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java.text
Class DecimalFormat

java.lang.Object
  extended byjava.text.Format
      extended byjava.text.NumberFormat
          extended byjava.text.DecimalFormat
All Implemented Interfaces:
Cloneable, Serializable
public class DecimalFormat
extends NumberFormat

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, and Indic digits. It also supports different kinds of numbers, including integers (123), fixed-point numbers (123.4), scientific notation (1.23E4), percentages (12%), and currency amounts ($123). All of these can be localized.

To obtain a NumberFormat for a specific locale, including the default locale, call one of NumberFormat's factory methods, such as getInstance(). In general, do not call the DecimalFormat constructors directly, 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);
 }

A DecimalFormat comprises a pattern and a set of symbols. The pattern may be set directly using applyPattern(), or indirectly using the API methods. The symbols are stored in a DecimalFormatSymbols object. When using the NumberFormat factory methods, the pattern and symbols are read from localized ResourceBundles.

Patterns

DecimalFormat patterns have the following syntax: 
 Pattern:
         PositivePattern
         PositivePattern ; NegativePattern
 PositivePattern:
         Prefixopt Number Suffixopt
 NegativePattern:
         Prefixopt Number Suffixopt
 Prefix:
         any Unicode characters except \uFFFE, \uFFFF, and special characters
 Suffix:
         any Unicode characters except \uFFFE, \uFFFF, and special characters
 Number:
         Integer Exponentopt
         Integer . Fraction Exponentopt
 Integer:
         MinimumInteger
         #
         # Integer
         # , Integer
 MinimumInteger:
         0
         0 MinimumInteger
         0 , MinimumInteger
 Fraction:
         MinimumFractionopt OptionalFractionopt
 MinimumFraction:
         0 MinimumFractionopt
 OptionalFraction:
         # OptionalFractionopt
 Exponent:
         E MinimumExponent
 MinimumExponent:
         0 MinimumExponentopt

A DecimalFormat pattern contains a positive and negative subpattern, for example, "#,##0.00;(#,##0.00)". Each subpattern has a prefix, numeric part, and suffix. The negative subpattern is optional; if absent, then the positive subpattern prefixed with the localized minus sign (code>'-' in most locales) is used as the negative 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 all the same as the positive pattern. That means that "#,##0.0#;(#)" produces precisely the same behavior 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 DecimalFormat.parse() to be able to distinguish positive from negative values. (If they are identical, then DecimalFormat will behave as if no negative subpattern was specified.) Another example is that the decimal separator and thousands separator should be distinct characters, or parsing will be impossible.

The grouping separator is commonly used for thousands, but in some countries it separates ten-thousands. The grouping size is a constant number of digits between the grouping characters, such as 3 for 100,000,000 or 4 for 1,0000,0000. If you supply a pattern with multiple grouping characters, the interval between the last one and the end of the integer is the one that is used. So "#,##,###,####" == "######,####" == "##,####,####".

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. They must be quoted, unless noted otherwise, if they are to appear in the prefix or suffix as literals.

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
# 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.
; 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 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".

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 10^3. The mantissa is often in the range 1.0 <= x < 10.0, but it need not be. DecimalFormat can be instructed to format and parse scientific notation only via a pattern; there is currently no factory method that creates a scientific notation format. 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".

Rounding

DecimalFormat uses half-even rounding (see ROUND_HALF_EVEN) for formatting.

Digits

For formatting, DecimalFormat uses the ten consecutive characters starting with the localized zero digit defined in the DecimalFormatSymbols object as digits. For parsing, these digits as well as all Unicode decimal digits, as defined by Character.digit, are recognized.

Special Values

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

Negative zero ("-0") parses to Double(-0.0), unless isParseIntegerOnly() is true, in which case it parses to Long(0).

Synchronization

Decimal formats are generally not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally.

Example

 // Print out a number using the localized number, integer, currency,
 // and percent format for each locale
 Locale[] locales = NumberFormat.getAvailableLocales();
 double myNumber = -1234.56;
 NumberFormat form;
 for (int j=0; j<4; ++j) {
     System.out.println("FORMAT");
     for (int i = 0; i < locales.length; ++i) {
         if (locales[i].getCountry().length() == 0) {
            continue; // Skip language-only locales
         }
         System.out.print(locales[i].getDisplayName());
         switch (j) {
         case 0:
             form = NumberFormat.getInstance(locales[i]); break;
         case 1:
             form = NumberFormat.getIntegerInstance(locales[i]); break;
         case 2:
             form = NumberFormat.getCurrencyInstance(locales[i]); break;
         default:
             form = NumberFormat.getPercentInstance(locales[i]); break;
         }
         if (form instanceof DecimalFormat) {
             System.out.print(": " + ((DecimalFormat) form).toPattern());
         }
         System.out.print(" -> " + form.format(myNumber));
         try {
             System.out.println(" -> " + form.parse(form.format(myNumber)));
         } catch (ParseException e) {}
     }
 }

