I am trying to write a test for my NHibernate mappings that will automatically pick up and test any new mappings that get added.
At the moment I have a test that opens a session to a known test database then attempts to load the first entity of each type and asserts that it is not null.
This all works fine but it means that every time I add a new entity mapping, I need to remember to update the test.
So, what I want to do is to inspect the mappings and try to load one of each of the mapped entities, but the NHibernate Configuration object that the sessionfactory is built from is not visible to my test so I was wondering if there is a way to access a list of mapped entities from the session or do I need to expose the original Configuration instead?
You can get SessionFactory from Session and SessionFactory has method GetAllClassMetadata() which returns list of IClassMetadata. And from IClassMetadata you can get MappedClass (GetMappedClass())
But you will need some extra work to get subclasses. This code can help:
var metaData = this.session.SessionFactory.GetClassMetadata(baseClass);
if (metaData != null && metaData.HasSubclasses)
{
foreach (string entityName in ((NHibernate.Persister.Entity.IEntityPersister)metaData).EntityMetamodel.SubclassEntityNames)
{
var metadata = this.session.SessionFactory.GetClassMetadata(entityName);
result.Add(metadata.GetMappedClass(EntityMode.Poco));
}
}
I expose the configuration object and do a mapping that queries all of my entities like this. It will output all errors from each of my mappings.:
[TestMethod()]
public void AllNHibernateMappingsAreOkay()
{
bool failed = false;
log4net.Config.XmlConfigurator.Configure();
using (ISession session = SessionFactory.GetCurrentSession())
{
foreach (var s in SessionFactory.GetConfig().ClassMappings)
{
try
{
SessionFactory.GetCurrentSession().CreateQuery(string.Format("from {0} e", s.MappedClass.Name))
.SetFirstResult(0).SetMaxResults(50).List();
}
catch (Exception ex)
{
failed = true;
log.ErrorFormat("\r\n\r\n {0} \r\n {1} \r\n\r\n", ex.Message, ex.InnerException.Message);
}
}
}
Assert.IsFalse(failed, "One or more mappings have errors in them. Please refer to output or logs.");
}
if you have only one row per entity then you could issue session.QueryOver<object>().List();
Related
I am working on a legacy non-Spring application, and it is being migrated from Hibernate 3 to Hibernate 5.6.0.Final (latest at this time). I have generally never used Hibernate Event Listeners in my work, so this is quite new to me, and I am studying these in Hibernate 5.
Currently in some test class we have defined the code this way for Hibernate 3:
protected static Configuration createSecuredDatabaseConfig() {
Configuration config = createUnrestrictedDatabaseConfig();
config.setListener("pre-insert", "com.app.server.services.db.eventlisteners.MySecurityHibernateEventListener");
config.setListener("pre-update", "com.app.server.services.db.eventlisteners.MySecurityHibernateEventListener");
config.setListener("pre-delete", "com.app.server.services.db.eventlisteners.MySecurityHibernateEventListener");
config.setListener("pre-load", "com.app.server.services.db.eventlisteners.EkoSecurityHibernateEventListener");
return config;
}
This is obviously no longer valid, and I believe I need to create a Hibernate Integrator, which I have done.
public class MyEventListenerIntegrator implements Integrator {
#Override
public void integrate(Metadata metadata, SessionFactoryImplementor sessionFactory,
SessionFactoryServiceRegistry serviceRegistry) {
EventListenerRegistry eventListenerRegistry = serviceRegistry.getService(EventListenerRegistry.class);
eventListenerRegistry.getEventListenerGroup(EventType.PRE_INSERT).appendListener(new MySecurityHibernateEventListener());
eventListenerRegistry.getEventListenerGroup(EventType.PRE_UPDATE).appendListener(new MySecurityHibernateEventListener());
eventListenerRegistry.getEventListenerGroup(EventType.PRE_DELETE).appendListener(new MySecurityHibernateEventListener());
eventListenerRegistry.getEventListenerGroup(EventType.PRE_LOAD).appendListener(new MySecurityHibernateEventListener());
}
So, now I believe the next step is to add this to the session via the registry builder. I am using this website to help me:
https://www.boraji.com/hibernate-5-event-listener-example
Because we were using older Hibernate 3, we had code to create our session factory as follows:
protected static SessionFactory buildSessionFactory(Database db)
{
if (db == null) {
throw new NullPointerException("Database specifier cannot be null");
}
try {
Configuration config = createSessionFactoryConfiguration(db);
String url = config.getProperty("connection.url");
String user = config.getProperty("connection.username");
String password = config.getProperty("connection.password");
try {
String dbDriver = config.getProperty("hibernate.connection.driver_class");
Class.forName(dbDriver);
Connection conn = DriverManager.getConnection(url, user, password);
}
catch (SQLException error) {
logger.info("Didn't find driver, on QA or production, so it's okay to assume we have DB connection");
error.printStackTrace();
}
SessionFactory sessionFactory = config.buildSessionFactory();
sessionFactoryConfigs.put(sessionFactory, config); // Cannot recover config from factory instance, must be stored.
