Class DecimalFormat

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable
    Direct Known Subclasses:
    CompactDecimalFormat

    public class DecimalFormat
    extends NumberFormat
    .

    IMPORTANT: New users are strongly encouraged to see if NumberFormatter fits their use case. Although not deprecated, this class, DecimalFormat, is only provided for java.text.DecimalFormat compatibility.


    DecimalFormat is the primary concrete subclass of NumberFormat. 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 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 number formatter for a specific locale (including the default locale), call one of NumberFormat's factory methods such as NumberFormat.getInstance(). Do not call DecimalFormat constructors directly unless you know what you are doing.

    DecimalFormat aims to comply with the specification UTS #35. Read the specification for more information on how all the properties in DecimalFormat fit together.

    NOTE: Starting in ICU 60, there is a new set of APIs for localized number formatting that are designed to be an improvement over DecimalFormat. New users are discouraged from using DecimalFormat. For more information, see the package com.ibm.icu.number.

    Example Usage

    Customize settings on a DecimalFormat instance from the NumberFormat factory:

     NumberFormat f = NumberFormat.getInstance(loc);
     if (f instanceof DecimalFormat) {
         ((DecimalFormat) f).setDecimalSeparatorAlwaysShown(true);
         ((DecimalFormat) f).setMinimumGroupingDigits(2);
     }
     

    Quick and dirty print out a number using the localized number, currency, and percent format for each locale:

     for (ULocale uloc : ULocale.getAvailableLocales()) {
         System.out.print(uloc + ":\t");
         System.out.print(NumberFormat.getInstance(uloc).format(1.23));
         System.out.print("\t");
         System.out.print(NumberFormat.getCurrencyInstance(uloc).format(1.23));
         System.out.print("\t");
         System.out.print(NumberFormat.getPercentInstance(uloc).format(1.23));
         System.out.println();
     }
     

    Properties and Symbols

    A DecimalFormat object encapsulates a set of properties and a set of symbols. Grouping size, rounding mode, and affixes are examples of properties. Locale digits and the characters used for grouping and decimal separators are examples of symbols.

    To set a custom set of symbols, use setDecimalFormatSymbols(com.ibm.icu.text.DecimalFormatSymbols). Use the various other setters in this class to set custom values for the properties.

    Rounding

    DecimalFormat provides three main strategies to specify the position at which numbers should be rounded:

    1. Magnitude: Display a fixed number of fraction digits; this is the most common form.
    2. Increment: Round numbers to the closest multiple of a certain increment, such as 0.05. This is common in currencies.
    3. Significant Digits: Round numbers such that a fixed number of nonzero digits are shown. This is most common in scientific notation.

    It is not possible to specify more than one rounding strategy. For example, setting a rounding increment in conjunction with significant digits results in undefined behavior.

    It is also possible to specify the rounding mode to use. The default rounding mode is "half even", which rounds numbers to their closest increment, with ties broken in favor of trailing numbers being even. For more information, see setRoundingMode(int) and the ICU User Guide.

    Pattern Strings

    A pattern string is a way to serialize some of the available properties for decimal formatting. However, not all properties are capable of being serialized into a pattern string; see applyPattern(java.lang.String) for more information.

    Most users should not need to interface with pattern strings directly.

    ICU DecimalFormat aims to follow the specification for pattern strings in UTS #35. Refer to that specification for more information on pattern string syntax.

    Pattern String BNF

    The following BNF is used when parsing the pattern string into property values:
     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 aims to be able to parse anything that it can output as a formatted string.

    There are two primary parse modes: lenient and strict. Lenient mode should be used if the goal is to parse user input to a number; strict mode should be used if the goal is validation. The default is lenient mode. For more information, see setParseStrict(boolean).

    DecimalFormat parses all Unicode characters that represent decimal digits, as defined by UCharacter.digit(int, 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.

    Grouping separators are ignored in lenient mode (default). In strict mode, grouping separators must match the locale-specified grouping sizes.

    When using parseCurrency(java.lang.CharSequence, java.text.ParsePosition), all currencies are accepted, not just the currency currently set in the formatter. In addition, the formatter is able to parse every currency style format for a particular locale no matter which style the formatter is constructed with. For example, a formatter instance gotten from NumberFormat.getInstance(ULocale, NumberFormat.CURRENCYSTYLE) can parse both "USD1.00" and "3.00 US dollars".

    Whitespace characters (lenient mode) and control characters (lenient and strict mode), collectively called "ignorables", do not need to match in identity or quantity between the pattern string and the input string. For example, the pattern "# %" matches "35 %" (with a single space), "35%" (with no space), "35 %" (with a non-breaking space), and "35  %" (with multiple spaces). Arbitrary ignorables are also allowed at boundaries between the parts of the number: prefix, number, exponent separator, and suffix. Ignorable whitespace characters are those having the Unicode "blank" property for regular expressions, defined in UTS #18 Annex C, which is "horizontal" whitespace, like spaces and tabs, but not "vertical" whitespace, like line breaks. Ignorable control characters are those in the Unicode set [:Default_Ignorable_Code_Point:].

