org.openimaj.time

Interface TimeKeeper<T extends Timecode>

Type Parameters:

T - The type of Timecode

All Superinterfaces:

Runnable

All Known Implementing Classes:

AudioPlayer, BasicMusicTimekeeper, VideoDisplay.BasicVideoTimeKeeper

public interface TimeKeeper<T extends Timecode>
extends Runnable

A time keeper knows what time it is. You can ask the time keeper what time it is using the getTime() method.

Subclasses must override the method to return appropriate time-based objects. Note that the time keeper is passive - it does not let anyone know when certain times occur - it merely provides times when asked.

Initially the timekeeper should not be started but should only start when run() is called. TimeKeepers may run continuously, so it is important that timekeepers are run in threads.

new Thread( timeKeeper ).start()

For time keepers that do not run continuously this will incur an overhead, so if you know that your time keeper does not run continuously, you should control it closely; otherwise timekeepers of unknown type should be run in threads. If your timekeeper does run in a thread, then the stop() method should cause the timekeeper to exit the run method.

The semantic difference between pause and stop is that pause is intended for short term stoppages in the running of the timekeeper that will result in the timekeeper being restarted either from the same position or from a newly seeked position. The stop method is expected to be called when the timekeeper is being shut down or will be required to start from the beginning again when restarted. Some timekeepers may not support mid-stream stopping and they should return false for the supportsPause() method. Similarly, timekeepers that do not support seeking should return false for the supportsSeek() method.

Author:

David Dupplaw (dpd@ecs.soton.ac.uk)

Created:

28 Nov 2011

Method Summary

Modifier and Type	Method and Description
T	getTime() Returns the current time.
void	pause() Pause the running of the timekeeper.
void	reset() Reset the timekeeper.
void	run() Use this method to start the time keeper running.
void	seek(long timestamp) Seek to a given timestamp.
void	stop() Use this method to stop the time keeper from running.
boolean	supportsPause() Returns whether the timekeeper supports pausing.
boolean	supportsSeek() Returns whether the timekeeper supports seeking.

Method Detail

run

void run()

Use this method to start the time keeper running.

Specified by:

run in interface Runnable

See Also:

Runnable.run()

pause

void pause()

Pause the running of the timekeeper.

stop

void stop()

Use this method to stop the time keeper from running.

getTime

T getTime()

Returns the current time.

Returns:

the current time object.

seek

void seek(long timestamp)

Seek to a given timestamp.

Parameters:

timestamp - The timestamp to seek to

reset

void reset()

Reset the timekeeper.

supportsPause

boolean supportsPause()

Returns whether the timekeeper supports pausing. If the timekeeper supports pausing then a stop() followed by a run() will continue from where the timekeeper was paused. Use reset() inbetween to force the timekeeper to start from the beginning again.

Returns:

TRUE if the timekeeper supports pausing.

supportsSeek

boolean supportsSeek()

Returns whether the timekeeper supports seeking.

Returns:

TRUE if the timekeeper supports seeking.