jtree population from database

I am trying to build a swing app that loads data into a tree from an oracle database.

The problem seems to be that I can't retrieve all the rows and just build the tree because of the large possibility of a tremendous amount of records.  Instead I thought that I should only initially populate the root nodes and when the user clicks to expand, retrieve the children of that node...and when the node is closed again, clear those objects -- or release the memory somehow.

My problem is I have no knowledge of how to do such a thing and from my searches, there isn't much documentation of an acutal database implementation of populating a jtree and definitiely none regarding dynamic loading / unloading.

So my question (and I'm willing to give away all my points for as much help as possible with this), how can I create a jtree that loads dynamically based on 1) first load (just load root nodes) or 2) clicking on node (load children based on parent value).

Table setup example:
Table.Data
ID //never 0 -- auto increment with each record
ParentID // references ID -- 0 is root.
Date  // Just other values that will
Time // be loaded in Value Object

Any help I would appreciate!
sapientconceptionsAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Mick BarryJava DeveloperCommented:
As db query could take some time, you really should do any database queries in a seperate thread  from the event dispatch thread. As doing any time consuming task in the event dispatch thread will block your gui.

To create a tree that dynamically you need to create a custom table model that initiates the database request whenever a node is requested, and caches all db results.
0
sapientconceptionsAuthor Commented:
a custom tree model right (not table)?

Do you have any examples of that and how the nodeClick might call a seperate thread in a SwingWorker?  I have the understanding, I just don't have a complete grasp for the implementation.
0
Mick BarryJava DeveloperCommented:
> a custom tree model right (not table)?

coorect (woops).

> Do you have any examples of that and how the nodeClick might call a seperate thread

You don't really worry about the node click directly, when the JTree needs data to display it will call your tree model. At this point you can handle initiating your db calls as required.
Shall see what I can find.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Mick BarryJava DeveloperCommented:
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Java

From novice to tech pro — start learning today.