DDD Archives | Cesar de la Torre [Microsoft]

Free eBook/Guide on ‘.NET Microservices – Architecture for Containerized .NET Applications’

Cesar De la TorreMay 10, 2017May 10, 201705/10/17

The microservices architecture is emerging as an important approach for distributed mission-critical applications. In a microservice-based architecture, the application is built on a collection of services that can be developed, tested, deployed, and versioned independently. In addition, enterprises are increasingly realizing cost savings,

Domain Events vs. Integration Events in Domain-Driven Design and microservices architectures

Cesar De la TorreFebruary 7, 2017Feb 7, 201702/7/17

This blog post is about comparing several approaches of Domain Events vs. Integration Events patterns already published by the community. I might evolve this post depending on feedback and some implementations we’ll be doing in the short/medium term. So, feel free to discuss about it with comments at the end of this post.

Just released our .NET Business Applications Technology Guide (MS PRESS eBook)

Cesar De la TorreJuly 11, 2013Jul 11, 201307/11/13

What is this guide / eBook about?
UPDATE – Dec.2013
This same Guide has been published now as free MS PRESS eBook, here:
http://blogs.msdn.com/b/microsoft_press/archive/2013/11/13/free-ebook-net-technology-guide-for-business-applications.aspx

—
A few days ago (late June 2013, at BUILD) we released a new paper showing a global and broad picture of Microsoft development technologies for custom LOB applications.

Scoping CQRS and Event-Sourcing Guidance Project

Cesar De la TorreJanuary 12, 2012Jan 12, 201201/12/12

I am collaborating with the patterns & practices team. We are considering doing a guidance project on implementing systems using the Command & Query Responsibility Segregation (CQRS) approach. This is not going to be a framework or reusable components. We are positioning this project as a learning journey and envision providing an experience report that describes building a sample app (reference implementation) to showcase various CQRS and Event Sourcing (ES) concepts &

We completed the IASA-DDD Conference! (November 7th 2011)

Cesar De la TorreNovember 9, 2011Nov 9, 201111/9/11

It was a remarkable DDD (Domain Driven Design) event in Madrid, Spain. We got around 150 attendees!!, and taking into account that this is the inaugural event from the IASA-Spain association, and this association was almost unknown in Spain, until now,

Value-Object pattern implementation in .NET

Cesar De la TorreJuly 20, 2011Jul 20, 201107/20/11

Regarding DDD patterns, here I link two nice Value-Object implementation samples:
http://elegantcode.com/2009/06/07/generic-value-object/
http://grabbagoft.blogspot.com/2007/06/generic-value-object-equality.html

Published first ALPHA version of Domain Oriented N-Layered Architecture V2.0

Cesar De la TorreJuly 3, 2011Jul 3, 201107/3/11

[UPDATED – April 2017] – IMPORTANT: For up-to-date architecture and development guidance using .NET (i.e. .NET Core, ASP.NET Core, Docker containers, etc.) including Domain-Driven Design patterns, microservices architectures and other .NET related technologies like Xamarin for mobile apps check this landing page pointing to multiple NEW guides and reference applications:
https://www.microsoft.com/net/architecture/
Specifically,

DDD-Exchange 2011

Cesar De la TorreJune 13, 2011Jun 13, 201106/13/11

So, it was such a great event with Eric Evans, Udi Dahan and Greg Young.
Here I post a few pictures I got.
Before starting:

Eric Evans presenting the Agenda:

Q&A to Eric, Udi and Greg:

Saying hello to Udi:

Strong discussions below…

Implementing a Value-Object Base class (Supertype pattern–DDD patterns related)

Cesar De la TorreJune 6, 2011Jun 6, 201106/6/11

It is usually a recommended practice to have Value-Object base-class so we can have common functionality which can be used by all of our value-object classes. Typically, comparison methods or any other common subject for Value-Objects, should be included here.
Below I show a sample Value-Object Base-Class:

public class <strong><span style="font-size: x-small">ValueObject<TValueObject></span></strong> : IEquatable<TValueObject><br />    where TValueObject : ValueObject<TValueObject><br />{

1	public class <strong><span style="font-size: x-small">ValueObject<TValueObject></span></strong> : IEquatable<TValueObject><br /> where TValueObject : ValueObject<TValueObject><br />{

