com.github.pnavais.machine

Class StateMachine

java.lang.Object

com.github.pnavais.machine.StateMachine

All Implemented Interfaces:

Transitioner<State,Message,StateTransition>

public class StateMachine
extends Object
implements Transitioner<State,Message,StateTransition>

The State Machine contains a simple map of Transitions between different nodes (States) triggered by incoming messages.

Constructor Summary

Constructors

Constructor and Description
StateMachine() Creates the state machine.
StateMachine(@NonNull TransitionChecker<State,Message> transitionChecker) Creates the state machine with the given transition checker.
StateMachine(@NonNull TransitionIndex<State,Message,StateTransition> transitionIndex) Creates the state machine with the given transition map.
StateMachine(@NonNull TransitionIndex<State,Message,StateTransition> transitionIndex, @NonNull TransitionChecker<State,Message> transitionChecker) Creates the state machine with the given transition map and checker

Method Summary

Modifier and Type	Method and Description
void	add(StateTransition transition) Adds a new Transition to the state machine.
void	addAll(@NonNull Collection<StateTransition> transitions) Adds a collection of Transition to the state machine.
void	clear() Removes all transitions from the state machine
Optional<State>	find(String stateName) Finds the state referenced by the given name in the state machine machine.
Collection<StateTransition>	getAllTransitions() Retrieves all state transitions currently defined.
State	getCurrent() Retrieves the current state
Optional<State>	getNext(Message m) Retrieves the next state upon message reception.
Collection<State>	getSiblings(String stateName) Retrieves the adjacent states i.e.
Collection<StateTransition>	getTransitions(String stateName) Retrieves the state transitions for the given state.
TransitionIndex<State,Message,StateTransition>	getTransitionsIndex() Retrieves the transition map
void	init() Initializes the current state to the first one added to the state machine (if any).
static StateMachineBuilder	newBuilder() Retrieves a new StateMachineBuilder instance to ease the State Machine creation process.
StateMachine	next() Sends a void message to the state machine triggering a potential transition.
List<State>	prune() Remove orphan states
void	remove(State state) Removes an existing state from the state machine.
void	remove(StateTransition transition) Removes an existing Transition from the state machine.
void	remove(String stateName) Removes an existing state from the state machine.
void	removeAllTransitions() Removes all existing Transitions from the state machine.
StateMachine	send(Message message) Sends a message to the state machine triggering a potential transition.
StateMachine	send(String message) Sends a message to the state machine triggering a potential transition.
void	setCurrent(@NonNull State state) Sets the current state if present
void	setCurrent(@NonNull String stateName) Sets the current state to the given one.
int	size() Retrieves the number of states currently present in the state machine.

Methods inherited from class java.lang.Object

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

Constructor Detail

StateMachine

public StateMachine()

Creates the state machine.

StateMachine

public StateMachine(@NonNull
                    @NonNull TransitionIndex<State,Message,StateTransition> transitionIndex)

Creates the state machine with the given transition map.

Parameters:

transitionIndex - the transition map

StateMachine

public StateMachine(@NonNull
                    @NonNull TransitionChecker<State,Message> transitionChecker)

Creates the state machine with the given transition checker.

Parameters:

transitionChecker - the transition checker

StateMachine

public StateMachine(@NonNull
                    @NonNull TransitionIndex<State,Message,StateTransition> transitionIndex,
                    @NonNull
                    @NonNull TransitionChecker<State,Message> transitionChecker)

Creates the state machine with the given transition map and checker

Parameters:

transitionIndex - the transition map

transitionChecker - the transition checker

Method Detail

newBuilder

public static StateMachineBuilder newBuilder()

Retrieves a new StateMachineBuilder instance to ease the State Machine creation process.

Returns:

a new StateMachineBuilder instance

add

public void add(StateTransition transition)

Adds a new Transition to the state machine. If already present, it is replaced silently.

Specified by:

add in interface Transitioner<State,Message,StateTransition>

Parameters:

transition - the transition to add

addAll

public void addAll(@NonNull
                   @NonNull Collection<StateTransition> transitions)

Adds a collection of Transition to the state machine. If already present, they are replaced silently.

Specified by:

addAll in interface Transitioner<State,Message,StateTransition>

Parameters:

transitions - the transition to add

remove

public void remove(StateTransition transition)

Removes an existing Transition from the state machine. In case the state does not exists is it ignored silently.

