com.atomikos.finitestates

Class FSMImp

java.lang.Object

com.atomikos.finitestates.FSMImp

All Implemented Interfaces:

FSM, FSMEnterEventSource, FSMTransitionEventSource, Stateful, StateMutable

public class FSMImp
extends Object
implements FSM

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

Constructors

Constructor and Description
FSMImp(Object eventsource, TxState initialstate) Creates a new instance with a given event source.
FSMImp(TxState initialstate) Constructor.

Method Summary

Modifier and Type	Method and Description
void	addFSMEnterListener(FSMEnterListener lstnr, TxState state) Add an enter event listener.
void	addFSMTransitionListener(FSMTransitionListener listener, TxState from, TxState to)
TxState	getState()
protected void	notifyListeners(Transition transition, boolean pre) Notify transition listeners.
protected void	notifyListeners(TxState state, boolean pre) Notify the enter listeners.
void	setState(TxState state)

Methods inherited from class java.lang.Object

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

Constructor Detail

FSMImp

public FSMImp(TxState initialstate)

Constructor.

Parameters:

transitiontable - The transitiontable with valid transitions.

initialstate - The initial state of the FSM.

FSMImp

public FSMImp(Object eventsource,
              TxState 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

notifyListeners

protected void notifyListeners(TxState state,
                               boolean pre)

Notify the enter listeners.

Parameters:

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

pre - True iff before entering.

notifyListeners

protected void notifyListeners(Transition transition,
                               boolean pre)

Notify transition listeners.

Parameters:

transition -

pre - True iff before transition.

getState

public TxState getState()

Specified by:

getState in interface Stateful

Returns:

The object representing the state.

See Also:

FSM

setState

public void setState(TxState state)
              throws IllegalStateException

Specified by:

setState in interface StateMutable

Throws:

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

See Also:

StateMutable

addFSMEnterListener

public void addFSMEnterListener(FSMEnterListener lstnr,
                                TxState state)

Description copied from interface: FSMEnterEventSource

Add an enter event listener.

Specified by:

addFSMEnterListener in interface FSMEnterEventSource

Parameters:

lstnr - The listener.

state - The state to listen on.

See Also:

FSMEnterEventSource

addFSMTransitionListener

public void addFSMTransitionListener(FSMTransitionListener listener,
                                     TxState from,
                                     TxState to)

Specified by:

addFSMTransitionListener in interface FSMTransitionEventSource

See Also:

FSMTransitionEventSource