Swing/SwingWorker Beginer's question

Question

Hi, I am trying to implement a GUI in java but I am beginner in swing. I want to make something clear. I read that in order to keep the GUI responsive I should use the SwingWorker class to do the task in a separate thread. Ok so far. No I have a model with around 15 methods that are remote methods. Each method returns different object type as a result than the others. In my view the user presses a button and the appropriate method in the model is called. Without using the swingworker the GUI froze. My question is, am I supposed to create 15 subclasses of Swingworker threads and create a NEW instance of each as needed according to user's actions? Is my understanding correct? Is there a standard way for this or what I say is a correct approach?

Thanks!

Answer 1

Have a look at this: Simple Background Tasks.

It seems you have two concerns. Firstly, regarding the amount of code required when using SwingWorker: you do need to create a subclass of SwingWorker for each action, but that doesn't mean they need to be top-level, named classes, or in their own files. They can be anonymous classes, as shown in the article, so that the code is within your GUI's event-handling code.

Secondly, regarding instantiation of SwingWorker objects: you can't reuse a SwingWorker, but since the jobs are being executed as a result of user activity (e.g. clicking a button), you shouldn't encounter any performance problems with instantiating new objects each time.

Answer 2

By all means, SwingWorkers get the job done. In my experience, I haven't liked using the SwingWorkers for just one little job. I prefer to spawn off a thread, and have that thread ask the EventDispatch thread to update the GUI. Only the EventDispatch thread should update the UI, though there are a few exceptions.

I would suggest reading about threads in threads in Swing.

Though threading can get heavy, and maybe this solution would not work for you in all cases, if a seperate thread needs to spark a change in GUI, use something like,

java.awt.EventQueue.invokeLater(new Runnable() 
{ 

    public void run() 
    { 
        // this codes runs on the event dispatch thread 
        // update the ui here.
    } 
});