RTT::SlaveActivity Class Reference
[Activity (thread) classes.]

An ActivityInterface implementation which executes 'step' upon the invocation of 'execute()', which is called by another Activity ('master'). More...

#include <rtt/SlaveActivity.hpp>

Inheritance diagram for RTT::SlaveActivity:

List of all members.

Public Types
typedef boost::shared_ptr < ActivityInterface >	shared_ptr
Public Member Functions
	SlaveActivity (ActivityInterface *master, RunnableInterface *run=0)
	Create an activity which is the slave of master.
	SlaveActivity (double period, RunnableInterface *run=0)
	Create an activity which is periodic.
	SlaveActivity (RunnableInterface *run=0)
	Create an activity for which trigger() will not be periodically called.
	~SlaveActivity ()
	Cleanup and notify the RunnableInterface that we are gone.
Seconds	getPeriod () const
	Get the periodicity of this activity in Seconds.
OS::ThreadInterface *	thread ()
	Returns a pointer to the thread which will run this activity.
bool	initialize ()
void	step ()
void	loop ()
bool	breakLoop ()
void	finalize ()
bool	start ()
	Start this slave.
bool	stop ()
	Stop the activity This will stop the activity by removing it from the 'run-queue' of a thread or call RunnableInterface::breakLoop().
bool	isRunning () const
	Query if the activity is initialized and executing.
bool	isPeriodic () const
	Inspect if this activity is periodic.
bool	isActive () const
	Query if the activity is started.
bool	execute ()
	Execute this activity such that it executes a step or loop of the RunnableInterface.
bool	trigger ()
	Trigger that work has to be done.
virtual bool	run (RunnableInterface *r)
	Run exclusively this RunnableInterface.
Protected Member Functions
void	disableRun (RunnableInterface *caller)
	This method is only meant for RunnableInterface (ie runner) in order to inform the ActivityInterface it should no longer be used.
Protected Attributes
RunnableInterface *	runner
Friends
class	RunnableInterface

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Detailed Description

An ActivityInterface implementation which executes 'step' upon the invocation of 'execute()', which is called by another Activity ('master').

The SlaveActivity can only be started if the master is active or if no master is present. If a master is used, this activity takes periodicity over from the master. If no master is present, use one of the alternative constructors to make a periodic slave or a non periodic slave.

Any activity object can be a master of a SlaveActivity, including itself. A master needs to keep track of its slave itself. There is no standard mechanism in RTT in which masters execute slaves. You need to code this yourself in your master activity by calling execute() on each Slave.

The only thing a slave does/can do is * be started and stopped independently. * notifying its master that it was triggered (if present) * copying the periodic/thread properties of its master (if present)

Reactions to execute():

In the non periodic case, RunnableInterface::loop() is called, in the periodic case, RunnableInterface::step() is called. In case the RunnableInterface did not implement loop(), step() is invoked by default. If no RunnableInterface is given, said functions are called upon SlaveActivity itself.

Reactions to trigger():

trigger() is ignored and returns false when no master is present.

When there is a master: In the non periodic case, trigger() is called upon the master (causing it to execute), in the periodic case, it is ignored (you can not trigger periodic activities).

Definition at line 89 of file SlaveActivity.hpp.

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Constructor & Destructor Documentation

RTT::SlaveActivity::SlaveActivity	(	ActivityInterface *	master,
		RunnableInterface *	run = 0
	)

Create an activity which is the slave of master.

Parameters:

	master	The activity which will execute this activity.
	run	Run this instance.

RTT::SlaveActivity::SlaveActivity	(	double	period,
		RunnableInterface *	run = 0
	)

Create an activity which is periodic.

If period == 0.0, this constructor is equivalent to the one below for non periodic activities.

Parameters:

	period	The periodicity at which you will trigger() this activity.
	run	Run this instance.

RTT::SlaveActivity::SlaveActivity

(

RunnableInterface *

run = 0

)

Create an activity for which trigger() will not be periodically called.

The period of this activity will be 0.0.

Parameters:

run

Run this instance.

