Using Command Design pattern

Question

Can any one explain with simple example of Command Pattern. I refer in internet but i got confused.

Answer 1

I would try to give you another rough analogy here.

Suppose that one day God calls on you and tells you that the world's in danger and He needs your help to save it. Further helping you , He tells you that He has sent some superheroes on earth.

Since He doesn't know oops and hence He doesn't call them superheroes (doesn't provide you any interface or abstract class over them) but just tell you their names for ex - batman, superman, iron man and the powers they have.

He also says that in future He might send more such guys in future.

Now He assigns you special responsibility -> control them and for that provides you with seven hands. He doesn't fixes the task of each hand Himself but leaves it on you.

You want flexibility in assigning any hand control of any superhero's power and don't want to repeatedly change things through multiple conditions.

You are in a fix. What do you do now?

Enter Command Pattern.

Create an interface Command and has only one method execute() in it. Encapsulate every power of each superhero and make that implement Command for ex - IronManCreatesSuitCommand

Now you can assign any hand to any command at any time giving you lot more flexibility because now none of your hands cares about the specific task it has to do. You just assign it any command to it. It calls execute on it and the command takes care of everything else.

Now even when God sends any other superhero with different powers, you know what to do.