Java API“如果不在EDT上运行，则在EDT上运行”

Question

我只是对我的一些重复代码进行了思考：

Runnable run = new Runnable() {
  @Override
  public void run() {
    // Some EDT code
  }
};

if (!EventQueue.isDispatchThread()) {
  SwingUtilities.invokeAndWait(run);
} else {
  run.run();
}

这并不是非常烦人，但似乎会有一些专有函数为您检查这一点，尽管我还没有找到它。

Answer 1

看起来有一些专有的函数可以帮你检查这个

没有。

Answer 2

除了物质外观和感觉，我从来不需要使用invokeAndWait或isDispatchThread / isEventDispatchThread测试，

物质外观在某些特殊情况下需要使用用于JTable、JTree、SwingX's TreeTable的invokeAndWait，在这种情况下真的不重要

延迟30秒是“EDT的到期”，然后您可以创建n_Threads，然后每个都可以运行EDT，简单，不需要特别的努力，另一个限制可能是本机操作系统的延迟

输出

run:
                         Time at : 00:00:45
There isn't Live EventQueue.isDispatchThread, why any reason for that 
There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that 

                         Time at : 00:00:45
EventQueue.isDispatchThread
SwingUtilities.isEventDispatchThread

                         Time at : 00:00:45
EventQueue.isDispatchThread
SwingUtilities.isEventDispatchThread

                         Time at : 00:01:15
There isn't Live EventQueue.isDispatchThread, why any reason for that 
There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that 

Push a new event to EDT
                         Time at : 00:01:45
EventQueue.isDispatchThread
SwingUtilities.isEventDispatchThread

                         Time at : 00:02:15
There isn't Live EventQueue.isDispatchThread, why any reason for that 
There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that 

                         Time at : 00:02:45
There isn't Live EventQueue.isDispatchThread, why any reason for that 
There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that 

Push a new event to EDT
                         Time at : 00:03:15
EventQueue.isDispatchThread
SwingUtilities.isEventDispatchThread

                         Time at : 00:03:45
There isn't Live EventQueue.isDispatchThread, why any reason for that 
There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that 

                         Time at : 00:04:15
There isn't Live EventQueue.isDispatchThread, why any reason for that 
There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that 

Push a new event to EDT
                         Time at : 00:04:45
EventQueue.isDispatchThread
SwingUtilities.isEventDispatchThread

Terminating this madness
BUILD SUCCESSFUL (total time: 4 minutes 31 seconds)

从…

import java.awt.EventQueue;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.*;

public class IsThereEDT {

    private ScheduledExecutorService scheduler;
    private AccurateScheduledRunnable periodic;
    private ScheduledFuture<?> periodicMonitor;
    private int taskPeriod = 30;
    private SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
    private Date dateRun;
    private JFrame frame1 = new JFrame("Frame 1");

    public IsThereEDT() {
        scheduler = Executors.newSingleThreadScheduledExecutor();
        periodic = new AccurateScheduledRunnable() {

            private final int ALLOWED_TARDINESS = 200;
            private int countRun = 0;
            private int countCalled = 0;
            private int maxCalled = 10;

            @Override
            public void run() {
                countCalled++;
                if (countCalled < maxCalled) {
                    if (countCalled % 3 == 0) {
                        SwingUtilities.invokeLater(new Runnable() {

                            @Override
                            public void run() {
                                System.out.println("Push a new event to EDT");
                                frame1.repaint();
                                isThereReallyEDT();
                            }
                        });
                    } else {
                        if (this.getExecutionTime() < ALLOWED_TARDINESS) {
                            countRun++;
                            isThereReallyEDT(); // non on EDT
                        }
                    }
                } else {
                    System.out.println("Terminating this madness");
                    System.exit(0);
                }
            }
        };
        periodicMonitor = scheduler.scheduleAtFixedRate(periodic, 0, taskPeriod, TimeUnit.SECONDS);
        periodic.setThreadMonitor(periodicMonitor);
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                isThereReallyEDT();
                frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame1.getContentPane().add(new JLabel("Hello in frame 1"));
                frame1.pack();
                frame1.setLocation(100, 100);
                frame1.setVisible(true);
            }
        });
        try {
            Thread.sleep(500);
        } catch (InterruptedException ex) {
            Logger.getLogger(IsThereEDT.class.getName()).log(Level.SEVERE, null, ex);
        }
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                JFrame frame2 = new JFrame("Frame 2");
                frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame2.getContentPane().add(new JLabel("Hello in frame 2"));
                frame2.pack();
                frame2.setLocation(200, 200);
                frame2.setVisible(true);
                isThereReallyEDT();
            }
        });
    }

    private void isThereReallyEDT() {
        dateRun = new java.util.Date();
        System.out.println("                         Time at : " + sdf.format(dateRun));
        if (EventQueue.isDispatchThread()) {
            System.out.println("EventQueue.isDispatchThread");
        } else {
            System.out.println("There isn't Live EventQueue.isDispatchThread, why any reason for that ");
        }
        if (SwingUtilities.isEventDispatchThread()) {
            System.out.println("SwingUtilities.isEventDispatchThread");
        } else {
            System.out.println("There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that ");
        }
        System.out.println();
    }

    public static void main(String[] args) {
        IsThereEDT isdt = new IsThereEDT();
    }
}

abstract class AccurateScheduledRunnable implements Runnable {

    private ScheduledFuture<?> thisThreadsMonitor;

    public void setThreadMonitor(ScheduledFuture<?> monitor) {
        this.thisThreadsMonitor = monitor;
    }

    protected long getExecutionTime() {
        long delay = -1 * thisThreadsMonitor.getDelay(TimeUnit.MILLISECONDS);
        return delay;
    }
}

你可以做任何事情，改变顺序，方法，冻结Thread.sleep(int)，在所有情况下都可以在假设的时刻激活EDT，没有阴影，任何奇迹，调用天堂而不是EDT的错误代码

Answer 3

考虑使用

http://docs.oracle.com/javase/7/docs/api/javax/swing/SwingWorker.html

或

http://docs.oracle.com/javase/7/docs/api/javax/swing/Timer.html

而不是。