3.3. Using the lifecycle API in your bundles

So far, you haven’t implemented much functionality for the shell—you just created the activator to start it up and shut it down. In this section, we’ll show you how to implement the bulk of its functionality. You’ll use a simple command pattern to provide the executable actions to let you interactively install, start, stop, update, and uninstall bundles. You’ll even add a persistent history to keep track of previously executed commands.

A high-level understanding of the approach will be useful before you start. The main piece is the telnet binding, which listens to the configured port for connection requests. It spawns a new thread for each connecting client. The client sends command lines to its thread, where a command line consists of a command name and the arguments for the command. The thread parses the command line, selects the appropriate command, and invokes it with any specified arguments, as shown in figure 3.7.