Are you happy with the 3-tier architecture in your Grails applications? This presentation explains how to apply the Life Preserver tool to implement the Hexagonal architecture in Grails applications. With plenty of code and a sample application, it contains discussion on using plugins, messaging and the features of Groovy itself to create the required structures and decoupling.
Video producer: http://greachconf.com/
Further reading: https://github.com/russmiles/life-preserver-introductory-article-developer-magazine