Package com.tangosol.util.fsm

Interface FiniteStateMachine<S extends Enum<S>>

Type Parameters:

S - the type of state of the FiniteStateMachine

All Known Implementing Classes:

NonBlockingFiniteStateMachine

public interface FiniteStateMachine<S extends Enum<S>>

A FiniteStateMachine implements a general purpose finite-state-machine.

Since:

Coherence 12.2.1

Author:

Brian Oliver

See Also:

• Model
• Transition
• TransitionAction
• StateEntryAction

Method Summary

Modifier and Type	Method	Description
void	addListener(FiniteStateMachineListener<S> listener)	Add a FiniteStateMachineListener to the FiniteStateMachine.
String	getName()	Obtains the name of the FiniteStateMachine.
S	getState()	Obtains the current state of the FiniteStateMachine.
long	getTransitionCount()	Obtains the number of transitions that have occurred in the FiniteStateMachine.
void	process(Event<S> event)	Request the FiniteStateMachine to process the specified Event.
void	removeListener(FiniteStateMachineListener<S> listener)	Remove a FiniteStateMachineListener from the FiniteStateMachine.
boolean	start()	Start the FiniteStateMachine and enter the initial state.
boolean	stop()	Stops the FiniteStateMachine as soon as possible.

Method Details

getName

String getName()

Obtains the name of the FiniteStateMachine. This is primarily used for display/logging/monitoring purposes.

Returns:

the name of the FiniteStateMachine

process

void process(Event<S> event)

Request the FiniteStateMachine to process the specified Event.

Note: There's no guarantee that the Event will be processed because:

1. the Transition to be performed for the Event is invalid as the FiniteStateMachine is not in the required starting state.
2. the FiniteStateMachine may have been stopped.

Parameters:

event - the Event for the FiniteStateMachine to process

getState

S getState()

Obtains the current state of the FiniteStateMachine.

Note: After returning the current state there's no guarantee that the state will be the same because a Transition may be executing asynchronously in the background on another thread.

Returns:

the current state of the FiniteStateMachine

getTransitionCount

long getTransitionCount()

Obtains the number of transitions that have occurred in the FiniteStateMachine.

Note: After returning the count there's no guarantee that the count will be the same on the next request because a Transition may be executing asynchronously in the background on another thread.

Returns:

the number of transitions that have occurred in the FiniteStateMachine

start

boolean start()

Start the FiniteStateMachine and enter the initial state.

Note: Once stopped a FiniteStateMachine can't be restarted; instead a new FiniteStateMachine should be created.

Returns:

true if the start was successful or the FiniteStateMachine is already stated, false if it has been stopped

Throws:

IllegalStateException - if the FiniteStateMachine was already stopped

stop

boolean stop()

Stops the FiniteStateMachine as soon as possible.

Note: Once stopped a FiniteStateMachine can't be restarted; instead a new FiniteStateMachine should be created.

Returns:

true if the stop was successful, false if it's already stopped

Throws:

IllegalStateException - if the FiniteStateMachine was never started

addListener

void addListener(FiniteStateMachineListener<S> listener)

Add a FiniteStateMachineListener to the FiniteStateMachine.

Note that unique instances of FiniteStateMachineListener are identified via their equals and hashCode implementations.

Parameters:

listener - the listener to be added

removeListener

void removeListener(FiniteStateMachineListener<S> listener)

Remove a FiniteStateMachineListener from the FiniteStateMachine.

Note that unique instances of FiniteStateMachineListener are identified via their equals and hashCode implementations.

Parameters:

listener - the listener to be removed