RTT::StateMachine Class Reference

A hierarchical StateMachine which is loaded in the Program Processor. More...

#include <rtt/StateMachine.hpp>

Inheritance diagram for RTT::StateMachine:

Classes
struct	Status
	Enumerates all possible state machine statuses. More...
Public Types
typedef std::vector < StateMachinePtr >	ChildList
Public Member Functions
virtual	~StateMachine ()
	The destructor is virtual since ParsedStateMachine still inherits this class.
	StateMachine (StateMachinePtr parent, const std::string &name="Default")
	Create a new StateMachine with an optional parent.
	StateMachine (StateMachinePtr parent, EventProcessor *ep, const std::string &name="Default")
	Create a new StateMachine in a TaskContext with an optional parent.
void	setStateMachineProcessor (StateMachineProcessor *smproc)
void	setEventProcessor (EventProcessor *smproc)
bool	requestState (const std::string &statename)
	Request a transition to a given state.
bool	inState (const std::string &state) const
	Check if the state machine is in a given state.
bool	inStrictState (const std::string &state) const
	Check if the state machine is in a given state and not in the entry or exit program.
const std::string &	getCurrentStateName () const
	Return name of current state, empty string if not active.
bool	isStrictlyActive () const
	Strictly active, means active and not in a transition.
bool	inInitialState () const
	Inspect if we are in the initial state.
bool	inFinalState () const
	Inspect if we are in the final state.
bool	stepDone () const
	When isPaused(), return true if no step is pending, when isReactive(), return isStrictlyActive().
bool	isActive () const
	Returns true if the state machine is activated.
bool	isStopped () const
	Returns true if the state machine is in the final state, after a stop() directive.
bool	inError () const
	Get the error status of this StateMachine.
bool	isReactive () const
	Query if the state machine is currently reacting only to events.
bool	isAutomatic () const
	Query if the state machine is reacting to events and evaluating transition conditions.
bool	isPaused () const
	Query if the state machine is paused.
bool	activate ()
	Start this StateMachine.
bool	pause ()
	Pause the state machine.
bool	step ()
	Execute a single action if the state machine is paused or evaluate the transition conditions if the state machine is reactive.
bool	automatic ()
	Enter automatic mode: evaluating the transition conditions continuously.
bool	start ()
	Enter automatic mode: evaluating the transition conditions continuously.
bool	stop ()
	Bring the state machine to the safe final state and wait for events or requests.
bool	reset ()
	Reset the state machine from the final state to the initial state and wait for events or requests.
bool	reactive ()
	Switch to reactive mode from automatic mode.
bool	deactivate ()
	Stop this StateMachine.
bool	execute ()
	Used by the StateMachineProcessor to execute the next action(s) or state transitions.
StateInterface *	requestNextState (bool stepping=false)
	Search from the current state a candidate next state.
StateInterface *	requestNextStateStep ()
	Go stepwise through evaluations to find out next state.
bool	requestFinalState ()
	Request going to the Final State.
bool	requestInitialState ()
	Request going to the Initial State.
StateInterface *	nextState ()
	Search from the current state a candidate next state.
std::vector< std::string >	getStateList () const
	Get a list of the names of all the present states.
StateInterface *	getState (const std::string &name) const
	Lookup a State by name.
Status::StateMachineStatus	getStatus () const
	Get the status of this state machine.
void	addState (StateInterface *s)
	Add a State.
bool	requestStateChange (StateInterface *s_n)
	Request a state transition to a new state.
bool	executePending (bool stepping=false)
	Execute any pending State (exit, entry, handle) programs.
void	preconditionSet (StateInterface state, ConditionInterface cnd, int line)
	Express a precondition for entering a state.
