Expose Grib2JpegDecoder

[archmoj]

Description of Changes

• Change Grib2JpegDecoder constructor to public access modifier

Exposing Grib2JpegDecoder constructor could help applications to extract data section in JPEG-2000 format directly.
Also according to this documentation (https://docs.unidata.ucar.edu/netcdf-java/4.6/javadocAll/index.html?ucar/nc2/grib/grib2/Grib2JpegDecoder.html) it is expected to be a public method.
Please let me know if I'm missing something.
Thank you.

PR Checklist

• Link to any issues that the PR addresses
• Add labels
• Open as a draft PR
  until ready for review
• Make sure GitHub tests pass
• Mark PR as "Ready for Review"

[CLAassistant]

All committers have signed the CLA.

[lesserwhirls]

Greetings @archmoj! Thank you for your suggestion. I am open to the idea of opening up access to this class, with the understanding that it isn't part of the actual netCDF-Java public API, and it isn't subject to the same guarantees implied with semantic versioning (the javadocAll javadocs are really meant for netCDF-Java developers, not application developers). That said, if a developer needs to call this, I'm guessing it is likely because a specific GRIB Grid Definition Section isn't supported (and thus netCDF-Java bails early), and I would much rather get that supported so that data can actually be read through the public API.

Can you tell me a little more about the specific use case you have for wanting to use this directly?

[archmoj]

Hi @lesserwhirls,
Thanks for the review and all your great contributions!
I'm working on this App where I handled various GRIB2 sections. But for the data section when it is encoded in JPEG-2000 format I need to use an external library.
For the moment I imported ucar.jpeg.jj2000.j2k.decoder.Grib2JpegDecoder and used its Grib2JpegDecoder here:
https://github.com/archmoj/grib2_solarchvision/blob/29325e31a2cd7ac20d15232de9526435544c6294/app/src/main/java/grib2_solarchvision/App.java#L9501-L9507

          String[] argv = new String[4];
          argv[0] = "-rate";
          argv[1] = nf(this.NumberOfBitsUsedForEachPackedValue, 0); // number of bits per pixel
          argv[2] = "-verbose";
          argv[3] = "off";

          Grib2JpegDecoder g2j = new Grib2JpegDecoder(argv);

But it would be nice to replace it with this adaptation of jj2000.j2k.decoder.Decoder, in order to read input from memory.

Also it would simplify providing the dependencies here:
https://github.com/archmoj/grib2_solarchvision/blob/29325e31a2cd7ac20d15232de9526435544c6294/app/build.gradle#L32-L34
by removing the need to provide ibs/grib-4.3.jar.

Thank you!