code: public static String getDumpFilePostfix(DumpContentType dumpContentType) {
  		if (WmfDumpFile.POSTFIXES.containsKey(dumpContentType)) {
  			return WmfDumpFile.POSTFIXES.get(dumpContentType);
  		} else {
  			throw new IllegalArgumentException("Unsupported dump type "
  					+ dumpContentType);
  		}
  	}
docs: Returns the ending used by the Wikimedia-provided dumpfile names of the
  given type.
  
  @param dumpContentType
  the type of dump
  @return postfix of the dumpfile name
  @throws IllegalArgumentException
  if the given dump file type is not known