Question

I wanted to know if this was thread safe/ good practice. My IOC is ninject, everything service layer call is via the default setting (In transient scope I think?).

Question, is instantiating new FileAllocation(loggedonuser,_repo) correct? The best way? What is the best way to do this? This is a domain class that holds logic that could be called from various services, there are usually a few database calls involved, most of the time no persistance is necessary…

Anyway, I call my service method via an interface e.g.

void SaveFile(int reportid, stream file); //Interface name: IReportFileService


public Class FileService: Servicebase, IReportFileService
{

  private readonly IRepoSession _repo;
  public FileService(IUserSession user, IRepoSession repo, IUpdateSession update)
 : base(user,update)
 {
   _repo = repo;
 }

 //save file if users 'counter' is ok..
 public void SaveFile(int reportid, stream file)
 {

  //here I want to instantiate a new class that I store in my domain and store the counters
  //etc and do related db calls to check up relevant values

  //note loggedonuser is a prop on my *base class*
  var userChecks = new FileAllocation(loggedonuser,_repo);
  userChecks.CountEmUp(); //exception is thrown if 0, less than "limit" etc...

  base.update(userChecks.mycompany); //persist
  base.commit(); //base class method includes try, catch block...

 }

}

public class FileAllocation
{

 private readonly IRepoSession _repo;
 private readonly Loggedonuser _user;
 private int CompanyUploads;
 private int UserUploads;
 public Company mycompany;

 public FileAllocation(Loggedonuser user, IRepoSession repo)
 {
  _repo = repo;
  _user = user;
 }

 public void CountEmUp()
 {
   //do error checking,
   //load up other tables can user upload - permissions, count is ok etc...
   // check the upload type if of certain type we cannot proceed - call another method on this class

   //set myCompany variable to new limits etc...

 }

}

Base Service includes a prop, I dont want to instantiate this from other services i.e. more that once, how do I avoid that?

    private LoggedonuserDTO _currentuser = null;
    protected LoggedonuserDTO loggedonuser
    {
        get
        {
            if (_currentuser == null)
            {

                _currentuser = _user.GetCurrentUser(); //make db call here...
            }
            return _currentuser;
        }
    }

@Darin suggested:

public interface IFileAllocation
{
  CountEmUp(Loggedonuser currentuser);
}


//pass in loggedonuser to any method that requires it...
public class FileAllocation: IFileAllocation
{
  CountEmUp(Loggedonuser currentuser)
  { 
   //do whatever here...

  }
}

Answer 1

var userChecks = new FileAllocation(loggedonuser,_repo);

introduces a strong coupling between the FileService and the FileAllocation classes. If this is not a problem for you then you can leave it that way. Otherwise you could abstract the operations of this FileAllocation class into an interface and then inject it into FileService. This way the FileService is weakly coupled with FileAllocation and could be reused in different contexts and unit tested in isolation.