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The Boost Statechart LibraryReference |
state_machineasynchronous_state_machineevent_processorfifo_schedulerexception_translatornull_exception_translatorhistory_modesimple_statestateshallow_historydeep_historyevent_baseeventtransitionterminationdeferralcustom_reactionresultA Scheduler type defines the following:
event_processor<>
subtypes and how the lifetime of such objects is managedevent_processor<> subtype
objects can share the same queue and scheduler threadevent_processor<> subtype objects and what happens
when such an event is processedevent_processor<> subtype objects propagates an
exceptionFor a Scheduler type S and an object cpc of
type const S::processor_context the following expressions must
be well-formed and have the indicated results:
| Expression | Type | Result |
cpc.my_scheduler() |
S & |
A reference to the scheduler |
cpc.my_handle() |
S::processor_handle |
The handle identifying the
event_processor<> subtype object |
To protect against abuse, all members of
S::processor_context should be declared private. As a result,
event_processor<> must be a friend of
S::processor_context.
A FifoWorker type defines the following:
For a FifoWorker type F, an object f of that
type, a const object cf of that type, a
parameterless function object w of arbitrary type and an
unsigned long value n the following
expressions/statements must be well-formed and have the indicated
results:
| Expression/Statement | Type | Effects/Result |
F::work_item |
boost::function0< void > |
|
F() or F( false ) |
F |
Constructs a non-blocking (see below) object of the FifoWorker type. In single-threaded builds the second expression is not well-formed |
F( true ) |
F |
Constructs a blocking (see below) object of the FifoWorker type. Not well-formed in single-threaded builds |
f.queue_work_item( w ); |
Constructs and queues an object of type
F::work_item, passing w as the only
argument |
|
f.terminate(); |
Creates and queues an object of type
F::work_item that, when later executed in
operator()(), leads to a modification of internal state so
that terminated() henceforth returns
true |
|
cf.terminated(); |
bool |
true if terminate() has been
called and the resulting work item has been executed in
operator()(). Returns false otherwiseMust only be called from the thread that also calls operator()() |
f( n ); |
unsigned long |
Enters a loop that, with each cycle, dequeues and calls
operator()() on the oldest work item in the queue.
The loop is left and the number of executed work items returned if one or more of the following conditions are met:
If the queue is empty and none of the above conditions are met
then the thread calling |
f(); |
unsigned long |
Has exactly the same semantics as f( n );
with n == 0 (see above) |
An ExceptionTranslator type defines how C++ exceptions occurring during state machine operation are translated to exception events.
For an ExceptionTranslator object et, a parameterless
function object a of arbitrary type returning result and a function object eh of
arbitrary type taking a const event_base & parameter and returning
result the following expression
must be well-formed and have the indicated results:
| Expression | Type | Effects/Result |
et( a, eh ); |
result |
|
A StateBase type is the common base of all states of a given state
machine type. state_machine<>::state_base_type is a
model of the StateBase concept.
For a StateBase type S and a const object
cs of that type the following expressions must be well-formed
and have the indicated results:
| Expression | Type | Result |
cs.outer_state_ptr() |
const S * |
0 if cs is an outermost state, a pointer to the
direct outer state of cs otherwise |
cs.dynamic_type() |
S::id_type |
A value unambiguously identifying the most-derived type
of cs. S::id_type values are comparable with
operator==() and operator!=(). An unspecified
collating order can be established with std::less< S::id_type
>. In contrast to typeid( cs ), this function is
available even on platforms that do not support C++ RTTI (or have been
configured to not support it) |
cs.custom_dynamic_type_ptr< |
const Type * |
A pointer to the custom type identifier or
0. If != 0, Type must match the
type of the previously set pointer. This function is only available if
BOOST_STATECHART_USE_NATIVE_RTTI
is not defined |
A SimpleState type defines one state of a particular state machine.
For a SimpleState type S and a pointer pS
pointing to an object of type S allocated with
new the following expressions/statements must be well-formed
and have the indicated effects/results:
| Expression/Statement | Type | Effects/Result/Notes |
simple_state< |
simple_state< S, C, I, h > must be
an unambiguous public base of S. See simple_state<>
documentation for the requirements and semantics of C,
I and h |
|
new S() |
S * |
Enters the state S. Certain functions must
not be called from S::S(), see simple_state<>
documentation for more information |
pS->exit(); |
Exits the state S (first stage). The
definition of an exit member function within models of the
SimpleState concept is optional since simple_state<>
already defines the following public member: void exit()
{}. exit() is not called when a state is exited
while an exception is pending, see simple_state<>::terminate()
for more information |
|
delete pS; |
Exits the state S (second stage) |
|
S::reactions |
An mpl::list<> that is either empty
or contains instantiations of the custom_reaction,
in_state_reaction,
deferral,
termination or
transition class
templates. If there is only a single reaction then it can also be
typedefed directly, without wrapping it into an
mpl::list<> |
The declaration of a reactions member
typedef within models of the SimpleState concept is
optional since simple_state<> already defines the
following public member: typedef mpl::list<>
reactions; |
A State is a refinement of SimpleState
(that is, except for the default constructor a State type must also satisfy
SimpleState requirements). For a State type S, a pointer
pS of type S * pointing to an object of type
S allocated with new, and an object
mc of type state< S, C, I, h
>::my_context the following expressions/statements
must be well-formed:
| Expression/Statement | Type | Effects/Result/Notes |
state< S, C, I, h > * |
state< S, C, I, h > must be an
unambiguous public base of S. See state<> documentation for the
requirements and semantics of C, I and
h |
|
new S( mc ) |
S * |
Enters the state S. No restrictions exist
regarding the functions that can be called from S::S() (in
contrast to the constructors of models of the SimpleState concept).
mc must be forwarded to state< S, C, I, h
>::state() |
A Event type defines an event for which state machines can define reactions.
For a Event type E and a pointer pCE of type
const E * pointing to an object of type E
allocated with new the following expressions/statements must
be well-formed and have the indicated effects/results:
| Expression/Statement | Type | Effects/Result/Notes |
const event<
E > * pCB = pCE; |
event< E > must be an unambiguous
public base of E |
|
new E( *pCE ) |
E * |
Makes a copy of pE |
state_machineThis is the base class template of all synchronous state machines.
state_machine parameters| Template parameter | Requirements | Semantics | Default |
MostDerived |
The most-derived subtype of this class template | ||
InitialState |
A model of the SimpleState
or State concepts. The Context
argument passed to the simple_state<> or
state<> base
of InitialState must be MostDerived.
