question: protected boolean isTokenChar ( char ch ) { if ( Character . isLetterOrDigit ( ch ) ) return true ; if ( Character . isISOControl ( ch ) ) return false ; if ( isHttpSeparator ( ch ) ) return false ; return true ; }
target:  Checks whether a character is a valid token character. Whitespace, control characters, and HTTP separators are not valid token characters. The HTTP specification (RFC 2616, section 2.2) defines tokens only for the US-ASCII character set, this method extends the definition to other character sets.