code: protected ArchiveReader getArchiveReader(final String f,
  			final InputStream is, final boolean atFirstRecord)
  			throws IOException {
      	// Check if it's compressed, based on file extension.
      	if( f.endsWith(".gz") ) {
      		return new CompressedWARCReader(f, is, atFirstRecord);
      	} else {
      		return new UncompressedWARCReader(f, is);
      	}
  	}
docs: /*
  Note that the ARC companion does this differently, with quite a lot of duplication.
  
  @see org.archive.io.arc.ARCReaderFactory.getArchiveReader(String, InputStream, boolean)