Jef Claes

[...] overview of the components looks like this. A queue host hosts multiple queue consumers. Each queue consumer will poll a queue for one type of message on a configurable interval, and dispatch dequeued [...]

[...] overview of the components looks like this. A queue host hosts multiple queue consumers. Each queue consumer will poll a queue for one type of message on a configurable interval, and dispatch dequeued [...]

[...] to be higher though. The constraint in this story is the CLR's thread pool. Every time a queue consumer's internal timer ticks, the callback which pulls from the queue and invokes the [...]

[...] to be higher though. The constraint in this story is the CLR's thread pool. Every time a queue consumer's internal timer ticks, the callback which pulls from the queue and invokes the [...]

[...] and tooling much easier compared to traditional systems. There are three things a minimalistic event store should be able to do: Store a new event stream  Append to an existing event stream [...]

[...] - there still are a great deal of event sourcing nuances left to be discovered. My current event store implementation only supports a single user. Due to an aggressive file lock, concurrently [...]

[...] able to have an aggregate record and play events, I looked at persisting them in an event store. Logically, the next question is: how do I query my aggregates, how do I get my state [...]

[...] , I guess I'll be putting out more technical bits here in the next few weeks. Using the Event Store, I tried to read all events of a specific event type. This stream turned out to be a tad too [...]

[...] of activity, or I could have a little function analyze the event streams for me. Looking at an event stream, we can identify a hot aggregate by having a lot of events in a short window of time. Let's [...]

[...] to external subscribers. Troubleshooting becomes easier since a developer can copy an event stream from production, and replay it locally - reproducing the exact issue without jumping through [...]

[...] in multiple pages - where all full pages are cacheable. Thus if you want to read the entire event stream, you should work your way through all pages. What confused me at first, but what actually is [...]

[...] process." To prevent concurrent file access, we can lock code accessing the aggregate's event stream. Instead of using a global lock, we maintain a dictionary of lock objects; one lock object per [...]

[...] sequence of events that caused them to be in the current state. In traditional systems, every time a change happens, we retrieve the old state, mutate it, [...]

[...] by implementing an event sourced aggregate. In traditional systems, we only persist the current state of an object. In event sourced systems, we don't persist the current state of an object, but [...]

[...] trying to support this concept. A request is actually a template. It will always contain the current state, and some meta data concerning previous state transitions, but the actual content is generic. [...]

[...] trying to support this concept. A request is actually a template. It will always contain the current state, and some meta data concerning previous state transitions, but the actual content is generic. [...]

[...] needs attention Possibly, your team hasn't fully grasped the power of cultivating the ubiquitous language. If you start listening to your domain experts, you might end up with totally different [...]

[...] way in less than twelve minutes. That's why I started over, focusing on the ubiquitous language alone. You can find my slides embedded below or on Slideshare.       & [...]

[...] did a DDDBE session on the strategic side of Domain Driven Design. My talk covered the Ubiquitous Language, and can be found on Slideshare or embedded below. I might end up writing down the content [...]

[...] an attractive compromise. Defining a bounded context A bounded context is where one ubiquitous language is consistent. This is by far the simplest definition of a bounded context. Bounded [...]

[...] of it too, post-its and markers. Mathias and Stijn took the lead introducing themselves as domain experts of the day. The domain? The United Schools of Kazachstan. We split up into groups of four, [...]

[...] other parts of the system.  Another brick in the wall Break down that paper wall between domain experts and developers. Learn the favorite coffee of the domain expert. Lots of organizations still [...]

[...] complex systems. Once they are well educated on the constraints, it must come natural for domain experts as well. Having worked with a team of mainframe programmers over the last year, it recently [...]

[...] you are solving. The model gives you an opportunity to learn from and to communicate with domain experts, peers and users. And that's exactly where most businesses make the difference, not by having [...]

[...] since that bloated constructor is all up in your face. Let's go ahead and extract two value objects: name and address. There, that looks better. Tell, don't ask In good OOP we tell objects what [...]

[...] . We also expect its birth date not to be in the future. Composition and extracting value objects I'm fairly confident that every self-respecting programmer is annoyed by the fact that the [...]

[...] An entity is identified by an identifier, while value objects are identified by their value. If I make a living renting cars to tourists, I might not care [...]

[...] An entity is identified by an identifier, while value objects are identified by their value. If I make a living renting cars to tourists, I might not care [...]