That is, InitialState must be an outermost state of this state
machine |
The state that is entered when
state_machine<> is called |
|
Allocator |
A model of the standard Allocator concept | Allocator::rebind<>::other is used
to allocate and deallocate all simple_state subtype
objects and internal objects of dynamic storage duration |
std::allocator< void > |
ExceptionTranslator |
A model of the ExceptionTranslator concept | see ExceptionTranslator concept | null_exception_translator |
state_machine synopsis
namespace boost
{
namespace statechart
{
template<
class MostDerived,
class InitialState,
class Allocator = std::allocator< void >,
class ExceptionTranslator = null_exception_translator >
class state_machine : noncopyable
{
public:
typedef MostDerived outermost_context_type;
void initiate();
void terminate();
bool terminated() const;
void process_event( const event_base & );
template< class Target >
Target state_cast() const;
template< class Target >
Target state_downcast() const;
// a model of the StateBase concept
typedef implementation-defined state_base_type;
// a model of the standard Forward Iterator concept
typedef implementation-defined state_iterator;
state_iterator state_begin() const;
state_iterator state_end() const;
void unconsumed_event( const event_base & ) {}
protected:
state_machine();
~state_machine();
void post_event(
const intrusive_ptr< const event_base > & );
void post_event( const event_base & );
const event_base * triggering_event() const;
};
}
}
state_machine constructor and
destructorstate_machine();
Effects: Constructs a non-running state machine
~state_machine();
Effects: Destructs the currently active outermost state and all
its direct and indirect inner states. Innermost states are destructed
first. Other states are destructed as soon as all their direct and indirect
inner states have been destructed. The inner states of each state are
destructed according to the number of their orthogonal region. The state in
the orthogonal region with the highest number is always destructed first,
then the state in the region with the second-highest number and so on
Note: Does not attempt to call any exit member
functions
state_machine modifier functionsvoid initiate();
Effects:
terminate()action with a
parameter-less operator()() returning result that
InitialState template parameterInitialState depth first. The inner states of
each state are entered according to the number of their orthogonal
region. The state in orthogonal region 0 is always entered first,
then the state in region 1 and so onexceptionEventHandler with
an operator()() returning result and accepting
an exception event parameter that processes the passed exception event,
with the following differences to the processing of normal events:
exit member
functions are calledexceptionEventHandler function object (that is,
ExceptionTranslator is not used to translate
exceptions thrown while processing an exception event)result object is returned equal to the one
returned by simple_state<>::discard_event()action and exceptionEventHandler to
ExceptionTranslator::operator()(). If
ExceptionTranslator::operator()() throws an exception, the
exception is propagated to the caller. If the caller catches the
exception, the currently active outermost state and all its direct and
indirect inner states are destructed. Innermost states are destructed
first. Other states are destructed as soon as all their direct and
indirect inner states have been destructed. The inner states of each
state are destructed according to the number of their orthogonal region.
The state in the orthogonal region with the highest number is always
destructed first, then the state in the region with the second-highest
number and so on. Continues with step 5 otherwise (the return value is
discarded)process_event()).
Returns to the caller if there are no more posted eventsThrows: Any exceptions propagated from
ExceptionTranslator::operator()(). Exceptions never originate
in the library itself but only in code supplied through template
parameters:
Allocator::rebind<>::other::allocate()react member functionsexit member functionsvoid terminate();
Effects:
action with a
parameter-less operator()() returning result that terminates the currently active outermost
state, discards all remaining events and clears all history
informationexceptionEventHandler with
an operator()() returning result and accepting an exception event
parameter that processes the passed exception event, with the following
differences to the processing of normal events:
exit member
functions are calledexceptionEventHandler function object (that is,
ExceptionTranslator is not used to translate
exceptions thrown while processing an exception event)result object is returned equal to the one
returned by simple_state<>::discard_event()action and exceptionEventHandler to
ExceptionTranslator::operator()(). If
ExceptionTranslator::operator()() throws an exception, the
exception is propagated to the caller. If the caller catches the
exception, the currently active outermost state and all its direct and
indirect inner states are destructed. Innermost states are destructed
first. Other states are destructed as soon as all their direct and
indirect inner states have been destructed. The inner states of each
state are destructed according to the number of their orthogonal region.
The state in the orthogonal region with the highest number is always
destructed first, then the state in the region with the second-highest
number and so on. Otherwise, returns to the callerThrows: Any exceptions propagated from
ExceptionTranslator::operator(). Exceptions never originate in
the library itself but only in code supplied through template
parameters:
Allocator::rebind<>::other::allocate()react member functionsexit member functionsvoid process_event( const event_base & );
Effects:
currentEvent)action with a
parameter-less operator()() returning result that does the following:
currentEvent,
starting with the current innermost state and moving outward until a
state defining a reaction for the event is found. Returns
simple_state<>::forward_event() if no reaction has
been foundsimple_state<>::forward_event() then resumes the
reaction search (step a). Returns the reaction result otherwiseexceptionEventHandler
returning result and accepting an
exception event parameter that processes the passed exception event, with
the following differences to the processing of normal events:
exit member
functions are calledexceptionEventHandler function object (that is,
ExceptionTranslator is not used to translate
exceptions thrown while processing an exception event)result object is returned equal to the one
returned by simple_state<>::discard_event()action and exceptionEventHandler to
ExceptionTranslator::operator()(). If
ExceptionTranslator::operator()() throws an exception, the
exception is propagated to the caller. If the caller catches the
exception, the currently active outermost state and all its direct and
indirect inner states are destructed. Innermost states are destructed
first. Other states are destructed as soon as all their direct and
indirect inner states have been destructed. The inner states of each
state are destructed according to the number of their orthogonal region.
The state in the orthogonal region with the highest number is always
destructed first, then the state in the region with the second-highest
number and so on. Otherwise continues with step 7ExceptionTranslator::operator()()
is equal to the one of simple_state<>::forward_event()
then continues with step 3ExceptionTranslator::operator()()
is equal to the one of simple_state<>::defer_event()
then the return value of currentEvent.intrusive_from_this() is stored in a
state-specific queue. Continues with step 11ExceptionTranslator::operator()()
is equal to the one of simple_state<>::discard_event()
then continues with step 11static_cast< MostDerived * >( this
)->unconsumed_event( currentEvent ). If
unconsumed_event() throws an exception, the exception is
propagated to the caller. Such an exception never leads to the
destruction of any states (in contrast to exceptions propagated from
ExceptionTranslator::operator()())currentEvent and continues with step 2.
