code: public List<ContentCodingType> getAcceptEncoding() {
  		String value = getFirst(ACCEPT_ENCODING);
  		return (value != null ? ContentCodingType.parseCodingTypes(value) : Collections.<ContentCodingType>emptyList());
  	}
docs: Return the list of acceptable {@linkplain ContentCodingType coding types}, as
  specified by the {@code Accept-Encoding} header.
  <p>Returns an empty list when the acceptable content coding types are unspecified.
  @return the acceptable content coding types