Specified by:

remove in interface Transitioner<State,Message,StateTransition>

Parameters:

transition - the transition to remove

remove

public void remove(String stateName)

Removes an existing state from the state machine. All Transitions having state as origin or target will be removed. In case the state does not exists a NullStateException is thrown.

Specified by:

remove in interface Transitioner<State,Message,StateTransition>

Parameters:

stateName - the state to remove

remove

public void remove(State state)

Removes an existing state from the state machine. All Transitions having state as origin or target will be removed. In case the state does not exists a NullStateException is thrown.

Specified by:

remove in interface Transitioner<State,Message,StateTransition>

Parameters:

state - the state to remove

removeAllTransitions

public void removeAllTransitions()

Removes all existing Transitions from the state machine.

Specified by:

removeAllTransitions in interface Transitioner<State,Message,StateTransition>

clear

public void clear()

Removes all transitions from the state machine

Specified by:

clear in interface Transitioner<State,Message,StateTransition>

find

public Optional<State> find(String stateName)

Finds the state referenced by the given name in the state machine machine.

Specified by:

find in interface Transitioner<State,Message,StateTransition>

Parameters:

stateName - the name of the node

Returns:

the node with the given name

init

public void init()

Initializes the current state to the first one added to the state machine (if any).

Specified by:

init in interface Transitioner<State,Message,StateTransition>

setCurrent

public void setCurrent(@NonNull
                       @NonNull String stateName)

Sets the current state to the given one. Throws a NullStateException in case the state is not found.

Specified by:

setCurrent in interface Transitioner<State,Message,StateTransition>

Parameters:

stateName - the node's name

setCurrent

public void setCurrent(@NonNull
                       @NonNull State state)

Sets the current state if present

Parameters:

state - the state to set

getCurrent

public State getCurrent()

Retrieves the current state

Specified by:

getCurrent in interface Transitioner<State,Message,StateTransition>

Returns:

the current node

getNext

public Optional<State> getNext(Message m)

Retrieves the next state upon message reception. In case the current state is not defined or no next state is defined , an empty state is returned.

Specified by:

getNext in interface Transitioner<State,Message,StateTransition>

Parameters:

m - the message

Returns:

the next state or empty if not found

next

public StateMachine next()

Sends a void message to the state machine triggering a potential transition.

Specified by:

next in interface Transitioner<State,Message,StateTransition>

Returns:

the Transitioner instance for chaining purposes

send

public StateMachine send(String message)

Sends a message to the state machine triggering a potential transition.

Parameters:

message - a string message

Returns:

the state machine for chaining purposes

send

public StateMachine send(Message message)

Sends a message to the state machine triggering a potential transition.

Specified by:

send in interface Transitioner<State,Message,StateTransition>

Parameters:

message - the message

Returns:

the state machine for chaining purposes

size

public int size()

Retrieves the number of states currently present in the state machine.

Specified by:

size in interface Transitioner<State,Message,StateTransition>

Returns:

the number of states of the state machine

getTransitions

public Collection<StateTransition> getTransitions(String stateName)

Retrieves the state transitions for the given state.

Specified by:

getTransitions in interface Transitioner<State,Message,StateTransition>

Parameters:

stateName - the state name

Returns:

the transitions from the given state

getSiblings

public Collection<State> getSiblings(String stateName)

Retrieves the adjacent states i.e. the states that can be reached from the given state by any transition.

Specified by:

getSiblings in interface Transitioner<State,Message,StateTransition>

Parameters:

stateName - the state's name

Returns:

the adjacent states

getAllTransitions

public Collection<StateTransition> getAllTransitions()

Retrieves all state transitions currently defined.

Specified by:

getAllTransitions in interface Transitioner<State,Message,StateTransition>

Returns:

all defined transitions

getTransitionsIndex

public TransitionIndex<State,Message,StateTransition> getTransitionsIndex()

Retrieves the transition map

Specified by:

getTransitionsIndex in interface Transitioner<State,Message,StateTransition>

Returns:

the transition map

prune

public List<State> prune()

Remove orphan states

Specified by:

prune in interface Transitioner<State,Message,StateTransition>

Returns:

the list of removed nodes