Returns to the caller otherwiseThrows: Any exceptions propagated from
MostDerived::unconsumed_event() or
ExceptionTranslator::operator(). Exceptions never originate in
the library itself but only in code supplied through template
parameters:
Allocator::rebind<>::other::allocate()react member functionsexit member functionsMostDerived::unconsumed_event()void post_event( const intrusive_ptr< const event_base > & );
Effects: Pushes the passed event into the posted events queue
Throws: Any exceptions propagated from
Allocator::allocate()
void post_event( const event_base & evt );
Effects: post_event( evt.intrusive_from_this()
);
Throws: Any exceptions propagated from
Allocator::allocate()
void unconsumed_event( const event_base & evt );
Effects: None
Note: This function (or, if present, the equally named derived class
member function) is called by process_event()
whenever a dispatched event did not trigger a reaction, see process_event() effects, point 10 for more
information.
state_machine observer functionsbool terminated() const;
Returns: true, if the machine is terminated. Returns
false otherwise
Note: Is equivalent to state_begin() == state_end()
template< class Target > Target state_cast() const;
Returns: Depending on the form of Target either a
reference or a pointer to const if at least one of the
currently active states can successfully be dynamic_cast to
Target. Returns 0 for pointer targets and throws
std::bad_cast for reference targets otherwise.
Target can take either of the following forms: const
Class * or const Class &
Throws: std::bad_cast if Target is a
reference type and none of the active states can be
dynamic_cast to Target
Note: The search sequence is the same as for process_event()
template< class Target > Target state_downcast() const;
Requires: For reference targets the compiler must support partial
specialization of class templates, otherwise a compile-time error will
result. The type denoted by Target must be a model of the
SimpleState or State
concepts
Returns: Depending on the form of Target either a
reference or a pointer to const if Target is
equal to the most-derived type of a currently active state. Returns
0 for pointer targets and throws std::bad_cast
for reference targets otherwise. Target can take either of the
following forms: const Class * or const Class
&
Throws: std::bad_cast if Target is a
reference type and none of the active states has a most derived type equal
to Target
Note: The search sequence is the same as for process_event()
state_iterator state_begin() const;
state_iterator state_end() const;
Return: Iterator objects, the range [state_begin(),
state_end()) refers to all currently active innermost states. For an object
i of type state_iterator, *i returns
a const state_base_type & and
i.operator->() returns a const state_base_type
*
Note: The position of a given innermost state in the range is
arbitrary. It may change with each call to a modifier function. Moreover,
all iterators are invalidated whenever a modifier function is called
const event_base * triggering_event();
Returns: A pointer to the event that triggered the reaction that is currently
being executed. Returns 0 if no reaction is being executed or if the current
reaction was triggered by either initiate() or
terminate()
asynchronous_state_machineThis is the base class template of all asynchronous state machines.
asynchronous_state_machine parameters| Template parameter | Requirements | Semantics | Default |
MostDerived |
The most-derived subtype of this class template | ||
InitialState |
A model of the SimpleState
or State concepts. The Context
argument passed to the simple_state<> or
state<> base of
InitialState must be MostDerived. That is,
InitialState must be an outermost state of this state
machine |
The state that is entered when the state machine is
initiated through the Scheduler object |
|
Scheduler |
A model of the Scheduler concept | see Scheduler concept | fifo_scheduler<> |
Allocator |
A model of the standard Allocator concept | std::allocator< void > |
|
ExceptionTranslator |
A model of the ExceptionTranslator concept | see ExceptionTranslator concept | null_exception_translator |
asynchronous_state_machine synopsis
namespace boost
{
namespace statechart
{
template<
class MostDerived,
class InitialState,
class Scheduler = fifo_scheduler<>,
class Allocator = std::allocator< void >,
class ExceptionTranslator = null_exception_translator >
class asynchronous_state_machine :
public state_machine<
MostDerived, InitialState, Allocator, ExceptionTranslator >,
public event_processor< Scheduler >
{
protected:
typedef asynchronous_state_machine my_base;
asynchronous_state_machine(
typename event_processor< Scheduler >::my_context ctx );
~asynchronous_state_machine();
};
}
}
asynchronous_state_machine constructor and
destructorasynchronous_state_machine( typename event_processor< Scheduler >::my_context ctx );
Effects: Constructs a non-running asynchronous state machine
Note: Users cannot create
asynchronous_state_machine<> subtype objects directly.
This can only be done through an object of the Scheduler
class
~asynchronous_state_machine();
Effects: Destructs the state machine
Note: Users cannot destruct
asynchronous_state_machine<> subtype objects directly.
This can only be done through an object of the Scheduler
class
event_processorThis is the base class template of all types that process events.
asynchronous_state_machine<> is just one possible event
processor implementation.
event_processor parameters| Template parameter | Requirements | Semantics |
Scheduler |
A model of the Scheduler concept | see Scheduler concept |
event_processor synopsis
namespace boost
{
namespace statechart
{
template< class Scheduler >
class event_processor
{
public:
virtual ~event_processor();
Scheduler & my_scheduler() const;
typedef typename Scheduler::processor_handle
processor_handle;
processor_handle my_handle() const;
void initiate();
void process_event( const event_base & evt );
void terminate();
protected:
typedef const typename Scheduler::processor_context &
my_context;
event_processor( my_context ctx );
private:
virtual void initiate_impl() = 0;
virtual void process_event_impl(
const event_base & evt ) = 0;
virtual void terminate_impl() = 0;
};
}
}
event_processor constructor and
destructorevent_processor( my_context ctx );
Effects: Constructs an event processor object and stores copies
of the reference returned by myContext.my_scheduler() and the
object returned by myContext.my_handle()
Note: Users cannot create event_processor<>
subtype objects directly. This can only be done through an object of the
Scheduler class
virtual ~event_processor();
Effects: Destructs an event processor object
Note: Users cannot destruct event_processor<>
subtype objects directly. This can only be done through an object of the
Scheduler class
event_processor modifier functionsvoid initiate();
Effects: initiate_impl();Throws: Any
exceptions propagated from the implementation of
initiate_impl()
void process_event( const event_base & evt );
Effects: process_event_impl( evt
);Throws: Any exceptions propagated from the
implementation of process_event_impl()
void terminate();
Effects: terminate_impl();Throws: Any
exceptions propagated from the implementation of
terminate_impl()
event_processor observer functionsScheduler & my_scheduler() const;
Returns: The Scheduler reference obtained in the
constructor
processor_handle my_handle() const;
Returns: The processor_handle object obtained in the
constructor
fifo_schedulerThis class template is a model of the Scheduler concept.
