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 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 change this pattern. A pattern consists of a string of characters from the table below. For example:

"$#,##0.00;($#,##0.00)"

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

In Java 5.0, DecimalFormat can return java.math.BigDecimal values from its parse( ) method. Call setParseBigDecimal( ) to enable this feature. This is useful when working with very large numbers, very precise numbers, or financial applications that use BigDecimal to avoid rounding errors.

Figure 15-9. java.text.DecimalFormat

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 DecimalFormatSymbols getDecimalFormatSymbols( );  
     public int getGroupingSize( );                        default:3
     public int getMultiplier( );                          default:1
     public String getNegativePrefix( );                   default:"-" 
     public String getNegativeSuffix( );                   default:""
     public String getPositivePrefix( );                   default:""
     public String getPositiveSuffix( );                   default:""
     public boolean isDecimalSeparatorAlwaysShown( );      default:false
5.0  public boolean isParseBigDecimal( );    default:false
     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);  
5.0  public void setParseBigDecimal(boolean newValue);  
     public void setPositivePrefix(String newValue);  
     public void setPositiveSuffix(String newValue);  
     public String toLocalizedPattern( );  
     public String toPattern( );  
// Public Methods Overriding NumberFormat
     public Object clone( );  
     public boolean equals(Object obj);  
5.0  public final StringBuffer format(Object number, StringBuffer toAppendTo, 
        FieldPosition pos);  
     public StringBuffer format(double number, StringBuffer result, 
        FieldPosition fieldPosition);  
     public StringBuffer format(long number, StringBuffer result, 
        FieldPosition fieldPosition);  
1.4  public java.util.Currency getCurrency( );  
5.0  public int getMaximumFractionDigits( ); default:3
5.0  public int getMaximumIntegerDigits( );           default:2147483647
5.0  public int getMinimumFractionDigits( );          default:0
5.0  public int getMinimumIntegerDigits( );           default:1
     public int hashCode( );  
     public Number parse(String text, ParsePosition pos);  
1.4  public void setCurrency(java.util.Currency currency);  
1.2  public void setMaximumFractionDigits(int newValue);  
1.2  public void setMaximumIntegerDigits(int newValue);  
1.2  public void setMinimumFractionDigits(int newValue);  
1.2  public void setMinimumIntegerDigits(int newValue);  
// Public Methods Overriding Format
1.4  public AttributedCharacterIterator formatToCharacterIterator(Object obj);  
}