Re: [netcdf-java] JNA Based NetCDF Access

• To: <netcdf-java@xxxxxxxxxxxxxxxx>
• Subject: Re: [netcdf-java] JNA Based NetCDF Access
• From: <Tisham.Dhar@xxxxxxxx>
• Date: Tue, 13 Sep 2011 10:07:41 +1000

Hi All,

I have successfully activated the JNA based C-library bridge by including
package: ucar.nc2.jni.netcdf , particularly these files: JniIosp.java,
NCLibrary.java . Thanks for the head start John. I have also tested on
Linux and Mac since the current code only loads DLL's by adding load calls
for .so and .dylibs as below.

            String osName = System.getProperty("os.name");
            boolean isWin = osName != null
                    && osName.toLowerCase().contains("win");
            boolean isMacOS = osName != null
                    && osName.toLowerCase().contains("mac");
            boolean isLinux = osName != null
                    && osName.toLowerCase().contains("linux");
            if(isWin)
            {
                String dir = "C:/dev/tds/thredds/lib/binary/win32/";
                System.setProperty("jna.library.path", dir);
    
                System.load(dir + "zlib1.dll");
                System.load(dir + "szlibdll.dll");
                System.load(dir + "hdf5dll.dll");
                System.load(dir + "hdf5_hldll.dll");
            }
            else if(isMacOS)
            {
                String dir = "/opt/local/lib/";
                System.setProperty("jna.library.path", dir);
                System.load(dir + "libz.dylib");
                System.load(dir + "libsz.dylib");
                System.load(dir + "libhdf5.dylib");
                System.load(dir + "libhdf5_hl.dylib");
            }
            else if(isLinux)
            {
                String dir = "/usr/lib/";
                System.setProperty("jna.library.path", dir);
                System.load(dir + "x86_64-linux-gnu/libz.so");
            }

The timing benchmarks indicate that the access is faster across the board
than pure Java for sub 1GB files, you can read details of the benchmark
here: http://forum.worldwindcentral.com/showpost.php?p=97182&postcount=6 .
I am hoping that the JNA bindings to the C-library will move from
experimental to testing to production soon.

Cheers,

Tisham.

• Follow-Ups:
  • Re: [netcdf-java] JNA Based NetCDF Access
    • From: John Caron