code: public static void extract(int format, Resource[] sources, Resource target) throws IOException {
  	if (format == FORMAT_ZIP || format == FORMAT_TAR) {
  	    for (int i = 0; i < sources.length; i++) {
  		extract(format, sources[i], target);
  	    }
  	}
  	else throw new IOException("can't extract in given format");
      }
docs: extract a zip file to a directory
  
  @param format
  @param sources
  @param target
  @throws IOException