Must-have features for milestone3, have impact on APIs (at least potential).

Here's the API for initialization and shutdown hooks: listen to the
projectManager's PROP_PROJECT_OPEN property and PROP_PROJECT_CLOSING
property.

PROP_PROJECT_OPEN will be fired AFTER a project has been fully opened
by the projects system. No locks are held when it is announced (no
project system locks that is.)   Modules may not assume anything about
the order in which other modules are notified of project open;
therefore, if you depend on the initialization performed by another
module you have to negotiate a contract with that module such that it
provides its own notification of when its initialization is done.

PROP_PROJECT_CLOSING will be fired BEFORE a project's closing process
is started (but after user confirmation). Thus, you can perform
project shutdown procedures and utility all the project contents. As
with PROPECT_OPEN no project system locks are held.
(Note - not only is the property change fired when the project
is about to be closed, but it is deliberately fired before the
final project save prior to closure; thus you can modify the
project contents and expect it to be reflected in the project
file.)

PROP_PROJECT_CLOSED is called after the project has been closed.

Sounds good for listeners "outside" of project, but it would be useful to allow similar notification for 
"inside" project stuff (e.g. Containers). The primary motivation for this was the implementation of 
Container which maintains list of subprojects. Since subprojects are deffered for PM4 this can be 
probably resolved later (until there isn't other requirement which I don't know about).

Can you be more specific? Are you suggesting creating an SPI
so modules can listen to container additions/removals?
(This wouldn't be tied to initialization/shutdown, right?)
Or something else?

Imagine that you write Container (some DataObject in ProjectFileSystem, /Containers folder) which 
maintains the list of subprojects. You need to open those subropjects when the parent project is being 
open and close them when the parent project is closed. Right now, there is no way how the Container could 
be notified about the project open event. It can't register listener to ProjectManager beacause it 
doesn't exist prior opening the project which contains this Container. So, I just wanted to remember that 
events on ProjectManger are useful for listeners "outside" of the project, which exist independently on 
the project system and can hook the ProjectManager at the begining of their live cycle. It would be 
useful to have some initialization/shitdown support for the "inside-project" components like Containers, 
etc.

I don't say that we have to do it right now. Subprojects has been deffered for milestone 4 and I don't 
know any other reason why this support would be neccessary

Ok - this would be like a "Startup" folder in the project where
components can place themselves and be called during startup. I agree
that we should add this later if a usage comes up.

For example, to solve the subprojects-open problem the module
providing subprojects could listen (not an object in the project
itself but rather a "subprojects manager" object) to the
ProjectManager for notification of project open, and when a project is
open it could check to see if it's a superproject and then go and open
other projects as necessary.

So I believe we should avoid adding additional APIs in this area until
we have more definite requirements. Most likely subprojects will be
implemented inside the projects infrastructure so it won't need an
exposed API.

Another possibility which comes to my mind is to place the open/close methods in the NatureInstall 
introduced by David. Since the project is getting more complicated with more possible stuff registered 
by natures, delegating to NatureInstalle would provide better flexibility for the future.

Feel free to extend NatureInstall as you need. The class was inspired 
by openide's ModuleInstall class, but I intentially put there only 
methods I really needed.

Vito, what is the status of this issue? There is a number of comments
that were added after this was marked as resolved/fixed.

I think this is still TBD (at least some parts of it). Adding correct
keywords.

As described in
http://www.netbeans.org/servlets/ReadMsg?msgId=619519&listName=nbdiscuss the
current work on projects prototype has been stopped.

--> VERIFIED