Module java.base
Package java.text

Class CompactNumberFormat

java.lang.Object
java.text.Format
java.text.NumberFormat
java.text.CompactNumberFormat
All Implemented Interfaces:
Serializable, Cloneable
public final class CompactNumberFormat extends NumberFormat

CompactNumberFormat is a concrete subclass of NumberFormat that formats a decimal number in its compact form. The compact number formatting is designed for the environment where the space is limited, and the formatted string can be displayed in that limited space. It is defined by LDML's specification for Compact Number Formats. A compact number formatting refers to the representation of a number in a shorter form, based on the patterns provided for a given locale.

For example:
In the US locale, 1000 can be formatted as "1K", and 1000000 as "1M", depending upon the style used.
In the "hi_IN" locale, 1000 can be formatted as "1 हज़ार", and 50000000 as "5 क.", depending upon the style used.

To obtain a CompactNumberFormat for a locale, use one of the factory methods given by NumberFormat for compact number formatting. For example, NumberFormat.getCompactNumberInstance(Locale, Style). 

NumberFormat fmt = NumberFormat.getCompactNumberInstance(
                            Locale.forLanguageTag("hi-IN"), NumberFormat.Style.SHORT);
String result = fmt.format(1000);

Style

A number can be formatted in the compact forms with two different styles, SHORT and LONG. Use NumberFormat.getCompactNumberInstance(Locale, Style) for formatting and parsing a number in SHORT or LONG compact form, where the given Style parameter requests the desired format. A SHORT style compact number instance in the US locale formats 10000 as "10K". However, a LONG style instance in same locale formats 10000 as "10 thousand".

Compact Number Patterns

The compact number patterns are represented in a series of patterns where each pattern is used to format a range of numbers. An example of SHORT styled compact number patterns for the US locale is {"", "", "", "0K", "00K", "000K", "0M", "00M", "000M", "0B", "00B", "000B", "0T", "00T", "000T"}, ranging from 100 to 1014. There can be any number of patterns and they are strictly index based starting from the range 100. For example, in the above patterns, pattern at index 3 ("0K") is used for formatting number >= 1000 and number < 10000, pattern at index 4 ("00K") is used for formatting number >= 10000 and number < 100000 and so on. In most of the locales, patterns with the range 100-102 are empty strings, which implicitly means a special pattern "0". A special pattern "0" is used for any range which does not contain a compact pattern. This special pattern can appear explicitly for any specific range, or considered as a default pattern for an empty string.

A compact pattern contains a positive and negative subpattern separated by a subpattern boundary character ';' (U+003B), for example, "0K;-0K". Each subpattern has a prefix, minimum integer digits, and suffix. The negative subpattern is optional, if absent, then the positive subpattern prefixed with the minus sign ('-' U+002D HYPHEN-MINUS) is used as the negative subpattern. That is, "0K" alone is equivalent to "0K;-0K". If there is an explicit negative subpattern, it serves only to specify the negative prefix and suffix. The number of minimum integer digits, and other characteristics are all the same as the positive pattern. That means that "0K;-00K" produces precisely the same behavior as "0K;-0K".

Many characters in a compact 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. They must be quoted, using single quote ' (U+0027) unless noted otherwise, if they are to appear in the prefix or suffix as literals. For example, 0क'.'.

Plurals

In case some localization requires compact number patterns to be different for plurals, each singular and plural pattern can be enumerated within a pair of curly brackets '{' (U+007B) and '}' (U+007D), separated by a space ' ' (U+0020). If this format is used, each pattern needs to be prepended by its count, followed by a single colon ':' (U+003A). If the pattern includes spaces literally, they must be quoted.

For example, the compact number pattern representing millions in German locale can be specified as "{one:0' 'Million other:0' 'Millionen}". The count follows LDML's Language Plural Rules.

A compact pattern has the following syntax: 

 Pattern:
         SimplePattern
         '{' PluralPattern [' ' PluralPattern]optional '}'
 SimplePattern:
         PositivePattern
         PositivePattern [; NegativePattern]optional
 PluralPattern:
         Count:SimplePattern
 Count:
         "zero" / "one" / "two" / "few" / "many" / "other"
 PositivePattern:
         Prefixoptional MinimumInteger Suffixoptional
 NegativePattern:
        Prefixoptional MinimumInteger Suffixoptional
 Prefix:
      Any Unicode characters except U+FFFE, U+FFFF, and
      special characters.
 Suffix:
      Any Unicode characters except U+FFFE, U+FFFF, and
      special characters.
 MinimumInteger:
      0
      0 MinimumInteger

Formatting

The default formatting behavior returns a formatted string with no fractional digits, however users can use the setMinimumFractionDigits(int) method to include the fractional part. The number 1000.0 or 1000 is formatted as "1K" not "1.00K" (in the US locale). For this reason, the patterns provided for formatting contain only the minimum integer digits, prefix and/or suffix, but no fractional part. For example, patterns used are {"", "", "", 0K, 00K, ...}. If the pattern selected for formatting a number is "0" (special pattern), either explicit or defaulted, then the general number formatting provided by DecimalFormat for the specified locale is used.

Parsing

The default parsing behavior does not allow a grouping separator until grouping used is set to true by using setGroupingUsed(boolean). The parsing of the fractional part depends on the isParseIntegerOnly(). For example, if the parse integer only is set to true, then the fractional part is skipped.

Rounding

CompactNumberFormat provides rounding modes defined in RoundingMode for formatting. By default, it uses RoundingMode.HALF_EVEN.
Since:
12
External Specifications
See Also:

  • Constructor Details

  • Method Details

    • format

      public final StringBuffer format(Object number, StringBuffer toAppendTo, FieldPosition fieldPosition)
      Formats a number to produce a string representing its compact form. The number can be of any subclass of Number.
      Overrides:
      format in class NumberFormat
      Parameters:
      number - the number to format
      toAppendTo - the StringBuffer to which the formatted text is to be appended
      fieldPosition - keeps track on the position of the field within the returned string. For example, for formatting a number 123456789 in the US locale, if the given fieldPosition is NumberFormat.INTEGER_FIELD, the begin index and end index of fieldPosition will be set to 0 and 3, respectively for the output string 123M. Similarly, positions of the prefix and the suffix fields can be obtained using NumberFormat.Field.PREFIX and NumberFormat.Field.SUFFIX respectively.
      Returns:
      the StringBuffer passed in as toAppendTo
      Throws:
      IllegalArgumentException - if number is null or not an instance of Number
      NullPointerException - if toAppendTo or fieldPosition is null
      ArithmeticException - if rounding is needed with rounding mode being set to RoundingMode.UNNECESSARY
      See Also:

    • format

      public StringBuffer format(double number, StringBuffer result, FieldPosition fieldPosition)
      Formats a double to produce a string representing its compact form.
      Specified by:
      format in class NumberFormat
      Parameters:
      number - the double number to format
      result - where the text is to be appended
      fieldPosition - keeps track on the position of the field within the returned string. For example, to format a number 1234567.89 in the US locale if the given fieldPosition is NumberFormat.INTEGER_FIELD, the begin index and end index of fieldPosition will be set to 0 and 1, respectively for the output string 1M. Similarly, positions of the prefix and the suffix fields can be obtained using NumberFormat.Field.PREFIX and NumberFormat.Field.SUFFIX respectively.
      Returns:
      the StringBuffer passed in as result
      Throws:
      NullPointerException - if result or fieldPosition is null
      ArithmeticException - if rounding is needed with rounding mode being set to RoundingMode.UNNECESSARY
      See Also:

    • format

      public StringBuffer format(long number, StringBuffer result, FieldPosition fieldPosition)
      Formats a long to produce a string representing its compact form.
      Specified by:
      format in class NumberFormat
      Parameters:
      number - the long number to format
      result - where the text is to be appended
      fieldPosition - keeps track on the position of the field within the returned string. For example, to format a number 123456789 in the US locale, if the given fieldPosition is NumberFormat.INTEGER_FIELD, the begin index and end index of fieldPosition will be set to 0 and 3, respectively for the output string 123M. Similarly, positions of the prefix and the suffix fields can be obtained using NumberFormat.Field.PREFIX and NumberFormat.Field.SUFFIX respectively.
      Returns:
      the StringBuffer passed in as result
      Throws:
      NullPointerException - if result or fieldPosition is null
      ArithmeticException - if rounding is needed with rounding mode being set to RoundingMode.UNNECESSARY
      See Also:

    • formatToCharacterIterator

      public AttributedCharacterIterator formatToCharacterIterator(Object obj)
      Formats an Object producing an AttributedCharacterIterator. The returned AttributedCharacterIterator can be used to build the resulting string, as well as to determine information about the resulting string.