return sessionFactory;
}
catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
logger.error("Initial SessionFactory creation failed.", ex);
throw new ExceptionInInitializerError(ex);
}
}
The link that I referred to above has a much different way of creating the sessionfactory. So, I'll be testing that out to see if it works in our app.
Without Spring handling our sessions and transactions, in this app it is coded by hand the way it was done before Spring, and I haven't seen that kind of code in years.
I solved this issue with the help from the link I provided above. However, I didn't copy exactly what they did, but some of it helped. My solution is as follows:
protected static SessionFactory createSecuredDatabaseConfig() {
Configuration config = createUnrestrictedDatabaseConfig();
BootstrapServiceRegistry bootstrapRegistry =
new BootstrapServiceRegistryBuilder()
.applyIntegrator(new EkoEventListenerIntegrator())
.build();
ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder(bootstrapRegistry).applySettings(config.getProperties()).build();
SessionFactory sessionFactory = config.buildSessionFactory(serviceRegistry);
return sessionFactory;
}
This was it. I tried multiple different ways to register the events without the BootstrapServiceRegistry, but none of those worked. I did have to create the integrator. What I did NOT include was the following:
MetadataSources sources = new MetadataSources(serviceRegistry )
.addPackage("com.myproject.server.model");
Metadata metadata = sources.getMetadataBuilder().build();
// did not create the sessionFactory this way
sessionFactory = metadata.getSessionFactoryBuilder().build();
If I had gone further and use this method to create the sessionFactory, then all of my queries would have been complaining about not being able to find the parameterName, which is something else.
The Hibernate Integrator and this method to create the sessionFactory is all for the unit tests. Without registering these events, one unit test would fail, and now it doesn't. So, this solves my problem for now.
I have a scenario similar to this:
Asp.NET MVC 4 website using nHibernate Session Per Request.
The session is injected using Ninject onto a Repository with the Get and Save methods.
There are a lot of articles talking about Session Per Request and saying that is the way to do things on a web application.
But i'm having problems implementing logic like this one:
Read Data From Database
Alter Entity information
Save to Database
Read another entity
Alter entity
Save ... but an EXCEPTION OCCURS
I want to show my view with a message to the user. But i have also to refresh the resulting web page,
so i have also to read some information from the database.
According to nHibernate documentation, the session with the exception must be discarded Documentation Here
But i can't find any articles about the best way to proceed here.
What's the best approach for this situation?. I will have to inject a new Session to my repository object?.
Thanks.
You can create a new session from the SessionFactory property of the original session. You can access the original session object by either exposing it in the repository class or injecting it into the controller. Then you can create a new repository with the new session.
I do this in some of my Actions where I expect unique key violations to occur and I have to reload lookup data in the model. Here's an example:
public ActionResult Create(MeasuresEditView model)
{
if (ModelState.IsValid)
{
using (var txn = _session.BeginTransaction())
{
try
{
var measure = new Measure { Code = model.Code };
_session.Save(measure);
txn.Commit();
return RedirectToAction("Index");
}
catch (UniqueKeyException)
{
txn.Rollback();
var msg = string.Format("A measure with the code '{0}' already exists, please enter a different code or cancel.", model.Code);
ModelState.AddModelError("Code", msg);
}
catch (Exception ex)
{
if (txn.IsActive)
{
txn.Rollback();
}
log.Error("Create", ex);
throw;
}
}
}
// have to rebuild selectlist on post in new txn in case it was rolled back
using (var session = _session.SessionFactory.OpenSession())
using (var txn = session.BeginTransaction())
{
SetProductGroupSelectList(session, model, manualId);
txn.Commit();
}
return View(model);
}
Are there any tools available, or perhaps utility methods within NHibernate, which may help me to nail down which mapping is throwing a "The given key is not present in the dictionary"?
