code: public static String getDumpFileName(DumpContentType dumpContentType,
  			String projectName, String dateStamp) {
  		if (dumpContentType == DumpContentType.JSON) {
  			return dateStamp + WmfDumpFile.getDumpFilePostfix(dumpContentType);
  		} else {
  			return projectName + "-" + dateStamp
  					+ WmfDumpFile.getDumpFilePostfix(dumpContentType);
  		}
  	}
docs: Returns the name under which this dump file. This is the name used online
  and also locally when downloading the file.
  
  @param dumpContentType
  the type of the dump
  @param projectName
  the project name, e.g. "wikidatawiki"
  @param dateStamp
  the date of the dump in format YYYYMMDD
  @return file name string