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Member Function Documentation

void RTT::ActivityInterface::disableRun

(

RunnableInterface *

caller

)

[inline, protected, inherited]

This method is only meant for RunnableInterface (ie runner) in order to inform the ActivityInterface it should no longer be used.

run(0) can not be used in this case because it would recurse.

Definition at line 73 of file ActivityInterface.hpp.

bool RTT::SlaveActivity::execute

(

)

[virtual]

Execute this activity such that it executes a step or loop of the RunnableInterface.

When you invoke execute() you intend to call the step() or loop() methods. Some activity implementations allow a user controlled execute, others ignore it, in which case execute() returns false.

Semantics: If execute() returns true, the activity has been executed exactly once during execute().

Return values:

	true	When this->isActive() and the implementation allows external executes.
	false	When !this->isActive() or the implementation does not allow external updating.

See also:

trigger() for use in callbacks which want execute() to be executed.

Implements RTT::ActivityInterface.

Seconds RTT::SlaveActivity::getPeriod

(

)

const [virtual]

Get the periodicity of this activity in Seconds.

Returns:

The execution period of this activity (zero if !this->isPeriodic() ).

Implements RTT::ActivityInterface.

bool RTT::SlaveActivity::isActive

(

)

const [virtual]

Query if the activity is started.

This is less strict than isRunning(), it is true during initialize(), step() or loop() and finalize(). Use this method to check if an activity was start()ed.

Returns:

true if it is active, false otherwise

Implements RTT::ActivityInterface.

bool RTT::SlaveActivity::isPeriodic

(

)

const [virtual]

Inspect if this activity is periodic.

If so, it will call RunnableInterface::step(). If the activity is not periodic, it will call RunnableInterface::loop().

Returns:

true if periodic.

Implements RTT::ActivityInterface.

bool RTT::SlaveActivity::isRunning

(

)

const [virtual]

Query if the activity is initialized and executing.

This is more strict than isActive(), it is only true after initialize() is executed and before finalize() is executed. More-over, an Activity may decide to be temporarily not running (not executing code), waiting for a signal to proceed. If this->isActive() and !this->isRunning() then the Activity is in a waiting state.

Returns:

true if it is running, false otherwise

Implements RTT::ActivityInterface.

virtual bool RTT::ActivityInterface::run

(

RunnableInterface *

r

)

[virtual, inherited]

Run exclusively this RunnableInterface.

Precondition:

this->isRunning() == false

Parameters:

r

The RunnableInterface to run exclusively.

Returns:

true if succeeded, false otherwise

Referenced by RTT::NonPeriodicActivity::run().

bool RTT::SlaveActivity::start

(

)

[virtual]

Start this slave.

Only allowed if the master activity is already running.

Return values:

	false	if !master->isRunning() || this->isRunning() || initialize() returns false
	true	othwerise.

Implements RTT::ActivityInterface.

bool RTT::SlaveActivity::stop

(

)

[virtual]

Stop the activity This will stop the activity by removing it from the 'run-queue' of a thread or call RunnableInterface::breakLoop().

If no errors occured, RunnableInterface::finalize() is called.

See also:

isPeriodic()

Returns:

true if the activity is stopped, false otherwise

Implements RTT::ActivityInterface.

OS::ThreadInterface* RTT::SlaveActivity::thread

(

)

[virtual]

Returns a pointer to the thread which will run this activity.

Will not be null.

Implements RTT::ActivityInterface.

bool RTT::SlaveActivity::trigger

(

)

[virtual]

Trigger that work has to be done.

When you invoke trigger(), you intend to notify the mechanism that calls execute(), that execute() should be called. This allows a separation between actually executing code (execute()) and notifying that code must be executed (trigger()). A trigger may be ignored by the implementation, in which case trigger returns false.

Semantics: If trigger() returns true, the activity will be executed at least once from the moment trigger() is called.

Return values:

	true	When this->isActive() and the implementation allows external triggers.
	false	When !this->isActive() or the implementation does not allow external triggering.

Implements RTT::ActivityInterface.

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

• rtt/SlaveActivity.hpp