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

    Under the hood, a state table parsing engine is used. To debug a parsing failure during development, use the following pattern to print details about the state table transitions:

     com.ibm.icu.impl.number.Parse.DEBUGGING = true;
     df.parse("123.45", ppos);
     com.ibm.icu.impl.number.Parse.DEBUGGING = false;
     

    Thread Safety and Best Practices

    Starting with ICU 59, instances of DecimalFormat are thread-safe.

    Under the hood, DecimalFormat maintains an immutable formatter object that is rebuilt whenever any of the property setters are called. It is therefore best practice to call property setters only during construction and not when formatting numbers online.

    See Also:
    Format, NumberFormat, Serialized Form
    • Method Detail

      • applyLocalizedPattern

        public void applyLocalizedPattern​(java.lang.String localizedPattern)
        Converts the given string to standard notation and then parses it using applyPattern(java.lang.String). This method is provided for backwards compatibility and should not be used in new projects.

        Localized notation means that instead of using generic placeholders in the pattern, you use the corresponding locale-specific characters instead. For example, in locale fr-FR, the period in the pattern "0.000" means "decimal" in standard notation (as it does in every other locale), but it means "grouping" in localized notation.

        Parameters:
        localizedPattern - The pattern string in localized notation.
      • format

        public java.lang.StringBuffer format​(double number,
                                             java.lang.StringBuffer result,
                                             java.text.FieldPosition fieldPosition)
        Specialization of format.
        Specified by:
        format in class NumberFormat
        See Also:
        Format.format(Object, StringBuffer, FieldPosition)
      • format

        public java.lang.StringBuffer format​(long number,
                                             java.lang.StringBuffer result,
                                             java.text.FieldPosition fieldPosition)
        Specialization of format.
        Specified by:
        format in class NumberFormat
        See Also:
        Format.format(Object, StringBuffer, FieldPosition)
      • format

        public java.lang.StringBuffer format​(java.math.BigInteger number,
                                             java.lang.StringBuffer result,
                                             java.text.FieldPosition fieldPosition)
        Formats a BigInteger. Specialization of format.
        Specified by:
        format in class NumberFormat
        See Also:
        Format.format(Object, StringBuffer, FieldPosition)
      • format

        public java.lang.StringBuffer format​(java.math.BigDecimal number,
                                             java.lang.StringBuffer result,
                                             java.text.FieldPosition fieldPosition)
        Formats a BigDecimal. Specialization of format.
        Specified by:
        format in class NumberFormat
        See Also:
        Format.format(Object, StringBuffer, FieldPosition)
      • format

        public java.lang.StringBuffer format​(BigDecimal number,
                                             java.lang.StringBuffer result,
                                             java.text.FieldPosition fieldPosition)
        Formats an ICU BigDecimal. Specialization of format.
        Specified by:
        format in class NumberFormat
        See Also:
        Format.format(Object, StringBuffer, FieldPosition)
      • formatToCharacterIterator

        public java.text.AttributedCharacterIterator formatToCharacterIterator​(java.lang.Object obj)
        Overrides:
        formatToCharacterIterator in class java.text.Format
      • format

        public java.lang.StringBuffer format​(CurrencyAmount currAmt,
                                             java.lang.StringBuffer result,
                                             java.text.FieldPosition fieldPosition)
        Formats a CurrencyAmount. Specialization of format.
        Overrides:
        format in class NumberFormat
        See Also:
        Format.format(Object, StringBuffer, FieldPosition)
      • parse

        public java.lang.Number parse​(java.lang.String text,
                                      java.text.ParsePosition parsePosition)
        Returns a Long if possible (e.g., within the range [Long.MIN_VALUE, Long.MAX_VALUE] and with no decimals); otherwise, returns another type, such as a BigDecimal, BigInteger, or Double. The return type is not guaranteed other than for the Long case.

        If IntegerOnly is set, will stop at a decimal point (or equivalent; e.g., for rational numbers "1 2/3", will stop after the 1).

        Does not throw an exception; if no object can be parsed, index is unchanged!

        For more detail on parsing, see the "Parsing" header in the class documentation of DecimalFormat.

        Specified by:
        parse in class NumberFormat
        See Also:
        NumberFormat.isParseIntegerOnly(), setParseBigDecimal(boolean), Format.parseObject(String, ParsePosition)
      • parseCurrency

        public CurrencyAmount parseCurrency​(java.lang.CharSequence text,
                                            java.text.ParsePosition parsePosition)
        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.
        Overrides:
        parseCurrency in class NumberFormat
        Parameters:
        text - the text to parse
        parsePosition - 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
      • getDecimalFormatSymbols

        public DecimalFormatSymbols getDecimalFormatSymbols()
        Returns a copy of the decimal format symbols used by this formatter.
        Returns:
        desired DecimalFormatSymbols
        See Also:
        DecimalFormatSymbols
      • setDecimalFormatSymbols

        public void setDecimalFormatSymbols​(DecimalFormatSymbols newSymbols)
        Sets the decimal format symbols used by this formatter. The formatter uses a copy of the provided symbols.
        Parameters:
        newSymbols - desired DecimalFormatSymbols
        See Also:
        DecimalFormatSymbols
      • getPositivePrefix

        public java.lang.String getPositivePrefix()
        Affixes: Gets the positive prefix string currently being used to format numbers.

        If the affix was specified via the pattern, the string returned by this method will have locale symbols substituted in place of special characters according to the LDML specification. If the affix was specified via setPositivePrefix(java.lang.String), the string will be returned literally.

        Returns:
        The string being prepended to positive numbers.
      • setPositivePrefix

        public void setPositivePrefix​(java.lang.String prefix)
        Affixes: Sets the string to prepend to positive numbers. For example, if you set the value "#", then the number 123 will be formatted as "#123" in the locale en-US.

        Using this method overrides the affix specified via the pattern, and unlike the pattern, the string given to this method will be interpreted literally WITHOUT locale symbol substitutions.

        Parameters:
        prefix - The literal string to prepend to positive numbers.
      • getNegativePrefix

        public java.lang.String getNegativePrefix()
        Affixes: Gets the negative prefix string currently being used to format numbers.

        If the affix was specified via the pattern, the string returned by this method will have locale symbols substituted in place of special characters according to the LDML specification. If the affix was specified via setNegativePrefix(java.lang.String), the string will be returned literally.

        Returns:
        The string being prepended to negative numbers.
      • setNegativePrefix

        public void setNegativePrefix​(java.lang.String prefix)
        Affixes: Sets the string to prepend to negative numbers. For example, if you set the value "#", then the number -123 will be formatted as "#123" in the locale en-US (overriding the implicit default '-' in the pattern).

        Using this method overrides the affix specified via the pattern, and unlike the pattern, the string given to this method will be interpreted literally WITHOUT locale symbol substitutions.

        Parameters:
        prefix - The literal string to prepend to negative numbers.
      • getPositiveSuffix

        public java.lang.String getPositiveSuffix()
        Affixes: Gets the positive suffix string currently being used to format numbers.

        If the affix was specified via the pattern, the string returned by this method will have locale symbols substituted in place of special characters according to the LDML specification. If the affix was specified via setPositiveSuffix(java.lang.String), the string will be returned literally.

        Returns:
        The string being appended to positive numbers.
      • setPositiveSuffix

        public void setPositiveSuffix​(java.lang.String suffix)
        Affixes: Sets the string to append to positive numbers. For example, if you set the value "#", then the number 123 will be formatted as "123#" in the locale en-US.

        Using this method overrides the affix specified via the pattern, and unlike the pattern, the string given to this method will be interpreted literally WITHOUT locale symbol substitutions.

        Parameters:
        suffix - The literal string to append to positive numbers.
      • getNegativeSuffix

        public java.lang.String getNegativeSuffix()
        Affixes: Gets the negative suffix string currently being used to format numbers.

        If the affix was specified via the pattern, the string returned by this method will have locale symbols substituted in place of special characters according to the LDML specification. If the affix was specified via setNegativeSuffix(java.lang.String), the string will be returned literally.

        Returns:
        The string being appended to negative numbers.
      • setNegativeSuffix

        public void setNegativeSuffix​(java.lang.String suffix)
        Affixes: Sets the string to append to negative numbers. For example, if you set the value "#", then the number 123 will be formatted as "123#" in the locale en-US.

        Using this method overrides the affix specified via the pattern, and unlike the pattern, the string given to this method will be interpreted literally WITHOUT locale symbol substitutions.

        Parameters:
        suffix - The literal string to append to negative numbers.
      • getSignAlwaysShown

        @Deprecated
        public boolean getSignAlwaysShown()
        Deprecated.
        ICU 59: This API is a technical preview. It may change in an upcoming release.
        Returns whether the sign is being shown on positive numbers.
        See Also:
        setSignAlwaysShown(boolean)
      • setSignAlwaysShown

        @Deprecated
        public void setSignAlwaysShown​(boolean value)
        Deprecated.
        ICU 59: This API is technical preview. It may change in an upcoming release.
        Sets whether to always shown the plus sign ('+' in en) on positive numbers. The rules in UTS #35 section 3.2.1 will be followed to ensure a locale-aware placement of the sign.

        More specifically, the following strategy will be used to place the plus sign:

        1. Patterns without a negative subpattern: The locale's plus sign will be prepended to the positive prefix.
        2. Patterns with a negative subpattern without a '-' sign (e.g., accounting): The locale's plus sign will be prepended to the positive prefix, as in case 1.
        3. Patterns with a negative subpattern that has a '-' sign: The locale's plus sign will substitute the '-' in the negative subpattern. The positive subpattern will be unused.
        This method is designed to be used instead of applying a pattern containing an explicit plus sign, such as "+0;-0". The behavior when combining this method with explicit plus signs in the pattern is undefined.
        Parameters:
        value - true to always show a sign; false to hide the sign on positive numbers.
      • getMultiplier

        public int getMultiplier()
        Returns the multiplier being applied to numbers before they are formatted.
        See Also:
        setMultiplier(int)
      • setMultiplier

        public void setMultiplier​(int multiplier)
        Sets a number that will be used to multiply all numbers prior to formatting. For example, when formatting percents, a multiplier of 100 can be used.

        If a percent or permille sign is specified in the pattern, the multiplier is automatically set to 100 or 1000, respectively.

        If the number specified here is a power of 10, a more efficient code path will be used.