Author:
Mark Davis, Alan Liu
See Also:
Java Tutorial, NumberFormat, DecimalFormatSymbols, ParsePosition, Serialized Form

Nested Class Summary
 
Nested classes inherited from class java.text.NumberFormat
NumberFormat.Field
 
Nested classes inherited from class java.text.Format
Format.FieldDelegate
 
Field Summary
private static Hashtable cachedLocaleData
          Cache to hold the NumberPattern of a Locale.
private static char CURRENCY_SIGN
          The CURRENCY_SIGN is the standard Unicode symbol for currency.
(package private) static int currentSerialVersion
           
private  boolean decimalSeparatorAlwaysShown
          If true, forces the decimal separator to always appear in a formatted number, even if the fractional part of the number is zero.
private  DigitList digitList
           
(package private) static int DOUBLE_FRACTION_DIGITS
           
(package private) static int DOUBLE_INTEGER_DIGITS
           
private static FieldPosition[] EmptyFieldPositionArray
           
private  byte groupingSize
          The number of digits between grouping separators in the integer portion of a number.
private  boolean isCurrencyFormat
          True if this object represents a currency format.
private  byte minExponentDigits
          The minimum number of digits used to display the exponent when a number is formatted in exponential notation.
private  int multiplier
          The multiplier for use in percent, permill, etc.
private  String negativePrefix
          The symbol used as a prefix when formatting negative numbers, e.g. "-".
private  FieldPosition[] negativePrefixFieldPositions
          FieldPositions describing the negative prefix String.
private  String negativeSuffix
          The symbol used as a suffix when formatting negative numbers.
private  FieldPosition[] negativeSuffixFieldPositions
          FieldPositions describing the negative suffix String.
private  String negPrefixPattern
          The prefix pattern for negative numbers.
private  String negSuffixPattern
          The suffix pattern for negative numbers.
private static char PATTERN_DECIMAL_SEPARATOR
           
private static char PATTERN_DIGIT
           
private static char PATTERN_EXPONENT
           
private static char PATTERN_GROUPING_SEPARATOR
           
private static char PATTERN_MINUS
           
private static char PATTERN_PER_MILLE
           
private static char PATTERN_PERCENT
           
private static char PATTERN_SEPARATOR
           
private static char PATTERN_ZERO_DIGIT
           
private  String positivePrefix
          The symbol used as a prefix when formatting positive numbers, e.g. "+".
private  FieldPosition[] positivePrefixFieldPositions
          FieldPositions describing the positive prefix String.
private  String positiveSuffix
          The symbol used as a suffix when formatting positive numbers.
private  FieldPosition[] positiveSuffixFieldPositions
          FieldPositions describing the positive suffix String.
private  String posPrefixPattern
          The prefix pattern for non-negative numbers.
private  String posSuffixPattern
          The suffix pattern for non-negative numbers.
private static char QUOTE
           
private  int serialVersionOnStream
          The internal serial version which says which version was written.
(package private) static long serialVersionUID
           
private static int STATUS_INFINITE
           
private static int STATUS_LENGTH
           
private static int STATUS_POSITIVE
           
private  DecimalFormatSymbols symbols
          The DecimalFormatSymbols object used by this format.
private  boolean useExponentialNotation
          True to force the use of exponential (i.e. scientific) notation when formatting numbers.
 
Fields inherited from class java.text.NumberFormat
FRACTION_FIELD, INTEGER_FIELD
 
Constructor Summary
DecimalFormat()
          Creates a DecimalFormat using the default pattern and symbols for the default locale.
DecimalFormat(String pattern)
          Creates a DecimalFormat using the given pattern and the symbols for the default locale.
DecimalFormat(String pattern, DecimalFormatSymbols symbols)
          Creates a DecimalFormat using the given pattern and symbols.
 
