CDF data source based on Nand Lal's pure-Java CDF reader. CDF, or Common Data Format, is a NASA data format.
To resolve bug 1002 we unload the cache after 10 seconds. Joe at Aerospace had a problem where he couldn't kill a lingering autoplot process and then couldn't get at the file because it held a reference to the file. Now we automatically unload all the cached files. I did look at just disabling the cache, but the file is open and closed three times during the load. See http://sourceforge.net/p/autoplot/bugs/1002.
check if the file really is a CDF, and throw IllegalArgumentException if it is not. NetCDF files occasionally use the extension .cdf.
get the abstract access object to the given CDF file. This provides read-only access to the file, and a cache is used to limit the number of references managed. See bug http://sourceforge.net/p/autoplot/bugs/922/ The result returns a CDF object which contains a read-only memory-mapped byte buffer.
{@inheritDoc }