void	transitionSet (StateInterface from, StateInterface to, ConditionInterface *cnd, int priority, int line)
	Express a possible transition from one state to another under a certain condition.
void	transitionSet (StateInterface from, StateInterface to, ConditionInterface *cnd, boost::shared_ptr< ProgramInterface > transprog, int priority, int line)
	Express a possible transition from one state to another under a certain condition.
bool	createEventTransition (EventService es, const std::string &ename, std::vector< DataSourceBase::shared_ptr > args, StateInterface from, StateInterface to, ConditionInterface guard, boost::shared_ptr< ProgramInterface > transprog, StateInterface *elseto=0, boost::shared_ptr< ProgramInterface > elseprog=boost::shared_ptr< ProgramInterface >())
	Express a possible transition from one state to another when an Event is fired under a certain condition (guard).
void	setInitialState (StateInterface *s)
	Set the initial state of this StateMachine.
void	setFinalState (StateInterface *s)
	Set the final state of this StateMachine.
StateInterface *	currentState () const
	Retrieve the current state of the state machine.
ProgramInterface *	currentProgram () const
	Retrieve the current program in execution.
StateInterface *	getInitialState () const
	Retrieve the initial state of the state machine.
StateInterface *	getFinalState () const
	Retrieve the final state of the state machine.
void	setInitCommand (CommandInterface *c)
	This was added for extra (non-user visible) initialisation when the StateMachine is activated.
CommandInterface *	getInitCommand () const
StateMachinePtr	getParent () const
	Get the parent, returns zero if no parent.
void	setParent (StateMachinePtr parent)
const ChildList &	getChildren () const
	Get a list of all child state machines.
void	addChild (StateMachinePtr child)
const std::string &	getName () const
	This method must be overloaded to get a useful hierarchy.
int	getLineNumber () const
	Returns the current program line in execution,.
virtual std::string	getText () const
	Return the text to which getLineNumber() refers.
bool	inTransition () const
	Inspect if the StateMachine is performing a state transition.
bool	interruptible () const
	Inspect if the StateMachine is interruptible by events.
Protected Types
typedef std::vector < boost::tuple < ConditionInterface , StateInterface , int, int, boost::shared_ptr < ProgramInterface > > >	TransList
	The key is the current state, the value is the transition condition to another state with a certain priority (int), on a line (int), with a transition program.
typedef std::map < StateInterface *, TransList >	TransitionMap
typedef std::multimap < StateInterface , std::pair < ConditionInterface , int > >	PreConditionMap
typedef std::vector < boost::tuple< EventService , std::string, std::vector < DataSourceBase::shared_ptr > , StateInterface , ConditionInterface , boost::shared_ptr < ProgramInterface >, Handle, StateInterface , boost::shared_ptr < ProgramInterface > > >	EventList
typedef std::map < StateInterface *, EventList >	EventMap
typedef boost::weak_ptr < StateMachine >	StateMachineParentPtr
Protected Member Functions
virtual void	handleUnload ()
void	changeState (StateInterface s, ProgramInterface tprog, bool stepping=false)
void	leaveState (StateInterface *s)
void	enterState (StateInterface *s)
void	runState (StateInterface *s)
void	handleState (StateInterface *s)
bool	executeProgram (ProgramInterface *&cp, bool stepping)
int	checkConditions (StateInterface *state, bool stepping=false)
void	enableEvents (StateInterface *s)
void	disableEvents (StateInterface *s)
Protected Attributes
std::vector< StateMachinePtr >	_children
StateMachineParentPtr	_parent
std::string	_name
EventProcessor *	eproc
Status::StateMachineStatus	smStatus
StateMachineProcessor *	smp
TransitionMap	stateMap
	A map keeping track of all States and conditional transitions between two states.
PreConditionMap	precondMap
	A map keeping track of all preconditions of a state.
EventMap	eventMap
	A map keeping track of all events of a state.

