This Ticket Selling System Component System displays the various components in the system; a particular application configuration may have multiple copies of an element. An interface is a coherent set of services represented by a small circle with a name. A solid line connecting a component and an interface indicates that the component offers the services listed in the interface. A dashed arrow connecting a component to an interface indicates that the component requires the interface's services. For example, subscription sales and group sales are provided by the ticket seller component; subscription sales can be accessed through ticket selling and clerks, but group sales can only be accessed through a clerk.