Method Summary
(package private)  void adjustForCurrencyDefaultFractionDigits()
          Adjusts the minimum and maximum fraction digits to values that are reasonable for the currency's default fraction digits.
private  void append(StringBuffer result, String string, Format.FieldDelegate delegate, FieldPosition[] positions, Format.Field signAttribute)
          Appends the String string to result.
private  void appendAffix(StringBuffer buffer, String affix, boolean localized)
          Append an affix to the given StringBuffer, using quotes if there are special characters.
private  void appendAffix(StringBuffer buffer, String affixPattern, String expAffix, boolean localized)
          Appends an affix pattern to the given StringBuffer, quoting special characters as needed.
 void applyLocalizedPattern(String pattern)
          Apply the given pattern to this Format object.
 void applyPattern(String pattern)
          Apply the given pattern to this Format object.
private  void applyPattern(String pattern, boolean localized)
          Does the real work of applying a pattern.
 Object clone()
          Standard override; no change in semantics.
 boolean equals(Object obj)
          Overrides equals
private  FieldPosition[] expandAffix(String pattern)
          Expand an affix pattern into an array of FieldPositions describing how the pattern would be expanded.
private  String expandAffix(String pattern, StringBuffer buffer)
          Expand an affix pattern into an affix string.
private  void expandAffixes()
          Expand the affix pattern strings into the expanded affix strings.
 StringBuffer format(double number, StringBuffer result, FieldPosition fieldPosition)
          Formats a double to produce a string.
private  StringBuffer format(double number, StringBuffer result, Format.FieldDelegate delegate)
          Formats a double to produce a string.
 StringBuffer format(long number, StringBuffer result, FieldPosition fieldPosition)
          Format a long to produce a string.
private  StringBuffer format(long number, StringBuffer result, Format.FieldDelegate delegate)
          Format a long to produce a string.
 AttributedCharacterIterator formatToCharacterIterator(Object obj)
          Formats an Object producing an AttributedCharacterIterator.
 Currency getCurrency()
          Gets the currency used by this decimal format when formatting currency values.
 DecimalFormatSymbols getDecimalFormatSymbols()
          Returns the decimal format symbols, which is generally not changed by the programmer or user.
 int getGroupingSize()
          Return the grouping size.
 int getMultiplier()
          Get the multiplier for use in percent, permill, etc.
 String getNegativePrefix()
          Get the negative prefix.
private  FieldPosition[] getNegativePrefixFieldPositions()
          Returns the FieldPositions of the fields in the prefix used for negative numbers.
 String getNegativeSuffix()
          Get the negative suffix.
private  FieldPosition[] getNegativeSuffixFieldPositions()
          Returns the FieldPositions of the fields in the suffix used for negative numbers.
 String getPositivePrefix()
          Get the positive prefix.
private  FieldPosition[] getPositivePrefixFieldPositions()
          Returns the FieldPositions of the fields in the prefix used for positive numbers.
 String getPositiveSuffix()
          Get the positive suffix.
private  FieldPosition[] getPositiveSuffixFieldPositions()
          Returns the FieldPositions of the fields in the suffix used for positive numbers.
 int hashCode()
          Overrides hashCode
 boolean isDecimalSeparatorAlwaysShown()
          Allows you to get the behavior of the decimal separator with integers.
 Number parse(String text, ParsePosition pos)
          Parses text from a string to produce a Number.
private  void readObject(ObjectInputStream stream)
          First, read the default serializable fields from the stream.
 void setCurrency(Currency currency)
          Sets the currency used by this number format when formatting currency values.
 void setDecimalFormatSymbols(DecimalFormatSymbols newSymbols)
          Sets the decimal format symbols, which is generally not changed by the programmer or user.
 void setDecimalSeparatorAlwaysShown(boolean newValue)
          Allows you to set the behavior of the decimal separator with integers.
 void setGroupingSize(int newValue)
          Set the grouping size.
 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 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 setMultiplier(int newValue)
          Set the multiplier for use in percent, permill, etc.
 void setNegativePrefix(String newValue)
          Set the negative prefix.
 void setNegativeSuffix(String newValue)
          Set the positive suffix.
 void setPositivePrefix(String newValue)
          Set the positive prefix.
 void setPositiveSuffix(String newValue)
          Set the positive suffix.
private  StringBuffer subformat(StringBuffer result, Format.FieldDelegate delegate, boolean isNegative, boolean isInteger)
          Complete the formatting of a finite number.
private  boolean subparse(String text, ParsePosition parsePosition, DigitList digits, boolean isExponent, boolean[] status)
          Parse the given text into a number.
 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.
private  String toPattern(boolean localized)
          Does the real work of generating a pattern.
 
