Hands-On Design Patterns with Java

Use case

To demonstrate the mediator design pattern, we will emulate a widget production system that includes a hopper for parts, a starter to start the system, an assembly system to combine hopper components, an accelerator, and an emergency break to manage the speed of the system.

There are inter-relations between the various components for our mediator to manage. These inter-relationships are detailed here:

Components in the left column have the listed impact on the components listed in columns two through six.
Starter	Assembly System	Hopper	Accelerator	Decelerator
Starter	N/A	Powers this component	Powers this component	Powers this component	Powers this component
Assembly System	Starter must be on for the assembly system to function ...