NumberFormat

NumberFormat

java.text

---

Java 1.1

cloneable serializable

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 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. getIntegerInstance( ) , getCurrencyInstance( ) , and getPercentInstance( ) return NumberFormat objects for formatting numbers that are integers, or represent monetary amounts or percentages. These methods return a NumberFormat suitable for the default locale, or for the specified Locale object. getAvailableLocales( ) returns an array of locales for which NumberFormat objects are available. In Java 1.4 and later, use setCurrency( ) to provide a java.util.Currency object for use when formating monetary values. Note that the NumberFormat class is 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.

Once you have created a suitable NumberFormat object, you can customize its localeindependent 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. You can also use the formatToCharacterIterator( ) method inherited from Format (and overridden by DecimalFormat ) in place of format( ) . The constants defined by this class are to be used by the FieldPosition object.

Figure 15-13. java.text.NumberFormat

 public abstract class  NumberFormat  extends Format {  // Public Constructors  public  NumberFormat  ( );  // Public Constants  public static final int  FRACTION_FIELD  ;  =1  public static final int  INTEGER_FIELD  ;  =0   // Nested Types   1.4  public static class  Field  extends Format.Field;  // Public Class Methods  public static java.util.Locale[ ]  getAvailableLocales  ( );        public static final NumberFormat  getCurrencyInstance  ( );        public static NumberFormat  getCurrencyInstance  (java.util.Locale  inLocale  );        public static final NumberFormat  getInstance  ( );        public static NumberFormat  getInstance  (java.util.Locale  inLocale  );  1.4  public static final NumberFormat  getIntegerInstance  ( );  1.4  public static NumberFormat  getIntegerInstance  (java.util.Locale  inLocale  );        public static final NumberFormat  getNumberInstance  ( );        public static NumberFormat  getNumberInstance  (java.util.Locale  inLocale  );        public static final NumberFormat  getPercentInstance  ( );        public static NumberFormat  getPercentInstance  (java.util.Locale  inLocale  );  // Public Instance Methods  public final String  format  (long  number  );        public final String  format  (double  number  );        public abstract StringBuffer  format  (long  number  , StringBuffer  toAppendTo  ,          FieldPosition  pos  );        public abstract StringBuffer  format  (double  number  , StringBuffer  toAppendTo  ,          FieldPosition  pos  );  1.4  public java.util.Currency  getCurrency  ( );        public int  getMaximumFractionDigits  ( );        public int  getMaximumIntegerDigits  ( );        public int  getMinimumFractionDigits  ( );        public int  getMinimumIntegerDigits  ( );        public boolean  isGroupingUsed  ( );        public boolean  isParseIntegerOnly  ( );        public Number  parse  (String  source  ) throws ParseException;        public abstract Number  parse  (String  source  , ParsePosition  parsePosition  );  1.4  public void  setCurrency  (java.util.Currency  currency  );        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  );  // Public Methods Overriding Format  public Object  clone  ( );        public StringBuffer  format  (Object  number  , StringBuffer  toAppendTo  ,          FieldPosition  pos  );        public final Object  parseObject  (String  source  , ParsePosition  pos  );  // Public Methods Overriding Object  public boolean  equals  (Object  obj  );        public int  hashCode  ( );   } 

Subclasses

ChoiceFormat , DecimalFormat

Passed To

DateFormat.setNumberFormat( )

Returned By

DateFormat.getNumberFormat( )

Type Of

DateFormat.numberFormat