Server

The Server Module is responsible for receiving and executing commands sent by clients. It identifies the appropriate handler for each command, builds the corresponding tasks, and schedules them for execution on worker threads. After processing, the server may reply to the client or send files stored on disk.

Lets Explain the above diagram in depth.

CommandSelectorDispatcher

This module is responsible for receiving different clients commands, unpack it to a Command and then proceeed to recognize the command type following it's CommandHandler. Then it will pass the client command to the handler for the next step.

CommandHandler

Each command type have a specified CommandHandler which is responsible for handling client commands of that type.
The handler takes the command then it does all the dirty work like checking for command validity or parameters, check if the user have a registerd session on the server SessionRegistry, etc.. Then, it uses TaskDispatcher to do the acctual work.

TaskDispatcher

Each user command is transformed into a set of tasks which can be done either Synchronously or Asynchronously. The module will take a Task and then schedules this task on it's ThreadPool.

ThreadPool

The Thread Pool Design is a common software design pattern which is used to perform many tasks at the same time with equal CPU utilization for all tasks. This is importatnt because we don't want some clients to have a better performance at the expense of some other clients which would results bad usability.