInteger if you want to set a real value. For negative numbers, use a second pattern, separated by a semicolon

Example "#,#00.0#" -> 1,234.56

This means a minimum of 2 integer digits, 1 fraction digit, and a maximum of 2 fraction digits.

Example: "#,#00.0#;(#,#00.0#)" for negatives in parantheses.

In negative patterns, the minimum and maximum counts are ignored; these are presumed to be set in the positive pattern.

Parameters
pattern

public void applyPattern (String pattern)

Applies the given pattern to this Format object. A pattern is a short-hand specification for the various formatting properties. These properties can also be changed individually through the various setter methods.

There is no limit to integer digits are set by this routine, since that is the typical end-user desire; use setMaximumInteger if you want to set a real value. For negative numbers, use a second pattern, separated by a semicolon

Example "#,#00.0#" -> 1,234.56

This means a minimum of 2 integer digits, 1 fraction digit, and a maximum of 2 fraction digits.

Example: "#,#00.0#;(#,#00.0#)" for negatives in parentheses.

In negative patterns, the minimum and maximum counts are ignored; these are presumed to be set in the positive pattern.

Parameters
pattern

public boolean areSignificantDigitsUsed ()

[icu] Returns true if significant digits are in use or false if integer and fraction digit counts are in use.

Returns
  • true if significant digits are in use

public Object clone ()

Overrides clone.

Returns
  • a clone of this instance.

public boolean equals (Object obj)

Overrides equals.

Parameters
obj the object to compare against
Returns
  • true if the object is equal to this.

public StringBuffer format (BigInteger number, StringBuffer result, FieldPosition fieldPosition)

Formats a BigInteger number.

Parameters
number
result
fieldPosition

public StringBuffer format (BigDecimal number, StringBuffer result, FieldPosition fieldPosition)

Formats a BigDecimal number.

Parameters
number
result
fieldPosition

public StringBuffer format (double number, StringBuffer result, FieldPosition fieldPosition)

Specialization of format.

Parameters
number
result
fieldPosition

public StringBuffer format (BigDecimal number, StringBuffer result, FieldPosition fieldPosition)

Formats a BigDecimal number.

Parameters
number
result
fieldPosition

public StringBuffer format (long number, StringBuffer result, FieldPosition fieldPosition)

Specialization of format.

Parameters
number
result
fieldPosition

public AttributedCharacterIterator formatToCharacterIterator (Object obj)

Formats the object to an attributed string, and return the corresponding iterator.

Parameters
obj The object to format
Returns
  • AttributedCharacterIterator describing the formatted value.

public CurrencyPluralInfo getCurrencyPluralInfo ()

[icu] Returns a copy of the CurrencyPluralInfo used by this format. It might return null if the decimal format is not a plural type currency decimal format. Plural type currency decimal format means either the pattern in the decimal format contains 3 currency signs, or the decimal format is initialized with PLURALCURRENCYSTYLE.

Returns
  • desired CurrencyPluralInfo

public Currency.CurrencyUsage getCurrencyUsage ()

Returns the Currency Usage object used to display currency

public DecimalFormatSymbols getDecimalFormatSymbols ()

Returns a copy of the decimal format symbols used by this format.

Returns
  • desired DecimalFormatSymbols

public int getFormatWidth ()

Returns the width to which the output of format() is padded. The width is counted in 16-bit code units.

Returns
  • the format width, or zero if no padding is in effect

public int getGroupingSize ()

Returns the grouping size. Grouping size is the number of digits between grouping separators in the integer portion of a number. For example, in the number "123,456.78", the grouping size is 3.

public MathContext getMathContext ()

[icu] Returns the MathContext used by this format.

Returns
  • desired MathContext
See Also

public MathContext getMathContextICU ()

[icu] Returns the MathContext used by this format.

Returns
  • desired MathContext
See Also

public int getMaximumSignificantDigits ()

[icu] Returns the maximum number of significant digits that will be displayed. This value has no effect unless areSignificantDigitsUsed() returns true.

Returns
  • the most significant digits that will be shown

public byte getMinimumExponentDigits ()

[icu] Returns the minimum exponent digits that will be shown.

Returns
  • the minimum exponent digits that will be shown

public int getMinimumSignificantDigits ()

[icu] Returns the minimum number of significant digits that will be displayed. This value has no effect unless areSignificantDigitsUsed() returns true.

Returns
  • the fewest significant digits that will be shown

public int getMultiplier ()

Returns the multiplier for use in percent, permill, etc. For a percentage, set the suffixes to have "%" and the multiplier to be 100. (For Arabic, use arabic percent symbol). For a permill, set the suffixes to have "‱" and the multiplier to be 1000.

