Switch TimeSeries to nanosecond precision

[rolnico]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Does this PR already have an issue describing the problem?
No

What kind of change does this PR introduce?
Feature

What is the current behavior?
TimeSeries time precision is currently limited to millisecond.
TimeSeries internal time values are stored in a Long variable.

What is the new behavior (if this is a feature change)?
TimeSeries time precision is now limited to nanosecond.
TimeSeries internal time values are stored in an Instant variable (using a long for second precision + an int for the second to nano precision).
Micro and Nano TimeFormat have been added.

By default, the new methods that have a TimeFormat parameter uses TimeFormat.MILLIS to keep backward compatibility.

Does this PR introduce a breaking change or deprecate an API?

• Yes
• No

If yes, please check if the following requirements are fulfilled

• The Breaking Change or Deprecated label has been added
• The migration steps are described in the following section

What changes might users need to make in their application due to this PR? (migration steps)

The interface TimeSeriesIndex has new methods that you have to implement, should you implement this interface:

• void writeJson(JsonGenerator generator, TimeSeries.TimeFormat format)
• String toJson(TimeSeries.TimeFormat format)

Since time is now managed by using Instant instead of long variables, a few methods have been deprecated and will be removed in a future release:

Class	Deprecated method	New method
TimeSeriesIndex and all classes implementing this interface	long getTimeAt(int point)	Instant getInstantAt(int point)
AbstractPoint and all classes extending this abstract class	public long getTime()	public Instant getInstant()
IrregularTimeSeriesIndex	public IrregularTimeSeriesIndex(long[] times)	public IrregularTimeSeriesIndex(Instant[] instants)
RegularTimeSeriesIndex	public RegularTimeSeriesIndex(long startTime, long endTime, long spacing)	public RegularTimeSeriesIndex(Instant startInstant, Instant endInstant, Duration timeStep)
RegularTimeSeriesIndex	public long getStartTime()	public Instant getStartInstant()
RegularTimeSeriesIndex	public long getEndTime()	public Instant getEndInstant()
RegularTimeSeriesIndex	public long getSpacing()	public Instant getTimeStep()
DoublePoint	public DoublePoint(int index, long time, double value)	public DoublePoint(int index, Instant instant, double value)
StringPoint	public StringPoint(int index, long time, String value)	public StringPoint(int index, Instant instant, String value)

Following the change of underlying date-time variable format (from long to Instant), the TimeSeriesIndex.toJson and TimeSeriesIndex.writeJson exported formats have been changed to allow nano-second precision while keeping the backward compatibility, thanks to a new enum TimeSeriesIndex.ExportFormat:

• Old format that will still be used when timeFormat = TimeSeriesIndex.ExportFormat.MILLISECONDS (default value) for backward compatibility:

{
  "startTime" : 1420070400000,
  "endTime" : 1420074000000,
  "spacing" : 900000
}

• New format that will be used when timeFormat = TimeSeriesIndex.ExportFormat.NANOSECONDS:

{
  "startInstant" : 1420070400000000000,
  "endInstant" : 1420074000000000000,
  "timeStep" : 900000000000
}

Other information:

[sonarqubecloud]

Quality Gate passed

Issues
21 New issues
0 Accepted issues

Measures
0 Security Hotspots
93.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud