Event Sourcing

Event Sourcing is a pattern for data storage, where instead of storing the current state of any entity, all past changes to that state are stored. With Axon Framework, you can implement Event Sourcing with minimal boilerplate code, giving you the benefits of Event Sourcing, without the hassle.

CQRS replay performance tuning

By Frans van Buul

    7 min

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    Jan 19, 2019

CQRS has become a popular pattern to avoid complex, and therefore slow, database queries in applications. Axon offers a mature and popular implementation of the CQRS/ES concepts on the JVM, but several other implementations exist. CQRS/ES presents a solution to a common performance problem. On the other hand, it introduces a couple of new potential performance challenges.

Parameter Resolvers in Axon

By Milan Savić

    4 min

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    Dec 20, 2018

Axon is an open-source Java framework for building systems in CQRS (Command Query Responsibility Separation), DDD (Domain Driven Design), and Event Sourcing. Axon Framework is message-based - commands, events, and queries are supported types of messages. Axon provides a potent mechanism to inject these dependencies into message handlers - Parameter Resolvers. This is the story about them. At the end of this article, you can find a cheat sheet of all resolvers provided by the Axon Framework.

Some CQRS and Event Sourcing Pitfalls

By Frans van Buul

    6 min

|

    Dec 10, 2018

In one of our recent blogs, we talked about constructing a real-life Axon application. Which areas should you distinguish on a high level, and what code should go where? Which pitfalls are there that we should avoid?  I will cover some of these in this blog. It’s based on stuff I’ve seen happening for real when working with many Axon clients.

Demystifying Tracking Event Processors in Axon Framework

By Milan Savić

    6 min

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    Nov 27, 2018

An important ingredient in the Framework is the explicit use of messages. One of the types of messages is events.In Axon Framework, there are two ways of event processing - subscribing and tracking. Therefore, the Framework provides Subscribing Event Processor (SEP) and Tracking Event Processor (TEP) components to support these two ways of event processing. This blog will discuss the features of TEP and how those are implemented.

How to write an Axon application?

By Frans van Buul

    6 min

|

    Nov 16, 2018

Learning to write a proper Axon application from scratch consists of various aspects. However, talking with AxonIQ customers, I found out that there's something we may need to be a little more clear about: What does the general structure of a real-life Axon application look like? What goes where, and how do you prevent a mess? In this blog, I'll try to shed some light on this topic.

Deepening Our Open Source Commitment

By Allard Buijze

    5 min

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    Oct 18, 2018

Axon Server, combination from AxonDB and AxonHub, will be accompanied by two new commercial offerings - Axon Server Enterprise and Axon GDPR Data Protection Module. We are also realigning the Axon Framework towards Axon Server and offering a new simplified, combined platform named Axon 4.0. These changes represent a major step towards further deepening our long-term commitment to open source and are worth explaining briefly.

Introducing Subscription Queries

By Frans van Buul

    8 min

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    Jul 24, 2018

Axon Framework 3.3 has just been released, and it has several interesting new features. In this blog, I'd like to highlight one that I’m particularly excited about: subscription queries. Before we look into the implementation and some sample code, let’s have a quick look at the background of this feature.

Running AxonHub and AxonDB on Kubernetes - part 1

By Frans van Buul

    9 min

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    Jul 18, 2018

A quickly increasing number of Axon Framework users are deploying their applications to Kubernetes. In this blog, we’ll explain how to set a non-clustered in part 1. In part 2 of this series, we'll cover the clustered setup. Again, we'll focus on simple deployments (no SSL, no authentication, mostly default settings) except for the clustering.

Building Reactive Systems with Axon Framework

By Milan Savić

    5 min

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    Jul 18, 2018

Unfortunately, old systems aren’t as responsive as we expect them to be. They cannot be scaled that easily. Instead, they use processor time, waiting for operations to complete when they could do something else (processing another request, doing some background calculations, etc.). In this blog, we will discuss why Axon Framework provides infrastructural components that help us build reactive systems.

A message’s journey through Axon Framework

By Steven van Beelen

    2 min

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    Dec 19, 2017

In your application, you probably have created a couple of components: client code that issues commands; a command handling component; an event handling component. But how does Axon Framework call these components precisely? This blog provides a representation that addresses this question.