code: protected String getDiscoveryResponseURL(String entityBaseURL, String entityAlias) {
          if (extendedMetadata != null && extendedMetadata.getIdpDiscoveryResponseURL() != null
                  && extendedMetadata.getIdpDiscoveryResponseURL().length() > 0) {
              return extendedMetadata.getIdpDiscoveryResponseURL();
          } else {
              Map<String, String> params = new HashMap<String, String>();
              params.put(SAMLEntryPoint.DISCOVERY_RESPONSE_PARAMETER, "true");
              return getServerURL(entityBaseURL, entityAlias, getSAMLEntryPointPath(), params);
          }
      }
docs: Provides set discovery response url or generates a default when none was provided. Primarily value set on
  extenedMetadata property idpDiscoveryResponseURL is used, when empty local property customDiscoveryResponseURL
  is used, when empty URL is automatically generated.
  
  @param entityBaseURL
  base URL for generation of endpoints
  @param entityAlias
  alias of entity, or null when there's no alias required
  @return URL to use for IDP discovery response