Methods inherited from class java.text.NumberFormat
format, format, format, getAvailableLocales, getCurrencyInstance, getCurrencyInstance, getInstance, getInstance, getIntegerInstance, getIntegerInstance, getMaximumFractionDigits, getMaximumIntegerDigits, getMinimumFractionDigits, getMinimumIntegerDigits, getNumberInstance, getNumberInstance, getPercentInstance, getPercentInstance, getScientificInstance, getScientificInstance, isGroupingUsed, isParseIntegerOnly, parse, parseObject, setGroupingUsed, setParseIntegerOnly
 
Methods inherited from class java.text.Format
createAttributedCharacterIterator, createAttributedCharacterIterator, createAttributedCharacterIterator, createAttributedCharacterIterator, format, parseObject
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

STATUS_INFINITE

private static final int STATUS_INFINITE
See Also:
Constant Field Values

STATUS_POSITIVE

private static final int STATUS_POSITIVE
See Also:
Constant Field Values

STATUS_LENGTH

private static final int STATUS_LENGTH
See Also:
Constant Field Values

digitList

private transient DigitList digitList

positivePrefix

private String positivePrefix
The symbol used as a prefix when formatting positive numbers, e.g. "+".

See Also:
getPositivePrefix()

positiveSuffix

private String positiveSuffix
The symbol used as a suffix when formatting positive numbers. This is often an empty string.

See Also:
getPositiveSuffix()

negativePrefix

private String negativePrefix
The symbol used as a prefix when formatting negative numbers, e.g. "-".

See Also:
getNegativePrefix()

negativeSuffix

private String negativeSuffix
The symbol used as a suffix when formatting negative numbers. This is often an empty string.

See Also:
getNegativeSuffix()

posPrefixPattern

private String posPrefixPattern
The prefix pattern for non-negative numbers. This variable corresponds to positivePrefix.

This pattern is expanded by the method expandAffix() to positivePrefix to update the latter to reflect changes in symbols. If this variable is null then positivePrefix is taken as a literal value that does not change when symbols changes. This variable is always null for DecimalFormat objects older than stream version 2 restored from stream.

Since:
1.3

posSuffixPattern

private String posSuffixPattern
The suffix pattern for non-negative numbers. This variable corresponds to positiveSuffix. This variable is analogous to posPrefixPattern; see that variable for further documentation.

Since:
1.3

negPrefixPattern

private String negPrefixPattern
The prefix pattern for negative numbers. This variable corresponds to negativePrefix. This variable is analogous to posPrefixPattern; see that variable for further documentation.

Since:
1.3

negSuffixPattern

private String negSuffixPattern
The suffix pattern for negative numbers. This variable corresponds to negativeSuffix. This variable is analogous to posPrefixPattern; see that variable for further documentation.

Since:
1.3

multiplier

private int multiplier
The multiplier for use in percent, permill, etc.

See Also:
getMultiplier()

groupingSize

private byte groupingSize
The number of digits between grouping separators in the integer portion of a number. Must be greater than 0 if NumberFormat.groupingUsed is true.

See Also:
getGroupingSize(), NumberFormat.isGroupingUsed()

decimalSeparatorAlwaysShown

private boolean decimalSeparatorAlwaysShown
If true, forces the decimal separator to always appear in a formatted number, even if the fractional part of the number is zero.

See Also:
isDecimalSeparatorAlwaysShown()

isCurrencyFormat

private transient boolean isCurrencyFormat
True if this object represents a currency format. This determines whether the monetary decimal separator is used instead of the normal one.

symbols

private DecimalFormatSymbols symbols
The DecimalFormatSymbols object used by this format. It contains the symbols used to format numbers, e.g. the grouping separator, decimal separator, and so on.

See Also:
setDecimalFormatSymbols(java.text.DecimalFormatSymbols), DecimalFormatSymbols

useExponentialNotation

private boolean useExponentialNotation
True to force the use of exponential (i.e. scientific) notation when formatting numbers.

Since:
1.2

positivePrefixFieldPositions

private transient FieldPosition[] positivePrefixFieldPositions
FieldPositions describing the positive prefix String. This is lazily created. Use getPositivePrefixFieldPositions when needed.

positiveSuffixFieldPositions

private transient FieldPosition[] positiveSuffixFieldPositions
FieldPositions describing the positive suffix String. This is lazily created. Use getPositiveSuffixFieldPositions when needed.

negativePrefixFieldPositions

private transient FieldPosition[] negativePrefixFieldPositions
FieldPositions describing the negative prefix String. This is lazily created. Use getNegativePrefixFieldPositions when needed.

negativeSuffixFieldPositions

private transient FieldPosition[] negativeSuffixFieldPositions
FieldPositions describing the negative suffix String. This is lazily created. Use getNegativeSuffixFieldPositions when needed.

minExponentDigits

private byte minExponentDigits
The minimum number of digits used to display the exponent when a number is formatted in exponential notation. This field is ignored if useExponentialNotation is not true.

