Added DBRefUnproxyObjectAccessHook

[joha78]

This extension solves problems with MongoDBs DBRef(lazy=true) annotation

[bartoszwalacik]

nice, but we need some test, I will write some

[joha78]

Thank you very much. I thought about doing it myself but I am not very familiar with groovy

[bartoszwalacik]

There is a problem with dependency management here.
Adding dep to spring-data-mongo brakes JaVers, because it downgrades mong-db-driver version from 3.6 to 3.4
Look like we need to upgrade the whole javers to Spring 5 and Sprint Boot 2

[joha78]

I found another problem. If I use the new DBRefUnproxyObjectAccessHook I get some strange things in MongoDB jv_snapshots:

nbrDest: "EE4344D",
toPlanet: Object {
           entity: "de.spacesystems.Planet"
           cdoId: Object {
                timestamp: 1498562478
                machineIdentifier:14306734
                processIdentifier: 26005
                counter: 13820548
           },
handlerStatus: "ConfirmedByHandler"

Obviously something is wrong with the cdoID ?!
Any suggestions what could be wrong?

Update:
Found out that it is persisting an InstanceId, investigating further
Shouldn't it be using the LocalID the DBRefUnproxyObjectAccessHook has extracted and not the GlobalID?
I think it has something todo with @ShallowReference. => NO, the CdoID is still wrong persisted if I remove the @ShallowReferences

I pause my investigations now.

[joha78]

There is a problem with dependency management here.
Adding dep to spring-data-mongo brakes JaVers, because it downgrades mong-db-driver version from 3.6 to 3.4
Look like we need to upgrade the whole javers to Spring 5 and Sprint Boot 2

I am not sure why this can be. I just reused an existing dependency in the new sub-project of javers.

[bartoszwalacik]

It looks like ObjectId, this problem is described here https://javers.org/documentation/repository-configuration/#custom-json-serialization and it's another issue to add out-of-the box support for mongo ObjectId's in JaVers.
In this issue we are focusing on DBRefs and making JaVers work with spring-data-mongo. I'll try to upgrade JaVers to Spring 5 and Sprint Boot 2.

[bartoszwalacik]

@joha78 I wrote a sketch of a test here https://github.com/javers/javers/pull/742/files
I can't find docs about DBRefs proxies. How does it works? How can I observe uninitialized DBRefs proxy?

[joha78]

I am not exactly sure about your question. As far as I know you can't observe uninitialized DBRefs proxy (interface LazyLoadingProxy). But if you call LazyLoadingProxy.getTarget() you get the fresh loaded Entity. Have a look at DefaultDbRefResolver to see how it works. Behind the scenes it is using a LazyLoadingInterceptor.

[joha78]

I don't know how to update the javers/joha78-master branch.
With this changes its possible to prove that there is a proxy and that it works:

@SpringBootTest(classes = [TestApplication])
@ActiveProfiles("test")
//@Ignore //TODO
class DBRefUnproxyObjectAccessHookTest extends Specification {

    @Autowired
    MyDummyEntityRepository dummyEntityRepository

    @Autowired
    MyDummyRefEntityRepository dummyRefEntityRepository

    def "should unproxy and commit DBRef to JaVers"() {
        given:

        def refEntity = new MyDummyRefEntity()
        refEntity.setName("Bert")
        refEntity = dummyRefEntityRepository.save(refEntity);

        def author = new MyDummyEntity();
        author.setRefEntity(refEntity)
        author = dummyEntityRepository.save(author)

        def loaded = dummyEntityRepository.findById(author.getId()).get()
        println loaded
        println loaded.class
        println loaded.refEntity
        println loaded.refEntity.class

        assert loaded.refEntity instanceof LazyLoadingProxy

        def realObj = ((LazyLoadingProxy) loaded.refEntity).getTarget()

        assert realObj instanceof MyDummyRefEntity
        assert "Bert".equals(realObj.name)
        assert "Bert".equals(loaded.refEntity.name)
    }
}

public class MyDummyEntity {
    private String id;

    @DBRef(lazy = true)
    private MyDummyRefEntity refEntity;

    @Id
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public MyDummyRefEntity getRefEntity() {
        return refEntity;
    }

    public void setRefEntity(MyDummyRefEntity refEntity) {
        this.refEntity = refEntity;
    }
}

@JaversSpringDataAuditable
public interface MyDummyEntityRepository extends CrudRepository<MyDummyEntity, String>{
}

public class MyDummyRefEntity {

    private  String id;

    private String name;

    @Id
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

public interface MyDummyRefEntityRepository extends CrudRepository<MyDummyRefEntity, String>{
}

[bartoszwalacik]

ok will check it. I want to have a test and see how it fails without the new hook and how it passes with the hook.

[bartoszwalacik]

btw, could you please provide the second PR to javers/joha78-master branch with this test?

[joha78]

btw, could you please provide the second PR to javers/joha78-master branch with this test?

I did, you should have a pull request.

[bartoszwalacik]

ok, I merged your second PR and made few fixes. Now I think the hook works and it's added to the starter.

see https://github.com/javers/javers/pull/742/files
is it what you need?

[bartoszwalacik]

merged from another branch, will be released as 4.0.0-RC5