To finish with this chapter, we will see also the Command pattern--a tiny design pattern but still frequently used. You need a way to connect types that are really unrelated? So design a Command for them.
The Command design pattern is quite similar to the Strategy design pattern but with key differences. While in the strategy pattern we focus on changing algorithms, in the Command pattern, we focus on the invocation of something or on the abstraction of some type.
A Command pattern is commonly seen as a container. You put something like the info for user interaction on a UI that could be
click on login and pass it as a command. You don't need to have the complexity related to the
click on login action in the command but simply the action itself.
An example for the organic world would be a box for a delivery company. We can put anything on it but, as a delivery company, we are interested in managing the box instead of its contents directly.
The command pattern...