code: public static Compress getInstance(Resource zipFile, int format, boolean caseSensitive) throws IOException {
  	ConfigImpl config = (ConfigImpl) ThreadLocalPageContext.getConfig();
  	return config.getCompressInstance(zipFile, format, caseSensitive);
      }
docs: return zip instance matching the zipfile, singelton instance only 1 zip for one file
  
  @param zipFile
  @param format
  @param caseSensitive
  @return
  @throws IOException