org.firstinspires.ftc.robotcore.external

Class StateMachine

java.lang.Object

org.firstinspires.ftc.robotcore.external.StateMachine

public class StateMachine
extends java.lang.Object

Infrastructure for a very simple generic state machine. Part of a collection of classes including State, Event, and StateTransition. All this class does is manage a directed graph and execute transitions on events. Create instances of a state machine by deriving from this class and defining states, events, and transitions. See usages of StateMachine for reference implementations.

Field Summary

Fields

Modifier and Type	Field and Description
protected State	currentState
protected java.util.ArrayList<Event>	maskList
protected java.util.HashMap<State,java.util.ArrayList<StateTransition>>	stateGraph

Constructor Summary

Constructors

Constructor and Description
StateMachine()

Method Summary

Modifier and Type	Method and Description
void	addTransition(StateTransition transition) addTransition Adds a transition to the state machine.
State	consumeEvent(Event event) consumeEvent Executes a state transition and returns the new state.
void	maskEvent(Event event)
protected void	start(State state) start Define the start state of the state machine.
java.lang.String	toString()
protected State	transition(Event event)
void	unMaskEvent(Event event)

Methods inherited from class java.lang.Object

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

Field Detail

currentState

protected State currentState

stateGraph

protected java.util.HashMap<State,java.util.ArrayList<StateTransition>> stateGraph

maskList

protected java.util.ArrayList<Event> maskList

Constructor Detail

StateMachine

public StateMachine()

Method Detail

start

protected void start(State state)

start Define the start state of the state machine. Should be called from the start method of the feature's state machine.

Parameters:

state - The initial state.

addTransition

public void addTransition(StateTransition transition)

addTransition Adds a transition to the state machine.

Parameters:

transition - the transition to add.

consumeEvent

public State consumeEvent(Event event)

consumeEvent Executes a state transition and returns the new state. *

Parameters:

event - The event to consume

Returns:

The new state, or the current state if the current state does not have a matching event edge.

maskEvent

public void maskEvent(Event event)

unMaskEvent

public void unMaskEvent(Event event)

transition

protected State transition(Event event)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object