Is registering and adding class of command possible?

Is registering and adding class of command possible?

 

Normally i am creating file for commands. I don't wanna create file. Is it possible?

WITHOUT PLUGIN.YML
WITHOUT COMMAND.PHP

 

PHP:

new PluginCommand('command', Plugin main class);
// Register this command to command map
// The onCommand() method gets trigger when the command runs

 

You can always handle the user input from chat messages yourself.

 

Thanks
I am gonna use CommandPreProcessEvent if i understood true