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Java in a Nutshell

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The java.text Package

29.9 java.text.DecimalFormat (JDK 1.1)

This is the concrete Format class used by NumberFormat for all locales that use base 10 numbers. Most applications do not need to use this class directly--they can use the static methods of NumberFormat to obtain a default NumberFormat object for a desired locale, and may then perform minor locale-independent customizations on that object.

Applications that require highly-customized number formatting and parsing may create custom DecimalFormat objects by passing a suitable pattern to the DecimalFormat() constructor method. The applyPattern() method can be used to change this pattern. A pattern consists of a string of characters from the following table. For example: "$#,##0.00;($#,##0.00)".

Character Meaning
# A digit; zeros show as absent
0 A digit; zeros show as 0
. The locale-specific decimal separator
, The locale-specific grouping separator
- The locale-specific negative prefix
% Show value as a percentage

Separates positive number format (on left) from optional negative number format (on right)


Quote a reserved character, so it appears literally in the output

other Appears literally in output

A DecimalFormatSymbols object may be optionally specified when creating a DecimalFormat object. If one is not specified, a DecimalFormatSymbols object suitable for the default locale is used.

public class DecimalFormat extends NumberFormat {
    // Public Constructors
            public DecimalFormat();
            public DecimalFormat(String pattern);
            public DecimalFormat(String pattern, DecimalFormatSymbols symbols);
    // Public Instance Methods
            public void applyLocalizedPattern(String pattern);
            public void applyPattern(String pattern);
            public Object clone();  // Overrides NumberFormat
            public boolean equals(Object obj);  // Overrides NumberFormat
            public StringBuffer format(double number, StringBuffer result, FieldPosition fieldPosition);  // Defines NumberFormat
            public StringBuffer format(long number, StringBuffer result, FieldPosition fieldPosition);  // Defines NumberFormat
            public DecimalFormatSymbols getDecimalFormatSymbols();
            public int getGroupingSize();
            public int getMultiplier();
            public String getNegativePrefix();
            public String getNegativeSuffix();
            public String getPositivePrefix();
            public String getPositiveSuffix();
            public int hashCode();  // Overrides NumberFormat
            public boolean isDecimalSeparatorAlwaysShown();
            public Number parse(String text, ParsePosition status);  // Defines NumberFormat
            public void setDecimalFormatSymbols(DecimalFormatSymbols newSymbols);
            public void setDecimalSeparatorAlwaysShown(boolean newValue);
            public void setGroupingSize(int newValue);
            public void setMultiplier(int newValue);
            public void setNegativePrefix(String newValue);
            public void setNegativeSuffix(String newValue);
            public void setPositivePrefix(String newValue);
            public void setPositiveSuffix(String newValue);
            public String toLocalizedPattern();
            public String toPattern();


Object->Format(Serializable, Cloneable)->NumberFormat(Cloneable)->DecimalFormat

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