I understand that I must have a bad mapping, but I have hundreds of domain objects. What can I do to locate the source of my error more quickly?
From the NHibernate 2.1.2GA Source:
private PersistentClass GetPersistentClass(string className)
{
PersistentClass pc = configuration.classes[className]; // <- "The given key was not present in the dictionary"
if (pc == null)
{
throw new MappingException("persistent class not known: " + className);
}
return pc;
}
And in this case, className is System.Int32.
Ok, so I had an int field marked <many-to-one> instead of <property>. I ended up digging up the source for NH and debugging to get to this point.
NHibernate Mapping: Creating Sanity Checks
[Test]
public void AllNHibernateMappingAreOkay()
{
IDictionary allClassMetadata = session.SessionFactory.GetAllClassMetadata();
foreach (DictionaryEntry entry in allClassMetadata)
{
session
.CreateCriteria((Type) entry.Key)
.SetMaxResults(0)
.List();
}
}
The entities and mappings I'm talking about in this question can be found here :)
Here is the context:
I have a parent view-model which helps to manage some entities, and which has its own session.
From this VM, I open another view-model (with its own session too), do some changements to the entity (add and/or remove children), and when I validate the changements, I commit the session and warns the first view-model to refresh the display:
public void Validate()
{
using (var tx = Session.BeginTransaction())
{
try
{
SelectedTeam.ClearRoster();
foreach (var teamPlayer in TeamPlayers)
SelectedTeam.AddPlayer(teamPlayer);
teamsRepository.SaveOrUpdate(SelectedTeam);
tx.Commit();
}
catch (Exception ex)
{
tx.Rollback();
}
finally
{
if (tx.WasCommitted)
ServiceLocator.Current.GetInstance<Mediator>().NotifyColleagues(MediatorMessages.DisplayEntityInfos, SelectedTeam.Id);
}
}
}
Here is the faulted method of the parent VM:
public void RefreshEntitiesListAndDisplayEntityInfos(int selectedEntityId)
{
TEntity entity = entitiesRepository.Load(selectedEntityId);
Session.Refresh(entity);
//...
}
The exception is thrown at the Refresh line:
NHibernate.UnresolvableObjectException
And the message is:
No row with the given identifier exists[Emidee.CommonEntities.PlayerInTeam#3
I can open and change the entity multiple times, but it seems that the exception is thrown when I delete a children, then add another one, and finally delete another one.
After some readings on the web, it seems that's because when I refresh the entity, and because I changed the HasMany relationship (because I have deleted a player for example), NH tries to reload the deleted row.
I've tried to add a NotFound.Ignore statement on the HasMany in my mappings, I've tried to force a new query to the DB instead of a Load, but I still get this exception.
Does someone know how I could fix that?
Thanks in advance
Mike
This is a known behavior when refreshing objects with modified collections.
To force reload, change your method to do session.Evict with the entity as a parameter. This is the code we use in our base model class:
public T ReGet<T>(T entity) where T : IEntity
{
var id = entity.Id;
Session.Evict(entity);
return Session.Get<T>(id);
}
Well, I've just spotted the problem.
To update the players list of the team, I used to clear the list, and add the new players, before updating the entity.
Now, I update the list by removing and adding only the players who have been moved by the user, and I don't have any problems at all now.
That's weird. I don't know what was wrong before, but as least that works now.
Ayende has an article about how to implement a simple audit trail for NHibernate (here) using event handlers.
Unfortunately, as can be seen in the comments, his implementation causes the following exception to be thrown: collection xxx was not processed by flush()
The problem appears to be the implicit call to ToString on the dirty properties, which can cause trouble if the dirty property is also a mapped entity.
I have tried my hardest to build a working implementation but with no luck.
Does anyone know of a working solution?
