#include <TaskCore.hpp>

Inheritance diagram for RTT::base::TaskCore:

Public Types
enum	TaskState { Init, PreOperational, FatalError, Exception, Stopped, Running, RunTimeError }
Public Member Functions
const ExecutionEngine *	engine () const
ExecutionEngine *	engine ()
virtual TaskState	getTargetState () const
virtual TaskState	getTaskState () const
void	setExecutionEngine (ExecutionEngine *engine)
	TaskCore (TaskState initial_state=Stopped)
	TaskCore (ExecutionEngine *parent, TaskState initial_state=Stopped)
virtual	~TaskCore ()
Operations
These TaskCore functions are exported in a TaskContext as script methods and are for configuration, starting and stopping its ExecutionEngine.
virtual bool	configure ()
virtual bool	activate ()
virtual bool	start ()
virtual bool	stop ()
virtual bool	cleanup ()
virtual bool	isConfigured () const
virtual bool	isActive () const
virtual bool	isRunning () const
virtual Seconds	getPeriod () const
virtual bool	setPeriod (Seconds s)
virtual unsigned	getCpuAffinity () const
virtual bool	setCpuAffinity (unsigned cpu)
virtual bool	inFatalError () const
virtual bool	inException () const
virtual bool	inRunTimeError () const
virtual bool	update ()
virtual bool	trigger ()
virtual void	error ()
virtual bool	recover ()
Protected Member Functions
virtual bool	breakUpdateHook ()
virtual void	cleanupHook ()
virtual bool	configureHook ()
virtual void	errorHook ()
virtual void	exception ()
virtual void	exceptionHook ()
virtual void	fatal ()
virtual bool	startHook ()
virtual void	stopHook ()
virtual void	updateHook ()
Protected Attributes
ExecutionEngine *	ee
TaskState	mTaskState
Private Member Functions
virtual void	prepareUpdateHook ()
	TaskCore (TaskCore &)
Private Attributes
TaskState const	mInitialState
TaskState	mTargetState
Friends
class	::RTT::ExecutionEngine
class	TaskContext

Detailed Description

The minimal Orocos task. It has a state and an ExecutionEngine to process messages and user functions.

Definition at line 54 of file TaskCore.hpp.

Member Enumeration Documentation

enum RTT::base::TaskCore::TaskState

Describes the different states a component can have. When a TaskContext is being constructed, it is in the Init state. After the construction ends, the component arrives in the PreOperational (additional configuration required) or the Stopped (ready to run) state. Invoking start() will make a transition to the Running state and stop() back to the Stopped state. The Running state executes updateHook(). Finally, there is an FatalError state, in which the component can enter by calling the protected method fatal(). In this state, the ExecutionEngine is stopped and updateHook() is no longer called. The object should then be disposed by a supervision system.

Next to the fatal error, one run-time error level is available in the Running state as well. This level allows 'automatic' recovery by the component in case the problem is temporal. In case of problems, one may call the protected method error() when the component is Running. The component will enter the RunTimeError state and will cause the errorHook() to be called instead of updateHook(). When recover() is called, this run-time error state is left and the nominal Running state is entered again.

In order to check if these transitions are allowed, hook functions are executed, which can be filled in by the component builder.

A transition from PreOperational to Stopped is checked by calling the configureHook() method. If this method returns true, the transition is made, otherwise, the state remains PreOperational.
A transition from Stopped to Running is checked by calling the startHook() method. If this method returns true, the transition is made, otherwise, the state remains Stopped.
A transition from Running to Stopped is always allowed and the stopHook() method is called to inform the component of this transtion.
A transition from Stopped to PreOperational is always allowed and the cleanupHook() method is called to inform the component of this transtion.

Enumerator:

Init	The state during component construction.
PreOperational	The state indicating additional configuration is required.
FatalError	The state indicating the component encountered a fatal error and is unable to execute.
Exception	The state indicating the component encountered a C++ exception.
Stopped	The state indicating the component is ready to run.
Running	The state indicating the component is running [green].
RunTimeError	The state indicating that a run-time error has occured [red] and needs attention.

Definition at line 99 of file TaskCore.hpp.

