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Interrupt multiple threads on the same time

I have 3 threads on a frame and when I press the "Exit" button I want o stop the threads which are currently running and after that to close the frame with the program. For that I created an array where I have all the Threads of the frame and when the button "Exit" is pressed the program iterates over the array and if is there any thread running I interrupt it. The problem with my approch is that the program stops only 1 thread, not all of them. So, even though the frame is closed, there will be 2 threads running on the background.
Here is my program:
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.Thread.State;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ProgramInterface extends JFrame {
private JButton stopThreadsAndExit;
private CounterThread[] counterThreadsArray = new CounterThread[3];
public static void main(String[] args) {
new ProgramInterface();
}
public ProgramInterface() {
// TODO Auto-generated constructor stub
addCounterThreadsToArray();
addThreadsOnTheFrame();
stopThreadsAndExit = new JButton("Exit");
addActionToExitButton();
add(stopThreadsAndExit);
setFrameSettings();
}
private void setFrameSettings() {
setSize(400, 400);
setLayout(new FlowLayout());
setVisible(true);
}
public void addThreadsOnTheFrame() {
for (CounterThread counter : counterThreadsArray) {
add(counter);
}
}
public void addActionToExitButton() {
stopThreadsAndExit = new JButton("Exit");
stopThreadsAndExit.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
new Thread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
exit();
}
}).start();
}
});
}
public void exit() {
for (CounterThread counter : counterThreadsArray) {
if (counter.isRunnable()) {
counter.interruptThread();
}
}
dispose();
}
private void addCounterThreadsToArray() {
counterThreadsArray[0] = new CounterThread("Thread 01");
counterThreadsArray[1] = new CounterThread("Thread 02");
counterThreadsArray[2] = new CounterThread("Thread 03");
}
}
class CounterThread extends JPanel {
Thread counter;
private String threadName;
private JButton startThread;
public CounterThread(String threadString) {
this.threadName = threadString;
initializesCounterThread();
addActionToStartButton();
setLayout(new FlowLayout());
add(startThread);
}
public void addActionToStartButton() {
startThread = new JButton("Start " + threadName);
startThread.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
counter.start();
}
});
}
private void initializesCounterThread() {
counter = new Thread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
try {
for (int i = 0; i < 1000000000; i++) {
if (Thread.currentThread().isInterrupted()) {
throw new InterruptedException();
}
System.out.println(threadName + " generated " + i);
}
} catch (InterruptedException e) {
// TODO: handle exception
Thread.currentThread().interrupt();
}
}
});
}
public void interruptThread() {
counter.interrupt();
}
public boolean isRunnable() {
return counter.getState() == State.RUNNABLE;
}
}

Don't check getState on the thread, you shouldn't have to care if it's currently running or not. Just call interrupt on it.
When you call interrupt on a thread that just sets a flag on that instance. That flag gets checked when the thread does certain things, like wait or sleep, or when the thread explicitly calls isInterrupted (which you are doing). So you don't need to care what state the thread is in.

Two setting backgrounds and sleeping a thread

I want to change the color of JTextField to red after typing something in it, and then after a second return to a default white background. I tried this outside the listener, and it worked, but when it comes to being a part of a listener, it doesn't (it just skips setting the red color). This is weird for me..
public class Test {
JFrame frame;
JTextField field;
public Test() {
frame = new JFrame();
field = new JTextField("A");
field.addKeyListener(new KeyBListener());
frame.getContentPane().add(field);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) { new Test(); }
private class KeyBListener implements KeyListener {
#Override
public void keyTyped(KeyEvent e) {
try {
field.setBackground(Color.RED);
Thread.sleep(1000);
field.setBackground(Color.WHITE);
} catch (InterruptedException es) { es.printStackTrace(); }
}
#Override
public void keyPressed(KeyEvent e) { }
#Override
public void keyReleased(KeyEvent e) { }
}
}

Try creating a separate Thread that listens to color change on the JTextField then changes it back. In this case at least you will not block the main Thread, although I'm not sure it's the most efficient way.
public Main() {
frame = new JFrame();
frame.setSize(800, 600);
field = new JTextField("A");
field.addKeyListener(new KeyBListener());
frame.getContentPane().add(field);
frame.pack();
frame.setVisible(true);
new Thread(() -> {
while(true) {
if(field.getBackground().equals(Color.RED))
try {
Thread.sleep(1000);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
field.setBackground(Color.WHITE);
}
}).start();
}

Your previous solution was working because it was executed from the AWT itself.
The keyTyped() method is executed on the Event dispatch thead (EDT), so you have to move the painting actions back to the AWT.
Have a look on SwingUtilities.invokeLater() (non-blocking) or SwingUtilities.invokeAndWait() (blocking), see
Oracle Doc
SwingUtilities.invokeLater(new Runnable() {
public void run() {
try {
field.setBackground(Color.RED);
Thread.sleep(1000);
field.setBackground(Color.WHITE);
} catch (InterruptedException es) {
es.printStackTrace();
}
}
});

