Validate Method on Base Entity

getoutofmylaboratory · October 24th, 2011, 09:58 AM

Scott,

Another developer made this comment referring to your use of a Validate() method on the base Entity class:

Quote:

Just the fact that you have a Validate() method on the entity means that you can mutate it into an invalid state. You should NEVER be able to mutate an entity to an invalid state.

Any insight/comments regarding this?

elbandit · October 24th, 2011, 12:12 PM

Hi getoutofmylaboratory,

I wrote the book around 2 years ago now and since my views on validation and DDD have changed a bit. I agree that domain entities shouldn't be able to get into an invalidate state and where possible I try and use immutable vlaue objects that have to be valid on construction. I also try not to use getters and setters and prefer methods that map to business user cases to ensure an always valid entitiy state.

Cheers
Scott

elbandit · October 24th, 2011, 12:15 PM

I have a git hub account https://github.com/elbandit where I have been working on a number of code katas (TicTacToe and Minesweeper) to demonstrate how I am implementing DDD since writing the book that maybe of intrest to you.

Cheers
Scott

getoutofmylaboratory · October 25th, 2011, 07:58 AM

Thanks for the reply! I will be checking out the code samples made available.