Constructor & Destructor Documentation

RTT::TaskCore::TaskCore ( TaskState initial_state = Stopped )

Create a TaskCore. It's ExecutionEngine will be newly constructed with private processing of commands, events, programs and state machines.

Parameters:

initial_state Provide the PreOperational parameter flag here to force users in calling configure(), before they call start().

Definition at line 51 of file TaskCore.cpp.

RTT::TaskCore::TaskCore	(	ExecutionEngine *	parent,
		TaskState	initial_state = `Stopped`
	)

Create a TaskCore. Its commands programs and state machines are processed by parent. Use this constructor to share execution engines among task contexts, such that the execution of their functionality is serialised (executed in the same thread).

Parameters:

initial_state Provide the PreOperational parameter flag here to force users in calling configure(), before they call start().

Definition at line 59 of file TaskCore.cpp.

RTT::TaskCore::~TaskCore ( ) [virtual]

Definition at line 69 of file TaskCore.cpp.

RTT::base::TaskCore::TaskCore ( TaskCore & ) [private]

Member Function Documentation

bool RTT::TaskCore::activate ( ) [virtual]

This method starts the ExecutionEngine of this component in case it was not running. Normally, it is always running. There is no way to deactivate it from the public interface.

Returns:: true if the ExecutionEngine is running (again) and false if it could not be started.

Reimplemented in RTT::corba::TaskContextProxy.

Definition at line 239 of file TaskCore.cpp.

bool RTT::TaskCore::breakUpdateHook ( ) [protected, virtual]

Implement this function if your code might block for long times inside the updateHook() function. Insert in this hook the code to wake up that code or signal it otherwise that updateHook() is requested to return (for example by setting a flag). The method returns false by default.

Returns:: true if well received and updateHook() will soon return. False otherwise.

Reimplemented in StatesTC.

Definition at line 311 of file TaskCore.cpp.

bool RTT::TaskCore::cleanup ( ) [virtual]

This method instructs a stopped component to enter the pre-operational state again. It calls cleanupHook().

Returns:: true if the component was in the Stopped state.

Reimplemented in RTT::corba::TaskContextProxy.

Definition at line 127 of file TaskCore.cpp.

void RTT::TaskCore::cleanupHook ( ) [protected, virtual]

Implement this method such that it contains the code which will be executed when cleanup() is called. The default implementation is an empty function.

Reimplemented in TestFileDescriptor, and StatesTC.

Definition at line 244 of file TaskCore.cpp.

bool RTT::TaskCore::configure ( ) [virtual]

This method instructs the component to (re-)read configuration data and try to enter the Stopped state. This can only succeed if the component is not running and configureHook() returns true.

Reimplemented in RTT::corba::TaskContextProxy.

Definition at line 104 of file TaskCore.cpp.

bool RTT::TaskCore::configureHook ( ) [protected, virtual]

Implement this method such that it contains the code which will be executed when configure() is called. The default implementation is an empty function which returns true.

Return values:

true	to indicate that configuration succeeded and the Stopped state may be entered.
false	to indicate that configuration failed and the Preoperational state is entered.

Reimplemented in StatesTC, and TestFileDescriptor.

Definition at line 292 of file TaskCore.cpp.

const ExecutionEngine* RTT::base::TaskCore::engine ( ) const [inline]

Get a const pointer to the ExecutionEngine of this Task.

Definition at line 327 of file TaskCore.hpp.

ExecutionEngine* RTT::base::TaskCore::engine ( ) [inline]

Get a pointer to the ExecutionEngine of this Task.

Definition at line 335 of file TaskCore.hpp.

void RTT::TaskCore::error ( ) [virtual]

Call this method in a Running state to indicate a run-time error condition. errorHook() will be called instead of updateHook(). If the error condition is solved, call recover().

Definition at line 152 of file TaskCore.cpp.

void RTT::TaskCore::errorHook ( ) [protected, virtual]

Implement this method to contain code that must be executed in the RunTimeError state, instead of updateHook(). This allows you to specify the behaviour in an erroneous component. errorHook() is called as long as the component is not recover()'ed. After recover()'ed, the updateHook() is called again.

Reimplemented in StatesTC.

