How to use Mongo Java driver @BsonCreator annotation?

Question

I'm trying to map an immutable object from MongoDB to my Java POJO and i keep getting the following error:

org.springframework.web.util.NestedServletException: 
Request processing failed; 
nested exception is java.lang.RuntimeException: 
org.mongodb.morphia.mapping.MappingException: 
No usable constructor for com.example.model.Item

It seems that when using immutable objects, I need to annotate using @BsonCreator however that doesn't appear to be working and I believe that might be because using this annotation requires me to somehow configure org.bson.codecs.pojo.Conventions#ANNOTATION_CONVENTION. Maybe I'm blind but i can't seem to find any examples anywhere on how to configure this. Any help would be greately appreciated. Here is my annotated POJO:

@Value /* Lombok auto generates getters */
@Builder /* Lombok auto generates builder method */
public class Item implements Serializable {
    private final @NotNull AnEnum type;
    private final int refId;
    private final int quantity;

    @BsonCreator
    public Item(@BsonProperty("type") AnEnum type,
                @BsonProperty("refId") int refId,
                @BsonProperty("quantity") int quantity) {
        this.type = type;
        this.refId = refId;
        this.quantity = quantity;
    }
}

Are you using Morphia or just the pure Java driver? @BsonCreator is part of the driver, but you've added the [morphia] keyword. — Nic Cottrell, Jun 04 '18 at 09:29

score 2 · Accepted Answer · answered Jun 04 '18 at 09:46

2

This should definitely work with the POJO support. I've just made a test case on github which passes.

I note two issues:

implements Serializable should not be necessary
you will need to specify getters for those 3 fields for the automatic codec builder to pick them up correctly.

answered Jun 04 '18 at 09:46

Nic Cottrell

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Thank you for the answer. My problem was that i didn't realize which annotations are part of which library so i was mixing the ones from Morhpia with Spring data and the mongo driver. This was a non issue when i moved to Spring data's mapping annotation @Document as it doesn't seem to need an annotation as long as i created a private, seemingly useless, no param constructor for an immutable multi param object. – nofunatall Sep 25 '18 at 00:37

score 0 · Answer 2 · answered Mar 18 '18 at 22:08

0

try to add an empty constructor, seems that Morphia needs those, at least in my project it helps. Please let me know if it fixed it for you.

answered Mar 18 '18 at 22:08

rhewid

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Adding a default constructor definitely works and is a usable workaround, however it feels messy. The developers seem to have provided `@BsonCreator` specifically for this purpose yet the documentation and examples seem to be lacking. – nofunatall Mar 20 '18 at 20:32

How to use Mongo Java driver @BsonCreator annotation?

2 Answers2