fifo_scheduler parameters| Template parameter | Requirements | Semantics | Default |
FifoWorker |
A model of the FifoWorker concept | see FifoWorker concept | fifo_worker<> |
Allocator |
A model of the standard Allocator concept | std::allocator< void > |
fifo_scheduler synopsis
namespace boost
{
namespace statechart
{
template<
class FifoWorker = fifo_worker<>,
class Allocator = std::allocator< void > >
class fifo_scheduler : noncopyable
{
public:
fifo_scheduler( bool waitOnEmptyQueue = false );
typedef implementation-defined processor_handle;
class processor_context : noncopyable
{
processor_context(
fifo_scheduler & scheduler,
const processor_handle & theHandle );
fifo_scheduler & my_scheduler() const;
const processor_handle & my_handle() const;
friend class fifo_scheduler;
friend class event_processor< fifo_scheduler >;
};
template< class Processor >
processor_handle create_processor();
template< class Processor, typename Param1 >
processor_handle create_processor( Param1 param1 );
// More create_processor overloads
void destroy_processor( processor_handle processor );
void initiate_processor( processor_handle processor );
void terminate_processor( processor_handle processor );
typedef intrusive_ptr< const event_base > event_ptr_type;
void queue_event(
const processor_handle & processor,
const event_ptr_type & pEvent );
typedef typename FifoWorker::work_item work_item;
void queue_work_item( const work_item & item );
void terminate();
bool terminated() const;
unsigned long operator()(
unsigned long maxEventCount = 0 );
};
}
}
fifo_scheduler constructorfifo_scheduler( bool waitOnEmptyQueue = false );
Effects: Constructs a fifo_scheduler<> object.
In multi-threaded builds, waitOnEmptyQueue is forwarded to the
constructor of a data member of type FifoWorker. In
single-threaded builds, the FifoWorker data member is
default-constructed
Note: In single-threaded builds the
fifo_scheduler<> constructor does not accept any
parameters and operator()() thus always returns to the caller
when the event queue is empty
fifo_scheduler modifier functionstemplate< class Processor > processor_handle create_processor();
Requires: The Processor type must be a direct or
indirect subtype of the event_processor class
template
Effects: Creates and passes to
FifoWorker::queue_work_item() an object of type
FifoWorker::work_item that, when later executed in
FifoWorker::operator()(), leads to a call to the constructor
of Processor, passing an appropriate
processor_context object as the only argument
Returns: A processor_handle object that henceforth
identifies the created event processor object
Throws: Any exceptions propagated from
FifoWorker::work_item() and
FifoWorker::queue_work_item()
Caution: The current implementation of this function makes an
(indirect) call to global operator new(). Unless global
operator new() is replaced, care must be taken when to call
this function in applications with hard real-time requirements
template< class Processor, typename Param1 > processor_handle create_processor( Param1 param1 );
Requires: The Processor type must be a direct or
indirect subtype of the event_processor class
template
Effects: Creates and passes to
FifoWorker::queue_work_item() an object of type
FifoWorker::work_item that, when later executed in
FifoWorker::operator()(), leads to a call to the constructor
of Processor, passing an appropriate
processor_context object and param1 as
arguments
Returns: A processor_handle object that henceforth
identifies the created event processor object
Throws: Any exceptions propagated from
FifoWorker::work_item() and
FifoWorker::queue_work_item()
Note: boost::ref() and boost::cref() can be
used to pass arguments by reference rather than by copy.
fifo_scheduler<> has 5 additional
create_processor<> overloads, allowing to pass up to 6
custom arguments to the constructors of event processors
Caution: The current implementation of this and all other overloads
make (indirect) calls to global operator new(). Unless global
operator new() is replaced, care must be taken when to call
these overloads in applications with hard real-time requirements
void destroy_processor( processor_handle processor );
Requires: processor was obtained from a call to one
of the create_processor<>() overloads on the same
fifo_scheduler<> object
Effects: Creates and passes to
FifoWorker::queue_work_item() an object of type
FifoWorker::work_item that, when later executed in
FifoWorker::operator()(), leads to a call to the destructor of
the event processor object associated with processor. The
object is silently discarded if the event processor object has been
destructed before
Throws: Any exceptions propagated from
FifoWorker::work_item() and
FifoWorker::queue_work_item()
Caution: The current implementation of this function leads to an
(indirect) call to global operator delete() (the call is made
when the last processor_handle object associated with the
event processor object is destructed). Unless global operator
delete() is replaced, care must be taken when to call this function
in applications with hard real-time requirements
void initiate_processor( processor_handle processor );
Requires: processor was obtained from a call to one
of the create_processor() overloads on the same
fifo_scheduler<> object
Effects: Creates and passes to
FifoWorker::queue_work_item() an object of type
FifoWorker::work_item that, when later executed in
FifoWorker::operator()(), leads to a call to initiate() on the event processor
object associated with processor. The object is silently
discarded if the event processor object has been destructed before
Throws: Any exceptions propagated from
FifoWorker::work_item() and
FifoWorker::queue_work_item()
void terminate_processor( processor_handle processor );
Requires: processor was obtained from a call to one
of the create_processor<>() overloads on the same
fifo_scheduler<> object
Effects: Creates and passes to
FifoWorker::queue_work_item() an object of type
FifoWorker::work_item that, when later executed in
FifoWorker::operator()(), leads to a call to terminate() on the event processor
object associated with processor. The object is silently
discarded if the event processor object has been destructed before
Throws: Any exceptions propagated from
FifoWorker::work_item() and
FifoWorker::queue_work_item()
void queue_event( const processor_handle & processor, const event_ptr_type & pEvent );
Requires: pEvent.get() != 0 and
processor was obtained from a call to one of the
create_processor<>() overloads on the same
fifo_scheduler<> object
Effects: Creates and passes to
FifoWorker::queue_work_item() an object of type
FifoWorker::work_item that, when later executed in
FifoWorker::operator()(), leads to a call to process_event( *pEvent ) on
the event processor object associated with processor. The
object is silently discarded if the event processor object has been
destructed before
Throws: Any exceptions propagated from
FifoWorker::work_item() and
FifoWorker::queue_work_item()
void queue_work_item( const work_item & item );
Effects: FifoWorker::queue_work_item( item );
Throws: Any exceptions propagated from the above call
void terminate();
Effects: FifoWorker::terminate()
Throws: Any exceptions propagated from the above call
unsigned long operator()( unsigned long maxEventCount = 0 );
Requires: Must only be called from exactly one thread
Effects: FifoWorker::operator()( maxEventCount )
Returns: The return value of the above call
Throws: Any exceptions propagated from the above call
fifo_scheduler observer functionsbool terminated() const;
Requires: Must only be called from the thread that also calls
operator()()
Returns: FifoWorker::terminated();
exception_translatorThis class template is a model of the ExceptionTranslator concept.
