Actions and events... (using code inside actionPerformed)

Question

Suppose I have an application that needs to be as fast as possible and have a very responsive ui. It is a client that runs against a server on the network.
And suppose the client have a button, with an actionlistener and an actionperformed method.
Inside this actionperformed method the client needs to send something to the server, which is basically doing something like:
public void actionPerformed(ActionEvent e){
    doSomeWork();
    out.print(someText);
}Where out is a PrintStream opened to the server. Now the server responds and sends a message back to the client which receives it in a network thread that runs and polls for input. When a line of input is received it is then printed to a textarea in the client gui as something like this:
public class NetworkThread extends Thread{
public void run() {
     byte[] b = new byte[4096];
     int n = 0;
     while (n >= 0 && connected) {
          try {
               n = iStream.read(b);
               String input = doSomeParsing(b, n);
               if (input != null){
                    textArea.append(input);
}What i would liek to know, is if it is ok to do the send call inside the actionPerformed method of the button listener and if it is ok to simply append the text to the text area in the network thread?
Or should i use SwingUtilities.invokeLater or SwingWorker threads anywhere?
(I would want it to run as fast as possible in the gui side)

Answer 1

The code that interacts with the Server needs to be in a separate Thread so you don't block the GUI Event Thread.
In general, if you then need to update the GUI from the second Thread you would need to use the SwingUtilities.invokeLater(..).
However, if you read the API documentation for the JTextArea.append(...) method you will see the following:
This method is thread safe, although most Swing methods are not. Please see Threads and Swing for more information. so you shouldn't need to worry about the invokeLater().