code: Map<String, String> getCasAuthenticationFilterInitParams() {
          Map<String, String> params = new HashMap<>();
          params.put("casServerLoginUrl", this.getCasLoginUrl());
          params.put("serverName", this.properties.getProxyCallbackServer());
          params.put("renew", Boolean.toString(this.properties.getCasLoginRenew()));
          params.put("gateway", Boolean.toString(this.properties.getCasLoginGateway()));
          if (LOGGER.isDebugEnabled()) {
              this.printParams(params);
          }
          return params;
      }
docs: Gets a parameter map with default values for the following
  CAS authentication filter parameters:
  * casServerLoginUrl
  * serverName
  * renew
  * gateway
  
  @return a newly created parameter map, guaranteed not null.