Hibernate Search 5 - ShardIdentifierProvider

darioc · **Joined:** Wed Aug 06, 2014 10:53 am **Posts:** 30

I'm using this interface for sharding. I'm not using the ShardIdentifierProviderTemplate because during the delete/purge/purgeAll methods I need to filter only some shards.

My problem is initialize method, where I must populate the initial shards. Is there a way to use current the SessionFactory for execute a selecting query on database?

The example on documentation uses the "requestService" method of the ServiceManager class, but in the current version the parameters of the method are changed and I can't seem to use it.

Code:

public static class AnimalShardIdentifierProvider extends ShardIdentifierProviderTemplate {

  ...

 @Override
 protected Set<String> loadInitialShardNames(Properties properties, BuildContext buildContext) {
    ServiceManager serviceManager = buildContext.getServiceManager();
    SessionFactory sessionFactory = serviceManager.requestService(
        HibernateSessionFactoryServiceProvider.class, buildContext);
    Session session = sessionFactory.openSession();
    try {
       Criteria initialShardsCriteria = session.createCriteria(Animal.class);
       initialShardsCriteria.setProjection( Projections.distinct(Property.forName("type")));

       @SuppressWarnings("unchecked")
       List<String> initialTypes = initialShardsCriteria.list();
       return new HashSet<String>(initialTypes);
    }
    finally {
       session.close();
    }
 }
}

sanne.grinovero · **Posted:** Mon Oct 06, 2014 9:44 am

thanks for noticinig! we missed to update that example.

I'll fix it as part of https://hibernate.atlassian.net/browse/HSEARCH-1595

A preview for the correct version is:

Code:

public static class AnimalShardIdentifierProvider extends ShardIdentifierProviderTemplate {

 @Override
 public String getShardIdentifier(Class<?> entityType, Serializable id,
         String idAsString, Document document) {
    if ( entityType.equals(Animal.class) ) {
       String typeValue = document.getField("type").stringValue();
       addShard(typeValue);
       return typeValue;
    }
    throw new RuntimeException("Animal expected but found " + entityType);
 }

 @Override
 protected Set<String> loadInitialShardNames(Properties properties, BuildContext buildContext) {
    ServiceManager serviceManager = buildContext.getServiceManager();
    SessionFactory sessionFactory = serviceManager.requestService(
        HibernateSessionFactoryService.class).getSessionFactory();
    Session session = sessionFactory.openSession();
    try {
       Criteria initialShardsCriteria = session.createCriteria(Animal.class);
       initialShardsCriteria.setProjection( Projections.distinct(Property.forName("type")));
       List<String> initialTypes = initialShardsCriteria.list();
       return new HashSet<String>(initialTypes);
    }
    finally {
       session.close();
    }
 }
}

darioc · **Joined:** Wed Aug 06, 2014 10:53 am **Posts:** 30

Hi Sanne,
thanks a lot, your example was been very usefull!