1) What is more appropriate/commonly used approach for concurrency control? Pessimistic or optimistic locking?
2) How do I notify a user if there's a lock on an item or whether rollback had occured?
3) Suppose I've added all needed markup (like optimistic-locking="false" to exclude properties I don't want to be involved in comparing) to my entity mapping files and defined a Version property on entity classes to handle concurrency control. Would that be enough and all stuff is processed within/by NHibernate. Or additional modifiactions should be present? For example in Repository?
public class Repository<T> : IRepository<T> where T : AbstractEntity<T>, IAggregateRoot
{
private ISession session;
public Repository(ISession session)
{
this.session = session;
}
public T Get(Guid id)
{
return this.session.Get<T>(id);
}
public IQueryable<T> Get(Expression<Func<T, Boolean>> predicate)
{
return this.session.Query<T>().Where(predicate);
}
public IQueryable<T> Get()
{
return this.session.Query<T>();
}
public T Load(Guid id)
{
return this.session.Load<T>(id);
}
public void Add(T entity)
{
using(var transaction = this.session.BeginTransaction())
{
this.session.Save(entity);
transaction.Commit();
}
}
public void Remove(T entity)
{
using(var transaction = this.session.BeginTransaction())
{
this.session.Delete(entity);
transaction.Commit();
}
}
public void Remove(Guid id)
{
using(var transaction = this.session.BeginTransaction())
{
this.session.Delete(this.session.Load<T>(id));
transaction.Commit();
}
}
public void Update(T entity)
{
using(var transaction = this.session.BeginTransaction())
{
this.session.Update(entity);
transaction.Commit();
}
}
public void Update(Guid id)
{
using(var transaction = this.session.BeginTransaction())
{
this.session.Update(this.session.Load<T>(id));
transaction.Commit();
}
}
}
// DI
public class DataAccessModule : Ninject.Modules.NinjectModule
{
public override void Load()
{
this.Bind<ISessionFactory>()
.ToMethod(c => new Configuration().Configure().BuildSessionFactory())
.InSingletonScope();
this.Bind<ISession>()
.ToMethod(ctx => ctx.Kernel.TryGet<ISessionFactory>().OpenSession())
.InRequestScope();
this.Bind(typeof(IRepository<>)).To(typeof(Repository<>));
}
}
I'm using a long session with multiple transactions.
Thanks!
