How to run long background jobs in ADF applications

Question

Hi,
I'm looking for some guidance on how to run an asynchronous job within an ADF application with proper progress notification in the current page.
Let's assume we have some long running task (e.g. generating notification emails from a bunch of rows in my view object and send them) with the corresponding classes implemented in the DataModel as part of the business logic (e.g. a class that sends a mail to a given recipient).
Let's assume all the relevant methods can be exposed in the appmodule's client interface so they can be invoked from the ViewController if needed.
In my jspx page I have implemented the standard af:poll+af:progressIndicator mechanism to give feedback about the running task, backed by a custom BoundedRangeModel
with methods getValue() and getMaximum(). This works.
However, all the examples I've found on the net are very very simplistic and only deal with simple counters or countdowns.
But how to actually implement the whole mechanism in a real life scenario? How do I run the job itself and make it give feedback to my BoundedRangeModel class
(which in turn is used by the progressIndicator on the page)?
Is there a recommended way to do this within ADF apps? I've tried to search something about asynchronous method execution in ADF but there seems to be nothing out there.
Do I need to use standard Java techniques such as a separate Thread running a Runnable worker? Should I use an observer/observable pattern to notify BoundedRangeModel
and update its internal variables (current value and maximum)? Would this work across a Datacontrol interface?
Is anything of this allowed within the ADF framework or I'm just gonna break the whole framework model because do-it-yourself concurrent programming isn't allowed in a multithreaded pooled environment?
Some explanation about the current recommended best practices and/or some practical examples or articles about that would be great.
(BTW: I'm using version 11.1.1.2.0 and yes, I've checked the contextual events thing too, but that's just an inter-page communication mechanism so it has has nothing to do with what I need to do.)

Answer 1

Hi
I have implement a "Runner" class to generate a pdf to every customer of a mailmerge file, which was uploaded. Its simply easy to do something like this. Just add a button, bound the button with a methode out of you applicationModule and start your implementing Thread in this methode.
public class Runner implements Runnable {
    private String docFileName;
    private String csvFileName;
    private byte[] csvData;
    private byte[] docData;
    private FtpClient client;
    private String category;
    public Runner(String category, String docFileName, byte[] docData,
                  String csvFileName, byte[] csvData, FtpClient client) {
        this.category = category;
        this.docFileName = docFileName;
        this.docData = docData;
        this.csvFileName = csvFileName;
        this.csvData = csvData;
        this.client = client;
    public void run() {
}In your applicationModule, you can start your Runner like this:
        Runner runner =
            new Runner(category, docFileName, docData, csvFileName, csvData, client);
        new Thread(runner).start();And to the problem with your progressBar. I would create a managedBean with a HashMap<String, HashMap<String, String>>. Every thread you start, add a HashMap<String, String> to this hashmap with the id of the username/session/whatever (must be bound to the user, which starts the thread). This added HashMap<String, String> should be used by your thread to put some status-information into. Now you can try to bind this info to your progressBar.
I dont know if this will work, it is just an idea ;-)
Regards
Majo