Re: [netcdf-java] Questions about IOServiceProvider

Thanks, this looks like what I might want.  My issue with the current
service-oriented approach to IOSP (although I completely understand
why it works this way from a plugin point of view) is that it might be
hard or expensive for an IOSP to detect a file of the correct format.
If you can force the use of a given IOSP you can get around this.

Cheers, Jon

On Thu, Feb 14, 2008 at 5:36 PM, John Caron <caron@xxxxxxxxxxxxxxxx> wrote:
> Im not sure what's the context, but this may be what you want:
>
>   static public NetcdfFile open(String location, String className, int 
> bufferSize, CancelTask
>  cancelTask, String iospClassName);
>
>  undocumented at the moment, but a look at the source should make it obvious.
>
>
>
>  Jon Blower wrote:
>  > Hi John,
>  >
>  > Is it possible to explicitly specify the IOServiceProvider that should
>  > be used when opening a Netcdf file/dataset?  In my case I will know
>  > what IOSP to use in advance and coding the isValidFile() method could
>  > be tricky in general.
>  >
>  > I guess I could use a single IOSP (whose isValidFile() always returns
>  > true) and use the spiObject as a signal to work out the internal logic
>  > (perhaps delegating to other IOSPs).
>  >
>  > Cheers, Jon
>  >
>  > On Sat, Jan 26, 2008 at 8:25 PM, John Caron <caron@xxxxxxxxxxxxxxxx> wrote:
>  >>
>  >>  Jon Blower wrote:
>  >>  > Hi,
>  >>  >
>  >>  > I have a couple of questions about IOServiceProviders:
>  >>  >
>  >>  > 1) What happens if two IOServiceProviders return true for
>  >>  > isValidFile()?  Which provider is used?
>  >>
>  >>  the first one thats asked. user-loaded iosps are loaded in front of the 
> system ones, so users can override.
>  >>
>  >>
>  >>
>  >>  > 2) When does sync() get called?
>  >>
>  >>  sync is an attempt to deal with files that change after being opened. 
> most IOSPs cant handle this, but we are curently trying to make it work for 
> netcdf-3 record dimension growth and grib files.
>  >>
>  >>  the main case is from NetcdfFileCache, sync is called when a cached file 
> is found. NcML aggregation also calls this.
>  >>
>  >>  >
>  >>  > Thanks,
>  >>  > Jon
>  >>  >
>  >>
>  >
>  >
>  >
>



-- 
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Technical Director Tel: +44 118 378 8741 (ESSC)
Reading e-Science Centre Fax: +44 118 378 6413
ESSC Email: jdb@xxxxxxxxxxxxxxxxxxxx
University of Reading
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