Synopse

To content | To menu | To search

Tag - ValueObject

Entries feed

2015, Monday May 18

CQRS Persistence Service of any DDD object with mORMot

We introduced DDD concepts some time ago, in a series of articles in this blog.
At that time, we proposed a simple way of using mORMot types to implement DDD in your applications.
But all Domain Entitities being tied to the framework TSQLRecord class did appear as a limitation, breaking the Persistence Ignorance principle, since it couples the DDD objects to the framework implementation details.

We introduced a new mORMotDDD.pas unit, which is able to easily create CQRS Persistence services for any plain Delphi class (the famous PODOs - Plain Old Delphi Objects).
No need to inherit from TSQLRecord, or pollute your class definition with attributes!

For instance, a TUser class may be persisted via such a service:

type
  IDomUserCommand = interface(IDomUserQuery)
    ['{D345854F-7337-4006-B324-5D635FBED312}']
    function Add(const aAggregate: TUser): TCQRSResult;
    function Update(const aUpdatedAggregate: TUser): TCQRSResult;
    function Delete: TCQRSResult;
    function Commit: TCQRSResult;
  end;

Here, the write operations are defined in a IDomUserCommand service, which is separated (but inherits) from IDomUserQuery, which is used for read operations.
Separating reads and writes is a powerful pattern also known as CQRS, i.e. Command Query Responsibility Segregation, which we followed when defining our persistence services.
The framework make it pretty easy to create such services for storing any kind of class type in any SQL or NoSQL engine, with almost no code to write.
Last but not least, using such interface-based services for data persistence will allow to stub or mock the data access layer, making unit testing straightforward: you would not fear to write TDD code any more!

Please refer to our updated documentation for this unique and powerful feature.
You may take a look at the corresponding dddDomUserTypes.pas, dddDomUserCQRS.pas, and dddInfraRepoUser.pas units, detailed as sample reference.
Feedback is welcome in our forum, as usual!

2014, Friday April 18

Introducing mORMot's architecture and design principles

We have just released a set of slides introducing 

  • ORM, SOA, REST, JSON, MVC, MVVM, SOLID, Mocks/Stubs, Domain-Driven Design concepts with Delphi, 
  • and showing some sample code using our Open Source mORMot framework.

You can follow the public link on Google Drive!

This is a great opportunity to discovers some patterns you may not be familiar with, and find out how mORMot try to implement them.
This set of slides may be less intimidating than our huge documentation - do not be terrified by our Online Documentation!
The first set of pages (presenting architecture and design principles) is worth reading.

Feedback is welcome on our forum, as usual.

2014, Saturday January 4

Domain-Driven Design: part 4

One year ago, we already made a quick presentation of Domain-Driven Design, in the context of our mORMot framework.
After one year of real-world application of those patterns, it is now time to give more light to DDD.

Let's continue with part 4, which will define Domain-Driven Design as could be implemented with our Synopse mORMot framework

Continue reading...

Domain-Driven Design: part 3

One year ago, we already made a quick presentation of Domain-Driven Design, in the context of our mORMot framework.
After one year of real-world application of those patterns, it is now time to give more light to DDD.

Let's continue with part 3, which will define Domain-Driven Design patterns and principles - this will be the main article of the whole serie!

Continue reading...

Domain-Driven Design: part 2

One year ago, we already made a quick presentation of Domain-Driven Design, in the context of our mORMot framework.
After one year of real-world application of those patterns, it is now time to give more light to DDD.

Let's continue with part 2, which will define Domain-Driven Design high-level model principles.

Continue reading...

Domain-Driven Design: part 1

One year ago, we already made a quick presentation of Domain-Driven Design, in the context of our mORMot framework.
After one year of real-world application of those patterns, and a training made by a great French software designer named Jérémie Grodziski, it is now time to give more light to DDD.

Let's start with part 1, which will be a general introduction to Domain-Driven Design, trying to state how it may be interesting (or not) for your projects.

Continue reading...

2013, Tuesday December 10

JSON record serialization

In Delphi, the record has some nice advantages:

  • record are value objects, i.e. accessed by value, not by reference - this can be very convenient, e.g. when defining a Domain-Driven Design
  • record can contain any other record or dynamic array, so are very convenient to work with (no need to define sub-classes or lists); 
  • record variables can be allocated on stack, so won't solicit the global heap; 
  • record instances automatically freed by the compiler when they come out of scope, so you won't need to write any try..finally Free; end block.

Serialization of record values are therefore a must-have for a framework like mORMot.

In recent commits, this JSON serialization of record has been enhanced.
In particular, we introduced JSON serialization via a new text-based record definition.

Continue reading...

2013, Sunday January 20

Adding JavaScript server-side support to mORMot

A long-time mORMot user and contributor just made a proposal on our forums.
He did use mORMot classes to integrate a SpiderMonkey JavaScript engine to our very fast and scaling HTTP server, including our optimized JSON serialization layer.

Today, he sent to me some of his source code, which sounds ready to be included in the main trunk!

This is a great contribution, and Pavel's goal is nothing less than offering
Delphi based, FAST multithreaded server with ORM and node.js modules compatible.

Continue reading...

2013, Saturday January 5

Domain-Driven-Design and mORMot

Implementing Domain-Driven-Design (DDD) is one goal of our mORMot framework.

We already presented this particular n-Tier architecture.

It is now time to enter deeper into the material, provide some definition and reference.
You can also search the web for reference, or look at the official web site.
A general presentation of the corresponding concepts, in the .NET world, was used as reference of this blog entry.

Stay tuned, and ride the mORMot!

Continue reading...