Examples: with 100, 1.23 -> "123", and "123" -> 1.23

Returns
  • the multiplier

public String getNegativePrefix ()

Returns the negative prefix.

Examples: -123, ($123) (with negative suffix), sFr-123

Returns
  • the prefix

public String getNegativeSuffix ()

Returns the negative suffix.

Examples: -123%, ($123) (with positive suffixes)

Returns
  • the suffix

public char getPadCharacter ()

[icu] Returns the character used to pad to the format width. The default is ' '.

Returns
  • the pad character

public int getPadPosition ()

[icu] Returns the position at which padding will take place. This is the location at which padding will be inserted if the result of format() is shorter than the format width.

Returns
  • the pad position, one of PAD_BEFORE_PREFIX, PAD_AFTER_PREFIX, PAD_BEFORE_SUFFIX, or PAD_AFTER_SUFFIX.

public int getParseMaxDigits ()

Get the current maximum number of exponent digits when parsing a number.

Returns
  • the maximum number of exponent digits for parsing

public String getPositivePrefix ()

Returns the positive prefix.

Examples: +123, $123, sFr123

Returns
  • the prefix

public String getPositiveSuffix ()

Returns the positive suffix.

Example: 123%

Returns
  • the suffix

public BigDecimal getRoundingIncrement ()

[icu] Returns the rounding increment.

Returns
  • A positive rounding increment, or null if a custom rounding increment is not in effect.

public int getRoundingMode ()

Returns the rounding mode.

Returns
  • A rounding mode, between BigDecimal.ROUND_UP and BigDecimal.ROUND_UNNECESSARY.

public int getSecondaryGroupingSize ()

[icu] Returns the secondary grouping size. In some locales one grouping interval is used for the least significant integer digits (the primary grouping size), and another is used for all others (the secondary grouping size). A formatter supporting a secondary grouping size will return a positive integer unequal to the primary grouping size returned by getGroupingSize(). For example, if the primary grouping size is 4, and the secondary grouping size is 2, then the number 123456789 formats as "1,23,45,6789", and the pattern appears as "#,##,###0".

Returns
  • the secondary grouping size, or a value less than one if there is none

public int hashCode ()

Overrides hashCode.

Returns
  • this object's hash code.

public boolean isDecimalPatternMatchRequired ()

[icu] Returns whether the input to parsing must contain a decimal mark if there is a decimal mark in the pattern.

Returns
  • true if input must contain a match to decimal mark in pattern

public boolean isDecimalSeparatorAlwaysShown ()

Returns the behavior of the decimal separator with integers. (The decimal separator will always appear with decimals.)

Example: Decimal ON: 12345 -> 12345.; OFF: 12345 -> 12345

public boolean isExponentSignAlwaysShown ()

[icu] Returns whether the exponent sign is always shown.

Returns
  • true if the exponent is always prefixed with either the localized minus sign or the localized plus sign, false if only negative exponents are prefixed with the localized minus sign.

public boolean isParseBigDecimal ()

Returns whether parse(String, ParsePosition) returns BigDecimal.

Returns

public boolean isScientificNotation ()

[icu] Returns whether or not scientific notation is used.

Returns
  • true if this object formats and parses scientific notation

public Number parse (String text, ParsePosition parsePosition)

Parses the given string, returning a Number object to represent the parsed value. Double objects are returned to represent non-integral values which cannot be stored in a BigDecimal. These are NaN, infinity, -infinity, and -0.0. If isParseBigDecimal() is false (the default), all other values are returned as Long, BigInteger, or BigDecimal values, in that order of preference. If isParseBigDecimal() is true, all other values are returned as BigDecimal valuse. If the parse fails, null is returned.

Parameters
text the string to be parsed
parsePosition defines the position where parsing is to begin, and upon return, the position where parsing left off. If the position has not changed upon return, then parsing failed.
Returns
  • a Number object with the parsed value or null if the parse failed

public CurrencyAmount parseCurrency (CharSequence text, ParsePosition pos)

Parses text from the given string as a CurrencyAmount. Unlike the parse() method, this method will attempt to parse a generic currency name, searching for a match of this object's locale's currency display names, or for a 3-letter ISO currency code. This method will fail if this format is not a currency format, that is, if it does not contain the currency pattern symbol (U+00A4) in its prefix or suffix.

Parameters
text the text to parse
pos input-output position; on input, the position within text to match; must have 0 <= pos.getIndex() < text.length(); on output, the position after the last matched character. If the parse fails, the position in unchanged upon output.
Returns
  • a CurrencyAmount, or null upon failure

public void setCurrency (Currency theCurrency)

Sets the Currency object used to display currency amounts. This takes effect immediately, if this format is a currency format. If this format is not a currency format, then the currency object is used if and when this object becomes a currency format through the application of a new pattern.

