Neo4j - Possible bug using Cross store support and remote server (REST)

[daniel.rochetti]

I just find what I consider a bug on the Cross store support of spring-data-neo4j.

I've noticed different behaviors on class org.springframework.data.neo4j.cross_store.support .node.CrossStoreNodeEntityInstantiator regarding the state synchronization between the graph and the relational database.

    public <T> T createEntityFromState(Node n, Class<T> entityClass, final MappingPolicy mappingPolicy) {
        if (n.hasProperty(CrossStoreNodeEntityState.FOREIGN_ID)) {
            final Object foreignId = n.getProperty(CrossStoreNodeEntityState.FOREIGN_ID);
            final T result = entityManager().find(entityClass, foreignId);
            ((NodeBacked)result).setPersistentState(n);
            return result;
        }
        return delegate.createEntityFromState(n, entityClass, mappingPolicy);
    }

When n is an instance of RestNode (that means your're using a remote REST Neo4j server) the n.getProperty(CrossStoreNodeEntityState.FOREIGN_ID ) returns a java.lang.Integer. When using a local database, it returns java.lang.Long. Since my id is a Long (and the spring-data-neo4j docs tells that it should be Long indeed), Hibernate (my JPA provider) throws an exception on find telling me that an id of the wrong type was provided:

org.springframework.dao.InvalidDataAccessApiUsageException: Provided id of the wrong type for class [MY_CLASS]. Expected: class java.lang.Long, got class java.lang.Integer; nested exception is java.lang.IllegalArgumentException: Provided id of the wrong type for class [MY_CLASS]. Expected: class java.lang.Long, got class java.lang.Integer
	at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:296)
	at org.springframework.orm.jpa.aspectj.JpaExceptionTranslatorAspect.ajc$afterThrowing$org_springframework_orm_jpa_aspectj_JpaExceptionTranslatorAspect$1$18a1ac9(JpaExceptionTranslatorAspect.aj:15)
	at org.springframework.data.neo4j.cross_store.support.node.CrossStoreNodeEntityInstantiator.createEntityFromState(CrossStoreNodeEntityInstantiator.java:59)
	at org.springframework.data.neo4j.cross_store.support.node.CrossStoreNodeEntityInstantiator.createEntityFromState(CrossStoreNodeEntityInstantiator.java:1)
...

I'm not sure if RestNode should return an Integer, but even if it should, spring-data-neo4j should convert it since it tells you to use Long ids.
I'm using a local database for now, but I'll need a remote server soon, so any feedback on this is greatly appreciated.

My setup:
spring-framework 3.0.7.RELEASE (several modules)
spring-data-neo4j 2.0.0.RELEASE (with cross-store support)
hibernate-core-3.6.9.GA
neo4j-1.6 (when using server, the server if the same version as the client libraries)

Exception occurs both on junit 4.9 and Tomcat 6.

Best regards,

Daniel

[MichaelHunger]

Daniel,

thanks for pointing this out. As of now Cross-Store and REST-Server have not been used and tested together. Could you please file an JIRA issue for that.

Otherwise, would it be possible for you to share your project (or a simplified version) as a test-project with us? Thanks a lot.

Michael