MongoDB in queries using DBRefs not working

[d3xt3r]

I am trying to query a MongoDB repository using in criteria on a DBRef. I gathered from the documentation - and by trying - that this isn't supported using the method name to query mapping framework. I am now trying to do this using a custom method and implementation, however, this too isn't working.

Domain objects:

public class Automaker implements Serializable {

	private static final long serialVersionUID = 1L;
	
	private String id;
	
	private String name;

	public Automaker() {
		super();
	}
	
	public Automaker(final String name) {
		super();
		this.name = name;
	}

	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 class Car implements Serializable {

	private static final long serialVersionUID = 1L;

	@Id
	public String id;
	
	@Indexed(unique=true)
	private String model;
	
	@DBRef
	private Automaker automaker;
	
	public Car() { }
	
	public Car(final Automaker make, final String model) {
		this.automaker = make;
		this.model = model;
	}

	public String getId() {
		return id;
	}

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

	public String getModel() {
		return model;
	}

	public void setModel(String model) {
		this.model = model;
	}

	public Automaker getAutomaker() {
		return automaker;
	}

	public void setAutomaker(Automaker automaker) {
		this.automaker = automaker;
	}
	
}

Repository:

@Repository
public interface CarRepository extends MongoRepository<Car, String>, CustomCarRepository {

	public List<Car> findByAutomaker(Automaker make);
	
	public List<Car> findByAutomakerIn(Automaker... makers);
	
}

public interface CustomCarRepository {
	public List<Car> findCarsByAutomakers(Automaker... makers);
}

public final class CarRepositoryImpl implements CustomCarRepository {
	
	@Autowired
	MongoTemplate template;

	@Override
	public List<Car> findCarsByAutomakers(Automaker... makers) {
		
		Query q = new Query(new Criteria("automaker").in( (Object[]) makers));
		
		return template.find(q, Car.class);
	}

}

Unit tests:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "/repositories.xml")
public final class CarRepositoryTest {

	@Autowired
	AutomakerRepository automakerRepository;
	
	@Autowired
	CarRepository carRepository;
	
	private Automaker ford;
	private Automaker honda;
	private Automaker toyota;
	
	@Before
	public void setUp() throws Exception {
		
		ford = automakerRepository.save(new Automaker("Ford"));
		honda = automakerRepository.save(new Automaker("Honda"));
		toyota = automakerRepository.save(new Automaker("Toyota"));
		
		carRepository.save(new Car(ford, "Explorer"));
		
		carRepository.save(new Car(honda, "Accord"));
		carRepository.save(new Car(honda, "Civic"));
		carRepository.save(new Car(honda, "Pilot"));
		
		carRepository.save(new Car(toyota, "Camry"));
		carRepository.save(new Car(toyota, "Yaris"));
		carRepository.save(new Car(toyota, "Highlander"));
	}

	@After
	public void tearDown() throws Exception {
		carRepository.deleteAll();
		automakerRepository.deleteAll();
	}

	@Test
	public void testFindByAutomaker() {
		assertEquals(1, carRepository.findByAutomaker(ford).size());
		assertEquals(3, carRepository.findByAutomaker(honda).size());
		assertEquals(3, carRepository.findByAutomaker(toyota).size());
	}
	
	@Test
	public void testFindByAutomakerIn() {
		assertEquals(4, carRepository.findByAutomakerIn(ford, toyota));
	}
	
	@Test
	public void testFindCarsByAutomakers() {
		assertEquals(4, carRepository.findCarsByAutomakers(ford, honda));
	}

}

Both testFindByAutomakerIn() and testFindCarsByAutomakers() fail. The former throws an exception:

org.springframework.data.mapping.model.MappingException: No id property found on class class [Lnet.rossillo.car.domain.Automaker;
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter.createDBRef(MappingMongoConverter.java:688)
	at org.springframework.data.mongodb.core.convert.MappingMongoConverter.toDBRef(MappingMongoConverter.java:281)
	at org.springframework.data.mongodb.repository.query.ConvertingParameterAccessor$ConvertingIterator.nextConverted(ConvertingParameterAccessor.java:161)
	at org.springframework.data.mongodb.repository.query.MongoQueryCreator.nextAsArray(MongoQueryCreator.java:266)
	at org.springframework.data.mongodb.repository.query.MongoQueryCreator.from(MongoQueryCreator.java:200)
	at org.springframework.data.mongodb.repository.query.MongoQueryCreator.create(MongoQueryCreator.java:102)
	at org.springframework.data.mongodb.repository.query.MongoQueryCreator.create(MongoQueryCreator.java:47)
	at org.springframework.data.repository.query.parser.AbstractQueryCreator.createCriteria(AbstractQueryCreator.java:109)
	at org.springframework.data.repository.query.parser.AbstractQueryCreator.createQuery(AbstractQueryCreator.java:88)
	at org.springframework.data.repository.query.parser.AbstractQueryCreator.createQuery(AbstractQueryCreator.java:73)
	at org.springframework.data.mongodb.repository.query.PartTreeMongoQuery.createQuery(PartTreeMongoQuery.java:69)
	at org.springframework.data.mongodb.repository.query.AbstractMongoQuery.execute(AbstractMongoQuery.java:77)
	at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:313)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
	at $Proxy25.findByAutomakerIn(Unknown Source)
	at net.rossillo.car.repository.CarRepositoryTest.testFindByAutomakerIn(CarRepositoryTest.java:62)

The latter returns an emptry array because the generated query criteria is incorrect. I posted the code, along with a Gradle build script to GitHub.

Has anyone found a work around or is there a solution to this?

Thanks in advance,
Scott

[d3xt3r]

I found a workable solution to doing $in queries with DBRefs. The solution uses a custom interface to declare the method with in criteria and custom implementation (below) to parse out the incoming DBRef objects and convert them to a collection of ObjectIds to be set as query criteria.

package net.rossillo.car.repository;

import java.util.ArrayList;
import java.util.List;

import net.rossillo.car.domain.Automaker;
import net.rossillo.car.domain.Car;

import org.bson.types.ObjectId;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.data.mongodb.core.query.Query;

public final class CarRepositoryImpl implements CustomCarRepository {
	
	@Autowired
	MongoTemplate template;

	@Override
	public List<Car> findCarsByAutomakers(Automaker... makers) {
		
		final List<ObjectId> idList = new ArrayList<ObjectId>(makers.length);
		
		for(final Automaker maker : makers) {
			idList.add(new ObjectId(maker.getId()));
		}
		
		Query q = new Query(new Criteria("automaker.$id").in(idList));
		
		return template.find(q, Car.class);
	}

}

I'm posting this update here and I updated the code on GitHub to use this working solution in case it helps others with the same problem.

I'd still be interested to hear if there is a simpler way to do this.

[Oliver Gierke]

Would you mind trying a recent snapshot build? I've created and fixed a few tickets covering these issues [0, 1].

[0] https://jira.springsource.org/browse/DATAMONGO-505
[1] https://jira.springsource.org/browse/DATAMONGO-511

[d3xt3r]

I tried the latest snapshots, still no luck. I pushed an update to master on GitHub with the broken test case.

[Oliver Gierke]

I've created and fixed DATAMONGO-517 [0] and fixed some glitches in your sample code to get the tests working. I've issued a pull request [1] with the necessary changes.

[0] https://jira.springsource.org/browse/DATAMONGO-517
[1] https://github.com/foo4u/spring-data-queries/pull/1

[d3xt3r]

Oliver, thank you for your help and the bug fix, this works great now. I have a more complex use-case to test out now, I'll reply here how that goes.

Thanks again.