SelectorBase Class Reference

Reports activity on a set of devices. More...

#include <cxxtools/selector.h>

Inheritance diagram for SelectorBase:

List of all members.

Public Member Functions
virtual	~SelectorBase ()
	Destructor.
void	add (Selectable &s)
	Adds an IOResult.
void	remove (Selectable &s)
	Cancel an IOResult.
void	add (Timer &timer)
	Adds a Timer.
void	remove (Timer &timer)
	Removes a Timer.
bool	wait (std::size_t msecs=WaitInfinite)
	Wait for activity.
void	wake ()
	Wakes the selctor from waiting.
Static Public Attributes
static const std::size_t	WaitInfinite = static_cast<const std::size_t>(-1)
Protected Member Functions
	SelectorBase ()
	Default constructor.
void	onAddTimer (Timer &timer)
void	onRemoveTimer (Timer &timer)
void	onTimerChanged (Timer &timer)
virtual void	onAdd (Selectable &)=0
	A Selectable is added to this Selector.
virtual void	onRemove (Selectable &)=0
	A Selectable is removed from this Selector.
virtual void	onReinit (Selectable &)=0
	A Selectable is reinitialised and needs to be updated.
virtual void	onChanged (Selectable &s)=0
	A Selectable in this Selector has changed.
virtual bool	onWait (std::size_t msecs)=0
virtual void	onWake ()=0
Friends
class	Selectable
class	Timer

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Detailed Description

A Selector can be used to monitor a set of Selectables and Timers and wait for activity on them. The wait call can be performed with a timeout and the respective timeout signal is sent if it occurs. Clients can be notified about Timer and Selectable activity by connecting to the appropriate signals of the Timer and Selectable classes.

The following example uses a Selector to wait on acitvity on a Timer, which is set to time-out after 1000 msecs.

        // slot to handle timer activity
        void onTimer();

        int main()
        {
            using cxxtools::System;

            Timer timer;
            timer.start(1000);
            connect(timer.timeout, ontimer);

            Selector selector;
            selector.addTimer(timer);
            selector wait();

            return 0;
        }

A Selector is the heart of the EventLoop, which calls Selector::wait continously. The EventLoop and Application classes provide the same API as the Selector itself.

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Member Function Documentation

void add

(

Selectable &

s

)

Adds an IOResult to the selector. IOResult are removed automatically when they get destroyed.

void add

(

Timer &

timer

)

Adds a Timer to the selector. Timers are removed automatically when they get destroyed.

Parameters:

timer

The device to add

void remove

(

Timer &

timer

)

Parameters:

timer

The timer to remove

bool wait

(

std::size_t

msecs = WaitInfinite

)

This method will wait for activity on the registered Selectables and Timers. Use Selector::WaitInfinite to wait without timeout.

Parameters:

msecs

timeout in miliseconds

void wake

(

)

This method can be used to end a Selector::wait call before the timeout expires. It is supposed to be used from another thread and thus is thread-safe.

virtual void onAdd

(

Selectable &

)

[protected, pure virtual]

Do not throw exceptions.

Implemented in EventLoop.

virtual void onRemove

(

Selectable &

)

[protected, pure virtual]

Do not throw exceptions.

Implemented in EventLoop.

virtual void onReinit

(

Selectable &

)

[protected, pure virtual]

Do not throw exceptions.

Implemented in EventLoop.

virtual void onChanged

(

Selectable &

s

)

[protected, pure virtual]

Do not throw exceptions.

Implemented in EventLoop.