Many applications involve an implicit Command design pattern; after all, we're processing data. To do this, there must be at least one active-voice verb, or command, that defines how the application transforms, creates, or consumes data. A simple application may have only a single verb, implemented as a function. Using the command class design pattern may not be helpful for simple applications.
More complex applications will have multiple, related verbs. One of the key features of GUIs and web servers is that they can do multiple things, leading to multiple commands. In many cases, the GUI menu options define the domain of the verbs for an application.
In some cases, an application's design stems from a decomposition ...