Since:
1.2

currentSerialVersion

static final int currentSerialVersion
See Also:
Constant Field Values

serialVersionOnStream

private int serialVersionOnStream
The internal serial version which says which version was written. Possible values are:

Since:
1.2

PATTERN_ZERO_DIGIT

private static final char PATTERN_ZERO_DIGIT
See Also:
Constant Field Values

PATTERN_GROUPING_SEPARATOR

private static final char PATTERN_GROUPING_SEPARATOR
See Also:
Constant Field Values

PATTERN_DECIMAL_SEPARATOR

private static final char PATTERN_DECIMAL_SEPARATOR
See Also:
Constant Field Values

PATTERN_PER_MILLE

private static final char PATTERN_PER_MILLE
See Also:
Constant Field Values

PATTERN_PERCENT

private static final char PATTERN_PERCENT
See Also:
Constant Field Values

PATTERN_DIGIT

private static final char PATTERN_DIGIT
See Also:
Constant Field Values

PATTERN_SEPARATOR

private static final char PATTERN_SEPARATOR
See Also:
Constant Field Values

PATTERN_EXPONENT

private static final char PATTERN_EXPONENT
See Also:
Constant Field Values

PATTERN_MINUS

private static final char PATTERN_MINUS
See Also:
Constant Field Values

CURRENCY_SIGN

private static final char CURRENCY_SIGN
The CURRENCY_SIGN is the standard Unicode symbol for currency. It is used in patterns and substitued with either the currency symbol, or if it is doubled, with the international currency symbol. If the CURRENCY_SIGN is seen in a pattern, then the decimal separator is replaced with the monetary decimal separator. The CURRENCY_SIGN is not localized.

See Also:
Constant Field Values

QUOTE

private static final char QUOTE
See Also:
Constant Field Values

EmptyFieldPositionArray

private static FieldPosition[] EmptyFieldPositionArray

DOUBLE_INTEGER_DIGITS

static final int DOUBLE_INTEGER_DIGITS
See Also:
Constant Field Values

DOUBLE_FRACTION_DIGITS

static final int DOUBLE_FRACTION_DIGITS
See Also:
Constant Field Values

serialVersionUID

static final long serialVersionUID
See Also:
Constant Field Values

cachedLocaleData

private static Hashtable cachedLocaleData
Cache to hold the NumberPattern of a Locale.

Constructor Detail

DecimalFormat

public DecimalFormat()
Creates a DecimalFormat using the default pattern and symbols for the default 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.

See Also:
NumberFormat.getInstance(), NumberFormat.getNumberInstance(), NumberFormat.getCurrencyInstance(), NumberFormat.getPercentInstance()

DecimalFormat

public DecimalFormat(String pattern)
Creates a DecimalFormat using the given pattern and the symbols for the default 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:
NullPointerException - if pattern is null
IllegalArgumentException - if the given pattern is invalid.
See Also:
NumberFormat.getInstance(), NumberFormat.getNumberInstance(), NumberFormat.getCurrencyInstance(), NumberFormat.getPercentInstance()

DecimalFormat

public DecimalFormat(String pattern,
                     DecimalFormatSymbols symbols)
Creates a DecimalFormat using 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:
NullPointerException - if any of the given arguments is null
IllegalArgumentException - if the given pattern is invalid
See Also:
NumberFormat.getInstance(), NumberFormat.getNumberInstance(), NumberFormat.getCurrencyInstance(), NumberFormat.getPercentInstance(), DecimalFormatSymbols
Method Detail

format

public StringBuffer format(double number,
                           StringBuffer result,
                           FieldPosition fieldPosition)
Formats a double to produce a string.

Specified by:
format in class NumberFormat
Parameters:
number - The double to format
result - where the text is to be appended
fieldPosition - On input: an alignment field, if desired. On output: the offsets of the alignment field.
Returns:
The formatted number string
See Also:
FieldPosition

format

private StringBuffer format(double number,
                            StringBuffer result,
                            Format.FieldDelegate delegate)
Formats a double to produce a string.

Parameters:
number - The double to format
result - where the text is to be appended
delegate - notified of locations of sub fields
Returns:
The formatted number string

format

public StringBuffer format(long number,
                           StringBuffer result,
                           FieldPosition fieldPosition)
Format a long to produce a string.

Specified by:
format in class NumberFormat
Parameters:
number - The long to format
result - where the text is to be appended
fieldPosition - On input: an alignment field, if desired. On output: the offsets of the alignment field.
Returns:
The formatted number string
See Also:
FieldPosition

format

private StringBuffer format(long number,
                            StringBuffer result,
                            Format.FieldDelegate delegate)
Format a long to produce a string.

Parameters:
number - The long to format
result - where the text is to be appended
delegate - notified of locations of sub fields
Returns:
The formatted number string
See Also:
FieldPosition

formatToCharacterIterator

public AttributedCharacterIterator formatToCharacterIterator(Object obj)
Formats an Object producing an AttributedCharacterIterator. You can use the returned AttributedCharacterIterator 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.

Overrides:
formatToCharacterIterator in class Format
Parameters:
obj - The object to format
Returns:
AttributedCharacterIterator describing the formatted value.
Throws:
NullPointerException - if obj is null.
IllegalArgumentException - when the Format cannot format the given object.
Since:
1.4

subformat

private StringBuffer subformat(StringBuffer result,
                               Format.FieldDelegate delegate,
                               boolean isNegative,
                               boolean isInteger)
Complete the formatting of a finite number. On entry, the digitList must be filled in with the correct digits.

append

private void append(StringBuffer result,
                    String string,
                    Format.FieldDelegate delegate,
                    FieldPosition[] positions,
                    Format.Field signAttribute)
Appends the String string to result. delegate is notified of all the FieldPositions in positions.

If one of the FieldPositions in positions identifies a SIGN attribute, it is mapped to signAttribute. This is used to map the SIGN attribute to the EXPONENT attribute as necessary.

This is used by subformat to add the prefix/suffix.

parse

public Number parse(String text,
                    ParsePosition pos)
Parses text 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 most economical subclass that can represent the number given by the string is chosen. Most integer values are returned as Long objects, no matter how they are written: "17" and "17.000" both parse to Long(17). Values that cannot fit into a Long are returned as Doubles. This includes values with a fractional part, infinite values, NaN, and the value -0.0. DecimalFormat does not decide whether to return a Double or a Long based on the presence of a decimal separator in the source string. Doing so would prevent integers that overflow the mantissa of a double, such as "10,000,000,000,000,000.00", from being parsed accurately. Currently, the only classes that parse returns are Long and Double, but callers should not rely on this. Callers may use the Number methods doubleValue, longValue, etc., to obtain the type they want.

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

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:
NumberFormat.isParseIntegerOnly(), Format.parseObject(java.lang.String, java.text.ParsePosition)

subparse

private final boolean subparse(String text,
                               ParsePosition parsePosition,
                               DigitList digits,
                               boolean isExponent,
                               boolean[] status)
Parse the given text into a number. The text is parsed beginning at parsePosition, until an unparseable character is seen.

Parameters:
text - The string to parse.
parsePosition - The position at which to being parsing. Upon return, the first unparseable character.
digits - The DigitList to set to the parsed value.
isExponent - If true, parse an exponent. This means no infinite values and integer only.
status - Upon return contains boolean status flags indicating whether the value was infinite and whether it was positive.

getDecimalFormatSymbols

public DecimalFormatSymbols getDecimalFormatSymbols()
Returns the decimal format symbols, which is generally not changed by the programmer or user.

Returns:
desired DecimalFormatSymbols
See Also:
DecimalFormatSymbols

setDecimalFormatSymbols

public void setDecimalFormatSymbols(DecimalFormatSymbols newSymbols)
Sets the decimal format symbols, which is generally not changed by the programmer or user.

Parameters:
newSymbols - desired DecimalFormatSymbols
See Also:
DecimalFormatSymbols

getPositivePrefix

public String getPositivePrefix()
Get the positive prefix.

Examples: +123, $123, sFr123

setPositivePrefix

public void setPositivePrefix(String newValue)
Set the positive prefix.

Examples: +123, $123, sFr123

getPositivePrefixFieldPositions

private FieldPosition[] getPositivePrefixFieldPositions()
Returns the FieldPositions of the fields in the prefix used for positive numbers. This is not used if the user has explicitly set a positive prefix via setPositivePrefix. This is lazily created.

Returns:
FieldPositions in positive prefix

getNegativePrefix

public String getNegativePrefix()
Get the negative prefix.

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

setNegativePrefix

public void setNegativePrefix(String newValue)
Set the negative prefix.

