Policy mode vs command mode

Before reading this article, you must have a certain understanding of the policy mode and command mode.

Policy mode: it is mainly used to encapsulate algorithms. The advantage of encapsulation is that the algorithm is replaced at will.

Command mode: the requester does not need to care about a specific command, how the command is executed, and how the execution process is. For example, give me a dish. It is just a command, and then the waiter (accept the request) calls the Kitchen Master's cooking (performer ). Throughout the execution process, the requester does not need to care about it. It only needs to provide a command, and someone will naturally help with this command.

The following uses a class diagram to analyze the policy mode: