question: protected Value parseValue ( ) throws IOException , RDFParseException , RDFHandlerException { int c = peekCodePoint ( ) ; if ( c == '<' ) { return parseURI ( ) ; } else if ( c == ':' || TurtleUtil . isPrefixStartChar ( c ) ) { return parseQNameOrBoolean ( ) ; } else if ( c == '_' ) { return parseNodeID ( ) ; } else if ( c == '"' || c == '\'' ) { return parseQuotedLiteral ( ) ; } else if ( ASCIIUtil . isNumber ( c ) || c == '.' || c == '+' || c == '-' ) { return parseNumber ( ) ; } else if ( c == - 1 ) { throwEOFException ( ) ; return null ; } else { reportFatalError ( "Expected an RDF value here, found '" + new String ( Character . toChars ( c ) ) + "'" ) ; return null ; } }
target:  Parses an RDF value. This method parses uriref, qname, node ID, quoted literal, integer, double and boolean.