public void serialize(SerializerOutput out, HashNode obj) throws IOException { if (obj.getClass() == HashBucket.class) { out.write(Serialization.HTREE_BUCKET); HashBucket b = (HashBucket) obj; b.writeExternal(out); } else { out.write(Serialization.HTREE_DIRECTORY); HashDirectory n = (HashDirectory) obj; n.writeExternal(out); } }