private Topic makeThreadFromJson(PostJson pj) throws ContentParseException {
if(pj.getNo() == 0) {
throw new ContentParseException("Could not parse thread (thread post num missing and could not be zero)");
}
Topic t = new Topic(pj.getNo(), pj.getOmittedPosts(), pj.getOmittedImages());
t.addPost(this.makePostFromJson(pj));
return t;
}