Parameters
theCurrency new currency object to use. Must not be null.

public void setCurrencyPluralInfo (CurrencyPluralInfo newInfo)

[icu] Sets the CurrencyPluralInfo used by this format. The format uses a copy of the provided information.

Parameters
newInfo desired CurrencyPluralInfo

public void setCurrencyUsage (Currency.CurrencyUsage newUsage)

Sets the Currency Usage object used to display currency. This takes effect immediately, if this format is a currency format.

Parameters
newUsage new currency context object to use.

public void setDecimalFormatSymbols (DecimalFormatSymbols newSymbols)

Sets the decimal format symbols used by this format. The format uses a copy of the provided symbols.

Parameters
newSymbols desired DecimalFormatSymbols

public void setDecimalPatternMatchRequired (boolean value)

When decimal match is not required, the input does not have to contain a decimal mark when there is a decimal mark specified in the pattern.

Parameters
value true if input must contain a match to decimal mark in pattern Default is false.

public void setDecimalSeparatorAlwaysShown (boolean newValue)

Sets the behavior of the decimal separator with integers. (The decimal separator will always appear with decimals.)

This only affects formatting, and only where there might be no digits after the decimal point, e.g., if true, 3456.00 -> "3,456." if false, 3456.00 -> "3456" This is independent of parsing. If you want parsing to stop at the decimal point, use setParseIntegerOnly.

Example: Decimal ON: 12345 -> 12345.; OFF: 12345 -> 12345

Parameters
newValue

public void setExponentSignAlwaysShown (boolean expSignAlways)

[icu] Sets whether the exponent sign is always shown. This has no effect unless scientific notation is in use.

Parameters
expSignAlways true if the exponent is always prefixed with either the localized minus sign or the localized plus sign, false if only negative exponents are prefixed with the localized minus sign.

public void setFormatWidth (int width)

Sets the width to which the output of format() is padded. The width is counted in 16-bit code units. This method also controls whether padding is enabled.

Parameters
width the width to which to pad the result of format(), or zero to disable padding
Throws
IllegalArgumentException if width is < 0

public void setGroupingSize (int newValue)

Sets the grouping size. Grouping size is the number of digits between grouping separators in the integer portion of a number. For example, in the number "123,456.78", the grouping size is 3.

Parameters
newValue

public void setMathContext (MathContext newValue)

[icu] Sets the MathContext used by this format.

Parameters
newValue desired MathContext
See Also

public void setMathContextICU (MathContext newValue)

[icu] Sets the MathContext used by this format.

Parameters
newValue desired MathContext
See Also

public void setMaximumFractionDigits (int newValue)

Sets the maximum number of digits allowed in the fraction portion of a number. This override limits the fraction digit count to 340.

Parameters
newValue the maximum number of fraction digits to be shown; if less than zero, then zero is used. The concrete subclass may enforce an upper limit to this value appropriate to the numeric type being formatted.

public void setMaximumIntegerDigits (int newValue)

Sets the maximum number of digits allowed in the integer portion of a number. This override limits the integer digit count to 2,000,000,000 to match ICU4C.

Parameters
newValue the maximum number of integer digits to be shown; if less than zero, then zero is used. Subclasses might enforce an upper limit to this value appropriate to the numeric type being formatted.

public void setMaximumSignificantDigits (int max)

[icu] Sets the maximum number of significant digits that will be displayed. If max is less than one then it is set to one. If the minimum significant digits count is greater than max, then it is set to max. This function also enables the use of significant digits by this formatter - areSignificantDigitsUsed() will return true.

Parameters
max the most significant digits to be shown

public void setMinimumExponentDigits (byte minExpDig)

[icu] Sets the minimum exponent digits that will be shown. This has no effect unless scientific notation is in use.

Parameters
minExpDig a value >= 1 indicating the fewest exponent digits that will be shown
Throws
IllegalArgumentException if minExpDig < 1

public void setMinimumFractionDigits (int newValue)

Sets the minimum number of digits allowed in the fraction portion of a number. This override limits the fraction digit count to 340.

Parameters
newValue the minimum number of fraction digits to be shown; if less than zero, then zero is used. Subclasses might enforce an upper limit to this value appropriate to the numeric type being formatted.

public void setMinimumIntegerDigits (int newValue)

Sets the minimum number of digits allowed in the integer portion of a number. This override limits the integer digit count to 309.

