Advancing Enterprise DDD - Entities, Value Objects, and Identity

In the previous essay of the Advancing Enterprise DDD series, we saw how we might improve our Domain Driven Design model by making our entity classes immutable. Here, we continue to investigate immutable entities by seeing how this affects one of the core DDD building blocks: the value object.


Advancing Enterprise DDD - Migrating to Immutability

In the previous essay of the Advancing Enterprise DDD series, we saw difficulties emerge in maintaining intra-aggregate constraints. These difficulties arose due to the mutability of our entities, and the Java collections they use to maintain relationships between entities. We also saw that it would be difficult or impossible to use immutable alternatives within JPA. In this essay, we set aside the constraints of JPA for a moment, and imagine a world where entities are composed of immutable objects.


Advancing Enterprise DDD - Maintaining Intra-aggregate Constraints

In this essay of the Advancing Enterprise DDD series, we begin look to at immutable objects - a common point of contrast between functional and object-oriented programming approaches. In the last essay, we saw at how MongoDB would be a much better vehicle than RDB for persisting well-shaped DDD aggregates. In this essay, we continue to investigate at the way the tools we use affect our thinking and coding, as we witness the contortions we have to go through to make something as straightforward as an intra-aggregate constraint work in the face of mutability.


Down Time

Some things have come up in my personal life that I need to attend to. I'm not going to stop writing and coding entirely, but it's going to have to take a lower priority for the next few weeks while I take care of things. I'm going to finish the Reactive Scala course, and I'll be able to complete the Advancing Enterprise DDD series on schedule. But the emblem documentation will be delayed, and my release dates for longevity are going to have to get pushed back.

Thanks for your patience, and thanks so much for your readership! I love to write. It really helps me formulate my thoughts and work them through. But it's especially fulfilling to have people reading what my material.


Advancing Enterprise DDD - Documents as Aggregates

In the last few essays of the Advancing Enterprise DDD series, we've taken a look at entity aggregates, and the challenges we face in implementing them well. We've seen a great many techniques we can employ using JPA to mitigate these challenges. In this essay, we step out of the JPA and relational database mindset, and consider modeling aggregates with a document database such as MongoDB.


Introducing Emblem - TypeKeys

This is the second post in the Introducing Emblem series, where I discuss a reflection-based utility library I have developed called emblem. The first post presented a high-level overview of the library. In this post, we look at the core building block of the emblem library: the TypeKey.


Introducing Emblem - A Reflection-based Utility Library for Scala

I've been working on this Scala project for a while now, and I found myself needing to develop some reflection-based tools to do some of the things I wanted to do. These things definitely weren't part of my core code, and I thought other people might find them useful as well, so I split them off into a separate library called emblem. It's open-source and on GitHub. The code is clean and has good API docs, but I haven't gotten around to writing any user documentation yet. I plan to do that here, and I'd like to start by describing my basic goals with emblem, and the design principles I decided to follow.