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

getNegativePrefixFieldPositions

private FieldPosition[] getNegativePrefixFieldPositions()
Returns the FieldPositions of the fields in the prefix used for negative numbers. This is not used if the user has explicitly set a negative prefix via setNegativePrefix. This is lazily created.

Returns:
FieldPositions in positive prefix

getPositiveSuffix

public String getPositiveSuffix()
Get the positive suffix.

Example: 123%

setPositiveSuffix

public void setPositiveSuffix(String newValue)
Set the positive suffix.

Example: 123%

getPositiveSuffixFieldPositions

private FieldPosition[] getPositiveSuffixFieldPositions()
Returns the FieldPositions of the fields in the suffix used for positive numbers. This is not used if the user has explicitly set a positive suffix via setPositiveSuffix. This is lazily created.

Returns:
FieldPositions in positive prefix

getNegativeSuffix

public String getNegativeSuffix()
Get the negative suffix.

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

setNegativeSuffix

public void setNegativeSuffix(String newValue)
Set the positive suffix.

Examples: 123%

getNegativeSuffixFieldPositions

private FieldPosition[] getNegativeSuffixFieldPositions()
Returns the FieldPositions of the fields in the suffix used for negative numbers. This is not used if the user has explicitly set a negative suffix via setNegativeSuffix. This is lazily created.

Returns:
FieldPositions in positive prefix

getMultiplier

public int getMultiplier()
Get 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

setMultiplier

public void setMultiplier(int newValue)
Set 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

getGroupingSize

public int getGroupingSize()
Return 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.

See Also:
setGroupingSize(int), NumberFormat.isGroupingUsed(), DecimalFormatSymbols.getGroupingSeparator()

setGroupingSize

public void setGroupingSize(int newValue)
Set 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.

See Also:
getGroupingSize(), NumberFormat.setGroupingUsed(boolean), DecimalFormatSymbols.setGroupingSeparator(char)

isDecimalSeparatorAlwaysShown

public boolean isDecimalSeparatorAlwaysShown()
Allows you to get the behavior of the decimal separator with integers. (The decimal separator will always appear with decimals.)

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

setDecimalSeparatorAlwaysShown

public void setDecimalSeparatorAlwaysShown(boolean newValue)
Allows you to set the behavior of the decimal separator with integers. (The decimal separator will always appear with decimals.)

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

clone

public Object clone()
Standard override; no change in semantics.

Overrides:
clone in class NumberFormat

equals

public boolean equals(Object obj)
Overrides equals

Overrides:
equals in class NumberFormat

hashCode

public int hashCode()
Overrides hashCode

Overrides:
hashCode in class NumberFormat

toPattern

public String toPattern()
Synthesizes a pattern string that represents the current state of this Format object.

See Also:
applyPattern(java.lang.String)

toLocalizedPattern

public String toLocalizedPattern()
Synthesizes a localized pattern string that represents the current state of this Format object.

See Also:
applyPattern(java.lang.String)

expandAffixes

private void expandAffixes()
Expand the affix pattern strings into the expanded affix strings. If any affix pattern string is null, do not expand it. This method should be called any time the symbols or the affix patterns change in order to keep the expanded affix strings up to date.

expandAffix

private String expandAffix(String pattern,
                           StringBuffer buffer)
Expand an affix pattern into an affix string. All characters in the pattern are literal unless prefixed by QUOTE. The following characters after QUOTE are recognized: PATTERN_PERCENT, PATTERN_PER_MILLE, PATTERN_MINUS, and CURRENCY_SIGN. If CURRENCY_SIGN is doubled (QUOTE + CURRENCY_SIGN + CURRENCY_SIGN), it is interpreted as an ISO 4217 currency code. Any other character after a QUOTE represents itself. QUOTE must be followed by another character; QUOTE may not occur by itself at the end of the pattern.

Parameters:
pattern - the non-null, possibly empty pattern
buffer - a scratch StringBuffer; its contents will be lost
Returns:
the expanded equivalent of pattern

expandAffix

private FieldPosition[] expandAffix(String pattern)
Expand an affix pattern into an array of FieldPositions describing how the pattern would be expanded. All characters in the pattern are literal unless prefixed by QUOTE. The following characters after QUOTE are recognized: PATTERN_PERCENT, PATTERN_PER_MILLE, PATTERN_MINUS, and CURRENCY_SIGN. If CURRENCY_SIGN is doubled (QUOTE + CURRENCY_SIGN + CURRENCY_SIGN), it is interpreted as an ISO 4217 currency code. Any other character after a QUOTE represents itself. QUOTE must be followed by another character; QUOTE may not occur by itself at the end of the pattern.