    <br />public bool <strong>Equals(</strong>TValueObject other)<br />{<br />    if ((object)other == null)<br />        return false;<br /> <br />    //compare all public properties<br />    PropertyInfo[] publicProperties = this.GetType().GetProperties();<br /> <br />    if ((object)publicProperties != null<br />        &&<br />        publicProperties.Any())<br />    {<br />        bool result = true;<br />        foreach (var item in publicProperties)<br />        {<br />            //compare two values using default equatable method<br />            if (!item.GetValue(this, null).Equals(item.GetValue(other, null)))<br />            {<br />                result = false;<br />                break;<br />            }<br />        }<br /> <br />        return result;<br />    }<br />    else<br />        return true;<br />}<br /> <br />public override bool <strong>Equals(</strong>object obj)<br />{<br />    if ((object)obj == null)<br />        return false;<br /> <br />    ValueObject<TValueObject> item = obj as ValueObject<TValueObject>;<br /> <br />    if ((object)item != null)<br />        return Equals((TValueObject)item);<br />    else<br />        return false;<br /> <br />}<br /> <br />public override int <strong>GetHashCode()</strong><br />{<br />    int hashCode = 31;<br />    bool changeMultiplier = false;<br />    int index = 1;<br /> <br />    //compare all public properties<br />    PropertyInfo[] publicProperties = this.GetType().GetProperties();<br /> <br />    if ((object)publicProperties != null<br />        &&<br />        publicProperties.Any())<br />    {<br />        foreach (var item in publicProperties)<br />        {<br />            object value = item.GetValue(this, null);<br /> <br />            if ((object)value != null)<br />            {<br /> <br />                hashCode = hashCode * ((changeMultiplier) ? 59 : 114) + value.GetHashCode();<br /> <br />                changeMultiplier = !changeMultiplier;<br />            }<br />            else<br />                hashCode = hashCode ^ (index * 13);//only for support {"a",null,null,"a"} <> {null,"a","a",null}<br />        }<br />    }<br /> <br />    return hashCode;<br />}<br /> <br />public static bool <strong><span style="font-size: x-small">operator ==</span></strong>(ValueObject<TValueObject> x, ValueObject<TValueObject> y)<br />{<br />    // If both are null, or both are same instance, return true.<br />    if (System.Object.ReferenceEquals(x, y))<br />    {<br />        return true;<br />    }<br /> <br />    // If one is null, but not both, return false.<br />    if (((object)x == null) || ((object)y == null))<br />    {<br />        return false;<br />    }<br /> <br />    // Return true if the fields match:<br /> <br />    return x.Equals(y);<br /> <br />}<br /> <br />public static bool <span style="font-size: x-small"><strong>operator !=</strong></span>(ValueObject<TValueObject> x, ValueObject<TValueObject> y)<br />{<br />    return !(x == y);<br />}<br />}

public bool Equals(TValueObject other) { if ((object)other == null) return false; //compare all public properties PropertyInfo[] publicProperties = this.GetType().GetProperties(); if ((object)publicProperties != null && publicProperties.Any()) { bool result = true; foreach (var item in publicProperties) { //compare two values using default equatable method if (!item.GetValue(this, null).Equals(item.GetValue(other, null))) { result = false; break; } } return result; } else return true; } public override bool Equals(object obj) { if ((object)obj == null) return false; ValueObject<TValueObject> item = obj as ValueObject<TValueObject>; if ((object)item != null) return Equals((TValueObject)item); else return false; } public override int GetHashCode() { int hashCode = 31; bool changeMultiplier = false; int index = 1; //compare all public properties PropertyInfo[] publicProperties = this.GetType().GetProperties(); if ((object)publicProperties != null && publicProperties.Any()) { foreach (var item in publicProperties) { object value = item.GetValue(this, null); if ((object)value != null) { hashCode = hashCode * ((changeMultiplier) ? 59 : 114) + value.GetHashCode(); changeMultiplier = !changeMultiplier; } else hashCode = hashCode ^ (index * 13);//only for support {"a",null,null,"a"} <> {null,"a","a",null} } } return hashCode; } public static bool operator ==(ValueObject<TValueObject> x, ValueObject<TValueObject> y) { // If both are null, or both are same instance, return true. if (System.Object.ReferenceEquals(x, y)) { return true; } // If one is null, but not both, return false. if (((object)x == null) || ((object)y == null)) { return false; } // Return true if the fields match: return x.Equals(y); } public static bool operator !=(ValueObject<TValueObject> x, ValueObject<TValueObject> y) { return !(x == y); } }

Don’t like EF 4.1 ‘Data Annotations’ for DDD Architectures implementation –’Fluent API’ fits better for that!

Cesar De la TorreMay 27, 2011May 27, 201105/27/11

I write this post in order to get some feedback regarding what I currently think about EF 4.1 Data Annotations and how it fits in DDD Architectural styles.
About DDD Architectural styles, here it is our Architecture Guide (Though we are actually writing its second edition,

Cesar de la Torre [Microsoft] - BLOG

DDD Archives | Cesar de la Torre [Microsoft] - BLOG