Fixed width JTextPane preferred size

I have a question about how I can easily calculate the preferred size / height of a fixed width JTextPane. What I have done so far is putting my JTextPane in a JScrollPane and whenever I update the text, I update the size of the JScrollPane. Now this works well (although I find my code is a bit garbled, but it works), but when I add a new line, my code that updates the scroll height needs to be called twice: once immediately and the second time with invokeLater

. I am looking for a way to avoid invokeLater()

. Everything will be done, including dispatching events on components, overriding Swing methods, etc.

Here's a snippet that illustrates all of this:

import java.awt.AWTEvent;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Toolkit;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextPane;
import javax.swing.SwingUtilities;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

public class Test {

    private static MyEventQueue queue;

    private static final class MyEventQueue extends EventQueue {

        public boolean log = false;

        @Override
        protected void dispatchEvent(AWTEvent event) {
            if (log) {
                System.err.println(event.getClass().getName() + " " + event.getSource());
            }
            super.dispatchEvent(event);
        }
    }

    public static class WrapApp extends JFrame {
        JTextPane edit = new JTextPane() {
            @Override
            public boolean getScrollableTracksViewportWidth() {
                return true;
            }

        };
        private JScrollPane comp;

        protected void updateVPSize() {
            updateSize(true);
        }

        protected void updateSize(boolean repeat) {
            edit.setSize(150, 1000);
            Dimension size = edit.getPreferredScrollableViewportSize();
            System.err.println("Before " + size);
            size.width = 150;
            comp.setSize(size);
            if (repeat) {
                queue.log = true;
                SwingUtilities.invokeLater(new Runnable() {
                    @Override
                    public void run() {
                        queue.log = false;
                        updateSize(false);
                    }
                });
            }
        }

        public WrapApp() {
            super("Forced wrap/no wrap example");
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            getContentPane().setLayout(null);
            edit.getDocument().addDocumentListener(new DocumentListener() {

                @Override
                public void removeUpdate(DocumentEvent e) {
                    updateVPSize();
                }

                @Override
                public void insertUpdate(DocumentEvent e) {
                    updateVPSize();
                }

                @Override
                public void changedUpdate(DocumentEvent e) {
                    updateVPSize();
                }
            });
            comp = new JScrollPane(edit) {
                @Override
                public void setSize(int width, int height) {
                    super.setSize(width, height);
                };
            };
            comp.setBorder(null);
            comp.setLocation(0, 0);
            comp.setViewportBorder(null);
            comp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
            edit.setText("Some long text that needs to be wrapped on several lines.\n\nBut this is not the end of it, it can go on and on and on and on...Some long text that needs to be wrapped on several lines.\n\nBut this is not the end of it, it can go on and on and on and on...");
            getContentPane().add(comp);
            setSize(300, 700);
            setLocationRelativeTo(null);
            updateVPSize();
        }
    }

    public static void main(String[] args) {
        Toolkit.getDefaultToolkit().getSystemEventQueue().push(queue = new MyEventQueue());
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                WrapApp m = new WrapApp();
                m.setVisible(true);

            }
        });
    }

}

      

        
        
        
      

    

Not really against all the things left there, I tried a bunch of things