        Parameters:
        multiplier - The number by which all numbers passed to format(double, java.lang.StringBuffer, java.text.FieldPosition) will be multiplied.
        Throws:
        java.lang.IllegalArgumentException - If the given multiplier is zero.
      • setRoundingIncrement

        public void setRoundingIncrement​(java.math.BigDecimal increment)
        Rounding and Digit Limits: Sets an increment, or interval, to which numbers are rounded. For example, a rounding increment of 0.05 will cause the number 1.23 to be rounded to 1.25 in the default rounding mode.

        The rounding increment can be specified via the pattern string: for example, the pattern "#,##0.05" encodes a rounding increment of 0.05.

        The rounding increment is applied after any multipliers might take effect; for example, in scientific notation or when setMultiplier(int) is used.

        See setMaximumFractionDigits(int) and setMaximumSignificantDigits(int) for two other ways of specifying rounding strategies.

        Parameters:
        increment - The increment to which numbers are to be rounded.
        See Also:
        setRoundingMode(int), setMaximumFractionDigits(int), setMaximumSignificantDigits(int)
      • getRoundingMode

        public int getRoundingMode()
        Returns the rounding mode being used to round numbers.
        Overrides:
        getRoundingMode in class NumberFormat
        Returns:
        A rounding mode, between BigDecimal.ROUND_UP and BigDecimal.ROUND_UNNECESSARY.
        See Also:
        setRoundingMode(int)
      • setRoundingMode

        public void setRoundingMode​(int roundingMode)
        Rounding and Digit Limits: Sets the RoundingMode used to round numbers. The default rounding mode is HALF_EVEN, which rounds decimals to their closest whole number, and rounds to the closest even number if at the midpoint.

        For more detail on rounding modes, see the ICU User Guide.

        For backwards compatibility, the rounding mode is specified as an int argument, which can be from either the constants in BigDecimal or the ordinal value of RoundingMode. The following two calls are functionally equivalent.

         df.setRoundingMode(BigDecimal.ROUND_CEILING);
         df.setRoundingMode(RoundingMode.CEILING.ordinal());
         
        Overrides:
        setRoundingMode in class NumberFormat
        Parameters:
        roundingMode - The integer constant rounding mode to use when formatting numbers.
        See Also:
        NumberFormat.getRoundingMode()
      • setMathContext

        public void setMathContext​(java.math.MathContext mathContext)
        Rounding and Digit Limits: Sets the MathContext used to round numbers. A "math context" encodes both a rounding mode and a number of significant digits. Most users should call setRoundingMode(int) and/or setMaximumSignificantDigits(int) instead of this method.

        When formatting, since no division is ever performed, the default MathContext is unlimited significant digits. However, when division occurs during parsing to correct for percentages and multipliers, a MathContext of 34 digits, the IEEE 754R Decimal128 standard, is used by default. If you require more than 34 digits when parsing, you can set a custom MathContext using this method.

        Parameters:
        mathContext - The MathContext to use when rounding numbers.
        See Also:
        MathContext
      • setMinimumIntegerDigits

        public void setMinimumIntegerDigits​(int value)
        Rounding and Digit Limits: Sets the minimum number of digits to display before the decimal separator. If the number has fewer than this many digits, the number is padded with zeros.

        For example, if minimum integer digits is 3, the number 12.3 will be printed as "001.23".

        Minimum integer and minimum and maximum fraction digits can be specified via the pattern string. For example, "#,#00.00#" has 2 minimum integer digits, 2 minimum fraction digits, and 3 maximum fraction digits. Note that it is not possible to specify maximium integer digits in the pattern except in scientific notation.

        If minimum and maximum integer, fraction, or significant digits conflict with each other, the most recently specified value is used. For example, if there is a formatter with minInt=5, and then you set maxInt=3, then minInt will be changed to 3.

        Overrides:
        setMinimumIntegerDigits in class NumberFormat
        Parameters:
        value - The minimum number of digits before the decimal separator.
        See Also:
        NumberFormat.getMinimumIntegerDigits()
      • setMaximumIntegerDigits

        public void setMaximumIntegerDigits​(int value)
        Rounding and Digit Limits: Sets the maximum number of digits to display before the decimal separator. If the number has more than this many digits, the number is truncated.

        For example, if maximum integer digits is 3, the number 12345 will be printed as "345".

        Minimum integer and minimum and maximum fraction digits can be specified via the pattern string. For example, "#,#00.00#" has 2 minimum integer digits, 2 minimum fraction digits, and 3 maximum fraction digits. Note that it is not possible to specify maximium integer digits in the pattern except in scientific notation.

        If minimum and maximum integer, fraction, or significant digits conflict with each other, the most recently specified value is used. For example, if there is a formatter with minInt=5, and then you set maxInt=3, then minInt will be changed to 3.

        Overrides:
        setMaximumIntegerDigits in class NumberFormat
        Parameters:
        value - The maximum number of digits before the decimal separator.
        See Also:
        NumberFormat.getMaximumIntegerDigits()
      • setMinimumFractionDigits

        public void setMinimumFractionDigits​(int value)
        Rounding and Digit Limits: Sets the minimum number of digits to display after the decimal separator. If the number has fewer than this many digits, the number is padded with zeros.

        For example, if minimum fraction digits is 2, the number 123.4 will be printed as "123.40".