      Each attribute key of the AttributedCharacterIterator will be of type NumberFormat.Field, with the attribute value being the same as the attribute key. The prefix and the suffix parts of the returned iterator (if present) are represented by the attributes NumberFormat.Field.PREFIX and NumberFormat.Field.SUFFIX respectively.

      Overrides:
      formatToCharacterIterator in class Format
      Parameters:
      obj - The object to format
      Returns:
      an AttributedCharacterIterator describing the formatted value
      Throws:
      NullPointerException - if obj is null
      IllegalArgumentException - when the Format cannot format the given object
      ArithmeticException - if rounding is needed with rounding mode being set to RoundingMode.UNNECESSARY

    • parse

      public Number parse(String text, ParsePosition pos)
      Parses a compact number from a string to produce a Number.

      The method attempts to parse text starting at the index given by pos. If parsing succeeds, then the index of pos is updated to the index after the last character used (parsing does not necessarily use all characters up to the end of the string), and the parsed number is returned. The updated pos can be used to indicate the starting point for the next call to this method. If an error occurs, then the index of pos is not changed, the error index of pos is set to the index of the character where the error occurred, and null is returned.

      The value is the numeric part in the given text multiplied by the numeric equivalent of the affix attached (For example, "K" = 1000 in US locale). The subclass returned depends on the value of isParseBigDecimal().

      • If isParseBigDecimal() is false (the default), most integer values are returned as Long objects, no matter how they are written: "17K" and "17.000K" both parse to Long.valueOf(17000). If the value cannot fit into Long, then the result is returned as Double. This includes values with a fractional part, infinite values, NaN, and the value -0.0.

        Callers may use the Number methods doubleValue, longValue, etc., to obtain the type they want.

      • If isParseBigDecimal() is true, values are returned as BigDecimal objects. The special cases negative and positive infinity and NaN are returned as Double instances holding the values of the corresponding Double constants.

      CompactNumberFormat parses all Unicode characters that represent decimal digits, as defined by Character.digit(). In addition, CompactNumberFormat also recognizes as digits the ten consecutive characters starting with the localized zero digit defined in the DecimalFormatSymbols object.

      CompactNumberFormat parse does not allow parsing scientific notations. For example, parsing a string "1.05E4K" in US locale breaks at character 'E' and returns 1.05.

      Specified by:
      parse in class NumberFormat
      Parameters:
      text - the string to be parsed
      pos - a ParsePosition object with index and error index information as described above
      Returns:
      the parsed value, or null if the parse fails
      Throws:
      NullPointerException - if text or pos is null
      See Also:

    • setMaximumIntegerDigits

      public void setMaximumIntegerDigits(int newValue)
      Sets the maximum number of digits allowed in the integer portion of a number. The maximum allowed integer range is 309, if the newValue > 309, then the maximum integer digits count is set to 309. Negative input values are replaced with 0.
      Overrides:
      setMaximumIntegerDigits in class NumberFormat
      Parameters:
      newValue - the maximum number of integer digits to be shown
      See Also:

    • setMinimumIntegerDigits

      public void setMinimumIntegerDigits(int newValue)
      Sets the minimum number of digits allowed in the integer portion of a number. The maximum allowed integer range is 309, if the newValue > 309, then the minimum integer digits count is set to 309. Negative input values are replaced with 0.
      Overrides:
      setMinimumIntegerDigits in class NumberFormat
      Parameters:
      newValue - the minimum number of integer digits to be shown
      See Also:

    • setMinimumFractionDigits

      public void setMinimumFractionDigits(int newValue)
      Sets the minimum number of digits allowed in the fraction portion of a number. The maximum allowed fraction range is 340, if the newValue > 340, then the minimum fraction digits count is set to 340. Negative input values are replaced with 0.
      Overrides:
      setMinimumFractionDigits in class NumberFormat
      Parameters:
      newValue - the minimum number of fraction digits to be shown
      See Also:

    • setMaximumFractionDigits

      public void setMaximumFractionDigits(int newValue)
      Sets the maximum number of digits allowed in the fraction portion of a number. The maximum allowed fraction range is 340, if the newValue > 340, then the maximum fraction digits count is set to 340. Negative input values are replaced with 0.
      Overrides:
      setMaximumFractionDigits in class NumberFormat
      Parameters:
      newValue - the maximum number of fraction digits to be shown
      See Also:

    • getRoundingMode

      public RoundingMode getRoundingMode()
      Gets the RoundingMode used in this CompactNumberFormat.
      Overrides:
      getRoundingMode in class NumberFormat
      Returns:
      the RoundingMode used for this CompactNumberFormat
      See Also:

    • setRoundingMode

      public void setRoundingMode(RoundingMode roundingMode)
      Sets the RoundingMode used in this CompactNumberFormat.
      Overrides:
      setRoundingMode in class NumberFormat
      Parameters:
      roundingMode - the RoundingMode to be used
      Throws:
      NullPointerException - if roundingMode is null
      See Also:

    • getGroupingSize

      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 compact number "12,347 trillion" for the US locale, the grouping size is 3.
      Returns:
      the grouping size
      See Also:

    • setGroupingSize

      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 compact number "12,347 trillion" for the US locale, the grouping size is 3. The grouping size must be greater than or equal to zero and less than or equal to 127.
      Parameters:
      newValue - the new grouping size
      Throws:
      IllegalArgumentException - if newValue is negative or larger than 127
      See Also:

    • isGroupingUsed

      public boolean isGroupingUsed()
      Returns true if grouping is used in this format. For example, with grouping on and grouping size set to 3, the number 12346567890987654 can be formatted as "12,347 trillion" in the US locale. The grouping separator is locale dependent.
      Overrides:
      isGroupingUsed in class NumberFormat
      Returns:
      true if grouping is used; false otherwise
      See Also:

    • setGroupingUsed

      public void setGroupingUsed(boolean newValue)
      Sets whether or not grouping will be used in this format.
      Overrides:
      setGroupingUsed in class NumberFormat
      Parameters:
      newValue - true if grouping is used; false otherwise
      See Also:

    • isParseIntegerOnly

      public boolean isParseIntegerOnly()
      Returns true if this format parses only an integer from the number component of a compact number. Parsing an integer means that only an integer is considered from the number component, prefix/suffix is still considered to compute the resulting output. For example, in the US locale, if this method returns true, the string "1234.78 thousand" would be parsed as the value 1234000 (1234 (integer part) * 1000 (thousand)) and the fractional part would be skipped. The exact format accepted by the parse operation is locale dependent.
      Overrides:
      isParseIntegerOnly in class NumberFormat
      Returns:
      true if compact numbers should be parsed as integers only; false otherwise

    • setParseIntegerOnly

      public void setParseIntegerOnly(boolean value)
      Sets whether or not this format parses only an integer from the number component of a compact number.
      Overrides:
      setParseIntegerOnly in class NumberFormat
      Parameters:
      value - true if compact numbers should be parsed as integers only; false otherwise
      See Also:

    • isParseBigDecimal

      public boolean isParseBigDecimal()
      Returns whether the parse(String, ParsePosition) method returns BigDecimal. The default value is false.
      Returns:
      true if the parse method returns BigDecimal; false otherwise
      See Also:

    • setParseBigDecimal

      public void setParseBigDecimal(boolean newValue)
      Sets whether the parse(String, ParsePosition) method returns BigDecimal.
      Parameters:
      newValue - true if the parse method returns BigDecimal; false otherwise
      See Also:

    • equals

      public boolean equals(Object obj)
      Checks if this CompactNumberFormat is equal to the specified obj. The objects of type CompactNumberFormat are compared, other types return false; obeys the general contract of Object.equals.
      Overrides:
      equals in class NumberFormat
      Parameters:
      obj - the object to compare with
      Returns:
      true if this is equal to the other CompactNumberFormat
      See Also:

    • hashCode

      public int hashCode()
      Returns the hash code for this CompactNumberFormat instance.
      Overrides:
      hashCode in class NumberFormat
      Returns:
      hash code for this CompactNumberFormat
      See Also:

    • clone

      public CompactNumberFormat clone()
      Creates and returns a copy of this CompactNumberFormat instance.
      Overrides:
      clone in class NumberFormat
      Returns:
      a clone of this instance
      See Also: