Question

For example, we have two domain objects: Cell and Body (as in human cell and body).

The Body class is just a collection of Cells, e.g.

class Body
{
    IList<Cell> cells;
    public void AddCell(Cell c) { ... }
    public void RemoveCell(Cell c) { ... }
}

The Cell has a Split method, which internally creates a clone of itself, e.g.

Class Cell
{
    public Cell Split()
    {
        Cell newCell = new Cell();
        // Copy this cell's properties into the new cell.
        return Cell;
    }
}

Now, in DDD when the cell splits should:

1. The cell add the newly created cell to the Body (which would mean that each Cell object held a reference to its containing body)?
2. Or should the service layer which received the intitial user request call Split, collect the returned Cell and add it to the Body? (feels like a more anemic design using controllers rather than domain objects)
3. Or should the Body contain a SplitCell method?

Thanks in advance.

Answer 1

After reading Domain Driven Design (Evans) it would seem that this scenario is best dealt with by using a service.