&& Objects.equals(a1.getDependencyFilter(), a2.getDependencyFilter())
                && a1.isOptional() == a2.isOptional();
    }

    private static int repositoryHashCode(ArtifactRepository repository) {
        int result = 17;
        result = 31 * result + (repository.getId() != null ? repository.getId().hashCode() : 0);
        return result;
    }

    }

    public static int repositoriesHashCode(List<RemoteRepository> repositories) {
        int result = 17;
        for (RemoteRepository repository : repositories) {
            result = 31 * result + repositoryHashCode(repository);
        }
        return result;
    }

    public static RepositorySystemSession overlay(
            ArtifactRepository repository, RepositorySystemSession session, RepositorySystem system) {