exception_translator parameters| Template parameter | Requirements | Semantics | Default |
ExceptionEvent |
A model of the Event concept | The type of event that is dispatched when an exception is propagated into the framework | exception_thrown |
exception_translator synopsis &
semantics
namespace boost
{
namespace statechart
{
class exception_thrown : public event< exception_thrown > {};
template< class ExceptionEvent = exception_thrown >
class exception_translator
{
public:
template< class Action, class ExceptionEventHandler >
result operator()(
Action action,
ExceptionEventHandler eventHandler )
{
try
{
return action();
}
catch( ... )
{
return eventHandler( ExceptionEvent() );
}
}
};
}
}
null_exception_translatorThis class is a model of the ExceptionTranslator concept.
null_exception_translator synopsis &
semantics
namespace boost
{
namespace statechart
{
class null_exception_translator
{
public:
template< class Action, class ExceptionEventHandler >
result operator()(
Action action, ExceptionEventHandler )
{
return action();
}
};
}
}
history_modeDefines the history type of a state.
namespace boost
{
namespace statechart
{
enum history_mode
{
has_no_history,
has_shallow_history,
has_deep_history,
has_full_history // shallow & deep
};
}
}
simple_stateThis is the base class template for all models of the SimpleState concept. Such models must not call any of
the following simple_state<> member functions from their
constructors:
void post_event(
const intrusive_ptr< const event_base > & );
void post_event( const event_base & );
template<
class HistoryContext,
implementation-defined-unsigned-integer-type
orthogonalPosition >
void clear_shallow_history();
template<
class HistoryContext,
implementation-defined-unsigned-integer-type
orthogonalPosition >
void clear_deep_history();
outermost_context_type & outermost_context();
const outermost_context_type & outermost_context() const;
template< class OtherContext >
OtherContext & context();
template< class OtherContext >
const OtherContext & context() const;
template< class Target >
Target state_cast() const;
template< class Target >
Target state_downcast() const;
state_iterator state_begin() const;
state_iterator state_end() const;
const event_base * triggering_event() const;
States that need to call any of these member functions from their
constructors must derive from the state class template.
simple_state parameters| Template parameter | Requirements | Semantics | Default |
MostDerived |
The most-derived subtype of this class template | ||
Context |
A most-derived direct or indirect subtype of the
state_machine or
asynchronous_state_machine
class templates or a model of the SimpleState or State concepts
or an instantiation of the simple_state<>::orthogonal
class template. Must be a complete type |
Defines the states' position in the state hierarchy | |
InnerInitial |
An mpl::list<> containing models of
the SimpleState or State concepts or instantiations of the shallow_history or
deep_history
class templates. If there is only a single inner initial state that is
not a template instantiation then it can also be passed directly,
without wrapping it into an mpl::list<>. The
Context argument passed to the simple_state<> or
state<> base
of each state in the list must correspond to the orthogonal region
it belongs to. That is, the first state in the list must pass
MostDerived::orthogonal< 0 >, the second
MostDerived::orthogonal< 1 > and so forth.
MostDerived::orthogonal< 0 > and
MostDerived are synonymous |
Defines the inner initial state for each orthogonal region. By default, a state does not have inner states | unspecified |
historyMode |
One of the values defined in the history_mode enumeration |
Defines whether the state saves shallow, deep or both histories upon exit | has_no_history |
simple_state synopsis
namespace boost
{
namespace statechart
{
template<
class MostDerived,
class Context,
class InnerInitial = unspecified,
history_mode historyMode = has_no_history >
class simple_state : implementation-defined
{
public:
// by default, a state has no reactions
typedef mpl::list<> reactions;
// see template parameters
template< implementation-defined-unsigned-integer-type
innerOrthogonalPosition >
struct orthogonal
{
// implementation-defined
};
typedef typename Context::outermost_context_type
outermost_context_type;
outermost_context_type & outermost_context();
const outermost_context_type & outermost_context() const;
template< class OtherContext >
OtherContext & context();
template< class OtherContext >
const OtherContext & context() const;
template< class Target >
Target state_cast() const;
template< class Target >
Target state_downcast() const;
// a model of the StateBase concept
typedef implementation-defined state_base_type;
// a model of the standard Forward Iterator concept
typedef implementation-defined state_iterator;
state_iterator state_begin() const;
state_iterator state_end() const;
const event_base * triggering_event() const;
void post_event(
const intrusive_ptr< const event_base > & );
void post_event( const event_base & );
result discard_event();
result forward_event();
result defer_event();
template< class DestinationState >
result transit();
template<
class DestinationState,
class TransitionContext,
class Event >
result transit(
void ( TransitionContext::* )( const Event & ),
const Event & );
result terminate();
template<
class HistoryContext,
implementation-defined-unsigned-integer-type
orthogonalPosition >
void clear_shallow_history();
template<
class HistoryContext,
implementation-defined-unsigned-integer-type
orthogonalPosition >
void clear_deep_history();
static id_type static_type();
template< class CustomId >
static const CustomId * custom_static_type_ptr();
template< class CustomId >
static void custom_static_type_ptr( const CustomId * );
// see transit() or terminate() effects
void exit() {}
protected:
simple_state();
~simple_state();
};
}
}
simple_state constructor and
destructorsimple_state();
Effects: Constructs a state object
~simple_state();
Effects: Pushes all events deferred by the state into the posted events queue
simple_state modifier functionsvoid post_event( const intrusive_ptr< const event_base > & pEvt );
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template. All direct and indirect
callers must be exception-neutral
Effects: outermost_context().post_event( pEvt );
Throws: Whatever the above call throws
void post_event( const event_base & evt );
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template. All direct and indirect
callers must be exception-neutral
Effects: outermost_context().post_event( evt );
Throws: Whatever the above call throws
result discard_event();
Requires: Must only be called from within react
member functions, which are called by custom_reaction<>
instantiations. All direct and indirect callers must be
exception-neutral
Effects: Instructs the state machine to discard the current event
and to continue with the processing of the remaining events (see
state_machine<>::process_event() for
details)
Returns: A result object.
The user-supplied react member function must return this
object to its caller
result forward_event();
Requires: Must only be called from within react
member functions, which are called by custom_reaction<>
instantiations. All direct and indirect callers must be
exception-neutral
Effects: Instructs the state machine to forward the current event to
the next state (see state_machine<>::process_event() for
details)
Returns: A result object.
