By jettro, on April 16th, 2010
In this post we focus on getting the task based user interface. We have the basic building blocks in the application, but the screens are a bit stupid. How many applications would you create where you have to manually copy the identifier of a contact to an address when you want to register an address for this contact. Well in the current version of the application this is what you really have to do.
What are the tasks that we focus on right now:
- Create a new contact
- Remove a contact
- Change the name of a contact
- Register an address of a certain type for a specific contact
- Remove an address from a contact
But before we step into creating the front-end, we install some plugins that I discussed in previous posts.
Continue reading Use Grails and Axon to create a CQRS application (part II)
By jettro, on April 8th, 2010
Allard has been working on a new framework to make it easier to create a CQRS application. CQRS is short for Command Query Responsibility Segregation. An architecture that separates data sources for storing state and querying data. The query datasource should be easy to use when creating screens. The framework Allard created is the Axon Framework. This framework makes it a lot easier to use commands, events, event sourcing. If these terms are not known to you, I suggest you start reading the reference manual that comes with axon.
What does grails do in this picture. Isn’t grails about rapid application creation? Well, yes. It is a good platform to rapidly create web applications using the groovy language and still be able to use existing libraries. Personally I really like the Gorm library of grails. I think that gorm would be an excellent choice to wrap the query datasource. Of course the gsp technology and the groovy language are nice to have when working with the web applications as well.
In this blog post I’ll discuss the integration between grails and axon. How can we create an application with grails that makes use of Axon to implement CQRS. I’ll discuss the way to create commands and send these to axon. I’ll also discuss responding to events coming from axon. First I have to show some aspects of a grails project that you need to know before you can use Axon. I’ll try to take you with me when I take the steps to create a good integration between Axon and Grails.
Continue reading Use Grails and Axon to create a CQRS application (part I)
By jettro, on February 25th, 2010
The last weeks or maybe even months, I have spent time getting to understand the Axon Framework created by Allard. Axon is a framework that can help developers created a scalable and maintainable application based on Command Query Responsibility Segregation (CQRS) principles. Each morning Allard and I discussed the framework and the sample we wanted to have. Since I know my way around flex and Axon makes heavily use of events, I decided to create a flex client that could demonstrate some cool features of the Axon framework.
This post is mainly about flex and Parsley. We will go into depth of the architecture of the client and how to talk to the server. I will describe the communication with the application that makes use of the axon framework, but I will not go into a lot of details. If you want more information about the Axon Framework I suggest you go to the website http://www.axonframework.org. There is good documentation available in the reference manual. If you want to learn about flex and the Parsley framework in general, please read on.
Continue reading Creating a sample for axon using flex and parsley
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