question: public static void appendPaddedInteger ( StringBuffer buf , long value , int size ) { int intValue = ( int ) value ; if ( intValue == value ) { appendPaddedInteger ( buf , intValue , size ) ; } else if ( size <= 19 ) { buf . append ( Long . toString ( value ) ) ; } else { if ( value < 0 ) { buf . append ( '-' ) ; if ( value != Long . MIN_VALUE ) { value = - value ; } else { for ( ; size > 19 ; size -- ) { buf . append ( '0' ) ; } buf . append ( "9223372036854775808" ) ; return ; } } int digits = ( int ) ( Math . log ( value ) / LOG_10 ) + 1 ; for ( ; size > digits ; size -- ) { buf . append ( '0' ) ; } buf . append ( Long . toString ( value ) ) ; } }
target:  Converts an integer to a string, prepended with a variable amount of '0' pad characters, and appends it to the given buffer. <p>This method is optimized for converting small values to strings.