The user-supplied react member function must return this
object to its caller
result defer_event();
Requires: Must only be called from within react
member functions, which are called by custom_reaction<>
instantiations. All direct and indirect callers must be
exception-neutral
Effects: Instructs the state machine to defer the current event and
to continue with the processing of the remaining events (see state_machine<>::process_event() for
details)
Returns: A result object.
The user-supplied react member function must return this
object to its caller
Throws: Any exceptions propagated from
Allocator::rebind<>::other::allocate() (the template
parameter passed to the base class of
outermost_context_type)
template< class DestinationState > result transit();
Requires: Must only be called from within react
member functions, which are called by custom_reaction<>
instantiations. All direct and indirect callers must be
exception-neutral
Effects:
DestinationState.
Innermost states are exited first. Other states are exited as soon as all
their direct and indirect inner states have been exited. The inner states
of each state are exited according to the number of their orthogonal
region. The state in the orthogonal region with the highest number is
always exited first, then the state in the region with the second-highest
number and so on.exit member function (see synopsis) of the most-derived state
object. If exit() throws then steps 3 and 4 are not
executedDestinationState
itself or a direct or indirect outer state of
DestinationStateDestinationState and beyond depth first. The inner states of
each state are entered according to the number of their orthogonal
region. The state in orthogonal region 0 is always entered first, then
the state in region 1 and so onstate_machine<>::process_event() for
details)Returns: A result object.
The user-supplied react member function must return this
object to its caller
Throws: Any exceptions propagated from:
Allocator::rebind<>::other::allocate() (the
template parameter passed to the base class of
outermost_context_type)exit member functionsCaution: Inevitably destructs this state before returning to the
calling react member function, which must therefore not
attempt to access anything except stack objects before returning to its
caller
template< class DestinationState, class TransitionContext, class Event > result transit( void ( TransitionContext::* )( const Event & ), const Event & );
Requires: Must only be called from within react
member functions, which are called by custom_reaction<>
instantiations. All direct and indirect callers must be
exception-neutral
Effects:
DestinationState.
Innermost states are exited first. Other states are exited as soon as all
their direct and indirect inner states have been exited. The inner states
of each state are exited according to the number of their orthogonal
region. The state in the orthogonal region with the highest number is
always exited first, then the state in the region with the second-highest
number and so on.exit member function (see synopsis) of the most-derived state
object. If exit() throws then steps 3 and 4 are not
executedDestinationState
itself or a direct or indirect outer state of
DestinationStateDestinationState and beyond depth first. The inner states of
each state are entered according to the number of their orthogonal
region. The state in orthogonal region 0 is always entered first, then
the state in region 1 and so onstate_machine<>::process_event() for
details)Returns: A result object.
The user-supplied react member function must return this
object to its caller
Throws: Any exceptions propagated from:
Allocator::rebind<>::other::allocate() (the
template parameter passed to the base class of
outermost_context_type)exit member functionsCaution: Inevitably destructs this state before returning to the
calling react member function, which must therefore not
attempt to access anything except stack objects before returning to its
caller
result terminate();
Requires: Must only be called from within react
member functions, which are called by custom_reaction<>
instantiations. All direct and indirect callers must be
exception-neutral
Effects: Exits this state and all its direct and indirect inner
states. Innermost states are exited first. Other states are exited as soon
as all their direct and indirect inner states have been exited. The inner
states of each state are exited according to the number of their orthogonal
region. The state in the orthogonal region with the highest number is
always exited first, then the state in the region with the second-highest
number and so on.
The process of exiting a state consists of the following steps:
exit member function (see synopsis) of the most-derived state
object. If exit() throws then steps 3 and 4 are not
executedAlso instructs the state machine to discard the current event and to
continue with the processing of the remaining events (see state_machine<>::process_event() for
details)
Returns: A result object.
The user-supplied react member function must return this
object to its caller
Throws: Any exceptions propagated from:
Allocator::rebind<>::other::allocate() (the
template parameter passed to the base class of
outermost_context_type, used to allocate space to save
history)exit member functionsNote: If this state is the only currently active inner state of
its direct outer state then the direct outer state is terminated also. The
same applies recursively for all indirect outer states
Caution: Inevitably destructs this state before returning to the
calling react member function, which must therefore not
attempt to access anything except stack objects before returning to its
caller
template<
class HistoryContext,
implementation-defined-unsigned-integer-type
orthogonalPosition >
void clear_shallow_history();
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template. The historyMode
argument passed to the simple_state<> or
state<> base
of HistoryContext must be equal to
has_shallow_history or has_full_history
Effects: Clears the shallow history of the orthogonal region
specified by orthogonalPosition of the state specified by
HistoryContext
Throws: Any exceptions propagated from
Allocator::rebind<>::other::allocate() (the template
parameter passed to the base class of
outermost_context_type)
template<
class HistoryContext,
implementation-defined-unsigned-integer-type
orthogonalPosition >
void clear_deep_history();
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template. The historyMode
argument passed to the simple_state<> or
state<> base
of HistoryContext must be equal to
has_deep_history or has_full_history
Effects: Clears the deep history of the orthogonal region specified
by orthogonalPosition of the state specified by
HistoryContext
Throws: Any exceptions propagated from
Allocator::rebind<>::other::allocate() (the template
parameter passed to the base class of
outermost_context_type)
simple_state observer functionsoutermost_context_type & outermost_context();
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template. If called from a destructor of a
direct or indirect subtype then the state_machine<> subclass
portion must still exist
Returns: A reference to the outermost context, which is always the
state machine this state belongs to
const outermost_context_type & outermost_context() const;
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template. If called from a destructor of a
direct or indirect subtype then the state_machine<> subclass
portion must still exist
Returns: A reference to the const outermost context, which is always
the state machine this state belongs to
template< class OtherContext > OtherContext & context();
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template. If called from a destructor of a
