alexaClientSDK::avsCommon::utils::timing::Timer Class Reference

Timer to schedule task for delayed and periodic execution. More...

#include <Timer.h>

Public Types
enum	PeriodType { PeriodType::ABSOLUTE, PeriodType::RELATIVE }
	Specifies different ways to apply the period of a recurring task. More...

Public Member Functions
	Timer (const std::shared_ptr< sdkInterfaces::timing::TimerDelegateFactoryInterface > &timerDelegateFactory=avs::initialization::SDKPrimitivesProvider::getInstance() ->getTimerDelegateFactory()) noexcept
	Constructs a Timer. More...
	~Timer () noexcept
	Destructs a Timer. More...
template<typename Delay , typename Period , typename Task , typename... Args>
bool	start (Delay &&delay, Period &&period, PeriodType periodType, size_t maxCount, Task &&task, Args &&... args) noexcept
	Submit a callable type for periodic execution. More...
template<typename Period , typename Task , typename... Args>
bool	start (Period &&period, PeriodType periodType, size_t maxCount, Task &&task, Args &&... args) noexcept
	Submit a callable type for periodic execution. More...
template<typename Delay , typename Task , typename... Args>
auto	start (Delay &&delay, Task &&task, Args &&... args) noexcept -> std::future< decltype(task(args...))>
	Submit a callable type for single execution with future result. More...
void	stop () noexcept
	Stop the timer. More...
bool	isActive () const noexcept
	Check if timer is active. More...

Static Public Member Functions
static size_t	getForever () noexcept
	Static member function to get FOREVER. More...

Static Public Attributes
static constexpr size_t	FOREVER = 0

Detailed Description

Timer to schedule task for delayed and periodic execution.

A Timer is used to schedule a callable type to run in the future.

Member Enumeration Documentation

PeriodType

enum alexaClientSDK::avsCommon::utils::timing::Timer::PeriodType

strong

Specifies different ways to apply the period of a recurring task.

Enumerator
ABSOLUTE	The period specifies the time from the start of one task call to the start of the next task call. This period type ensures task calls occur on a predictable cadence. Note A timer makes one task call at a time, so if a task call takes more than one period to execute, the subsequent calls which would have occured while the task was still executing will be skipped, and the next call will not occur until the next period-multiple after the original task call completes.
RELATIVE	The period specifies the time from the end of one task call to the start of the next task call. This period type ensures a specific amount of idle time between task calls.

Constructor & Destructor Documentation

Timer()

alexaClientSDK::avsCommon::utils::timing::Timer::Timer ( const std::shared_ptr< sdkInterfaces::timing::TimerDelegateFactoryInterface > &  timerDelegateFactory = avs::initialization::SDKPrimitivesProvider::getInstance() ->getTimerDelegateFactory() )

noexcept

Constructs a Timer.

Parameters

[in]

timerDelegateFactory

A factory to create the TimerDelegate. By if the parameter is nullptr, implementation will use TimerDelegateFactory.

~Timer()

alexaClientSDK::avsCommon::utils::timing::Timer::~Timer ( )

noexcept

Destructs a Timer.

Member Function Documentation

getForever()

static size_t alexaClientSDK::avsCommon::utils::timing::Timer::getForever ( )

inlinestaticnoexcept

Static member function to get FOREVER.

isActive()

bool alexaClientSDK::avsCommon::utils::timing::Timer::isActive ( ) const

noexcept

Check if timer is active.

Reports whether the Timer is active. A timer is considered active if it is waiting to start a call to the task, or if a call to the task is in progress. A timer is only considered inactive if it has not been started, if all requested/scheduled calls to the task have completed, or after a call to stop().

Returns

true if the Timer is active, else false.

start() [1/3]

template<typename Delay , typename Period , typename Task , typename... Args>

bool alexaClientSDK::avsCommon::utils::timing::Timer::start ( Delay &&  delay, Period &&  period, PeriodType  periodType, size_t  maxCount, Task &&  task, Args &&...  args  )

noexcept

Submit a callable type for periodic execution.

Submits a callable type (function, lambda expression, bind expression, or another function object) to be executed after an initial delay, and then called repeatedly on a fixed time schedule. A Timer instance manages only one running Timer at a time; calling start() on an already-running Timer will fail. Note that the template parameters are typically inferred from the function paramters when calling start().

