private static void setDefaults()
	{
		// variables that always must be set
		if ( encoding == null )
			encoding = Charset.defaultCharset().name();
		if ( groupName == null )
			groupName = "top level";
		if ( longName == null )
			longName = "version "+Short.toString(version);
		if ( shortName == null )
			shortName = Short.toString(version);
		if ( mvdFile == null )
			mvdFile = "untitled.mvd";
		if ( folderId == 0 )
			folderId = 1;
		if ( xmlFile == null )
		{
			int dotPos = mvdFile.indexOf(".");
			xmlFile = mvdFile.substring( 0,dotPos )+".xml";
		}
	}