moffdub | 20 Aug 03:57

Multiple Interfaces

I recently had a vision about how to combat the abuse of the
pesky-but-needed getters and setters that are necessary for domain
objects that live in a real system and that have to be stored,
displayed, and sometimes created by external factories.

Anyway, since the getters and setters will end up being there anyway,
alongside your actual business logic methods, would it be better to
have the domain object implement multiple interfaces, one for each
layer of the system that has to see assorted getters and setters?

Here is what I'm talking about:

// for use with other domain objects; exposes meaningful business
logic methods only
        public interface Customer
        {
// our lone business logic method
            void describe(CustomerDescription description);
        }

// to be used when displaying a customer in UI and capturing a new one
from the user; TO stands for Transfer Object
        public interface CustomerTO
        {
            String getFullName();
            String getAddress();
            void setFullName(String name);
            void setAddress(String addr);
        }

(Continue reading)

chris.sano | 18 Aug 21:09

Sample DDD projects in C#?

Does anyone know where I can find a sample C# project that exercises 
different DDD concepts and patterns?

Thanks!

------------------------------------

Ted Epstein | 19 Aug 16:43

Maps in Public Interfaces Considered Harmful


Hi,

I'm new to this group, and don't mean to start a flame war with this
somewhat provocative subject line.

But I've been working on a complex domain model that will be available
as part of a runtime framework.  Some of the developers working on this
have prototyped public interfaces that return maps, or dictionaries. 
I've instinctively avoided using maps in public APIs, and have recently
had to examine my reasons for this more closely, for discussion within
the team.

In thinking through this, I'm increasingly of the opinion that maps
shouldn't be regarded as first-class modeling abstractions, and in most
cases shouldn't be exposed through public APIs.  Before I get to the
reasons for this, I'm looking for some pointers from the DDD community
to past discussions, blog entries, references, etc.   I did a cursory
search of this mail group and a a few google searches, but didn't come
up with much.

Is this something that has been discussed or addressed in DDD, modeling
or API design literature?  Any background information would be much
appreciated.

Thanks and Best Regards,

  - Ted Epstein

------------------------------------
(Continue reading)

Krister | 19 Aug 19:08

Feedback on DDD architecture in application

In some days I have created my first simple Silverlight application. 
Other technics I have used is Linq, WCF, DDD and TDD. I would 
appreciate some feedback on the DDD part of the application.
You can download the source code from this address: 
http://dev.levasunt.nu/MyMemory.zip

The code is coded in C# Visual Studio 2008.

The game you can find on this address: http://dev.levasunt.nu

Regards
Krister

------------------------------------

elton albuquerque | 15 Aug 03:42

DDD

What is the difference between the groups of 
patterns: 
1 - Entities, Values Aggregate Objects ... 
2-Shared Kernel, 
Distillation, ... conformist

Elton

      Novos endereços, o Yahoo! que você conhece. Crie um email novo com a sua cara @ymail.com ou @rocketmail.com.
http://br.new.mail.yahoo.com/addresses

------------------------------------

ashley.fernandes | 18 Aug 07:13

Can Specifications reside in the App Layer? Can a Build To Order Spec Produce a Domain Object?

Hi All,

 

 

1)      Can Specifications (external) reside in the App Layer?

 

Eg. My Application (Loans)  in the app layer needs to call many validations which reside in the other domains. We call these services exposed by other domains (like security) etc via Adapters, but the loans Application object looks ugly since the various method calls are encompassed in it.

 

Is it advisable to create a separate External Specification Object and in turn that object talk to the various adapters which in turn talk to the External Services.

 

 

 

2)      Can a Build To Order Spec Produce an Domain Object?

 

Currently we pass a build to order spec to a factory to produce a Domain Object, Can the Build To Order Spec itself Produce a Domain Object, thus avoiding the use of a factory?

 

 

 

Thanks & Regards

Ashley

 

Ashley Fernandes

Consultant | Banking Products Division | Goregaon Annex, Mumbai

Direct: +91 22 6718 7421| Mobile: +91 9820842428

 

i-flex solutions has proposed to change its name to Oracle Financial Services

(read more about the proposed name change at www.iflexsolutions.com)

 

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Miika Makinen | 14 Aug 09:47

Diagrams and tools

Hi all,
I'm wondering how do you usually draw diagrams for your domains. Do you do UML class diagrams? Or something like ERD? I take it there is no "official" DDD visual language? Wouldn't it be useful to have some simple diagram styleto recognize value objects / entities / services from each other?

Cheers,
Miika
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nichols_mike_s | 13 Aug 00:47

Getting references to internal entities from outside aggregate boundary

I have an entity 'Calibration' which is a variant entity under the
Aggregate 'MixDesign'. MixDesigns create calibrations and calibrations
are only valid as they represent a valuation based on mix design
properties. There is no such thing as a calibration without a mix design.

I have other objects outside the mix design aggregate boundary which
need to know which calibration is being used for their calculation,
but DDD dictates that no references to inner variants are held. 

I have considered moving Calibration to be its own aggregate but this
is awkward since a calibration really only exists as a valuation from
a mix design.

How have other people here dealt with this kind of pseudo-aggregate
reference problem? I really don't want to implement a service to deal
with associations in the domain for something as simple as object
references.
Should I reference the calibration by some kind of business key like
the Creation date (which is unique) or something?
thanks,
mike

------------------------------------

aizikovsky | 12 Aug 20:48

Value objects, entities, services


Most of the time it's very important to distinguish between value
objects and
entities on one side and services on the other.
Do you have or can you suggest a good general name
for value objects
and entities?
Maybe we should call them objects and consider
services as non-objects?

Thanks,
Alex

------------------------------------

ashley.fernandes | 12 Aug 05:56

Can the App Layer be used to communicate between two domains or can two Domain Services directly talk two each other without the App Layer?

Hi All,

 

We have three domains , namely Global, Security and Loans, had two requirements,

 

1)      My Loans Account Need to get information from my global domain…like Bank, Branch Information etc….Should my Loans Application Service(Loans App Layer) talk to the Domain Service of my Global Domain(Global  Domain Service) (via an adapter that resides in my loan app layer)? or should my Loans Domain Service (Loans Domain Layer) talk directly to my Global Domain Service (Loans Domain Layer)

 

2)      For Authenticating the users using the Loans Domain Service , Again similar query, should my loans app layer talk to the Security domain via an adapter or can my Loans Domain Services directly talk to the Security Domain?

 

Thanks & Regards

Ashley

 

Ashley Fernandes

Consultant | Banking Products Division | Goregaon Annex, Mumbai

Direct: +91 22 6718 7421| Mobile: +91 9820842428

 

i-flex solutions has proposed to change its name to Oracle Financial Services

(read more about the proposed name change at www.iflexsolutions.com)

 

DISCLAIMER:
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Casey Charlton | 8 Aug 12:08

Internationalised entities

Let me give a very basic example ...
 
I have a News entity ... it has Title and Content and some additional functional properties ... However, when displayed there may be many language versions of the Title/Content
 
For the sake of information (if it matters), this is being done in ActiveRecord, currently mapping the single EN record onto a table
 
How could this be best represented? 
 
At a really superfluous level, there could be multiple records per language, and you could just apply a filter when searching ("Language='en') but this would mean the news items were not related to their other language counterparts.
 
Another way might be to store their resources in linked tables, but this will be the vast majority of the entities in this domain (News, Publications, Content, Reports, Subscriptions, etc)
 
Another way might be to have the Repository do the "clever" work ... but "clever" is a bit fuzzy ...
 
 
 
Any thoughts?
 
 
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