Terrier Core

Some operations would benefit from the ability to cache a file locally.

For instance, direct -> inverted inversion can involve multiple passes of the direct file. Ideally, the direct files should then be cached locally.

{code}
class Files
{
 public static void cacheFile(String filename, String temporaryFolder) throws IOException
}
{code}

What are the failure modes. and how should these be signalled to the client code?