A class encapsulating a software loop. More...

#include <QDaqJob.h>

Inheritance diagram for QDaqLoop:

Collaboration diagram for QDaqLoop:

Public Slots
bool	arm ()
	Arm the loop. More...

void	disarm ()
	Disarm the loop.

QString	stat ()
	Print loop statistics.

void	createLoopEngine ()
	Create a dedicated QDaqScriptEngine. More...

Public Slots inherited from QDaqObject
QString	errorBacktrace (int maxItems=10) const
	Print a backtrace of recent errors in this QDaqObject.

QString	path () const
	Return the object's path in the QDaq tree. More...

QString	objectTree () const
	Output in a string the object hierarchy beneath this object.

QString	listProperties () const
	List the objects properties.

QString	listFunctions () const
	List the objects scriptable functions.

QDaqObject *	parent () const

QDaqObjectList	children () const
	Return a list of children of this object.

bool	hasChildren () const
	Returns true if the object has children.

QDaqObject *	appendChild (QDaqObject *obj)
	Adds a new child QDaqObject, as the last child and returns a pointer to it.

QDaqObject *	insertBefore (QDaqObject newobj, QDaqObject existingobj)
	Adds a new child QDaqObject, before an existing child and returns a pointer to it.

QDaqObject *	clone ()
	Clone a QDaqObject with its child objects.

QDaqObject *	removeChild (QDaqObject *obj)
	Remove a child and return a pointer to it.

QDaqObject *	replaceChild (QDaqObject newobj, QDaqObject oldobj)
	Replace a child and return a pointer to the old child.

QDaqObject *	findChild (const QString &name) const
	Find the first child QDaqObject with objectName equal to name.

Signals
void	abort ()
	This is emitted if the loop aborts due to an error.

Signals inherited from QDaqObject
void	propertiesChanged ()
	Fired when object properties have changed.

void	updateWidgets ()
	Fired when widgets need update.

Public Member Functions
bool	isTop () const
	Return true if this is a top level loop.

QDaqLoop *	parentLoop () const
	Return the parent loop of this loop.

Public Member Functions inherited from QDaqJob
Q_INVOKABLE	QDaqJob (const QString &name)
	QDaqJob constructor. More...

virtual void	attach ()
	Attach this QDaqObject to the QDaq tree. More...

virtual void	detach ()
	Detach this QDaqObject from the QDaq tree. More...

QDaqLoop *	topLoop () const
	Returns the top level loop that this job belongs to.

QDaqLoop *	loop () const
	Returns the loop that this job belongs to.

virtual QDaqScriptEngine *	loopEngine () const
	Returns the QDaqScriptEngine of the top level loop.

Public Member Functions inherited from QDaqObject
Q_INVOKABLE	QDaqObject (const QString &name)
	Construct a QDaqObject with a name. More...

bool	isAttached () const
	Returns true is this object is attached to the QDaq tree.

Protected Member Functions
virtual bool	exec ()
	Called when a loop is executed. More...

virtual bool	arm_ ()
	Performs internal initialization for the job. More...

virtual void	disarm_ ()
	Performs internal de-initialization. More...

Protected Member Functions inherited from QDaqJob
bool	setArmed (bool on)
	Arms or disarms a job. More...

virtual bool	run ()
	This function performs the actual task of this QDaqJob. More...

Protected Member Functions inherited from QDaqObject
void	pushError (const QString &type, const QString &descr=QString()) const
	Push an error in the error queue.

void	throwScriptError (const QString &msg) const
	Throw a script error with message msg.

bool	checkName (const QString &name) const
	Check if name is a legal name for an QDaqObject. More...

virtual void	writeh5 (H5::Group g, QDaqH5File f) const
	Write contents of the object to a H5 group. More...

virtual void	readh5 (H5::Group g, QDaqH5File f)
	Read contents of the object from a H5 group. More...

Properties
uint	count
	Number of executed loop cycles (read-only). More...

uint	limit
	Total number of cycles to be executed. More...

uint	delay
	Number of parent loop cycles before this loop is called. More...

uint	preload
	Preload the internal counter. More...

uint	period
	The repetition period in ms. More...

Properties inherited from QDaqJob
bool	armed
	True if job is armed. More...

QString	runCode
	Script code executed by the job at each repetition. More...

QString	armCode
	Script code executed by the job in the arming face. More...

QString	disarmCode
	Script code executed by the job in the dis-arming face. More...