You can spawn a different thread in which you do the color manipulation. That ensures that the color manipulation is not happening inside EDT.
import java.awt.Color;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.concurrent.atomic.AtomicBoolean;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.WindowConstants;
public class Test {
JFrame frame;
JTextField field;
AtomicBoolean isColorChangeOn = new AtomicBoolean();
public Test() {
frame = new JFrame();
field = new JTextField("A");
field.addKeyListener(new KeyBListener());
frame.getContentPane().add(field);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
isColorChangeOn.set(false);
}
public static void main(String[] args) {
new Test();
}
private class KeyBListener implements KeyListener {
#Override
public void keyTyped(KeyEvent e) {
if(!isColorChangeOn.get()) {
isColorChangeOn.set(true);
Runnable setcolor = ()->{
try {
System.out.println("color changing");
field.setBackground(Color.RED);
Thread.sleep(1000);
field.setBackground(Color.WHITE);
isColorChangeOn.set(false);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
};
new Thread(setcolor).start();
}
}
#Override
public void keyPressed(KeyEvent e) {
}
#Override
public void keyReleased(KeyEvent e) {
}
}
}

Java foxtrot Worker produce deadlock when use with invokeLater

We are using foxtrot package for stop freeze the swing application.
But in this below code it make a deadlock.
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridBagLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import foxtrot.Task;
import foxtrot.Worker;
public class FoxtrotExample extends JFrame {
public static void main(String[] args) {
FoxtrotExample example = new FoxtrotExample();
example.setVisible(true);
}
boolean st = true;
public FoxtrotExample() {
super("Foxtrot Example");
final JButton button = new JButton("Take a nap !");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Start..");
button.setText("Sleeping...");
String text = null;
try {
text = (String) Worker.post(new Task() {
public Object run() throws Exception {
System.out.println("Inside Worker 1");
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
System.out.println("Inside invokeLater");
Worker.post(new Task() {
#Override
public Object run()
throws Exception {
System.out.println("Inside Worker 2");
st = false;
return null;
}
});
} catch (Exception e) {
e.printStackTrace();
}
}
});
while (st) {
System.out.println("Inside the loop..");
try {
Thread.sleep(1000);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
}
return "Slept !";
}
});
} catch (Exception x) {
}
button.setText(text);
System.out.println("Finished.....");
}
});
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
Container c = getContentPane();
c.setLayout(new GridBagLayout());
c.add(button);
setSize(300, 200);
Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();
Dimension size = getSize();
int x = (screen.width - size.width) >> 1;
int y = (screen.height - size.height) >> 1;
setLocation(x, y);
}
}
If use ConcurrentWorker this will work fine.Can any one explane this.
I am bit confuse how EDT behave here ?

This is the result of my program.
Start 1st worker
In the loop
Start invoke later
In the loop
In the loop
In the loop
In the loop
......
It start the 1st worker.Then part of the code is in invokeLater.So request is enqued in the event queue and start the loop.Later execute the invokeLater but not execute the 2nd worker because first worker still doing some work.Since worker are ruining one after another and it runs on a single worker queue 2nd worker cannot execute and deadlock comes.
Thanks to MadProgrammer i understood this.Hope this is correct.

Pause and Resume SwingWorker.doInBackground()

I have a basic Swing UI with a single button marked "Play." When the button is pressed the label changes to "Pause". When the button is pressed now it changes to say "Resume."
On "Play" I am instantiating and executing a SwingWorker. What I would like is to be able to pause this thread (NOT cancel it) and resume it according to the button presses described above. However, I'd prefer not to resort to Thread.sleep() in doInBackground(). That seems a bit hackish. Is there any way for the thread running doInBackground to block?

