Generic Mapping Class in Component Element With Alpha

mnichols · **Joined:** Mon Aug 21, 2006 9:18 am **Posts:** 179

Does the alpha Nhibernate support using generics on components? for example, say I have class Range that will implemented as Range<DateTime>

Code:

    public class Range<T> : IRange<T> where T : IComparable<T>
    {
        private readonly T start;
        private readonly T end;

        public Range(T start, T end)
        {
            if (start.CompareTo(end) <= 0)
            {
                this.start = start;
                this.end = end;
            }
            else
            {
                this.start = end;
                this.end = start;
            }
        }

        public T Start
        {
            get { return this.start; }
        }

        public T End
        {
            get { return this.end; }
        }

...

Now my mapping in the class for the component is

Code:

    <component name="PayrollPeriod" class="Cei.eMerge.Common.Range`1[System.DateTime], Cei.eMerge.Common" >
      <property name="Start" access="field.camelcase" column="StartDate"  />
      <property name="End" access="field.camelcase" column="EndDate"/>
    </component>

I am getting the following error from the mapping configuration when i write my sql

Code:

Write Ddl script? (Y/N)  y
Working...

Failed!
EXCEPTION:NHibernate.MappingException
-------------------------------------------------------------------------
MESSAGE:Value cannot be null.
Parameter name: con
-------------------------------------------------------------------------
STACK TRACE:   at NHibernate.Cfg.Configuration.AddInputStream(Stream xmlInputStream)
   at NHibernate.Cfg.Configuration.AddAssembly(Assembly assembly, Boolean skipOrdering)
   at NHibernate.Cfg.Configuration.AddAssembly(Assembly assembly)
   at NHibernate.Cfg.Configuration.AddAssembly(String assemblyName)
   at Cei.eMerge.Data.NHibernateSessionManager.GetConfiguration() in C:\Documents and Settings\mnichols\My Documents\Visual Studio 2005\Projects\eMerge\src\app\Cei.eMerge.Data\NHibernate\NHibernateSes
sionManager.cs:line 82
   at Cei.eMerge.Data.NHibernateSessionManager.get_Configuration() in C:\Documents and Settings\mnichols\My Documents\Visual Studio 2005\Projects\eMerge\src\app\Cei.eMerge.Data\NHibernate\NHibernateSe
ssionManager.cs:line 53
   at TestConsole.Program.WriteDdlScript() in C:\Documents and Settings\mnichols\My Documents\Visual Studio 2005\Projects\eMerge\src\app\Cei.eMerge.NHibernateUtil\Program.cs:line 55
   at TestConsole.Program.Main(String[] args) in C:\Documents and Settings\mnichols\My Documents\Visual Studio 2005\Projects\eMerge\src\app\Cei.eMerge.NHibernateUtil\Program.cs:line 24
-------------------------------------------------------------------------

that exception doesn't give me much to go on...am I mapping a generic class correctly? I only find one example for mapping a class in the .Tests

Thanks in advance

mnichols · **Joined:** Mon Aug 21, 2006 9:18 am **Posts:** 179

Never mind...I had forgotten a default constructor on my class. I forgot to look in my log file for the stack trace that told me more.
Still the error message is pretty obscure with this.
Once I put the default constructor in, all works as I wanted...awesome job Sergey and team! Generics rock.