[netcdf-java] Problem using Redefine mode in netcdf-java 4.1

• To: <netcdf-java@xxxxxxxxxxxxxxxx>
• Subject: [netcdf-java] Problem using Redefine mode in netcdf-java 4.1
• From: <James.Dempsey@xxxxxxxx>
• Date: Sat, 20 Mar 2010 11:37:47 +1100

Hi,

I am using the current 4.1 netcdf-java library (4.1.20100311.2157 or change 14  
I believe) and encountering a problem when trying to use redefine mode. A 
similar problem also occurs using the latest 4.0 library.

Our aim is to create some command line tools that allow a netCDF file to be 
build up. First, define a dimension, then add a variable to it, then populate 
the variable. However when we close and reopen the file, any attempt to add a 
variable results in the following stack trace:

Exception in thread "main" java.io.IOException: The parameter is incorrect
at java.io.RandomAccessFile.setLength(Native Method)
at ucar.unidata.io.RandomAccessFile.close(RandomAccessFile.java:339)
at ucar.nc2.iosp.netcdf3.N3iosp.close(N3iosp.java:878)
at ucar.nc2.NetcdfFileWriteable.close(NetcdfFileWriteable.java:769)
at au.csiro.netcdf.CreateFile.main(CreateFile.java:45)

The following code demonstrates the problem.

package au.csiro.netcdf;

import java.io.IOException;

import ucar.ma2.DataType;
import ucar.nc2.Dimension;
import ucar.nc2.NetcdfFileWriteable;

public class CreateFile {

    private static String dimensionName = "lat";
    private static int dimensionSize = 20;
    private static String variableName = "temp";
    private static DataType variableDataType = DataType.getType("Float");

    public static void main(String[] args) throws IOException {
        String outputFilename = args[0];
        NetcdfFileWriteable ncFile = 
NetcdfFileWriteable.createNew(outputFilename, true);
        try  {
            Dimension dimension = new Dimension(dimensionName, dimensionSize, 
true /* isShared */,
                    false /* isUnlimited */, false /* isVariableLength */);
            ncFile.addDimension(null, dimension);
            ncFile.create();
        } finally {
            ncFile.close();
        }

        ncFile = NetcdfFileWriteable.openExisting(outputFilename, true);
        try {
            ncFile.setRedefineMode(true);
            ncFile.addVariable(variableName, variableDataType, dimensionName);
            ncFile.setRedefineMode(false);
        } finally {
            ncFile.close();
        }
    }

}

If the ncFile.close() and NetcdfFileWriteable.openExisting calls are commented 
out the file is successfully created with the variable. Could anyone advise if 
this is something I am doing wrong or a problem with the library please?

Cheers,
James Dempsey
Java Technical Lead | Software Services
Information Management and Technology
CSIRO Australia

• Follow-Ups:
  • Re: [netcdf-java] Problem using Redefine mode in netcdf-java 4.1
    • From: John Caron