javax.realtime
Class Clock

java.lang.Object
  javax.realtime.Clock

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(), and it can have events queued on it which will be fired when their appointed time is reached.

Clock

public Clock()

Constructor for the abstract class.

getEpochOffset

public abstract RelativeTime getEpochOffset()

Returns the relative time of the offset of the epoch of this clock from the Epoch. For the real-time clock it will return a RelativeTime value equal to 0. An UnsupportedOperationException is thrown if the clock does not support the concept of date.

Returns:

A newly allocated RelativeTime object in the current execution context with the offset past the Epoch for this clock. The returned object is associated with this clock.

Throws:

java.lang.UnsupportedOperationException - Thrown if the clock does not have the concept of date.

Since:

1.0.1

getRealtimeClock

public static Clock getRealtimeClock()

There is always at least one clock object available: the system real-time clock. This is the default Clock.

Returns:

The singleton instance of the default Clock

getResolution

public abstract RelativeTime getResolution()

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

Returns:

A newly allocated RelativeTime object in the current execution context representing the resolution of this. The returned object is associated with this clock.

getTime

public abstract AbsoluteTime getTime()

Gets the current time in a newly allocated object.
Note: This method will return an absolute time value that represents the clock's notion of an absolute time. For clocks that do not measure calendar time this absolute time may not represent a wall clock time.

Returns:

A newly allocated instance of AbsoluteTime in the current allocation context, representing the current time. The returned object is associated with this clock.

getTime

public abstract AbsoluteTime getTime(AbsoluteTime dest)

Gets the current time in an existing object. The time represented by the given AbsoluteTime is changed at some time between the invocation of the method and the return of the method. Note: This method will return an absolute time value that represents the clock's notion of an absolute time. For clocks that do not measure calendar time this absolute time may not represent a wall clock time.

Parameters:

dest - The instance of AbsoluteTime object which will be updated in place. The clock association of the dest parameter is ignored. When dest is not null the returned object is associated with this clock. If dest is null, then nothing happens.

Returns:

The instance of AbsoluteTime passed as parameter, representing the current time, associated with this clock, or null if dest was null.

Since:

1.0.1 The return value is updated from void to AbsoluteTime.

setResolution

public abstract void setResolution(RelativeTime resolution)

Set the resolution of this. For some hardware clocks setting resolution is impossible and if this method is called on those clocks, then an UnsupportedOperationException is thrown.

Parameters:

resolution - The new resolution of this, if the requested value is supported by this clock. If resolution is smaller than the minimum resolution supported by this clock then it throws IllegalArgumentException. If the requested resolution is not available and it is larger than the minimum resolution, then the clock will be set to the closest resolution that the clock supports, via truncation. The value of the resolution parameter is not altered. The clock association of the resolution parameter is ignored.

Throws:

java.lang.IllegalArgumentException - Thrown if resolution is null, or if the requested resolution is smaller than the minimum resolution supported by this clock.

java.lang.UnsupportedOperationException - Thrown if the clock does not support setting its resolution.