javax.realtime

Class Clock

java.lang.Object

javax.realtime.Clock

Direct Known Subclasses:

RealtimeClock

@SCJAllowed
public abstract class Clock
extends java.lang.Object

A clock marks the passing of time. It has a concept of now that can be queried through Clock.getTime().
The Clock instance returned by getRealtimeClock() may be used in any context that requires a clock.

Version:

1.2; - December 2013

Author:

Anders P. Ravn, Aalborg University, apr@cs.aau.dk,
Hans Søndergaard, VIA University College, Denmark, hso@via.dk

Relative_to_SCJ_Draft_Version_0.94:

- SCJ issue: The semantics of getTime with dest differs from getTime with no arguments. It is made consistent below.

- semantic issue: EpochOffSet must be relative to RealTimeClock?

- implementation issue: The constructor public Clock() is public, if user-defined clocks are allowed, else package protected.
- implementation issue: Omitted ? , - the following methods are not implemented:

• public abstract boolean drivesEvents();
  
• public abstract void registerCallBack(AbsoluteTime t, ClockCallBack clockEvent);
  
• public abstract boolean resetTargetTime(AbsoluteTime time);

Method Summary

Methods

Modifier and Type	Method and Description
abstract RelativeTime	getEpochOffset() Returns the relative time of the offset of the epoch of this clock from the Epoch of the RealtimeClock.
static Clock	getRealtimeClock()
abstract RelativeTime	getResolution() Gets the resolution of the clock, the nominal interval between ticks.
abstract RelativeTime	getResolution(RelativeTime dest) Gets the resolution of the clock, the nominal interval between ticks and stores the result in dest.
abstract AbsoluteTime	getTime() Creates a new object representing now of this clock.
abstract AbsoluteTime	getTime(AbsoluteTime dest) Stores now of this clock in dest.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getEpochOffset

@SCJAllowed
public abstract RelativeTime getEpochOffset()

Returns the relative time of the offset of the epoch of this clock from the Epoch of the RealtimeClock.

Returns:

the offset of this clock epoch from the RealtimeClock. The returned object is associated with this clock.

getRealtimeClock

public static Clock getRealtimeClock()

Returns:

The singleton instance of the default Clock.

getResolution

@SCJAllowed
public abstract RelativeTime getResolution()

Gets the resolution of the clock, the nominal interval between ticks.

Returns:

The initially allocated resolution object. The returned object is associated with this clock.

getResolution

@SCJAllowed
public abstract RelativeTime getResolution(RelativeTime dest)

Gets the resolution of the clock, the nominal interval between ticks and stores the result in dest.

Parameters:

dest - if dest is null, allocate a new RelativeTime instance to hold the returned value.

Returns:

if dest is not null, it is set to the resolution object of this. Otherwise a newly allocated object is returned. The returned object is associated with this clock.

getTime

@SCJAllowed
public abstract AbsoluteTime getTime()

Creates a new object representing now of this clock.

Returns:

A new AbsoluteTime object whose time is now of this clock.

getTime

@SCJAllowed
public abstract AbsoluteTime getTime(AbsoluteTime dest)

Stores now of this clock in dest.

Parameters:

dest - If dest is null, allocate a new AbsoluteTime instance to hold the returned value.

Returns:

The resulting value.