Encapsulates a request as an object - operation and its arguments are wrapped into an object.
Thanks to this encapsulation creation of command lines and undo operation support is possible.
Example:
A good example is a scheduler in an operating system. For instance we want a computer to turn on a certain task (program)
at given time and date. In the scheduler we define an operation/program which has to be done and what the program
should do (operation arguments).
