[Chapter 29] 29.14 java.text.NumberFormat (JDK 1.1)

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| Chapter 29 The java.text Package |

## 29.14 java.text.NumberFormat (JDK 1.1)

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This class formats and parses numbers in a locale-specific way. As an abstract class, it cannot be instantiated directly, but it provides a number of static methods that return instances of a concrete subclass which you can use for formatting. The `getInstance()` method returns a `NumberFormat` object suitable for normal formatting of numbers in either the default locale or in a specified locale. `getCurrencyInstance()` and `getPercentInstance()` return `NumberFormat` objects for formatting numbers that represent monetary amounts and percentages in either the default locale or in a specified locale. `getAvailableLocales()` returns an array of locales for which `NumberFormat` objects are available.

Once you have created a suitable `NumberFormat` object, you may customize its locale-independent behavior with `setMaximumFractionDigits()`, `setGroupingUsed()` and similar `set` methods. In order to customize the locale-dependent behavior, you can use `instanceof` to test if the `NumberFormat` object is an instance of `DecimalFormat`, and if so, cast it to that type. The `DecimalFormat` class provides complete control over number formatting. Note, however, that a `NumberFormat` customized in this way may no longer be appropriate for the desired locale.

After creating and customizing a `NumberFormat` object, you can use the various `format()` methods to convert numbers to strings or string buffers, and you can use the `parse()` or `parseObject()` methods to convert strings to numbers.

The constants defined by this class are intended to be used by the `FieldPosition` object.

The `NumberFormat` class in not intended for the display of very large or very small numbers that require exponential notation, and it may not gracefully handle infinite or `NaN` (not-a-number) values.

    public abstract class NumberFormat extends Format implements Cloneable {
        // Default Constructor: public NumberFormat()
        // Constants
                public static final int FRACTION_FIELD;
                public static final int INTEGER_FIELD;
        // Class Methods
                public static Locale[] getAvailableLocales();
                public static final NumberFormat getCurrencyInstance();
                public static NumberFormat getCurrencyInstance(Locale inLocale);
                public static final NumberFormat getInstance();
                public static NumberFormat getInstance(Locale inLocale);
                public static final NumberFormat getNumberInstance();
                public static NumberFormat getNumberInstance(Locale inLocale);
                public static final NumberFormat getPercentInstance();
                public static NumberFormat getPercentInstance(Locale inLocale);
        // Public Instance Methods
                public Object clone();  // Overrides Format
                public boolean equals(Object obj);  // Overrides Object
                public final StringBuffer format(Object number, StringBuffer toAppendTo, FieldPosition pos);  // Defines Format
                public final String format(double number);
                public final String format(long number);
                public abstract StringBuffer format(double number, StringBuffer toAppendTo, FieldPosition pos);
                public abstract StringBuffer format(long number, StringBuffer toAppendTo, FieldPosition pos);
                public int getMaximumFractionDigits();
                public int getMaximumIntegerDigits();
                public int getMinimumFractionDigits();
                public int getMinimumIntegerDigits();
                public int hashCode();  // Overrides Object
                public boolean isGroupingUsed();
                public boolean isParseIntegerOnly();
                public abstract Number parse(String text, ParsePosition parsePosition);
                public Number parse(String text) throws ParseException;
                public final Object parseObject(String source, ParsePosition parsePosition);  // Defines Format
                public void setGroupingUsed(boolean newValue);
                public void setMaximumFractionDigits(int newValue);
                public void setMaximumIntegerDigits(int newValue);
                public void setMinimumFractionDigits(int newValue);
                public void setMinimumIntegerDigits(int newValue);
                public void setParseIntegerOnly(boolean value);
    }

### Hierarchy:

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

### Extended By:

ChoiceFormat, DecimalFormat

### Passed To:

DateFormat.setNumberFormat()

### Returned By:

DateFormat.getNumberFormat(), NumberFormat.getCurrencyInstance(), NumberFormat.getInstance(), NumberFormat.getNumberInstance(), NumberFormat.getPercentInstance()

### Type Of:

DateFormat.numberFormat

java.text.MessageFormat (JDK 1.1) |  | java.text.ParseException (JDK 1.1)