Additional Inherited Members
Static Public Member Functions inherited from QDaqObject
static QDaqRoot *	root ()
	Obtain a pointer to the one-and-only QDaqRoot object.

static QDaqObject *	fromPath (const QString &path)
	Return a pointer to an object given its full path in the QDaq tree. More...

Public Attributes inherited from QDaqObject
QMutex	comm_lock
	A recursive mutex for synching thread access to this object.

Detailed Description

A class encapsulating a software loop.

QDaqLoop is used to execute a number of child-jobs and/or child-loops.

By setting the class properties we can arrange for a number of different execution scenarios: repetitive with given period repeat for ever or for a given number of cycles skip execution every delay cycles single shot

A QDaqLoop that has no QDaqLoop ancestor is considered a "top level loop" (isTop() returns true). Otherwise the loop is a child-loop.

When arm() is called on a top level loop, a new QTimerThread is spawned that calls exec() at each timer repetition.

If arm() is called on a child loop, then it simply arms all child jobs. The exec() function of a child loop is called from the top level loop thread.

To use QDaqLoop, create the object and build underneath it a tree of child-jobs and child-loops that perform the required tasks in the correct order. Then attach the loop to the QDaq tree either as a child of the root object ("qdaq") or under another object that does not have a QDaqLoop anchestor. Thus the loop becomes top level.

Definition at line 285 of file QDaqJob.h.

Member Function Documentation

bool QDaqLoop::arm ( )

inlineslot

Arm the loop.

If this is a top level loop then this function starts the timer thread after succesfully arming all child jobs.

If it is a child loop then only the arming is done.

Returns: true if the loop is succesfully armed.

Definition at line 409 of file QDaqJob.h.

bool QDaqLoop::arm_ ( )

protectedvirtual

Performs internal initialization for the job.

It is called by the setArmed() function.

This function can be reimplemented to perform specific initialization for a job. The parent class arm_() function should be called afterwards.

In the default implementation, if a loopEngine() exists the script code is checked against the script engine for errors.

If initialization is sucessfull it returns true, otherwise the function returns false.

Reimplemented from QDaqJob.

Definition at line 288 of file QDaqJob.cpp.

void QDaqLoop::createLoopEngine ( )

slot

Create a dedicated QDaqScriptEngine.

The created script engine will be used for running script code of child jobs.

The created script engine lives executes code within the loop timer thread.

All child jobs can obtain a pointer to this engine with loopEngine().

Definition at line 378 of file QDaqJob.cpp.

void QDaqLoop::disarm_ ( )

protectedvirtual

Performs internal de-initialization.

It is called by the setArmed() function.

Can be reimplemented to define special behavior during dis-arming. The parent class disarm_() should be called.

Reimplemented from QDaqJob.

Definition at line 306 of file QDaqJob.cpp.

bool QDaqLoop::exec ( )

protectedvirtual

Called when a loop is executed.

In a top level loop this function is called at each repetition of the timer thread.

In a child-loop exec() is called from the parent loop according to the order of the child-loop in the tree structure.

This function first locks the mutexes of all child jobs to prevent access from other threads. Then it calls QDaqJob::exec() which runs all child jobs. Finally it unlocks the mutexes in the reverse order as they were locked.

The signals updateWidgets() and propertiesChanged() are emitted at each valid repetition.

Returns

Reimplemented from QDaqJob.

Definition at line 242 of file QDaqJob.cpp.

Property Documentation

uint QDaqLoop::count

read

Number of executed loop cycles (read-only).

It is reset to 0 when the loop is armed.

Definition at line 292 of file QDaqJob.h.

uint QDaqLoop::delay

readwrite

Number of parent loop cycles before this loop is called.

The loop is executed every delay repetitions of the parent loop.

If delay is 0 or 1 then the loop is executed at each repetition.

Definition at line 305 of file QDaqJob.h.

uint QDaqLoop::limit

readwrite

Total number of cycles to be executed.

If limit is equal to 0 (default) then the loop runs indefinately.

Definition at line 297 of file QDaqJob.h.

uint QDaqLoop::period

readwrite

The repetition period in ms.

This is meaningful only for the top level loop.

Definition at line 317 of file QDaqJob.h.

uint QDaqLoop::preload

readwrite

Preload the internal counter.

Can be used in combination with delay to run loops out of phase.

Definition at line 312 of file QDaqJob.h.

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

/home/george/Dev/rtlab/qdaq/lib/core/QDaqJob.h
/home/george/Dev/rtlab/qdaq/lib/core/QDaqJob.cpp

Public Slots

Signals

Public Member Functions

Protected Member Functions

Properties

Additional Inherited Members

Detailed Description

Member Function Documentation

Property Documentation