I was able to solve the same problem using following workaround: set the processed flag to true on all collections in the current persistence context within the listener
public void OnPostUpdate(PostUpdateEvent postEvent)
{
if (IsAuditable(postEvent.Entity))
{
//skip application specific code
foreach (var collection in postEvent.Session.PersistenceContext.CollectionEntries.Values)
{
var collectionEntry = collection as CollectionEntry;
collectionEntry.IsProcessed = true;
}
//var session = postEvent.Session.GetSession(EntityMode.Poco);
//session.Save(auditTrailEntry);
//session.Flush();
}
}
Hope this helps.
The fix should be the following. Create a new event listener class and derive it from NHibernate.Event.Default.DefaultFlushEventListener:
[Serializable]
public class FixedDefaultFlushEventListener: DefaultFlushEventListener
{
private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
protected override void PerformExecutions(IEventSource session)
{
if (log.IsDebugEnabled)
{
log.Debug("executing flush");
}
try
{
session.ConnectionManager.FlushBeginning();
session.PersistenceContext.Flushing = true;
session.ActionQueue.PrepareActions();
session.ActionQueue.ExecuteActions();
}
catch (HibernateException exception)
{
if (log.IsErrorEnabled)
{
log.Error("Could not synchronize database state with session", exception);
}
throw;
}
finally
{
session.PersistenceContext.Flushing = false;
session.ConnectionManager.FlushEnding();
}
}
}
Register it during NHibernate configuraiton:
cfg.EventListeners.FlushEventListeners = new IFlushEventListener[] { new FixedDefaultFlushEventListener() };
You can read more about this bug in Hibernate JIRA:
https://hibernate.onjira.com/browse/HHH-2763
The next release of NHibernate should include that fix either.
This is not easy at all. I wrote something like this, but it is very specific to our needs and not trivial.
Some additional hints:
You can test if references are loaded using
NHibernateUtil.IsInitialized(entity)
or
NHibernateUtil.IsPropertyInitialized(entity, propertyName)
You can cast collections to the IPersistentCollection. I implemented an IInterceptor where I get the NHibernate Type of each property, I don't know where you can get this when using events:
if (nhtype.IsCollectionType)
{
var collection = previousValue as NHibernate.Collection.IPersistentCollection;
if (collection != null)
{
// just skip uninitialized collections
if (!collection.WasInitialized)
{
// skip
}
else
{
// read collections previous values
previousValue = collection.StoredSnapshot;
}
}
}
When you get the update event from NHibernate, the instance is initialized. You can safely access properties of primitive types. When you want to use ToString, make sure that your ToString implementation doesn't access any referenced entities nor any collections.
You may use NHibernate meta-data to find out if a type is mapped as an entity or not. This could be useful to navigate in your object model. When you reference another entity, you will get additional update events on this when it changed.
I was able to determine that this error is thrown when application code loads a Lazy Propery where the Entity has a collection.
My first attempt involed watching for new CollectionEntries (which I've never want to process as there shouldn't actually be any changes). Then mark them as IsProcessed = true so they wouldn't cause problems.
var collections = args.Session.PersistenceContext.CollectionEntries;
var collectionKeys = args.Session.PersistenceContext.CollectionEntries.Keys;
var roundCollectionKeys = collectionKeys.Cast<object>().ToList();
var collectionValuesClount = collectionKeys.Count;
// Application code that that loads a Lazy propery where the Entity has a collection
var postCollectionKeys = collectionKeys.Cast<object>().ToList();
var newLength = postCollectionKeys.Count;
if (newLength != collectionValuesClount) {
foreach (var newKey in postCollectionKeys.Except(roundCollectionKeys)) {
var collectionEntry = (CollectionEntry)collections[newKey];
collectionEntry.IsProcessed = true;
}
}
However this didn't entirly solve the issue. In some cases I'd still get the exception.
When OnPostUpdate is called the values in the CollectionEntries dictionary should all already be set to IsProcessed = true. So I decided to do an extra check to see if the collections not processed matched what I expected.
var valuesNotProcessed = collections.Values.Cast<CollectionEntry>().Where(x => !x.IsProcessed).ToList();
if (valuesNotProcessed.Any()) {
// Assert: valuesNotProcessed.Count() == (newLength - collectionValuesClount)
}
In the cases that my first attempt fixed these numbers would match exactly. However in the cases where it didn't work there were extra items alreay in the dictionary. In my I could be sure these extra items also wouldn't result in updates so I could just set IsProcessed = true for all the valuesNotProcessed.