Long otherUserId = 2L;
Comment c1 = comments.create("comment1", userId.intValue(), 1L, 0);
Comment c2 = comments.create("comment2", userId.intValue(), 1L, 0);
Comment c3 = comments.create("comment3", userId.intValue(), 1L, 0);
Comment c4 = comments.create("comment4", otherUserId.intValue(), 1L, 0);
Comment c5 = comments.create("comment5", 3, 1L, 0);
Set<Long> commenterIds = new HashSet<Long>();
commenterIds.add(userId);
commenterIds.add(otherUserId);
Set<Comment> userComments = comments.findAllByForeignKey("commenter_id", commenterIds);