CODEWITHSUNDEEP
spring-dataspring-data-mongodb
zouroto
zouroto

Reputation: 185

spring-data-mongo update null value in document with MappingMongoConverter

With spring data mongo, i need to update document in mongo.

My entity is define like this : 

@Document(collection = "Orders")
public class Order{

    @Id
    private Long id;
    private String clientContainerReference;
    private String status;
    private Bigdecimal amount;
    private BigDecimal remainingQuantity;
    ...
}

At first, this document is inserted in mongo with a remainingQuantity of 100. Next, the order is updated with a null remainingQuantity. After the update (upsert), the remainingQuantity is always set to 100.

This is due to the class :

org.springframework.data.mongodb.core.convert.MappingMongoConverter

in the method writeInternal a null check is done on every property of the document. If the property is null, it is exclued from the generated DBObject. 

entity.doWithProperties(new PropertyHandler<MongoPersistentProperty>() {
        public void doWithPersistentProperty(MongoPersistentProperty prop) {

            if (prop.equals(idProperty)) {
                return;
            }

            Object propertyObj = wrapper.getProperty(prop);

            if (null != propertyObj) {

                if (!conversions.isSimpleType(propertyObj.getClass())) {
                    writePropertyInternal(propertyObj, dbo, prop);
                } else {
                    writeSimpleInternal(propertyObj, dbo, prop);
                }
            }
        }
    });

I can understand that it is more efficient because the generate DBObject is smaller and the update request is more digest for mongo. But how can i update real null values ?

More specific, in my case, all fields of all document could be null. so i doesn't want to write custom converter and map one by one each java field to DBObject Field.

For more my usecase, i have created a "NullAwareMappingMongoConverter" that override MappingMongoConverter to let the converter write the value if it is a null value. 

entity.doWithProperties(new PropertyHandler<MongoPersistentProperty>() {
        public void doWithPersistentProperty(MongoPersistentProperty prop) {

            if (prop.equals(idProperty)) {
                return;
            }


            Object propertyObj = wrapper.getProperty(prop);

            if (null != propertyObj) {

                if (!conversions.isSimpleType(propertyObj.getClass())) {
                    writePropertyInternal(propertyObj, dbo, prop);
                } else {
                    writeSimpleInternal(propertyObj, dbo, prop);
                }
            }
            else{
                writeSimpleInternal(propertyObj, dbo, prop);
            }
        }
    });

It's an very uggly solution, because, the MappingMongoConverter For spring data mongo has a package visibility. Does spring provide a way to tell : don't ignore null value on this properties with annotation or something else ?

Thank you

here is the code used to update the entity

 public T setNotificationDateAndSave(T entity) {
    Assert.notNull(entity, "Entity must not be null!");
    BasicDBObject dbObject = new BasicDBObject();
    mongoTemplate.getConverter().write(entity, dbObject);

    DateTime expirationDate = getDeprecatedStatus().contains(getStatus(entity)) ?
            new DateTime().plusSeconds(EXPIRE_AFTER_SECONDS) : null;

    dbObject.put(EXPIRATION_DATE_COLUMN, mongoTemplate.getConverter()
            .convertToMongoType(expirationDate, ClassTypeInformation.from(DateTime.class)));


    NotificationDateUpdate update = new NotificationDateUpdate(dbObject, NOTIFICATION_DATE_COLUMN);
    Query q = Query.query(Criteria.where("_id").is(entity.getId()).andOperator(Criteria.where(REGISTER_DATE_COLUMN).lte(entity.getRegisterDate())));
    try{
        mongoTemplate.upsert(q, update, parameterClass);
    }catch (DuplicateKeyException e) {
        logger.info(format("could not save notification : a more recent notification exists for collection %s and entity id : %s", parameterClass.getName(), entity.getId()));
    }
    return entity;
}

Upvotes: 5

Views: 4296

Answers (1)

Jeremie
Jeremie

Reputation: 1307

Same problem, but I didn't want to mess with the converter, it felt too complicated for the need. I simply automated the unsetting of all null fields for my object.

Slightly adapted to your code, it would look like:

DBObject dbObject = new BasicDBObject();
mongoTemplate.getConverter().write(entity, dbObject);
Update update = Update.fromDBObject(dbObject);
for (Field f : entity.class.getDeclaredFields()) {
  try {
     f.setAccessible(true);
     if (f.get(entity) == null)
        update.unset(f.getName());
  } catch (IllegalAccessException e) {
     e.printStackTrace();
  }
}
ops.upsert(query,update);

Upvotes: 2

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