Definition at line 301 of file TaskCore.cpp.

void RTT::TaskCore::exception ( ) [protected, virtual]

Call this method to indicate a run-time exception happend. First the TaskState is set to Exception. Next, if the taskstate was >= Running, stopHook() is called. Next, if the taskstate was >= Stopped, cleanupHook() is called. Finally, exceptionHook() is called. If any exception happens in exceptionHook(), fatal() is called.

Definition at line 159 of file TaskCore.cpp.

void RTT::TaskCore::exceptionHook ( ) [protected, virtual]

Implement this method to contain code that must be executed when transitioning to the Exception state. This allows you to specify the last actions in an erroneous component, after stopHook() and cleanupHook() were called.

See also:: recover() to leave the Exception state.

Reimplemented in StatesTC.

Definition at line 316 of file TaskCore.cpp.

void RTT::TaskCore::fatal ( ) [protected, virtual]

Call this method from any place to indicate that this component encountered a fatal error. It calls no hooks, the ExecutionEngine is stopped and the component waits destruction.

Definition at line 146 of file TaskCore.cpp.

unsigned RTT::TaskCore::getCpuAffinity ( ) const [virtual]

Get the configured cpu affinity of this component.

See also:: ActivityInterface::getCpuAffinity()

Definition at line 282 of file TaskCore.cpp.

Seconds RTT::TaskCore::getPeriod ( ) const [virtual]

Get the configured execution period of this component. Note that this value only is used when the component isActive() or isRunning().

Return values:

0.0	if the component is non-periodic (event based).
a	negative number when the component is not executable.
a	positive value when the component is periodic. The period is expressed in seconds.

Todo:: : add a bool setPeriod(double) function to allow changing the period at run-time.

Definition at line 272 of file TaskCore.cpp.

TaskCore::TaskState RTT::TaskCore::getTargetState ( ) const [virtual]

Returns the state this TaskCore is going to, or in case no transition is taking place, returns getTaskState(). For example, before start(), this function returns Stopped. During startHook(), it returns Running and after start() it also returns Running.

If getTaskState() != getTargetState, a transition is taking place.

See also:: getTaskState()

Definition at line 86 of file TaskCore.cpp.

TaskCore::TaskState RTT::TaskCore::getTaskState ( ) const [virtual]

Returns the current state of the TaskCore. For example, before start(), this function returns Stopped. During startHook() it returns Stopped, and after start() it returns Running.

See also:: getTargetState()

Reimplemented in RTT::corba::TaskContextProxy.

Definition at line 82 of file TaskCore.cpp.

bool RTT::TaskCore::inException ( ) const [virtual]

Inspect if the component is in the Exception state.

Definition at line 259 of file TaskCore.cpp.

bool RTT::TaskCore::inFatalError ( ) const [virtual]

Inspect if the component is in the FatalError state. There is no possibility to recover from this state. You need to destroy and recreate your component.

Reimplemented in RTT::corba::TaskContextProxy.

Definition at line 255 of file TaskCore.cpp.

bool RTT::TaskCore::inRunTimeError ( ) const [virtual]

Inspect if the component is in the RunTimeError state.

Reimplemented in RTT::corba::TaskContextProxy.

Definition at line 263 of file TaskCore.cpp.

bool RTT::TaskCore::isActive ( ) const [virtual]

Inspect if the component's ExecutionEngine is processing requests. Normally this is always the case, but user code could stop the ExecutionEngine manually.

Reimplemented in RTT::corba::TaskContextProxy.

Definition at line 267 of file TaskCore.cpp.

bool RTT::TaskCore::isConfigured ( ) const [virtual]

Inspect if the component is configured, i.e. in the Stopped, Active or Running state.

Reimplemented in RTT::corba::TaskContextProxy.

Definition at line 251 of file TaskCore.cpp.

bool RTT::TaskCore::isRunning ( ) const [virtual]

Inspect if the component is in the Running or RunTimeError state. As RunTimeError is a substate of Running, this method also returns true when the component is in one of these states. See inRunTimeError() or testing the run-time error state.

Reimplemented in RTT::corba::TaskContextProxy.