        Minimum integer and minimum and maximum fraction digits can be specified via the pattern string. For example, "#,#00.00#" has 2 minimum integer digits, 2 minimum fraction digits, and 3 maximum fraction digits. Note that it is not possible to specify maximium integer digits in the pattern except in scientific notation.

        If minimum and maximum integer, fraction, or significant digits conflict with each other, the most recently specified value is used. For example, if there is a formatter with minInt=5, and then you set maxInt=3, then minInt will be changed to 3.

        See setRoundingIncrement(java.math.BigDecimal) and setMaximumSignificantDigits(int) for two other ways of specifying rounding strategies.

        Overrides:
        setMinimumFractionDigits in class NumberFormat
        Parameters:
        value - The minimum number of integer digits after the decimal separator.
        See Also:
        setRoundingMode(int), setRoundingIncrement(java.math.BigDecimal), setMaximumSignificantDigits(int)
      • setMaximumFractionDigits

        public void setMaximumFractionDigits​(int value)
        Rounding and Digit Limits: Sets the maximum number of digits to display after the decimal separator. If the number has more than this many digits, the number is rounded according to the rounding mode.

        For example, if maximum fraction digits is 2, the number 123.456 will be printed as "123.46".

        Minimum integer and minimum and maximum fraction digits can be specified via the pattern string. For example, "#,#00.00#" has 2 minimum integer digits, 2 minimum fraction digits, and 3 maximum fraction digits. Note that it is not possible to specify maximium integer digits in the pattern except in scientific notation.

        If minimum and maximum integer, fraction, or significant digits conflict with each other, the most recently specified value is used. For example, if there is a formatter with minInt=5, and then you set maxInt=3, then minInt will be changed to 3.

        Overrides:
        setMaximumFractionDigits in class NumberFormat
        Parameters:
        value - The maximum number of integer digits after the decimal separator.
        See Also:
        setRoundingMode(int)
      • areSignificantDigitsUsed

        public boolean areSignificantDigitsUsed()
        Returns whether significant digits are being used in rounding.
        See Also:
        setSignificantDigitsUsed(boolean)
      • setSignificantDigitsUsed

        public void setSignificantDigitsUsed​(boolean useSignificantDigits)
        Rounding and Digit Limits: Sets whether significant digits are to be used in rounding.

        Calling df.setSignificantDigitsUsed(true) is functionally equivalent to:

         df.setMinimumSignificantDigits(1);
         df.setMaximumSignificantDigits(6);
         
        Parameters:
        useSignificantDigits - true to enable significant digit rounding; false to disable it.
      • getMinimumSignificantDigits

        public int getMinimumSignificantDigits()
        Returns the effective minimum number of significant digits displayed.
        See Also:
        setMinimumSignificantDigits(int)
      • setMinimumSignificantDigits

        public void setMinimumSignificantDigits​(int value)
        Rounding and Digit Limits: Sets the minimum number of significant digits to be displayed. If the number of significant digits is less than this value, the number will be padded with zeros as necessary.

        For example, if minimum significant digits is 3 and the number is 1.2, the number will be printed as "1.20".

        If minimum and maximum integer, fraction, or significant digits conflict with each other, the most recently specified value is used. For example, if there is a formatter with minInt=5, and then you set maxInt=3, then minInt will be changed to 3.

        Parameters:
        value - The minimum number of significant digits to display.
      • getMaximumSignificantDigits

        public int getMaximumSignificantDigits()
        Returns the effective maximum number of significant digits displayed.
        See Also:
        setMaximumSignificantDigits(int)
      • setMaximumSignificantDigits

        public void setMaximumSignificantDigits​(int value)
        Rounding and Digit Limits: Sets the maximum number of significant digits to be displayed. If the number of significant digits in the number exceeds this value, the number will be rounded according to the current rounding mode.

        For example, if maximum significant digits is 3 and the number is 12345, the number will be printed as "12300".

        If minimum and maximum integer, fraction, or significant digits conflict with each other, the most recently specified value is used. For example, if there is a formatter with minInt=5, and then you set maxInt=3, then minInt will be changed to 3.

        See setRoundingIncrement(java.math.BigDecimal) and setMaximumFractionDigits(int) for two other ways of specifying rounding strategies.

        Parameters:
        value - The maximum number of significant digits to display.
        See Also:
        setRoundingMode(int), setRoundingIncrement(java.math.BigDecimal), setMaximumFractionDigits(int)
      • getFormatWidth

        public int getFormatWidth()
        Returns the minimum number of characters in formatted output.
        See Also:
        setFormatWidth(int)
      • setFormatWidth

        public void setFormatWidth​(int width)
        Padding: Sets the minimum width of the string output by the formatting pipeline. For example, if padding is enabled and paddingWidth is set to 6, formatting the number "3.14159" with the pattern "0.00" will result in "··3.14" if '·' is your padding string.

        If the number is longer than your padding width, the number will display as if no padding width had been specified, which may result in strings longer than the padding width.

        Padding can be specified in the pattern string using the '*' symbol. For example, the format "*x######0" has a format width of 7 and a pad character of 'x'.

        Padding is currently counted in UTF-16 code units; see ticket #13034 for more information.

