private static DBObject normalize(DBObject obj) {
BasicDBObjectBuilder builder = BasicDBObjectBuilder.start();
Iterator<String> iterator = obj.keySet().iterator();
builder.push("$set");
while (iterator.hasNext()) {
String key = iterator.next();
if (Constants.ID_PROPERTY.equals(key)) continue;
Object value = obj.get(key);
if (value == null) continue;
builder.add(key, value);
}
return builder.get();
}
