Tom and Dick are neighbors. Dick makes a lot of noise on Sunday mornings, which drives Tom crazy. Communication has become difficult between them because of this.

If Tom and Dick cannot talk to each other directly, Dick will continue to make noise and Tom will get angry every Sunday.

When communication is difficult between two objects or in a system (here the neighborhood), the solution is delegation to a third-party object. This object will make communication easier between all other objects.

This is exactly the solution proposed by the Mediator pattern. To implement this pattern, we need:

• Object literals to represent Tom and Dick (who are neighbors)
• An object literal to represent Harry (who is the mediator)

Tom and Dick have both a "send" and "receive" methods, but they do not communicate directly. They communicate through the mediator who acts a bit like a router. Thus, Harry must have a reference to both neighbor objects and, depending on the sender, he will know the receiver...