This smells like a homework assignment...  Here's a start

public class StateMachine {
}

Cheers

    robert

Sounds like homework, but here's the general idea (no code):

- define a set of classes representing the states, each with a similar
 transition method that receives an event, processes it and returns
 the next state.

- define a class representing the state machine, with a method that
 receives events, invokes the transition method of the current state,
 then changes state accordingly.

/gordon

Here is a variety of ways of writing state machines:

http://jerry.cs.uiuc.edu/~plop/plop2003/Papers/Adamczyk-State-Machine.pdf

If depends on the state machine's complexity. If you have a simple
state machine of ~6 states and few transitions, then use an enum to
list the states, a class member to store the current state and switch
statements based on the current state to decide how to respond to an
event based on the current state.

I use this solution when I have a simple "connecting, connected,
disconnecting, disconnected" FSM and transitions between states are
straight forward.

But as the number of states and transitions grow, this mechanism
becomes difficult to correctly implement.  The switch statements are
scattered throughout your event processing code. Adding a new state or
transition requires touching all these switch statements.

The State Pattern is one solution to this problem. Each state is a
class and each transition is a state class' method. So all the FSM code
is collected into these states. The downside is writing code for those
state classes and transition methods. The solution to that problem is
to define your FSM in a separate file and use another program to
generate the State Pattern code for you based on your FSM definition.

The open source application SMC does just that. It allows you to define
complex state machines and SMC generates the State Pattern code in
several  different languages - including Java. You learn about SMC at
http://smc.sourceforge.net. The site contains both a Programmer's
Manual and a FAQ.

Charles Rapp

Don't re-invent - use an existing one, like

http://unimod.sourceforge.net/