Summary

In this chapter, we considered our first request processing component—the Catalina engine. We looked at the containment hierarchy implemented by Tomcat and also reviewed the super class of all containers, the ContainerBase. Each container is associated with a pipeline that aggregates the request processing functionality for that container. We walked through the StandardPipeline, which is the default implementation of a pipeline. Finally, we considered the constituent parts of a pipeline, the Valves. We looked at the base implementation, ValveBase, and visited some of the key valve implementations. The valves that we explored included the StandardEngineValve, which is the core request component for an Engine, as well as some key general purpose valves such as the Request Dumper Valve, the Request Filter Valve, and the Access Log Valve. In the next chapter, we'll take a closer look at the virtual host component.