Template Parameters

Delay	Initial delay type. This can be any specialization of std::chrono::duration convertible to std::chrono::nanoseconds.
Period	Period type. This can be any specialization of std::chrono::duration convertible to std::chrono::nanoseconds.
Task	The type of task to execute.
Args	The argument types for the task to execute.

Parameters

[in]	delay	The non-negative time to wait before making the first task call. Negative values will cause this function to return false.
[in]	period	The non-negative time to wait between subsequent task calls. Negative values will cause this function to return false.
[in]	periodType	The type of period to use when making subsequent task calls.
[in]	maxCount	The desired number of times to call task. Timer::getForever() means to call forever until Timer::stop() is called. Note that fewer than maxCount calls may occur if periodType is PeriodType::ABSOLUTE and the task runtime exceeds period.
[in]	task	A callable type representing a task.
[in]	args	The arguments to call the task with.

Returns

true if the timer started, else false.

start() [2/3]

template<typename Period , typename Task , typename... Args>

bool alexaClientSDK::avsCommon::utils::timing::Timer::start ( Period &&  period, PeriodType  periodType, size_t  maxCount, Task &&  task, Args &&...  args  )

noexcept

Submit a callable type for periodic execution.

Submits a callable type (function, lambda expression, bind expression, or another function object) to be executed repeatedly on a fixed time schedule. A Timer instance manages only one running Timer at a time; calling start() on an already-running Timer will fail. Note that the template parameters are typically inferred from the function paramters when calling start().

Template Parameters

Period	Period and initial delay type. This can be any specialization of std::chrono::duration convertible to std::chrono::nanoseconds.
Task	The type of task to execute. This must be callable with args parameters.
Args	The argument types for the task to execute.

Parameters

[in]	period	The non-negative time to wait before each task call. Negative values will cause this function to return false.
[in]	periodType	The type of period to use when making subsequent task calls.
[in]	maxCount	The desired number of times to call task. Timer::getForever() means to call forever until Timer::stop() is called. Note that fewer than maxCount calls may occur if periodType is PeriodType::ABSOLUTE and the task runtime exceeds period.
[in]	task	A callable type representing a task.
[in]	args	The arguments to call task with.

Returns

true if the timer started, else false.

start() [3/3]

template<typename Delay , typename Task , typename... Args>

auto alexaClientSDK::avsCommon::utils::timing::Timer::start ( Delay &&  delay, Task &&  task, Args &&...  args  ) -> std::future<decltype(task(args...))>

noexcept

Submit a callable type for single execution with future result.

Submits a callable type (function, lambda expression, bind expression, or another function object) to be executed once, after the specified duration. A Timer instance manages only one running Timer at a time; calling start() on an already-running Timer will fail. Note that the template parameters are typically inferred from the function parameters when calling start().

Template Parameters

Delay	Delay type. This can be any specialization of std::chrono::duration convertible to std::chrono::nanoseconds.
Task	The type of task to execute.
Args	The argument types for the task to execute.

Parameters

[in]	delay	The non-negative time to wait before calling task. Negative values will cause this function to return an invalid future.
[in]	task	A callable type representing a task.
[in]	args	The arguments to call task with.

Returns

A valid std::future for the return value of task if the timer started, else an invalid std::future. Note that the promise will be broken if Timer::stop() is called before task is called.

stop()

void alexaClientSDK::avsCommon::utils::timing::Timer::stop ( )

noexcept

Stop the timer.

Stops the Timer (if running). This will not interrupt an active call to the task, but will prevent any subsequent calls to the task. If stop() is called while the task is executing, this function will block until the task completes.

Note

In the special case that stop() is called from inside the task function, stop() will still prevent any subsequent calls to the task, but will not block as described above.

Member Data Documentation

FOREVER

constexpr size_t alexaClientSDK::avsCommon::utils::timing::Timer::FOREVER = 0

static

Value for start()'s maxCount parameter which indicates that the Timer should continue firing indefinitely.

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

• /workplace/avs-device-sdk/AVSCommon/Utils/include/AVSCommon/Utils/Timing/Timer.h