Java Swing How to - Handle time consuming task in SwingWorker and block user interaction

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Question

We would like to know how to handle time consuming task in SwingWorker and block user interaction.

Answer

import java.awt.BorderLayout;
import java.awt.Cursor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
//from w ww.  j  a  v a  2  s. com
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingWorker;

public class Main extends JPanel {
  JButton startButton;
  JTextArea taskOutput;

  public Main() {
    super(new BorderLayout());
    JProgressBar progressBar = new JProgressBar(0, 100);
    progressBar.setValue(0);
    progressBar.setStringPainted(true);

    taskOutput = new JTextArea(5, 20);
    taskOutput.setEditable(false);

    startButton = new JButton("Start");
    startButton.setActionCommand("start");
    startButton.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent ae) {
        startButton.setEnabled(false);
        setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));

        final Task task = new Task();
        task.addPropertyChangeListener(new PropertyChangeListener() {
          @Override
          public void propertyChange(PropertyChangeEvent pce) {
            if ("progress".equals(pce.getPropertyName())) {
              int progress = (Integer) pce.getNewValue();
              progressBar.setValue(progress);
              taskOutput.append(String.format("Completed %d%% of task.\n",
                  task.getProgress()));
            }
          }
        });
        task.execute();
      }
    });

    JPanel panel = new JPanel();
    panel.add(startButton);
    panel.add(progressBar);

    add(panel, BorderLayout.PAGE_START);
    add(new JScrollPane(taskOutput), BorderLayout.CENTER);

  }
  public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JPanel progressBarPanel = new Main();
    frame.add(progressBarPanel);

    frame.pack();
    frame.setVisible(true);
  }

  private class Task extends SwingWorker<Void, Void> {
    @Override
    public Void doInBackground() {
      int progress = 0;
      setProgress(0);
      while (progress < 100) {
        try {
          Thread.sleep(1000);
        } catch (Exception ignore) {
        }
        progress += 1;
        setProgress(Math.min(progress, 100));
      }
      return null;
    }

    @Override
    public void done() {
      startButton.setEnabled(true);
      setCursor(null);
      taskOutput.append("Done!\n");
    }
  }
}

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