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javaswingswingworker

SwingWorker performance

I'm working on a Java Swing program. Could there be some performance degradation if I use the following approach?

jButton.addActionListener(new ActionListener() {
  public void actionPerformed(ActionEvent e) {
    SwingWorker worker = new SwingWorker() {
      protected Object doInBackground() throws Exception {
        return null;
      }

      protected void done() {
        // do stuff
      }
    };
    worker.execute();
  }
});

If I'm doing some heavy processing task inside done(), is it better to define the SwingWorker instance as a global member rather than a local anonymous class declaration?

I think if it's local, it's created every time actionPerformed is invoked(is it?). Will using a global instance lead to increase in performance? Any differences in memory utilization in global/local approaches?

Solution

  • In your specific example, it is very easy to answer. A SwingWorker is designed to be only run once, as specified in the class javadoc (see also this SO question)

    SwingWorker is only designed to be executed once. Executing a SwingWorker more than once will not result in invoking the doInBackground method twice.

    So in this case you will have to create a new instance each time the actionPerformed is invoked.

    Side-note: the heavy processing work should be done in the doInBackground method, not in the done method or you will block the EDT