Regis wrote: > Recently I'm trying to optimize implementation of java.File,
Cool. > and find File.getCanonicalPath is very time cost and is heavily used > by checking file permission. But in the most of cases, the canonical > path is never change, so I think it's better to cache them to avoid > calculate every time. And I found RI also has cache: > File.getCanonicalPath doesn't reflect change in file system > real-time. Hmm, sounds risky to me -- at least liable to create unpredictable behavior. > I have created a JIRA HARMONY-6200 for this, and attach a simple cache > implementation for file's canonical path, someone interested in this may > can help to review it. > > The cache has fixed size, when it's full oldest element would be remove, > and elements would be expired in 10 minutes, that mean if the element > stay in cache more than 10 minutes, it's not validate and will be removed. Ten minutes seems like a very long time. I would have thought that having a cache that expires in a relatively short time (since that file path was last accessed) would be sufficient. > It's a initial implementation, I believe there are still many places can > be improved, any comments and suggestions are welcome. My initial thought is that it would be preferable to have the OS tell you when a file path changes so you can invalidate the cache, but there may not be enough info to be able to do that... Regards, Tim
