NHibernate Map class name and resolve it with Reflection

Question

I have a property of a class that is mapped to another class that can't be stored in the database and can't be serialized; it implements the state pattern. So I have something like this:

public IState MyState { get; set; }

Where I have two different states

public class LockedState : IState ...

public class UnlockedState : IState ...

In the database I need to persist the name of the current state that can be accomplished using, for example:

string name = myState.GetType().Name;

Do I have to write a custom and verbose IUserState or is there anything around?

Answer 1

In order to do that I had to implement a custom IUserType in the following way:

public sealed class StateMapper : IUserType

// get
public object NullSafeGet(IDataReader rs, string[] names, object owner)
{
string objectName = (string)NHibernateUtil.String.NullSafeGet(rs, names[0]);
Type stateType = Type.GetType(objectName, false, true);
if (stateType == null)
{
    return null;
}
// StateFacility is used by my code to create a new Type
return StateFacility.CreateState(stateType);
} 

// set
public void NullSafeSet(IDbCommand cmd, object value, int index)
{
if (value == null)
{
    NHibernateUtil.String.NullSafeSet(cmd, null, index);
    return;
}
  NHibernateUtil.String.NullSafeSet(cmd, value, index);
}