Hi John,
Thanks for that - we'll grab the update once it is ready and give a workout. At
the moment we have used a workaround involving a temporary variable that we
delete as part of the first add variable operation.
Thanks for the warning about define mode too - we'll keep an eye on that. The
good news is that so far it seems to be working nicely other than this one
issue.
Cheers,
James Dempsey
Java Technical Lead | Software Services
Information Management and Technology
CSIRO Australia
-----Original Message-----
From: John Caron [mailto:caron@xxxxxxxxxxxxxxxx]
Sent: Tuesday, 23 March 2010 10:30 AM
To: Dempsey, James (CSIRO IM&T, Yarralumla)
Cc: netcdf-java@xxxxxxxxxxxxxxxx
Subject: Re: [netcdf-java] Problem using Redefine mode in netcdf-java 4.1
Hi James:
Turns out its a bug when there are no variables in the file. Ill make a fix as
soon as i can (probably tommorrow or day after).
BTW, im sorry to say going in and out of define mode is not very robust in
netcdf-java. Id use it as minimally as possible, or at least be sure to test
things are working correctly. Also its quite inefficient, as it forces a
complete file rewrite in many cases.
Thanks for reporting the bug.
John
James.Dempsey@xxxxxxxx wrote:
> 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