Detailed Description

A hierarchical StateMachine which is loaded in the Program Processor.

A StateMachine can have children and one parent.

Todo:: Implement the whole transition mechanism with the Strategy software pattern to allow cleaner implementation.

Definition at line 78 of file StateMachine.hpp.

Constructor & Destructor Documentation

RTT::StateMachine::StateMachine	(	StateMachinePtr	parent,
		const std::string &	name = `"Default"`
	)

Create a new StateMachine with an optional parent.

Set parent to zero for the top state machine. The initial Status of a StateMachine is always inactive.

RTT::StateMachine::StateMachine	(	StateMachinePtr	parent,
		EventProcessor *	ep,
		const std::string &	name = `"Default"`
	)

Create a new StateMachine in a TaskContext with an optional parent.

Set parent to zero for the top state machine. The initial Status of a StateMachine is always inactive.

Parameters:

ep

The EventProcessor of this StateMachine when transition events are used.

Member Function Documentation

bool RTT::StateMachine::activate ( )

Start this StateMachine.

The Initial state will be entered.

void RTT::StateMachine::addState ( StateInterface * s )

Add a State.

If already present, changes nothing.

bool RTT::StateMachine::createEventTransition	(	EventService *	es,
		const std::string &	ename,
		std::vector< DataSourceBase::shared_ptr >	args,
		StateInterface *	from,
		StateInterface *	to,
		ConditionInterface *	guard,
		boost::shared_ptr< ProgramInterface >	transprog,
		StateInterface *	elseto = `0`,
		boost::shared_ptr< ProgramInterface >	elseprog = `boost::shared_ptr< ProgramInterface >()`
	)

Express a possible transition from one state to another when an Event is fired under a certain condition (guard).

Parameters:

	ename	The name of the Event under which a transition should be made
	args	The arguments which the event handler must set upon occurence.
	from	The state which should be left
	to	The state which should be entered
	guard	The Condition under which the transition may succeed
	transprog	The program to be executed between exit of from and entry of to.
	es	The EventService in which ename can be found.

ProgramInterface* RTT::StateMachine::currentProgram ( ) const

Retrieve the current program in execution.

Returns null if the StateMachine is not active or no programs are being run.

StateInterface* RTT::StateMachine::currentState ( ) const

Retrieve the current state of the state machine.

Returns null if the StateMachine is not active.

bool RTT::StateMachine::deactivate ( )

Stop this StateMachine.

The current state is left unconditionally.

bool RTT::StateMachine::executePending ( bool stepping = false )

Execute any pending State (exit, entry, handle) programs.

You must executePending, before calling requestState() or requestNextState(). You should only call requestState() or requestNextState() if executePending returns true.

Due to the pending requests, the currentState() may have changed.

Parameters:

stepping

provide true if the pending programs should be executed one step at a time.

Return values:

	true	if nothing was pending
	false	if there was some program executing.

int RTT::StateMachine::getLineNumber ( ) const

Returns the current program line in execution,.

Returns:: 1 if not active

StateInterface* RTT::StateMachine::getState ( const std::string & name ) const

Lookup a State by name.

Returns null if not found.

bool RTT::StateMachine::interruptible ( ) const

Inspect if the StateMachine is interruptible by events.

Only the run program may be interrupted, or if no program is currently executed.

bool RTT::StateMachine::inTransition ( ) const

Inspect if the StateMachine is performing a state transition.

A transition is in progress if entry, transition or exit programs are executed.

Returns:: true if it is executing a program (except run or handle program), false if it is not executing a program OR executing the run/handle program.

StateInterface* RTT::StateMachine::nextState ( )

Search from the current state a candidate next state.

If none is found, the current state is returned.

Note:: The mere calling of this method, may influence future possible results. Multiple invocations of nextState() may return different results, so use with care.

See also:: requestNextState()

void RTT::StateMachine::preconditionSet	(	StateInterface *	state,
		ConditionInterface *	cnd,
		int	line
	)

Express a precondition for entering a state.

The precondition will be chained (Logical AND) with any transition to this state. This means that any transition to this state will only succeed if all preconditions hold. If state is the initial state, the preconditions must be true to make actiate() succeed. If state is the final state, they will not be checked upon requestFinalState, since requestFinalState always succeeds.

