question: private static Pattern compilePattern ( final String s ) { StringBuilder rc = new StringBuilder ( ) ; for ( int i = 0 ; i < s . length ( ) ; i ++ ) { char ch = s . charAt ( i ) ; switch ( ch ) { case '?' : rc . append ( '.' ) ; break ; case '*' : rc . append ( ".*" ) ; break ; case '.' : rc . append ( '\\' ) ; default : rc . append ( ch ) ; } } return Pattern . compile ( rc . toString ( ) ) ; }
target:  Convert host pattern from glob format to regexp. Note that the function assumes a valid host pattern, so characters that might not happen in the host name but must be escaped in regular expressions are not escaped.