        Parameters:
        width - The minimum number of characters in the output.
        See Also:
        setPadCharacter(char), setPadPosition(int)
      • getPadCharacter

        public char getPadCharacter()
        Returns the character used for padding.
        See Also:
        setPadCharacter(char)
      • setPadCharacter

        public void setPadCharacter​(char padChar)
        Padding: Sets the character used to pad numbers that are narrower than the width specified in setFormatWidth(int).

        In the pattern string, the padding character is the token that follows '*' before or after the prefix or suffix.

        Parameters:
        padChar - The character used for padding.
        See Also:
        setFormatWidth(int)
      • getPadPosition

        public int getPadPosition()
        Returns the position used for padding.
        See Also:
        setPadPosition(int)
      • isScientificNotation

        public boolean isScientificNotation()
        Returns whether scientific (exponential) notation is enabled on this formatter.
        See Also:
        setScientificNotation(boolean)
      • setScientificNotation

        public void setScientificNotation​(boolean useScientific)
        Scientific Notation: Sets whether this formatter should print in scientific (exponential) notation. For example, if scientific notation is enabled, the number 123000 will be printed as "1.23E5" in locale en-US. A locale-specific symbol is used as the exponent separator.

        Calling df.setScientificNotation(true) is functionally equivalent to calling df.setMinimumExponentDigits(1).

        Parameters:
        useScientific - true to enable scientific notation; false to disable it.
        See Also:
        setMinimumExponentDigits(byte)
      • getMinimumExponentDigits

        public byte getMinimumExponentDigits()
        Returns the minimum number of digits printed in the exponent in scientific notation.
        See Also:
        setMinimumExponentDigits(byte)
      • setMinimumExponentDigits

        public void setMinimumExponentDigits​(byte minExpDig)
        Scientific Notation: Sets the minimum number of digits to be printed in the exponent. For example, if minimum exponent digits is 3, the number 123000 will be printed as "1.23E005".

        This setting corresponds to the number of zeros after the 'E' in a pattern string such as "0.00E000".

        Parameters:
        minExpDig - The minimum number of digits in the exponent.
      • isExponentSignAlwaysShown

        public boolean isExponentSignAlwaysShown()
        Returns whether the sign (plus or minus) is always printed in scientific notation.
        See Also:
        setExponentSignAlwaysShown(boolean)
      • setExponentSignAlwaysShown

        public void setExponentSignAlwaysShown​(boolean expSignAlways)
        Scientific Notation: Sets whether the sign (plus or minus) is always to be shown in the exponent in scientific notation. For example, if this setting is enabled, the number 123000 will be printed as "1.23E+5" in locale en-US. The number 0.0000123 will always be printed as "1.23E-5" in locale en-US whether or not this setting is enabled.

        This setting corresponds to the '+' in a pattern such as "0.00E+0".

        Parameters:
        expSignAlways - true to always shown the sign in the exponent; false to show it for negatives but not positives.
      • setGroupingUsed

        public void setGroupingUsed​(boolean enabled)
        Grouping: Sets whether grouping is to be used when formatting numbers. Grouping means whether the thousands, millions, billions, and larger powers of ten should be separated by a grouping separator (a comma in en-US).

        For example, if grouping is enabled, 12345 will be printed as "12,345" in en-US. If grouping were disabled, it would instead be printed as simply "12345".

        Calling df.setGroupingUsed(true) is functionally equivalent to setting grouping size to 3, as in df.setGroupingSize(3).

        Overrides:
        setGroupingUsed in class NumberFormat
        Parameters:
        enabled - true to enable grouping separators; false to disable them.
        See Also:
        setGroupingSize(int), setSecondaryGroupingSize(int)
      • getGroupingSize

        public int getGroupingSize()
        Returns the primary grouping size in use.
        See Also:
        setGroupingSize(int)
      • setGroupingSize

        public void setGroupingSize​(int width)
        Grouping: Sets the primary grouping size (distance between grouping separators) used when formatting large numbers. For most locales, this defaults to 3: the number of digits between the ones and thousands place, between thousands and millions, and so forth.

        For example, with a grouping size of 3, the number 1234567 will be formatted as "1,234,567".

        Grouping size can also be specified in the pattern: for example, "#,##0" corresponds to a grouping size of 3.

        Parameters:
        width - The grouping size to use.
        See Also:
        setSecondaryGroupingSize(int)
      • getSecondaryGroupingSize

        public int getSecondaryGroupingSize()
        Returns the secondary grouping size in use.
        See Also:
        setSecondaryGroupingSize(int)
      • setSecondaryGroupingSize

        public void setSecondaryGroupingSize​(int width)
        Grouping: Sets the secondary grouping size (distance between grouping separators after the first separator) used when formatting large numbers. In many south Asian locales, this is set to 2.

        For example, with primary grouping size 3 and secondary grouping size 2, the number 1234567 will be formatted as "12,34,567".

        Grouping size can also be specified in the pattern: for example, "#,##,##0" corresponds to a primary grouping size of 3 and a secondary grouping size of 2.