Parameters:

	state	The state for which the preconditions must hold
	cnd	The Pre-Condition under which a transition to this state may succeed
	line	The line number where this precondition was introduced.

bool RTT::StateMachine::requestFinalState ( )

Request going to the Final State.

This will always proceed.

bool RTT::StateMachine::requestInitialState ( )

Request going to the Initial State.

This function will only proceed if the current state is the Final State or the Initial State. If it fails, one can try to requestNextState() which may lead to the initial state anyway if the transition is set. This path is not tried by this function.

Returns:: The true on success, false if not allowed.

StateInterface* RTT::StateMachine::requestNextState ( bool stepping = false )

Search from the current state a candidate next state.

If none is found, the current state is taken. Next, handle the resulting state.

Note:: This call is not equivalent to this->requestState( this->nextState() ), since multiple invocations of this->nextState() may result in different results, hence, this->requestState( this->nextState() ) may return false. Use this method instead to automatically go to the next state.

Parameters:

stepping

provide true if the transition evaluations should be executed one at a time.

Returns:: The current state.

StateInterface* RTT::StateMachine::requestNextStateStep ( )

Go stepwise through evaluations to find out next state.

See also:: requestNextState()

bool RTT::StateMachine::requestStateChange ( StateInterface * s_n )

Request a state transition to a new state.

If the transition is not set by transitionSet(), acquiering the state will fail.

Parameters:

s_n

The state to change to

Return values:

	true	if the transition is successfull
	false	if the transition is not allowed

void RTT::StateMachine::setInitCommand ( CommandInterface * c ) [inline]

This was added for extra (non-user visible) initialisation when the StateMachine is activated.

Parameters:

c

The command to execute upon each activate. c is aggregated by this state machine and deleted in the destructor.

Definition at line 549 of file StateMachine.hpp.

void RTT::StateMachine::transitionSet	(	StateInterface *	from,
		StateInterface *	to,
		ConditionInterface *	cnd,
		boost::shared_ptr< ProgramInterface >	transprog,
		int	priority,
		int	line
	)

Express a possible transition from one state to another under a certain condition.

Parameters:

	from	The state which should be left
	to	The state which should be entered
	cnd	The Condition under which the transition may succeed
	transprog	The program to be executed between exit of from and entry of to. May be null to indicate the empty program.
	priority	The priority of this transition; low number (like -1000) is low priority high number is high priority (like + 1000). Transitions of equal priority are traversed in an unspecified way.
	line	The line number where this transition was introduced.

Postcondition:: All transitions from from to to will succeed under condition cnd

void RTT::StateMachine::transitionSet	(	StateInterface *	from,
		StateInterface *	to,
		ConditionInterface *	cnd,
		int	priority,
		int	line
	)

Express a possible transition from one state to another under a certain condition.

Parameters:

	from	The state which should be left
	to	The state which should be entered
	cnd	The Condition under which the transition may succeed
	priority	The priority of this transition; low number (like -1000) is low priority high number is high priority (like + 1000). Transitions of equal priority are traversed in an unspecified way.
	line	The line number where this transition was introduced.

Postcondition:: All transitions from from to to will succeed under condition cnd

Member Data Documentation

EventMap RTT::StateMachine::eventMap [protected]

A map keeping track of all events of a state.

Not all states need to be present as a key in this map.

Definition at line 636 of file StateMachine.hpp.

PreConditionMap RTT::StateMachine::precondMap [protected]

A map keeping track of all preconditions of a state.

Not all states need to be present as a key in this map.

Definition at line 630 of file StateMachine.hpp.

TransitionMap RTT::StateMachine::stateMap [protected]

A map keeping track of all States and conditional transitions between two states.

Every state of this StateMachine must be] present as a key in this map.

Definition at line 624 of file StateMachine.hpp.

The documentation for this class was generated from the following file:

rtt/StateMachine.hpp

RTT::StateMachine Class Reference

Classes

Public Types

Public Member Functions

Protected Types

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation