se.fearless.fettle

Interface StateMachine<S,E,C>

Type Parameters:

S - the type of the states

E - the type of the events that can trigger state changes

C - the context events are fired in

All Known Implementing Classes:

TemplateBasedStateMachine

public interface StateMachine<S,E,C>

A view of a state machine from a users perspective, i.e it is immutable and already set up.

Method Summary

Modifier and Type	Method and Description
boolean	fireEvent(E event) Fires an event at the state machine, possibly triggering a state change
boolean	fireEvent(E event, C context) Fires an event at the state machine, possibly triggering a state change
boolean	forceSetState(S forcedState) Forces the state machine to enter the forcedState even if there are no transitions leading to it No transition actions are run but exit actions on the current state and entry actions on the new state are run
S	getCurrentState() Gets the current state of the machine
java.util.Map<E,java.util.Collection<? extends Transition<S,C>>>	getPossibleTransitions(S fromState) Returns all possible transitions from a given state grouped by the event that triggers the transition.
void	rawSetState(S rawState) Sets the state of the state machine to the rawState even if there are no transitions leading to it No transition, entry or exit actions are run

Method Detail

getCurrentState

S getCurrentState()

Gets the current state of the machine

Returns:

the state the machine is currently in

fireEvent

boolean fireEvent(E event)

Fires an event at the state machine, possibly triggering a state change

Parameters:

event - the event that is fired

Returns:

true if the event resulted in a state change, false otherwise

fireEvent

boolean fireEvent(E event,
                  C context)

Fires an event at the state machine, possibly triggering a state change

Parameters:

event - the event that is fired

context - the context to be sent to any actions that are run on a state change. Used to supply parameters to actions and conditions

Returns:

true if the event resulted in a state change, false otherwise

rawSetState

void rawSetState(S rawState)

Sets the state of the state machine to the rawState even if there are no transitions leading to it No transition, entry or exit actions are run

Parameters:

rawState - the state the machine will be in after this method is called

forceSetState

boolean forceSetState(S forcedState)

Forces the state machine to enter the forcedState even if there are no transitions leading to it No transition actions are run but exit actions on the current state and entry actions on the new state are run

Parameters:

forcedState - the state the machine will be in after this method is called

Returns:

true if the state machine changed state

getPossibleTransitions

java.util.Map<E,java.util.Collection<? extends Transition<S,C>>> getPossibleTransitions(S fromState)

Returns all possible transitions from a given state grouped by the event that triggers the transition.

Parameters:

fromState - the state to retrieve the outgoing transitions from.

Returns:

a map from all registered events in the fromState to the transitions they would trigger if fired.