Fortress provides a framework for you to easily create your own application specific containers. We strive to make it easy for you to do without sacrificing any power. Fortress allows you to focus on the core issues in your system, without worrying about the component management getting in your way.
Most component management functions don't take that long to perform, but the time they do take can directly affect how many requests your system can process at the same time. For that reason, we use the CommandManager from the Event package to manage our components. By moving all the management functions to a limited number of background threads, we are able to save you time in the critical processing path.
The CommandManager can be extended to your components as well. That way, your components can perform management tasks in the background as well. Fortress will likely be your choice of containers if you have strict performance constraints.
Fortress has support for an experimental feature that allows you to extend your component lifecycle in an application specific manner. If it proves to be a truly useful feature, other Avalon containers will adopt it.
Fortress is integrated with the Instrumentation package so you can get a graphical view of the health of your system at runtime. We integrate sampling points for each of the component handlers so that you can see how many component instances each handler is responsible for. Using that information, you can tune your container more intelligently.
Instead of using a "roles" file to keep track of the component configuration name, and what kind of lifestyle the component has, Fortress provides some tools so that you can keep track of that information with your java source code. You have to use the ANT tasks that are defined in the Fortress tools jar. It collects all the attributes defined as JavaDoc doc tags and generates the meta info files which are then read at runtime. It makes it a whole lot easier to manage critical aspects like lifestyle and which classes represent components. You can find out more about it here.