public static Set<String> buildActiveAttributeRepositoryIds(
        final PersonDirectoryPrincipalResolverProperties... personDirectory) {
        return Arrays.stream(personDirectory)
            .filter(p -> StringUtils.isNotBlank(p.getActiveAttributeRepositoryIds()))
            .map(p -> org.springframework.util.StringUtils.commaDelimitedListToSet(p.getActiveAttributeRepositoryIds()))
            .filter(p -> !p.isEmpty())
            .flatMap(Set::stream)
            .collect(Collectors.toSet());
    }
Build active attribute repository ids.

@param personDirectory the person directory
@return the set
support/cas-server-support-person-directory-core/src/main/java/org/apereo/cas/authentication/principal/resolvers/PrincipalResolverUtils.java