[NETBEANS-3193] Support remote files in Open Recent File menu

[SiddheshRane]

This patch replaces system dependent file paths with URLs
and FileUtil.toFileObject with URLMapper.findFileObject to enable
opening remote files from Open Recent File menu

[SiddheshRane]

This commit changes the format of file paths in recent files list stored on disk. If a user updates this module, then the first time none of the recent files will be able to open as they are in old format. The recent list will get cleared. After that recent list will populate with newly closed files and work normally.

A smoother transition can be provided in which URLs are constructed with context new URL(<url of C: or />, <url or file path in recent list>), although I am not sure whether it would be necessary

[matthiasblaesing]

While I see the use case, this changeset is IMHO not a good fit for a solution. Much of the code is run on the event dispatching thread. File access is bad enough, but at least you can pretent that a local disk is always fast an snappy (yeah...)
But this change introduces potentially much higher delays (think laggy networks). I don't think this is a good idea as is.

[SiddheshRane]

File access was already present in the original code and also in the current releases of netbeans. The only change I have made is replace file paths with URL schemes.

I do think the overall history handling could benefit from code overhaul. But what alternative remains to support remote files? This may become more important, now that talks of a cloud based netbeans are ongoing.
Please suggest me if you have any workarounds.

[matthiasblaesing]

Ok - for me local file access and network access fall into to different categories:

For local file access you can normally expect quick responses and thus get away with running it on the EDT. To be clear: It should not be done on the EDT (virus scanners, mounted network drives), but it can work.

For the remote part all bets are off. If you are on a high latency link round trip times in the range of seconds are possible and this is a no-go on the EDT.

The suggestion I have: Move things that may be caught doing high latency work into a background thread (RequestProcessor).

[ebarboni]

@matthiasblaesing can we move to 12.0 ?

[matthiasblaesing]

@ebarboni yes - I have removed the milestone, as said in the review for me having this on the EDT sounds dangerous, so this is work in progress.

[Chris2011]

Hey @SiddheshRane are you still want to change the things as requested?