        Parameters:
        width - The secondary grouping size to use.
        See Also:
        setGroupingSize(int)
      • getMinimumGroupingDigits

        @Deprecated
        public int getMinimumGroupingDigits()
        Deprecated.
        ICU 59: This API is a technical preview. It may change in an upcoming release.
        Returns the minimum number of digits before grouping is triggered.
        See Also:
        setMinimumGroupingDigits(int)
      • setMinimumGroupingDigits

        @Deprecated
        public void setMinimumGroupingDigits​(int number)
        Deprecated.
        ICU 59: This API is a technical preview. It may change in an upcoming release.
        Sets the minimum number of digits that must be before the first grouping separator in order for the grouping separator to be printed. For example, if minimum grouping digits is set to 2, in en-US, 1234 will be printed as "1234" and 12345 will be printed as "12,345".
        Parameters:
        number - The minimum number of digits before grouping is triggered.
      • setDecimalSeparatorAlwaysShown

        public void setDecimalSeparatorAlwaysShown​(boolean value)
        Separators: Sets whether the decimal separator (a period in en-US) is shown on integers. For example, if this setting is turned on, formatting 123 will result in "123." with the decimal separator.

        This setting can be specified in the pattern for integer formats: "#,##0." is an example.

        Parameters:
        value - true to always show the decimal separator; false to show it only when there is a fraction part of the number.
      • setCurrency

        public void setCurrency​(Currency currency)
        Sets the currency to be used when formatting numbers. The effect is twofold:
        1. Substitutions for currency symbols in the pattern string will use this currency
        2. The rounding mode will obey the rules for this currency (see setCurrencyUsage(com.ibm.icu.util.Currency.CurrencyUsage))
        Important: Displaying the currency in the output requires that the patter associated with this formatter contains a currency symbol '¤'. This will be the case if the instance was created via NumberFormat.getCurrencyInstance() or one of its friends.
        Overrides:
        setCurrency in class NumberFormat
        Parameters:
        currency - The currency to use.
      • setCurrencyUsage

        public void setCurrencyUsage​(Currency.CurrencyUsage usage)
        Sets the currency-dependent strategy to use when rounding numbers. There are two strategies:
        • STANDARD: When the amount displayed is intended for banking statements or electronic transfer.
        • CASH: When the amount displayed is intended to be representable in physical currency, like at a cash register.
        CASH mode is relevant in currencies that do not have tender down to the penny. For more information on the two rounding strategies, see UTS #35. If omitted, the strategy defaults to STANDARD. To override currency rounding altogether, use setMinimumFractionDigits(int) and setMaximumFractionDigits(int) or setRoundingIncrement(java.math.BigDecimal).
        Parameters:
        usage - The strategy to use when rounding in the current currency.
      • setCurrencyPluralInfo

        public void setCurrencyPluralInfo​(CurrencyPluralInfo newInfo)
        Sets a custom instance of CurrencyPluralInfo. CurrencyPluralInfo generates pattern strings for printing currency long names.

        Most users should not call this method directly. You should instead create your formatter via NumberFormat.getInstance(NumberFormat.PLURALCURRENCYSTYLE).

        Parameters:
        newInfo - The CurrencyPluralInfo to use when printing currency long names.
      • getParseMaxDigits

        @Deprecated
        public int getParseMaxDigits()
        Deprecated.
        Setting max parse digits has no effect since ICU4J 59.
        Always returns 1000, the default prior to ICU 59.
      • setParseMaxDigits

        @Deprecated
        public void setParseMaxDigits​(int maxDigits)
        Deprecated.
        Setting max parse digits has no effect since ICU4J 59.
        Parameters:
        maxDigits - Prior to ICU 59, the maximum number of digits in the output number after exponential notation is applied.
      • setParseStrict

        public void setParseStrict​(boolean parseStrict)
        Sets whether strict parsing is in effect. When this is true, the string is required to be a stronger match to the pattern than when lenient parsing is in effect. More specifically, the following conditions cause a parse failure relative to lenient mode (examples use the pattern "#,##0.#"):
        • The presence and position of special symbols, including currency, must match the pattern.
          '+123' fails (there is no plus sign in the pattern)
        • Leading or doubled grouping separators
          ',123' and '1,,234" fail
        • Groups of incorrect length when grouping is used
          '1,23' and '1234,567' fail, but '1234' passes
        • Grouping separators used in numbers followed by exponents
          '1,234E5' fails, but '1234E5' and '1,234E' pass ('E' is not an exponent when not followed by a number)
        When strict parsing is off, all grouping separators are ignored. This is the default behavior.
        Overrides:
        setParseStrict in class NumberFormat
        Parameters:
        parseStrict - True to enable strict parsing. Default is false.
        See Also:
        NumberFormat.isParseStrict()
      • isParseIntegerOnly

        public boolean isParseIntegerOnly()
        Returns true if this format will parse numbers as integers only. For example in the English locale, with ParseIntegerOnly true, the string "1234." would be parsed as the integer value 1234 and parsing would stop at the "." character. The decimal separator accepted by the parse operation is locale-dependent and determined by the subclass.
        Overrides:
        isParseIntegerOnly in class NumberFormat
        Returns:
        true if this will parse integers only
        See Also:
        setParseIntegerOnly(boolean)
      • setParseIntegerOnly

        public void setParseIntegerOnly​(boolean parseIntegerOnly)
        Parsing: Sets whether to ignore the fraction part of a number when parsing (defaults to false). If a string contains a decimal point, parsing will stop before the decimal point. Note that determining whether a character is a decimal point depends on the locale.

        For example, in en-US, parsing the string "123.45" will return the number 123 and parse position 3.

