fix for location udig bug-166

[nprigour]

fix for location udig bug-166
(https://bugs.locationtech.org/show_bug.cgi?id=166) related to Map
restoration from file

[nprigour]

It seems that the provided commit fixes the problem in windows OS.
@fgdrf are you able to check it in other operating systems (i.e. linux)

[fgdrf]

See my comments on the BUG 166

[nprigour]

Hi @fgdrf,
In order to assist me in debug:

1. temporary apply the attached projectImpl_debug.patch (adds some system.out prints for debug purpose)
2. delete all .umap files from disk
3. start udig (create a couple of Maps) and exit
4. restart udig
5. collect the print out results and send them to me by email.

projectImpl_debug.zip

[fgdrf]

@nprigour I tested today again and I was wondering that my build was quite fast :) Now I found out that I started an older compiled product than expected because I missed to use -Pproduct for the maven build.

Finally I can confirm, that your fix works on MacOSX. Therefore I'm going to squash commits soon

[fgdrf]

Just to clarify : Whenever a project resource (e.g. a Map) is deleted using the context menu in the layers view the resource on the filesystem is not deleted. Files of deleted resources are still present and are not removed closing uDig application. This is possible another issue ..

[nprigour]

@fgdrf shouldn't we also check it in a linux environment before accepting it?

Concerning the deletion of resources in the file system it is another thing which however is to a large extend related to the solution we provide to this one. I have filed a seperate bug report on that (see https://bugs.locationtech.org/show_bug.cgi?id=168) and will soon provide a fix via a pull request provided that the present pull request is tested in all major platforms (windows, macOS, linux).

[nprigour]

Fix verified successfully also in Linux (Ubuntu) environment.