The following changes are proposed:
1. Add a factory/registry of FileSystem implementations. Given a protocol, hostname and port, it should be possible to get a FileSystem implementation.
2. Path's constructor should accept URI-formatted strings & a configuration.
3. A new Path method should be added: FileSystem.getFileSystem(). This returns the filesystem named in the path or the default configured filesystem.
4. Most methods which currently take FileSystem and Path parameters can be changed to take only Path.
5. Many FileSystem operations (create, open, delete, list, etc.) can become convenience methods on Path.
6. A URLStreamHandler can be defined in terms of the FileSystem API, so that URLs for any protocol with a registered FileSystem implementation can be accessed with a java.net.URL, permitting FileSystem implementations to be used on the classpath, etc.
It is tempting to try to replace Path with java.net.URL, but URL's methods are insufficient for mapreduce. We require directory listings, random access, location hints, etc., which are not supported by existing URLStreamHandler implementations. But we can expose all FileSystem implementations for access with java.net.URL.
(From a brainstorm with Owen.)
- is depended upon by
HADOOP-574 want FileSystem implementation for Amazon S3