Pause and Resume SwingWorker.doInBackground()
First of all you have to be sure the background task being performed can be paused, otherwise the question doesn't make sense. So let's say the task can be paused, then you might extend SwingWorker class and make your own pausable worker using a simple flag variable to control the background thread status: paused or not paused.
public abstract class PausableSwingWorker<K, V> extends SwingWorker<K, V> {
private volatile boolean isPaused;
public final void pause() {
if (!isPaused() && !isDone()) {
isPaused = true;
firePropertyChange("paused", false, true);
}
}
public final void resume() {
if (isPaused() && !isDone()) {
isPaused = false;
firePropertyChange("paused", true, false);
}
}
public final boolean isPaused() {
return isPaused;
}
}
Subclasses might check isPaused() status in order to efectively proceed with the task or not. For example:
PausableSwingWorker<Void, String> worker = new PausableSwingWorker<Void, String>() {
#Override
protected Void doInBackground() throws Exception {
while (!isCancelled()) {
if (!isPaused()) {
// proceed with background task
} else {
Thread.sleep(200); // Optional sleep to avoid check status continuously
}
}
return null;
}
};
You can also add a PropertyChangeListener to the worker and listen for paused property changes:
worker.addPropertyChangeListener(new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if ("paused".equals(evt.getPropertyName())) {
System.out.println("Old status: " + evt.getOldValue());
System.out.println("New status: " + evt.getNewValue());
}
}
});
Example (updated to make use of PropertyChangeListener)
Here is a complete example to play with. Please note that if worker is stopped then it cannot be paused nor resumed anymore.
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
public class Demo {
private void createAndShowGUI() {
final JTextArea textArea = new JTextArea(20, 50);
final PausableSwingWorker<Void, String> worker = new PausableSwingWorker<Void, String>() {
#Override
protected Void doInBackground() throws Exception {
while (!isCancelled()) {
if (!isPaused()) {
publish("Writing...");
} else {
Thread.sleep(200);
}
}
return null;
}
#Override
protected void process(List<String> chunks) {
String text = String.format("%s%n", chunks.get(chunks.size() - 1));
textArea.append(text);
}
};
worker.addPropertyChangeListener(new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if ("paused".equals(evt.getPropertyName())) {
String text = (Boolean)evt.getNewValue() ? "Paused..." : "Resumed...";
textArea.append(String.format("%s%n", text));
}
}
});
Action pause = new AbstractAction("Pause") {
#Override
public void actionPerformed(ActionEvent e) {
worker.pause();
}
};
Action resume = new AbstractAction("Resume") {
#Override
public void actionPerformed(ActionEvent e) {
worker.resume();
}
};
Action stop = new AbstractAction("Stop") {
#Override
public void actionPerformed(ActionEvent e) {
worker.cancel(true);
}
};
JPanel buttonsPanel = new JPanel(new FlowLayout(FlowLayout.CENTER));
buttonsPanel.add(new JButton(pause));
buttonsPanel.add(new JButton(resume));
buttonsPanel.add(new JButton(stop));
JPanel content = new JPanel(new BorderLayout(8, 8));
content.setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
content.add(new JScrollPane(textArea), BorderLayout.CENTER);
content.add(buttonsPanel, BorderLayout.SOUTH);
JFrame frame = new JFrame("Demo");
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
frame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent e) {
if (!worker.isDone()) {
worker.cancel(true);
}
e.getWindow().dispose();
}
});
frame.add(content);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
worker.execute();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Demo().createAndShowGUI();
}
});
}
abstract class PausableSwingWorker<K, V> extends SwingWorker<K, V> {
private volatile boolean isPaused;
public final void pause() {
if (!isPaused() && !isDone()) {
isPaused = true;
firePropertyChange("paused", false, true);
}
}
public final void resume() {
if (isPaused() && !isDone()) {
isPaused = false;
firePropertyChange("paused", true, false);
}
}
public final boolean isPaused() {
return isPaused;
}
}
}

this.notifyAll(); is not working in java code

This is a part of my java code, in this code there are labels which are counting numbers from 0 up to so on, I want to stop labels to count when I click the button 1st time, and I want to restart the labels to count again when I click the button 2nd time, the problem is that the labels are not restarting there counting when I am clicking the button 2nd time, so please tell how should I notify all the labels to restart there counting???
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingWorker;
public class Main implements ActionListener {
JButton button = new JButton("Click");
JFrame frame = new JFrame();
boolean wait=false;
public static void main(String arg[]) {
new Main();
}
public Main() {
frame.setLayout(new FlowLayout());
frame.getContentPane().setBackground(Color.BLACK);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
button.addActionListener(this);
frame.add(button);
frame.setVisible(true);
new Producer().execute();
}
public class Producer extends SwingWorker<Void, Void> {
public Void doInBackground() {
for(int infinite=0; infinite!=-1; infinite++) {
new Counter().execute();
try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}
}
return null;
}
}
public class Counter extends SwingWorker<Void, Void> {
JLabel label = new JLabel();
public Counter() {
label.setForeground(Color.WHITE);
frame.add(label);
}
public Void doInBackground() {
synchronized (this) {
for(int i=0; i!=-1; i++) {
if(wait==true)
try {this.wait();} catch(Exception exp) {exp.printStackTrace();}
label.setText(""+i);
try {Thread.sleep(200);} catch (InterruptedException e) {e.printStackTrace();}
}
}
return null;
}
}
public void actionPerformed(ActionEvent clicked) {
if(wait==false)
wait=true;
else if(wait==true) {
synchronized (this) {
this.notifyAll();
}
}
}
}

I don't see a place where you ever reset wait to false. Try this and see if it gets you unstuck:
public void actionPerformed(ActionEvent clicked) {
if(wait==false) {
wait=true;
} else {
wait=false;
synchronized (this) {
this.notifyAll();
}
}
}