Constructor given the URI string.
Parameters: uriString - The imbedded URI string. throws: URISyntaxException - When there is a syntaz error in theimbedded URI.
Sets the value of the "scheme" of
this URI, for example "sip", "sips" or "tel".
Ref. RFC 3261, p. 224:
scheme = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
Parameters: sch - the scheme of this URI throws: IllegalArgumentException - if the scheme is invalid