A Formatter object is used by a Handler to convert a LogRecord to a String prior to logging it. Most applications can simply use one one of the pre-defined concrete subclasses: SimpleFormatter or XMLFormatter. Applications requiring custom formatting of log messages will need to subclass this class and define the format( ) method to perform the desired conversion. Such subclasses may find the formatMessage( ) method useful: it performs localization using java.util.ResourceBundle and formatting using the facilities of the java.text package. getHead( ) and getTail( ) return a prefix and suffix (such as opening and closing XML tags) for a log file.

public abstract class Formatter {
// Protected Constructors
     protected Formatter( );  
// Public Instance Methods
     public abstract String format(LogRecord record);  
     public String formatMessage(LogRecord record);                     synchronized
     public String getHead(Handler h);  
     public String getTail(Handler h);  
}

Subclasses

SimpleFormatter, XMLFormatter

Passed To

Handler.setFormatter( ), StreamHandler.StreamHandler( )

Returned By

Handler.getFormatter( )