com.atomikos.finitestates
Class FSMImp<Status>

java.lang.Object
  com.atomikos.finitestates.FSMImp<Status>

All Implemented Interfaces:

FSM<Status>, FSMEnterEventSource<Status>, FSMPreEnterEventSource<Status>, FSMPreTransitionEventSource<Status>, FSMTransitionEventSource<Status>, Stateful<Status>, StateMutable<Status>

public class FSMImp<Status>
extends Object
implements FSM<Status>

Implementation of a finite state machine. The following consistency is provided:

• getState returns a snapshot (state may change continuously)
• FSMPreEnterListeners have the guarantee that getState() returns the same value each time during the preEnter notification.
• FSMEnterListeners have no guarantee that the getState() method will return the state that was entered - this state may have changed since.

Constructor Summary

FSMImp(Object eventsource, TransitionTable<Status> transitiontable, Status initialstate)
Creates a new instance with a given event source.

FSMImp(TransitionTable<Status> transitiontable, Status initialstate)
Constructor.

Method Summary

protected void	addEnterListener(Hashtable<Status,Hashtable<EventListener,Object>> listeners, EventListener lstnr, Status state) Help function for adding enter listeners.
void	addFSMEnterListener(FSMEnterListener<Status> lstnr, Status state) Add an enter event listener.
void	addFSMPreEnterListener(FSMPreEnterListener<Status> lstnr, Status state)
void	addFSMPreTransitionListener(FSMPreTransitionListener<Status> lstnr, Status from, Status to)
void	addFSMTransitionListener(FSMTransitionListener<Status> lstnr, Status from, Status to)
protected void	addTransitionListener(Hashtable listeners, Object lstnr, Status from, Status to) Help function for adding transition listeners.
Status	getState()
protected void	notifyListeners(Hashtable<Status,Hashtable<EventListener,Object>> listeners, Status state, boolean pre) Notify the enter listeners.
protected void	notifyListeners(Hashtable<Status,Hashtable<EventListener,Object>> listeners, Status from, Status to, boolean pre) Notify transition listeners.
void	setState(Status state) To set a new state.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FSMImp

public FSMImp(TransitionTable<Status> transitiontable,
              Status initialstate)

Constructor.

Parameters:

transitiontable - The transitiontable with valid transitions.

initialstate - The initial state of the FSM.

FSMImp

public FSMImp(Object eventsource,
              TransitionTable<Status> transitiontable,
              Status initialstate)

Creates a new instance with a given event source. Useful for cases where finite state machine behaviour is modelled by delegation to an instance of this class.

Parameters:

eventsource - The object to be used as source of events.

transitiontable - The transitiontable for state changes.

initialstate - The initial state of the FSM.

Method Detail

addEnterListener

protected void addEnterListener(Hashtable<Status,Hashtable<EventListener,Object>> listeners,
                                EventListener lstnr,
                                Status state)

Help function for adding enter listeners.

Parameters:

listeners - One of the listener tables.

lstnr - The listener to add.

state - The state for which the listener wants to be notified.

addTransitionListener

protected void addTransitionListener(Hashtable listeners,
                                     Object lstnr,
                                     Status from,
                                     Status to)

Help function for adding transition listeners.

Parameters:

listeners - One of the transition listener tables.

lstnr - The listener to add.

from - The start state of the transition.

to - The end state of the transition.

notifyListeners

protected void notifyListeners(Hashtable<Status,Hashtable<EventListener,Object>> listeners,
                               Status state,
                               boolean pre)

Notify the enter listeners.

Parameters:

listeners - One of the enter listener tables.

state - The state about to enter (or entered).

pre - True iff before entering.

notifyListeners

protected void notifyListeners(Hashtable<Status,Hashtable<EventListener,Object>> listeners,
                               Status from,
                               Status to,
                               boolean pre)

Notify transition listeners.

Parameters:

listeners - One of the transition listener tables.

from - The initial state.

to - The end state.

pre - True iff before transition.

getState

public Status getState()

Specified by:

getState in interface Stateful<Status>

Returns:

The object representing the state.

See Also:

FSM

setState

public void setState(Status state)
              throws IllegalStateException

Description copied from interface: StateMutable

To set a new state.

Specified by:

setState in interface StateMutable<Status>

Parameters:

state - The new state.

Throws:

IllegalStateException - if the new state transition to the new state is not allowed.

See Also:

StateMutable

addFSMEnterListener

public void addFSMEnterListener(FSMEnterListener<Status> lstnr,
                                Status state)

Description copied from interface: FSMEnterEventSource

Add an enter event listener.

Specified by:

addFSMEnterListener in interface FSMEnterEventSource<Status>

Parameters:

lstnr - The listener.

state - The state to listen on.

See Also:

FSMEnterEventSource

addFSMPreEnterListener

public void addFSMPreEnterListener(FSMPreEnterListener<Status> lstnr,
                                   Status state)

Specified by:

addFSMPreEnterListener in interface FSMPreEnterEventSource<Status>

See Also:

FSMPreEnterEventSource

addFSMTransitionListener

public void addFSMTransitionListener(FSMTransitionListener<Status> lstnr,
                                     Status from,
                                     Status to)

Specified by:

addFSMTransitionListener in interface FSMTransitionEventSource<Status>

See Also:

FSMTransitionEventSource

addFSMPreTransitionListener

public void addFSMPreTransitionListener(FSMPreTransitionListener<Status> lstnr,
                                        Status from,
                                        Status to)

Specified by:

addFSMPreTransitionListener in interface FSMPreTransitionEventSource<Status>

See Also:

FSMPreTransitionEventSource