        This is functionally equivalent to calling setDecimalPatternMatchRequired(boolean) and a pattern without a decimal point.

        Overrides:
        setParseIntegerOnly in class NumberFormat
        Parameters:
        parseIntegerOnly - true to ignore fractional parts of numbers when parsing; false to consume fractional parts.
        See Also:
        NumberFormat.isParseIntegerOnly()
      • isDecimalPatternMatchRequired

        public boolean isDecimalPatternMatchRequired()
        Returns whether the presence of a decimal point must match the pattern.
        See Also:
        setDecimalPatternMatchRequired(boolean)
      • setDecimalPatternMatchRequired

        public void setDecimalPatternMatchRequired​(boolean value)
        Parsing: This method is used to either require or forbid the presence of a decimal point in the string being parsed (disabled by default). This feature was designed to be an extra layer of strictness on top of strict parsing, although it can be used in either lenient mode or strict mode.

        To require a decimal point, call this method in combination with either a pattern containing a decimal point or with setDecimalSeparatorAlwaysShown(boolean).

         // Require a decimal point in the string being parsed:
         df.applyPattern("#.");
         df.setDecimalPatternMatchRequired(true);
        
         // Alternatively:
         df.setDecimalSeparatorAlwaysShown(true);
         df.setDecimalPatternMatchRequired(true);
         
        To forbid a decimal point, call this method in combination with a pattern containing no decimal point. Alternatively, use setParseIntegerOnly(boolean) for the same behavior without depending on the contents of the pattern string.
         // Forbid a decimal point in the string being parsed:
         df.applyPattern("#");
         df.setDecimalPatternMatchRequired(true);
         
        Parameters:
        value - true to either require or forbid the decimal point according to the pattern; false to disable this feature.
        See Also:
        setParseIntegerOnly(boolean)
      • getParseNoExponent

        @Deprecated
        public boolean getParseNoExponent()
        Deprecated.
        ICU 59: This API is a technical preview. It may change in an upcoming release.
        Returns whether to ignore exponents when parsing.
        See Also:
        setParseNoExponent(boolean)
      • setParseNoExponent

        @Deprecated
        public void setParseNoExponent​(boolean value)
        Deprecated.
        ICU 59: This API is a technical preview. It may change in an upcoming release.
        Specifies whether to stop parsing when an exponent separator is encountered. For example, parses "123E4" to 123 (with parse position 3) instead of 1230000 (with parse position 5).
        Parameters:
        value - true to prevent exponents from being parsed; false to allow them to be parsed.
      • getParseCaseSensitive

        @Deprecated
        public boolean getParseCaseSensitive()
        Deprecated.
        ICU 59: This API is a technical preview. It may change in an upcoming release.
        Returns whether to force case (uppercase/lowercase) to match when parsing.
        See Also:
        setParseNoExponent(boolean)
      • setParseCaseSensitive

        @Deprecated
        public void setParseCaseSensitive​(boolean value)
        Deprecated.
        ICU 59: This API is a technical preview. It may change in an upcoming release.
        Specifies whether parsing should require cases to match in affixes, exponent separators, and currency codes. Case mapping is performed for each code point using UCharacter.foldCase(int, boolean).
        Parameters:
        value - true to force case (uppercase/lowercase) to match when parsing; false to ignore case and perform case folding.
      • equals

        public boolean equals​(java.lang.Object obj)
        Tests for equality between this formatter and another formatter.

        If two DecimalFormat instances are equal, then they will always produce the same output. However, the reverse is not necessarily true: if two DecimalFormat instances always produce the same output, they are not necessarily equal.

        Overrides:
        equals in class NumberFormat
        Parameters:
        obj - the object to compare against
        Returns:
        true if the object is equal to this.
      • toString

        public java.lang.String toString()
        Returns the default value of toString() with extra DecimalFormat-specific information appended to the end of the string. This extra information is intended for debugging purposes, and the format is not guaranteed to be stable.
        Overrides:
        toString in class java.lang.Object
      • toPattern

        public java.lang.String toPattern()
        Serializes this formatter object to a decimal format pattern string. The result of this method is guaranteed to be functionally equivalent to the pattern string used to create this instance after incorporating values from the setter methods.

        For more information on decimal format pattern strings, see UTS #35.

        Important: Not all properties are capable of being encoded in a pattern string. See a list of properties in applyPattern(java.lang.String).

        Returns:
        A decimal format pattern string.
      • toLocalizedPattern

        public java.lang.String toLocalizedPattern()
        Calls toPattern() and converts the string to localized notation. For more information on localized notation, see applyLocalizedPattern(java.lang.String). This method is provided for backwards compatibility and should not be used in new projects.
        Returns:
        A decimal format pattern string in localized notation.
      • toNumberFormatter

        public LocalizedNumberFormatter toNumberFormatter()
        Converts this DecimalFormat to a NumberFormatter. Starting in ICU 60, NumberFormatter is the recommended way to format numbers.
        Returns:
        An instance of LocalizedNumberFormatter with the same behavior as this instance of DecimalFormat.
        See Also:
        NumberFormatter
      • getFixedDecimal

        @Deprecated
        public PluralRules.IFixedDecimal getFixedDecimal​(double number)
        Deprecated.
        This API is ICU internal only.