Parameters:
pattern - the non-null, possibly empty pattern
Returns:
FieldPosition array of the resulting fields.

appendAffix

private void appendAffix(StringBuffer buffer,
                         String affixPattern,
                         String expAffix,
                         boolean localized)
Appends an affix pattern to the given StringBuffer, quoting special characters as needed. Uses the internal affix pattern, if that exists, or the literal affix, if the internal affix pattern is null. The appended string will generate the same affix pattern (or literal affix) when passed to toPattern().

Parameters:
buffer - the affix string is appended to this
affixPattern - a pattern such as posPrefixPattern; may be null
expAffix - a corresponding expanded affix, such as positivePrefix. Ignored unless affixPattern is null. If affixPattern is null, then expAffix is appended as a literal affix.
localized - true if the appended pattern should contain localized pattern characters; otherwise, non-localized pattern chars are appended

appendAffix

private void appendAffix(StringBuffer buffer,
                         String affix,
                         boolean localized)
Append an affix to the given StringBuffer, using quotes if there are special characters. Single quotes themselves must be escaped in either case.

toPattern

private String toPattern(boolean localized)
Does the real work of generating a pattern.

applyPattern

public void applyPattern(String pattern)
Apply 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.

Throws:
NullPointerException - if pattern is null
IllegalArgumentException - if the given pattern is invalid.

applyLocalizedPattern

public void applyLocalizedPattern(String pattern)
Apply 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 parentheses.

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

Throws:
NullPointerException - if pattern is null
IllegalArgumentException - if the given pattern is invalid.

applyPattern

private void applyPattern(String pattern,
                          boolean localized)
Does the real work of applying a pattern.

setMaximumIntegerDigits

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 309.

Overrides:
setMaximumIntegerDigits in class NumberFormat
Parameters:
newValue - the maximum number of integer 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.
See Also:
NumberFormat.setMaximumIntegerDigits(int)

setMinimumIntegerDigits

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.

Overrides:
setMinimumIntegerDigits in class NumberFormat
Parameters:
newValue - the minimum number of integer 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.
See Also:
NumberFormat.setMinimumIntegerDigits(int)

setMaximumFractionDigits

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.

Overrides:
setMaximumFractionDigits in class NumberFormat
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.
See Also:
NumberFormat.setMaximumFractionDigits(int)

setMinimumFractionDigits

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.

Overrides:
setMinimumFractionDigits in class NumberFormat
Parameters:
newValue - the minimum 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.
See Also:
NumberFormat.setMinimumFractionDigits(int)

getCurrency

public Currency getCurrency()
Gets the currency used by this decimal format when formatting currency values. The currency is obtained by calling DecimalFormatSymbols.getCurrency on this number format's symbols.

Overrides:
getCurrency in class NumberFormat
Returns:
the currency used by this decimal format, or null
Since:
1.4

setCurrency

public void setCurrency(Currency currency)
Sets the currency used by this number format when formatting currency values. This does not update the minimum or maximum number of fraction digits used by the number format. The currency is set by calling DecimalFormatSymbols.setCurrency on this number format's symbols.

Overrides:
setCurrency in class NumberFormat
Parameters:
currency - the new currency to be used by this decimal format
Throws:
NullPointerException - if currency is null
Since:
1.4

adjustForCurrencyDefaultFractionDigits

void adjustForCurrencyDefaultFractionDigits()
Adjusts the minimum and maximum fraction digits to values that are reasonable for the currency's default fraction digits.

readObject

private void readObject(ObjectInputStream stream)
                 throws IOException,
                        ClassNotFoundException
First, read the default serializable fields from the stream. Then if serialVersionOnStream is less than 1, indicating that the stream was written by JDK 1.1, initialize useExponentialNotation to false, since it was not present in JDK 1.1. Finally, set serialVersionOnStream back to the maximum allowed value so that default serialization will work properly if this object is streamed out again.

If the minimum or maximum integer digit count is larger than DOUBLE_INTEGER_DIGITS or if the minimum or maximum fraction digit count is larger than DOUBLE_FRACTION_DIGITS, then the stream data is invalid and this method throws an InvalidObjectException.

Stream versions older than 2 will not have the affix pattern variables posPrefixPattern etc. As a result, they will be initialized to null, which means the affix strings will be taken as literal values. This is exactly what we want, since that corresponds to the pre-version-2 behavior.

Throws:
IOException
ClassNotFoundException
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