Parameters
newValue the minimum number of integer digits to be shown; if less than zero, then zero is used. Subclasses might enforce an upper limit to this value appropriate to the numeric type being formatted.

public void setMinimumSignificantDigits (int min)

[icu] Sets the minimum number of significant digits that will be displayed. If min is less than one then it is set to one. If the maximum significant digits count is less than min, then it is set to min. This function also enables the use of significant digits by this formatter - areSignificantDigitsUsed() will return true.

Parameters
min the fewest significant digits to be shown

public void setMultiplier (int newValue)

Sets the multiplier for use in percent, permill, etc. For a percentage, set the suffixes to have "%" and the multiplier to be 100. (For Arabic, use arabic percent symbol). For a permill, set the suffixes to have "‱" and the multiplier to be 1000.

Examples: with 100, 1.23 -> "123", and "123" -> 1.23

Parameters
newValue the multiplier

public void setNegativePrefix (String newValue)

Sets the negative prefix.

Examples: -123, ($123) (with negative suffix), sFr-123

Parameters
newValue the prefix

public void setNegativeSuffix (String newValue)

Sets the positive suffix.

Examples: 123%

Parameters
newValue the suffix

public void setPadCharacter (char padChar)

[icu] Sets the character used to pad to the format width. If padding is not enabled, then this will take effect if padding is later enabled.

Parameters
padChar the pad character

public void setPadPosition (int padPos)

[icu] Sets the position at which padding will take place. This is the location at which padding will be inserted if the result of format() is shorter than the format width. This has no effect unless padding is enabled.

Parameters
padPos the pad position, one of PAD_BEFORE_PREFIX, PAD_AFTER_PREFIX, PAD_BEFORE_SUFFIX, or PAD_AFTER_SUFFIX.
Throws
IllegalArgumentException if the pad position in unrecognized

public void setParseBigDecimal (boolean value)

Sets whether parse(String, ParsePosition) returns BigDecimal. The default value is false.

Parameters
value true if parse(String, ParsePosition) returns BigDecimal.

public void setParseMaxDigits (int newValue)

Set the maximum number of exponent digits when parsing a number. If the limit is set too high, an OutOfMemoryException may be triggered. The default value is 1000.

Parameters
newValue the new limit

public void setPositivePrefix (String newValue)

Sets the positive prefix.

Examples: +123, $123, sFr123

Parameters
newValue the prefix

public void setPositiveSuffix (String newValue)

Sets the positive suffix.

Example: 123%

Parameters
newValue the suffix

public void setRoundingIncrement (BigDecimal newValue)

[icu] Sets the rounding increment. In the absence of a rounding increment, numbers will be rounded to the number of digits displayed.

Parameters
newValue A positive rounding increment, or null or BigDecimal(0.0) to use the default rounding increment.
Throws
IllegalArgumentException if newValue is < 0.0

public void setRoundingIncrement (BigDecimal newValue)

[icu] Sets the rounding increment. In the absence of a rounding increment, numbers will be rounded to the number of digits displayed.

Parameters
newValue A positive rounding increment, or null or BigDecimal(0.0) to use the default rounding increment.
Throws
IllegalArgumentException if newValue is < 0.0

public void setRoundingIncrement (double newValue)

[icu] Sets the rounding increment. In the absence of a rounding increment, numbers will be rounded to the number of digits displayed.

Parameters
newValue A positive rounding increment, or 0.0 to use the default rounding increment.
Throws
IllegalArgumentException if newValue is < 0.0

public void setRoundingMode (int roundingMode)

Sets the rounding mode. This has no effect unless the rounding increment is greater than zero.

Parameters
roundingMode A rounding mode, between BigDecimal.ROUND_UP and BigDecimal.ROUND_UNNECESSARY.
Throws
IllegalArgumentException if roundingMode is unrecognized.

public void setScientificNotation (boolean useScientific)

[icu] Sets whether or not scientific notation is used. When scientific notation is used, the effective maximum number of integer digits is <= 8. If the maximum number of integer digits is set to more than 8, the effective maximum will be 1. This allows this call to generate a 'default' scientific number format without additional changes.

Parameters
useScientific true if this object formats and parses scientific notation

public void setSecondaryGroupingSize (int newValue)

[icu] Sets the secondary grouping size. If set to a value less than 1, then secondary grouping is turned off, and the primary grouping size is used for all intervals, not just the least significant.

Parameters
newValue

public void setSignificantDigitsUsed (boolean useSignificantDigits)

[icu] Sets whether significant digits are in use, or integer and fraction digit counts are in use.

Parameters
useSignificantDigits true to use significant digits, or false to use integer and fraction digit counts

public String toLocalizedPattern ()

Synthesizes a localized pattern string that represents the current state of this Format object.

public String toPattern ()

Synthesizes a pattern string that represents the current state of this Format object.