code: public Map<String, String> getAssociationResponse(final HttpServletRequest request) {
          val parameters = new ParameterList(request.getParameterMap());
  
          val mode = parameters.hasParameter(OpenIdProtocolConstants.OPENID_MODE)
              ? parameters.getParameterValue(OpenIdProtocolConstants.OPENID_MODE)
              : null;
  
          val response = FunctionUtils.doIf(StringUtils.equals(mode, OpenIdProtocolConstants.ASSOCIATE),
              () -> this.serverManager.associationResponse(parameters),
              () -> null)
              .get();
  
          val responseParams = new HashMap<String, String>();
          if (response != null) {
              responseParams.putAll(response.getParameterMap());
          }
          return responseParams;
      }
docs: Gets the association response. Determines the mode first.
  If mode is set to associate, will set the response. Then
  builds the response parameters next and returns.
  
  @param request the request
  @return the association response