Help Update Swing

Question

Hi,
I'm having some trouble with a swing application, let me explain it to you.
I have a function (provided by a library, so it wont be easy to modify it), that retrieves files from a server; An object must be handed over to this function so the programmer can execute some code when a file is retrieved. What I'm trying to do is to update (append some text) on a JTextArea whenever a file is retrieved so the user has some idea of whats going on during the (usually) lengthy process.
Problem here is that the JTextArea, does not get updated on the screen until during the retriving process, so it goes from an empty JTextArea (at the beginning and during the file transmission process), to a JTextArea with all the information of the process after the last file has been retrieved.
The function which updates the JTextArea looked like this:
public void sendReceivedObjectIndication(final String dicomFileName, final String transferSyntax, final String callingAETitle) throws DicomNetworkException, DicomException, IOException {
        if (dicomFileName != null) {
                     area.append("\nReceived: " + dicomFileName + " from " + callingAETitle);
         } else {
            //Notify failure
    }I also tried this
public void sendReceivedObjectIndication(final String dicomFileName, final String transferSyntax, final String callingAETitle) throws DicomNetworkException, DicomException, IOException {
        if (dicomFileName != null) {
            //System.out.println("Received: " + dicomFileName + " from " + callingAETitle + " in " + transferSyntax);
            Runnable r=new Runnable() {
                public void run() {
                   area.append("\nReceived: " + dicomFileName + " from " + callingAETitle);
            SwingUtilities.invokeLater(r);           
        } else {
           //Notify failure
    }But none of them works as expected.
Anybody knows what to do here?
Thanks in advance
Jc

Answer 1

You need to perform your lengthy task off of the EDT. Use a javax.swing.SwingWorker, as it facilitates periodically updating a GUI (on the EDT) while doing the lengthy task off of the EDT.
Also, read this for a general tutorial and background on the subject: [Concurrency in Swing|http://java.sun.com/docs/books/tutorial/uiswing/concurrency/initial.html] .