Pushing data from server into client's JTable

Question

Hi!
Here is the scenario:
Server updates a clients HashMap. Then the TableModel should update it's own data from that HashMap and update its JTable. The user can add/remove/edit rows in the JTable which should update the HashMap too.
Questions:
1. Does the TableModel for each update need to create a Object[][] and create a new JTable whenever the HashMap has changed? Or can it use the setValue/getValue methods to get and set the data in the HashMap
2. Could the data from the user/server be inserted directly into the HashMap and then calling the tableChangedEvent for updating the TableModel and JTable without extra code?
Thx, for now.
/KK

Answer 1

Hi,
This is a pretty standard thing to have to do when dealing with a Gui in general. Basically any changes anywhere should trigger notification of all interested parties. So that means each table or tree or whatever that contains data that may change should register itself as a listener on the apportiate list. This means that everything that comes from the server should cause all listeners to be notified. Now in a table the best one to notify is the table model not the Gui. You should have your own model not take a default. AbstractTable model is a good place to start. The listener will get updated with something that it knows what to do with. It would be nice if this was the object you are using for your table model(rows) but it sounds like you have to go back to the hashtable to get the object. Then just see if the object is new so add it or exists and update your tablemodel with it. Then do something like
te = new TableModelEvent(this,loop,loop);
fireTableChanged(te);
Well that may not format well here but hope you get the idea. Also you may have to take care to do this on the Gui thread, but I usually wait until I get into trouble before doing that. Anyhow that is pretty easy just take the code create a runnable (abstract type is fine) and throw the offending code into the run() and usually do an InvokeLater since you may be on the Servers thread (JMS , Tibco) and do not want to wait.
Howie