direct or indirect subtype with a state_machine<> subtype as
argument then the state_machine<> subclass portion must still
exist
Returns: A reference to a direct or indirect context or any public base
type of the contexts
template< class OtherContext > const OtherContext & context() const;
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template. If called from a destructor of a
direct or indirect subtype with a state_machine<> subtype as
argument then the state_machine<> subclass portion must still
exist
Returns: A reference to a const direct or indirect context or any public
base type of the contexts
template< class Target > Target state_cast() const;
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template
Returns: Has exactly the same semantics as state_machine<>::state_cast<>()
Throws: Has exactly the same semantics as state_machine<>::state_cast<>()
Note: The result is unspecified if this function is called when
the machine is unstable
template< class Target > Target state_downcast() const;
Requires: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template. Moreover, state_machine<>::state_downcast<>()
requirements also apply
Returns: Has exactly the same semantics as state_machine<>::state_downcast<>()
Throws: Has exactly the same semantics as state_machine<>::state_downcast<>()
Note: The result is unspecified if this function is called when
the machine is unstable
state_iterator state_begin() const;
state_iterator state_end() const;
Require: If called from a constructor of a direct or indirect
subtype then the most-derived type must directly or indirectly derive from
the state class template
Return: Have exactly the same semantics as state_machine<>::state_begin() and
state_machine<>::state_end()
Note: The result is unspecified if these functions are called
when the machine is unstable
const event_base * triggering_event();
Returns: Has exactly the same semantics as
state_machine<>::triggering_event()
simple_state static functionsstatic id_type static_type();
Returns: A value unambiguously identifying the type of
MostDerived
Note: id_type values are comparable with
operator==() and operator!=(). An unspecified
collating order can be established with std::less< id_type
>
template< class CustomId > static const CustomId * custom_static_type_ptr();
Requires: If a custom type identifier has been set then
CustomId must match the type of the previously set
pointer
Returns: The pointer to the custom type identifier for
MostDerived or 0
Note: This function is not available if BOOST_STATECHART_USE_NATIVE_RTTI
is defined
template< class CustomId > static void custom_static_type_ptr( const CustomId * );
Effects: Sets the pointer to the custom type identifier for
MostDerived
Note: This function is not available if BOOST_STATECHART_USE_NATIVE_RTTI
is defined
stateThis is the base class template for all models of the State concept. Such models typically need to call at least one
of the following simple_state<> member
functions from their constructors:
void post_event(
const intrusive_ptr< const event_base > & );
void post_event( const event_base & );
template<
class HistoryContext,
implementation-defined-unsigned-integer-type
orthogonalPosition >
void clear_shallow_history();
template<
class HistoryContext,
implementation-defined-unsigned-integer-type
orthogonalPosition >
void clear_deep_history();
outermost_context_type & outermost_context();
const outermost_context_type & outermost_context() const;
template< class OtherContext >
OtherContext & context();
template< class OtherContext >
const OtherContext & context() const;
template< class Target >
Target state_cast() const;
template< class Target >
Target state_downcast() const;
state_iterator state_begin() const;
state_iterator state_end() const;
const event_base * triggering_event() const;
States that do not need to call any of these member functions from their
constructors should rather derive from the simple_state class template, what
saves the implementation of the forwarding constructor.
state synopsis
namespace boost
{
namespace statechart
{
template<
class MostDerived,
class Context,
class InnerInitial = unspecified,
history_mode historyMode = has_no_history >
class state : public simple_state<
MostDerived, Context, InnerInitial, historyMode >
{
protected:
struct my_context
{
// implementation-defined
};
typedef state my_base;
state( my_context ctx );
~state();
};
}
}
Direct and indirect subtypes of state<> must provide
a constructor with the same signature as the state<>
constructor, forwarding the context parameter.
shallow_historyThis class template is used to specify a shallow history transition target or a shallow history inner initial state.
shallow_history parameters| Template parameter | Requirements | Semantics |
DefaultState |
A model of the SimpleState
or State concepts. The type passed as
Context argument to the simple_state<> or
state<> base
of DefaultState must itself pass
has_shallow_history or has_full_history as
historyMode argument to its simple_state<> or
state<> base |
The state that is entered if shallow history is not available |
shallow_history synopsis
namespace boost
{
namespace statechart
{
template< class DefaultState >
class shallow_history
{
// implementation-defined
};
}
}
deep_historyThis class template is used to specify a deep history transition target or a deep history inner initial state. The current deep history implementation has some limitations.
deep_history parameters| Template parameter | Requirements | Semantics |
DefaultState |
A model of the SimpleState
or State concepts. The type passed as
Context argument to the simple_state<> or
state<> base
of DefaultState must itself pass
has_deep_history or has_full_history as
historyMode argument to its simple_state<> or
state<> base |
The state that is entered if deep history is not available |
deep_history synopsis
namespace boost
{
namespace statechart
{
template< class DefaultState >
class deep_history
{
// implementation-defined
};
}
}
event_baseThis is the common base of all events.
event_base synopsis
namespace boost
{
namespace statechart
{
class event_base
{
public:
intrusive_ptr< const event_base >
intrusive_from_this() const;
typedef implementation-defined id_type;
id_type dynamic_type() const;
template< typename CustomId >
const CustomId * custom_dynamic_type_ptr() const;
protected:
event_base( unspecified-parameter );
virtual ~event_base();
};
}
}
event_base constructor and destructorevent_base( unspecified-parameter );
Effects: Constructs the common base portion of an event
virtual ~event_base();
Effects: Destructs the common base portion of an event
event_base observer functionsintrusive_ptr< const event_base > intrusive_from_this() const;
Returns: Another intrusive_ptr< const event_base
> referencing this if this is
already referenced by an intrusive_ptr<>. Otherwise,
returns an intrusive_ptr< const event_base > referencing
a newly created copy of the most-derived object
id_type dynamic_type() const;
Returns: A value unambiguously identifying the most-derived
type
Note: id_type values are comparable with
operator==() and operator!=(). An unspecified
collating order can be established with std::less< id_type
>. In contrast to typeid( cs ), this function is
available even on platforms that do not support C++ RTTI (or have been
configured to not support it)
template< typename CustomId > const CustomId * custom_dynamic_type_ptr() const;
Requires: If a custom type identifier has been set then
CustomId must match the type of the previously set
pointer
Returns: A pointer to the custom type identifier or 0
Note: This function is not available if BOOST_STATECHART_USE_NATIVE_RTTI
is defined
eventThis is the base class template of all events.
