Re: CQRS cross aggregate interaction + private state

Hi Roger, 

You can find all those called "collaboration patterns" in the great book StreamLined Object Modeling. I
know it thanks to Nuno.
You can download the patterns chapter for free on the net.

Cheers.

--- In domaindrivendesign <at> yahoogroups.com, "rogeralsing" <roger.alsing@...> wrote:
>
> Ah, ofcourse, it's how the old MUD games works 
> 
> player.Eat(apple);
> apple.CanBeEaten(player);
> 
> I knew this, just wanted to see if your all awake *jk*
> 
> --- In domaindrivendesign <at> yahoogroups.com, Nuno Lopes <nbplopes@> wrote:
> >
> > Maybe I can help:
> > 
> > class Product : IOrderableItem
> > 	....
> > 	void TestAddOrder(Order order, double qty)
> > 	{
> > 		if (this.IsObsolete())
> > 			throw new BusinessException("An obsolete product cannot be ordered")
> > 	}
> > 
> > 	void Order (Order o, double qty) {
> > 		o.AddItem(this, this.REF, this.Description, this.Price, qty) 
> > 	}
> > 	.....
> > 
> > class Order 
> > {
> > 	void AddItem(IOrderableItem i, string REF, string description, double price, double qty)
> > 	{
> > 		...
> > 		i.TestAddOrder(this, qty)
> > 		......
> > 		this.DoAddItem(new OrderLine(REF, description, price, qty));
> > 	}
> > }
> > 
> > Hope it helps.
> > 
> > Nuno
> > 
> > 
> > On Feb 9, 2010, at 12:38 PM, rogeralsing wrote:
> > 
> > > If entities only have private state, how do you deal with interaction between aggregates?
> > > 
> > > e.g.
> > > 
> > > product = GetProduct(123);
> > > order.AddProduct(product,3);
> > > 
> > > Lets for the sake of the argument that addproduct can not occur if product is marked as obsolete.
> > > 
> > > How would you deal with that?
> > > What's the idea behind completely private state?
> > > Why shouldn't order be able to read properties on product?
> > > 
> > >
> >
>

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