Fongo DataStoreProvider

lordofthejars · **Joined:** Wed Jan 21, 2015 7:24 am **Posts:** 6

Hi,
Hibernate OGM is an awesome tool which have an integration with MongoDB, but there is one missing engine and it is Fongo. Fongo is a project which uses Mongo client to create a Java embedded in-memory MongoDB. In fact no server endpoint is provided it is pure Java project (we can think like a Map). So if you want to use Hibernate OGM and write tests using Fongo you need to create your own DataStore provider.

Currently I have done this by:

Code:

public class FongoDBDatastoreProvider extends MongoDBDatastoreProvider {

    private static final long serialVersionUID = -4709436439644997081L;

    private static final Log log = LoggerFactory.getLogger();

    private MongoClient mongo;
    private DB mongoDb;
    private MongoDBConfiguration config;
    private ServiceRegistryImplementor serviceRegistry;

    @Override
    public void start() {
        try {
            if (mongo == null) {
                mongo = new Fongo("fongo").getMongo();
            }
            mongoDb = extractDatabase(mongo, config);
        } catch (Exception e) {
            // Wrap Exception in a ServiceException to make the stack trace more
            // friendly
            // Otherwise a generic unable to request service is thrown
            throw log.unableToStartDatastoreProvider(e);
        }
    }
    
    @Override
    public void stop() {
    }

    @Override
    public void injectServices(ServiceRegistryImplementor serviceRegistry) {
        this.serviceRegistry = serviceRegistry;
    }

    @Override
    public void configure(Map configurationValues) {
        OptionsService optionsService = serviceRegistry
                .getService(OptionsService.class);
        ClassLoaderService classLoaderService = serviceRegistry
                .getService(ClassLoaderService.class);
        ConfigurationPropertyReader propertyReader = new ConfigurationPropertyReader(
                configurationValues, classLoaderService);

        try {
            this.config = new MongoDBConfiguration(propertyReader,
                    optionsService.context().getGlobalOptions());
        } catch (Exception e) {
            // Wrap Exception in a ServiceException to make the stack trace more
            // friendly
            // Otherwise a generic unable to request service is thrown
            throw log.unableToConfigureDatastoreProvider(e);
        }
    }

    public DB getDatabase() {
        return mongoDb;
    }

    private DB extractDatabase(MongoClient mongo, MongoDBConfiguration config) {
        String databaseName = config.getDatabaseName();
        log.connectingToMongoDatabase(databaseName);

        if (!mongo.getDatabaseNames().contains(databaseName)) {
            if (config.isCreateDatabase()) {
                log.creatingDatabase(databaseName);
            } else {
                throw log.databaseDoesNotExistException(config
                        .getDatabaseName());
            }
        }
        return mongo.getDB(databaseName);
    }

}

I can extend from MongoDBDataStoreProvider because Fongo in fact follows MongoDB driver but overrides it to store all data locally instead of creating a remote connection.

And then in persistence.xml

Code:

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
   version="2.0">

   <!-- Use this for Neo4j -->
   <!--
   <persistence-unit name="hikePu" transaction-type="RESOURCE_LOCAL">
      <provider>org.hibernate.ogm.jpa.HibernateOgmPersistence</provider>

      <properties>
         <property name="hibernate.ogm.datastore.provider" value="neo4j_embedded" />
         <property name="hibernate.ogm.datastore.database" value="HikeDB" />
         <property name="hibernate.ogm.neo4j.database_path" value="target/test_data_dir" />
      </properties>
   </persistence-unit>
   -->

   <!-- Use this for MongoDB -->
   <persistence-unit name="hikePu" transaction-type="RESOURCE_LOCAL">
      <provider>org.hibernate.ogm.jpa.HibernateOgmPersistence</provider>

      <properties>
         <property name="hibernate.ogm.datastore.provider" value="org.hibernate.ogm.demos.ogm101.part1.provider.FongoDBDatastoreProvider" />
         <property name="hibernate.ogm.datastore.database" value="HikeDB" />
         <property name="hibernate.ogm.datastore.create_database" value="true" />
      </properties>
   </persistence-unit>
</persistence>

And with these changes I have been able to run Hibernate-OGM Hiker example test using Fongo instead of a remote(although it is a localhost) MongoDB.

My next step is to provide an integration to NoSQLUnit, so you can write applications and test them in NoSQLUnit.

Gunnar · **Joined:** Sat Jan 24, 2009 12:46 pm **Posts:** 388

Hi,

Didn't know about Fongo, thanks for giving that a try and reporting the outcome! That looks very interesting, would you be interested in contributing this feature to Hibernate OGM? That'd be awesome. I've created https://hibernate.atlassian.net/browse/OGM-725 to track this.

--Gunnar

lordofthejars · **Joined:** Wed Jan 21, 2015 7:24 am **Posts:** 6

Sure, in fact I have already signed the jboss confidentiality document (because of Arquillian) so no problem to add support for Fongo in Hibernate OGM.

I am going to create an account to JIRA and assign it to me. I will try to do it this weekend :)