event parameters| Template parameter | Requirements | Semantics | Default |
MostDerived |
The most-derived subtype of this class template | ||
Allocator |
A model of the standard Allocator concept | Allocator::rebind< MostDerived
>::other is used to allocate and deallocate all event subtype
objects of dynamic storage duration, see operator new |
std::allocator< void > |
event synopsis
namespace boost
{
namespace statechart
{
template< class MostDerived, class Allocator = std::allocator< void > >
class event : implementation-defined
{
public:
static void * operator new( std::size_t size );
static void * operator new( std::size_t size, void * p );
static void operator delete( void * pEvent );
static id_type static_type();
template< class CustomId >
static const CustomId * custom_static_type_ptr();
template< class CustomId >
static void custom_static_type_ptr( const CustomId * );
protected:
event();
virtual ~event();
};
}
}
event constructor and destructorevent();
Effects: Constructs an event
virtual ~event();
Effects: Destructs an event
event static functionsstatic void * operator new( std::size_t size );
Effects: Allocator::rebind< MostDerived
>::other().allocate( 1, static_cast< MostDerived * >( 0 )
);
Returns: The return value of the above call
Throws: Whatever the above call throws
static void * operator new( std::size_t size, void * p );
Effects: None
Returns: p
static void operator delete( void * pEvent );
Effects: Allocator::rebind< MostDerived
>::other().deallocate( static_cast< MostDerived * >( pEvent ), 1
);
static id_type static_type();
Returns: A value unambiguously identifying the type of
MostDerived
Note: id_type values are comparable with
operator==() and operator!=(). An unspecified
collating order can be established with std::less< id_type
>
template< class CustomId > static const CustomId * custom_static_type_ptr();
Requires: If a custom type identifier has been set then
CustomId must match the type of the previously set
pointer
Returns: The pointer to the custom type identifier for
MostDerived or 0
Note: This function is not available if BOOST_STATECHART_USE_NATIVE_RTTI
is defined
template< class CustomId > static void custom_static_type_ptr( const CustomId * );
Effects: Sets the pointer to the custom type identifier for
MostDerived
Note: This function is not available if BOOST_STATECHART_USE_NATIVE_RTTI
is defined
transitionThis class template is used to specify a transition reaction.
Instantiations of this template can appear in the reactions
member typedef in models of the SimpleState and State concepts.
transition parameters| Template parameter | Requirements | Semantics | Default |
Event |
A model of the Event concept or
the class event_base |
The event triggering the transition. If event_base is specified, the transition
is triggered by all models of the Event
concept |
|
Destination |
A model of the SimpleState
or State concepts, any of their public base types or an instantiation of the
shallow_history or
deep_history
class templates. The source state (the state for which this transition
is defined) and Destination must have a common direct or
indirect context |
The destination state to make a transition to | |
TransitionContext |
A common context of the source and
Destination state |
The state of which the transition action is a member | unspecified |
pTransitionAction |
A pointer to a member function of
TransitionContext. The member function must accept a
const Event & parameter and return
void |
The transition action that is executed during the transition. By default no transition action is executed | unspecified |
transition synopsis
namespace boost
{
namespace statechart
{
template<
class Event,
class Destination,
class TransitionContext = unspecified,
void ( TransitionContext::*pTransitionAction )(
const Event & ) = unspecified >
class transition
{
// implementation-defined
};
}
}
transition semanticsWhen executed, one of the following calls to a member function of the state for which the reaction was defined is made:
transit< Destination >(),
if no transition action was specifiedtransit< Destination >(
pTransitionAction, currentEvent ), if a transition
action was specifiedin_state_reactionThis class template is used to specify an in-state reaction.
Instantiations of this template can appear in the reactions
member typedef in models of the SimpleState and State concepts.
in_state_reaction parameters| Template parameter | Requirements | Semantics | Default |
Event |
A model of the Event concept or
the class event_base |
The event triggering the in-state reaction. If
event_base is specified,
the in-state reaction is triggered by all models of the Event concept |
|
ReactionContext |
Either the state defining the in-state reaction itself, one of its direct or indirect contexts or any of their public base types | The state of which the action is a member | unspecified |
pAction |
A pointer to a member function of
ReactionContext. The member function must accept a
const Event & parameter and return
void |
The action that is executed during the in-state reaction | unspecified |
in_state_reaction synopsis
namespace boost
{
namespace statechart
{
template<
class Event,
class ReactionContext = unspecified,
void ( ReactionContext::*pAction )(
const Event & ) = unspecified >
class in_state_reaction
{
// implementation-defined
};
}
}
in_state_reaction semanticsWhen executed then the following happens:
pAction is called, passing
the triggering event as the only argumentdiscard_event
member function of the state for which the reaction was defined
terminationThis class template is used to specify a termination reaction.
Instantiations of this template can appear in the reactions
member typedef in models of the SimpleState and State concepts.
termination parameters| Template parameter | Requirements | Semantics |
Event |
A model of the Event concept or
the class event_base |
The event triggering the termination. If event_base is specified, the termination
is triggered by all models of the Event
concept |
termination synopsis
namespace boost
{
namespace statechart
{
template< class Event >
class termination
{
// implementation-defined
};
}
}
termination semanticsWhen executed, a call is made to the terminate member function of the
state for which the reaction was defined.
deferralThis class template is used to specify a deferral reaction.
Instantiations of this template can appear in the reactions
member typedef in models of the SimpleState and State concepts.
deferral parameters| Template parameter | Requirements | Semantics |
Event |
A model of the Event concept or
the class event_base |
The event triggering the deferral. If event_base is specified, the deferral is
triggered by all models of the Event concept |
deferral synopsis
namespace boost
{
namespace statechart
{
template< class Event >
class deferral
{
// implementation-defined
};
}
}
deferral semanticsWhen executed, a call is made to the defer_event member function of the state
for which the reaction was defined.
custom_reactionThis class template is used to specify a custom reaction. Instantiations
of this template can appear in the reactions member
typedef in models of the SimpleState and State concepts.
custom_reaction parameters| Template parameter | Requirements | Semantics |
Event |
A model of the Event concept or
the class event_base |
The event triggering the custom reaction. If
event_base is specified,
the custom reaction is triggered by all models of the Event concept |
custom_reaction synopsis
namespace boost
{
namespace statechart
{
template< class Event >
class custom_reaction
{
// implementation-defined
};
}
}
custom_reaction semanticsWhen executed, a call is made to the user-supplied react
member function of the state for which the reaction was defined. The
react member function must have the following signature:
result react( const Event & );
and must call exactly one of the following reaction functions and return
the obtained result object:
result discard_event(); result forward_event(); result defer_event(); template< class DestinationState > result transit(); template< class DestinationState, class TransitionContext, class Event > result transit( void ( TransitionContext::* )( const Event & ), const Event & ); result terminate();
resultDefines the nature of the reaction taken in a user-supplied
react member function (called when a custom_reaction is executed).
Objects of this type are always obtained by calling one of the reaction
functions and must be returned from the react member function
immediately.
namespace boost
{
namespace statechart
{
class result
{
public:
result( const result & other );
~result();
private:
// Result objects are not assignable
result & operator=( const result & other );
};
}
}
result constructor and destructorresult( const result & other );
Requires: other is not consumed
Effects: Copy-constructs a new result object and marks
other as consumed. That is, result has
destructive copy semantics
~result();
Requires: this is marked as consumed
Effects: Destructs the result object
Revised 06 January, 2008
Copyright © 2003-2008 Andreas Huber Dönni
Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)