等待多个SwingWorkers [英] Waiting for multiple SwingWorkers
问题描述
请考虑以下代码片段：
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.InvocationTargetException;
import javax.swing.*;
public class TestApplet extends JApplet
{
@Override
public void init()
{
try
{
SwingUtilities.invokeAndWait(new Runnable()
{
@Override
public void run()
{
createGUI();
}
});
}
catch(InterruptedException | InvocationTargetException ex)
{
}
}
private void createGUI()
{
getContentPane().setLayout(new FlowLayout());
JButton startButton = new JButton("Do work");
startButton.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent ae)
{
JLabel label = new JLabel();
new Worker(label).execute();
}
});
getContentPane().add(startButton);
}
private class Worker extends SwingWorker<Void, Void>
{
JLabel label;
public Worker(JLabel label)
{
this.label = label;
}
@Override
protected Void doInBackground() throws Exception
{
// do work
return null;
}
@Override
protected void done()
{
getContentPane().remove(label);
getContentPane().revalidate();
}
}
}
这里添加一个标签显示Worker线程的一些中间结果的applet（使用发布/进程方法）。最后，标签将从applet的窗格中删除。我的问题是，如何创建多个标签，每个标签都有自己的工作线程，并在完成后将其删除？
Here is add a label to the applet that displays some intermediate results of the Worker thread (using publish/process methods). At the end, the label is removed from the applet's pane. My question is, how could I create several labels, each with its own Worker thread, and remove them when they are all done?
提前致谢。
更新：
我希望这会澄清我的问题。当所有工人完成任务时，我希望一次性删除标签，而不是在每个工人完成后立即删除。
I hope this will clarify my question. I'd like the labels to be removed all at once, when all of the workers have finished their tasks, not immediately after each worker has finished.
UPDATE 2：
以下代码似乎正在做我需要的事情。请评论我是否以正确的方式做到了。我觉得有些不对劲。一个问题是按钮右侧的标签虽然被移除但仍然可见。 setVisible（false）似乎解决了这个问题。是这样做的吗？
The following code seems to be doing what I need. Please comment whether I did it the right way. I have a feeling there is something wrong. One problem is that the labels to the right of the button remain visible although they are removed. setVisible(false) seems to solve this issue. Is that the way to do it?
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.InvocationTargetException;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Random;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import javax.swing.*;
public class TestApplet extends JApplet
{
private Queue<JLabel> labels = new LinkedList<>();
private static final Random rand = new Random();
@Override
public void init()
{
try
{
SwingUtilities.invokeAndWait(new Runnable()
{
@Override
public void run()
{
createGUI();
}
});
}
catch(InterruptedException | InvocationTargetException ex){}
}
private void createGUI()
{
getContentPane().setLayout(new FlowLayout());
JButton startButton = new JButton("Do work");
startButton.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent ae)
{
ExecutorService executor = Executors.newFixedThreadPool(10);
for(int i = 0; i < 10; i++)
{
JLabel label = new JLabel();
getContentPane().add(label);
executor.execute(new Counter(label));
}
}
});
getContentPane().add(startButton);
}
private class Counter extends SwingWorker<Void, Integer>
{
private JLabel label;
public Counter(JLabel label)
{
this.label = label;
}
@Override
protected Void doInBackground() throws Exception
{
for(int i = 1; i <= 100; i++)
{
publish(i);
Thread.sleep(rand.nextInt(80));
}
return null;
}
@Override
protected void process(List<Integer> values)
{
label.setText(values.get(values.size() - 1).toString());
}
@Override
protected void done()
{
labels.add(label);
if(labels.size() == 10)
{
while(!labels.isEmpty())
getContentPane().remove(labels.poll());
getContentPane().revalidate();
}
}
}
}
推荐答案
我打算在所有工人完成任务后一起删除所有标签。
I intend to remove all of the labels together when all of the workers have completed their tasks.
如此处所述， CountDownLatch 在这种情况下运作良好。在下面的示例中，每个工作程序在完成时调用 latch.countDown（），并在<$上调用 Supervisor 工作程序块c $ c> latch.await（）直到所有任务完成。出于演示目的，主管更新标签。批评删除，在评论中显示，在技术上是可行的，但通常没有吸引力。相反，请考虑 JList 或 JTable 。
As described here, a CountDownLatch works well in this context. In the example below, each worker invokes latch.countDown() on completion, and a Supervisor worker blocks on latch.await() until all tasks complete. For demonstration purposes, the Supervisor updates the labels. Wholesale removal, shown in comments, is technically possible but generally unappealing. Instead, consider a JList or JTable.
< img src =https://i.stack.imgur.com/xFPey.pngalt =工人闩锁测试>
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Random;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import javax.swing.*;
/**
* @see https://stackoverflow.com/a/11372932/230513
* @see https://stackoverflow.com/a/3588523/230513
*/
public class WorkerLatchTest extends JApplet {
private static final int N = 8;
private static final Random rand = new Random();
private Queue<JLabel> labels = new LinkedList<JLabel>();
private JPanel panel = new JPanel(new GridLayout(0, 1));
private JButton startButton = new JButton(new StartAction("Do work"));
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame();
frame.setTitle("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new WorkerLatchTest().createGUI());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
@Override
public void init() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
add(new WorkerLatchTest().createGUI());
}
});
}
private JPanel createGUI() {
for (int i = 0; i < N; i++) {
JLabel label = new JLabel("0", JLabel.CENTER);
label.setOpaque(true);
panel.add(label);
labels.add(label);
}
panel.add(startButton);
return panel;
}
private class StartAction extends AbstractAction {
private StartAction(String name) {
super(name);
}
@Override
public void actionPerformed(ActionEvent e) {
startButton.setEnabled(false);
CountDownLatch latch = new CountDownLatch(N);
ExecutorService executor = Executors.newFixedThreadPool(N);
for (JLabel label : labels) {
label.setBackground(Color.white);
executor.execute(new Counter(label, latch));
}
new Supervisor(latch).execute();
}
}
private class Supervisor extends SwingWorker<Void, Void> {
CountDownLatch latch;
public Supervisor(CountDownLatch latch) {
this.latch = latch;
}
@Override
protected Void doInBackground() throws Exception {
latch.await();
return null;
}
@Override
protected void done() {
for (JLabel label : labels) {
label.setText("Fin!");
label.setBackground(Color.lightGray);
}
startButton.setEnabled(true);
//panel.removeAll(); panel.revalidate(); panel.repaint();
}
}
private static class Counter extends SwingWorker<Void, Integer> {
private JLabel label;
CountDownLatch latch;
public Counter(JLabel label, CountDownLatch latch) {
this.label = label;
this.latch = latch;
}
@Override
protected Void doInBackground() throws Exception {
int latency = rand.nextInt(42) + 10;
for (int i = 1; i <= 100; i++) {
publish(i);
Thread.sleep(latency);
}
return null;
}
@Override
protected void process(List<Integer> values) {
label.setText(values.get(values.size() - 1).toString());
}
@Override
protected void done() {
label.setBackground(Color.green);
latch.countDown();
}
}
}
这篇关于等待多个SwingWorkers的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
