class TopicList {

    public List<String> getTopicNames() {
        final List<String> topicNames = new ArrayList<>();
        for (final TopicListing topicListing: getTopics()) {
            topicNames.add(topicListing.getName());
        }
        return Collections.unmodifiableList(topicNames);
    }

    public  TopicList(final List<TopicListing> topics);

}