question: private static StringBuilder escapeRegex ( final StringBuilder regex , final String value , final boolean unquote ) { regex . append ( "\\Q" ) ; for ( int i = 0 ; i < value . length ( ) ; ++ i ) { char c = value . charAt ( i ) ; switch ( c ) { case '\'' : if ( unquote ) { if ( ++ i == value . length ( ) ) { return regex ; } c = value . charAt ( i ) ; } break ; case '\\' : if ( ++ i == value . length ( ) ) { break ; } regex . append ( c ) ; c = value . charAt ( i ) ; if ( c == 'E' ) { regex . append ( "E\\\\E\\" ) ; c = 'Q' ; } break ; default : break ; } regex . append ( c ) ; } regex . append ( "\\E" ) ; return regex ; }
target:  Escape constant fields into regular expression