How Can I Generate and Catch RepaintManager Exceptions from SwingWorker Threads?

Generation of RepaintManager Exceptions within SwingWorker Threads

While working on a related issue, it was discovered that specific exceptions within RepaintManager can be difficult to capture and output from SwingWorker threads. This article will delve into the topic of generating RepaintManager exceptions and provide a solution.

Approach: Utilizing CheckThreadViolationRepaintManager

The CheckThreadViolationRepaintManager class allows for the detection of thread violations within Swing-based applications. By setting it as the current repaint manager, it can monitor component invalidations and dirty region additions to ensure they are performed on the Event Dispatch Thread (EDT). When violations occur, exceptions are thrown.

The provided example demonstrates the usage of this class by throwing exceptions for various phases of frame UI delegate initialization. This approach has proven effective in detecting and printing multiple types of RepaintManager exceptions.

Syntax and Implementation:

import javax.swing.RepaintManager;
import javax.swing.SwingUtilities;

public class RepaintManagerExceptions {

    public static void main(String[] args) {
        RepaintManager.setCurrentManager(new CheckThreadViolationRepaintManager());
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    private static class CheckThreadViolationRepaintManager extends RepaintManager {

        @Override
        public void addInvalidComponent(JComponent component) {
            checkThreadViolations(component);
            super.addInvalidComponent(component);
        }

        @Override
        public void addDirtyRegion(JComponent component, int x, int y, int w, int h) {
            checkThreadViolations(component);
            super.addDirtyRegion(component, x, y, w, h);
        }

        private void checkThreadViolations(JComponent component) {
            if (!SwingUtilities.isEventDispatchThread()) {
                violationFound(component, Thread.currentThread().getStackTrace());
            }
        }

        protected void violationFound(JComponent component, StackTraceElement[] stackTrace) {
            System.out.println("EDT violation detected.");
            System.out.println(component);
            for (StackTraceElement st : stackTrace) {
                System.out.println("\tat " + st);
            }
        }
    }
}

Conclusion:

By leveraging the CheckThreadViolationRepaintManager class, it is possible to generate exceptions within RepaintManager, providing valuable insights into thread violations within Swing applications. This allows developers to identify and resolve potential issues related to EDT compliance, ensuring smoother and more reliable application execution.

The above is the detailed content of How Can I Generate and Catch RepaintManager Exceptions from SwingWorker Threads?. For more information, please follow other related articles on the PHP Chinese website!