Definition at line 247 of file TaskCore.cpp.

void RTT::TaskCore::prepareUpdateHook ( ) [private, virtual]

This is how the EE informs the TaskContext that it is about to run updateHook. This function might be replaced by another mechanism in the future and currently serves to handle event ports callbacks.

Reimplemented in RTT::TaskContext.

Definition at line 304 of file TaskCore.cpp.

bool RTT::TaskCore::recover ( ) [virtual]

Call this method in a RunTimeError or Exception state to indicate that the run-time error conditions are gone and nominal operation is resumed. Makes transition to Running or PreOperational, depending on the state it was in.

Returns:: false if not applicable in the current state.

Definition at line 180 of file TaskCore.cpp.

bool RTT::TaskCore::setCpuAffinity ( unsigned cpu ) [virtual]

Sets the cpu affinity of this component.

Returns:: false if not allowed by the component's activity.

See also:: ActivityInterface::setCpuAffinity()

Definition at line 287 of file TaskCore.cpp.

void RTT::TaskCore::setExecutionEngine ( ExecutionEngine * engine )

Use this method to re-set the execution engine of this task core.

Parameters:

engine The new execution engine which will execute this TaskCore or null if a new execution engine must be created (the old is deleted in that case).

Postcondition:: The TaskCore is being run by engine or a new execution engine.

Definition at line 323 of file TaskCore.cpp.

bool RTT::TaskCore::setPeriod ( Seconds s ) [virtual]

Sets the period of this component. You may call this at any time, it is simply forwarded to the component's activity object.

Returns:: false if not allowed by the component's activity.

See also:: ActivityInterface::setPeriod()

Definition at line 277 of file TaskCore.cpp.

bool RTT::TaskCore::start ( ) [virtual]

This method starts the execution of the updateHook() with each trigger or period. This function calls the user function startHook(), which must return true in order to allow this component to run.

Return values:

false	if startHook() returned false if the component was not Stopped
true	if the Running state was entered.

Reimplemented in RTT::TaskContext, and RTT::corba::TaskContextProxy.

Definition at line 192 of file TaskCore.cpp.

bool RTT::TaskCore::startHook ( ) [protected, virtual]

Implement this method such that it contains the code which will be executed when start() is called. The default implementation is an empty function which returns true.

Return values:

true	to indicate that the component may run and the Running state may be entered.
false	to indicate that the component may not run and the Stopped state is entered.

Reimplemented in StatesTC, and TestFileDescriptor.

Definition at line 296 of file TaskCore.cpp.

bool RTT::TaskCore::stop ( ) [virtual]

This method stops the execution of updateHook() of this component. You can override this method to do something else or in addition. This function calls stopHook() as well.

Returns:: false if the component was not Running or not Active.

Reimplemented in RTT::TaskContext, and RTT::corba::TaskContextProxy.

Definition at line 214 of file TaskCore.cpp.

void RTT::TaskCore::stopHook ( ) [protected, virtual]

Implement this method such that it contains the code which will be executed when stop() is called. The default implementation is an empty function.

Reimplemented in StatesTC.

Definition at line 319 of file TaskCore.cpp.

bool RTT::TaskCore::trigger ( ) [virtual]

Invoke this method to trigger the thread of this TaskContext to execute its ExecutionEngine and the update() method.

Return values:

false	if this->engine()->getActivity()->trigger() == false
true	otherwise.

Definition at line 97 of file TaskCore.cpp.

bool RTT::TaskCore::update ( ) [virtual]

Invoke this method to execute the ExecutionEngine and the update() method.

Return values:

false	if this->engine()->getActivity()->execute() == false
true	otherwise.

Definition at line 90 of file TaskCore.cpp.

void RTT::TaskCore::updateHook ( ) [protected, virtual]

Function where the user must insert his 'application' code. When the ExecutionEngine's Activity is a periodic, this function is called by the ExecutionEngine in each periodic step after all messages are processed. When it is executed by a non periodic activity, this function is called after a message is received and executed. It should not loop forever, since no commands or events are processed when this function executes. The default implementation is an empty function.

Reimplemented in StatesTC, TestFileDescriptor, TheServer, TheServer, and EventPortsTC.

Definition at line 307 of file TaskCore.cpp.