/**
* Find entities according to the given example entity.
*
* @param type The entity type.
* @param entity The example entity.
* @param <T> The entity type.
* @return A {@link com.buschmais.xo.api.ResultIterable}.
*/
private <T> ResultIterable<T> findByExample(
Class<?> type, Map<PrimitivePropertyMethodMetadata<PropertyMetadata>, Object> entity) {
EntityTypeMetadata<EntityMetadata> entityTypeMetadata =
sessionContext.getMetadataProvider().getEntityMetadata(type);
EntityDiscriminator entityDiscriminator =
entityTypeMetadata.getDatastoreMetadata().getDiscriminator();
if (entityDiscriminator == null) {
throw new XOException(
"Type "
+ type.getName()
+ " has no discriminator (i.e. cannot be identified in datastore).");
}
ResultIterator<Entity> iterator =
sessionContext
.getDatastoreSession()
.getDatastoreEntityManager()
.findEntity(entityTypeMetadata, entityDiscriminator, entity);
ResultIterator<T> resultIterator =
new ResultIterator<T>() {
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public T next() {
Entity entity = iterator.next();
AbstractInstanceManager<EntityId, Entity> entityInstanceManager =
sessionContext.getEntityInstanceManager();
return entityInstanceManager.readInstance(entity);
}
@Override
public void remove() {
throw new UnsupportedOperationException("Cannot remove instance.");
}
@Override
public void close() {
iterator.close();
}
};
XOTransaction xoTransaction = sessionContext.getXOTransaction();
final ResultIterator<T> transactionalIterator =
xoTransaction != null
? new TransactionalResultIterator<>(resultIterator, xoTransaction)
: resultIterator;
return sessionContext
.getInterceptorFactory()
.addInterceptor(
new AbstractResultIterable<T>() {
@Override
public ResultIterator<T> iterator() {
return transactionalIterator;
}
},
ResultIterable.class);
}
@Override
public <DS> DS getDatastoreSession(Class<DS> sessionType) {
DatastoreSession<
EntityId,
Entity,
EntityMetadata,
EntityDiscriminator,
RelationId,
Relation,
RelationMetadata,
RelationDiscriminator,
PropertyMetadata>
datastoreSession = sessionContext.getDatastoreSession();
return sessionType.cast(datastoreSession);
}