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Java - Why does my print statement not run

So this is my code:
System.out.println("System Exiting...");
long current = System.currentTimeMillis();
long disired = current + 4000;
boolean done = false;
while (!done)
{
current = System.currentTimeMillis();
if (current == disired)
{
done = true;
System.exit(0);
}
}
My problem is that the print statement doesn't run, well it does run, but it runs at the same time as the exit statement, so you don't see it
[EDIT] Ok, so i just ran this code in its own file(with nothing else), and it works as i want, it prints "system Exiting..." it waits 4 seconds, and the code exits.
so it has to be something to do with the fact that i have this code inside an event listener

Your if condition is much too restrictive since your code will almost never get the times to be exactly equal, but the change needed is very simple:
Change
// hitting this exactly is like finding the proverbial needle
// in the haystack -- almost impossible to do.
if (current == disired)
to
// this is guaranteed to work.
// note if this is in English, you'll want to change disired to desired
if (current >= disired)
Having said this, your while (true) loop is not a good thing to do as it will needlessly tie up the CPU with empty cycles. Instead use some type of event notification or call-back system like ChangeListener or a PropertyChangeListener or a Timer.
You state:
yes it is within a swing GUI
You're calling a long while (true) block of code on the Swing event thread, rendering this thread ineffective. Since the event thread is responsible for all Swing graphics and user interactions, this effectively freezes your GUI until the while loop completes. The solution is obvious: 1) use a Swing Timer for your delay, not a while true loop (this is the callback mechanism that I mentioned in my original answer), and 2) in the future, please give us this important relevant information with the original question since it changes the entire nature of the question.
e.g.
// caveat: code not tested
System.out.println("System Exiting...");
int delay = 4 * 1000;
new Timer(delay, new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
System.out. println("Exited");
System.exit(0);
}
}).start();
e.g.,
import java.awt.Component;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class TestDelayedExit extends JPanel {
private static final int GAP = 100;
public TestDelayedExit() {
add(new JButton(new DisposeAction("Exit", KeyEvent.VK_X)));
setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
}
private static void createAndShowGui() {
JFrame frame = new JFrame("TestDelayedExit");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new TestDelayedExit());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
private class DisposeAction extends AbstractAction {
private int count = 4;
private Timer timer;
public DisposeAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic); // for alt-key combo
}
#Override
public void actionPerformed(ActionEvent e) {
if (timer != null && timer.isRunning()) {
return;
}
final Component c = (Component) e.getSource();
int timerDelay = 1000;
putValue(NAME, String.valueOf(count));
timer = new Timer(timerDelay, new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (count == 0) {
((Timer) e.getSource()).stop();
// this will not work for JMenuItems, and for that
// you would need to get the pop up window's parent component
Window win = SwingUtilities.getWindowAncestor(c);
if (win != null) {
win.dispose();
}
} else {
count--;
putValue(NAME, String.valueOf(count));
}
}
});
timer.start();
}
}
}

java keylistener on linux

I'm trying to write a game in java3d on Linux and for that I need a proper KeyListener.
Did anyone of you know how to do it? I'm currently using following code, I found somewhere on the net. It's working pretty good, holding down just one key, but as soon, as I press more than one (like space and w) it will do unexpected things...
public class RepeatingReleasedEventsFixer implements AWTEventListener {
private final HashMap<Integer, ReleasedAction> _map = new HashMap<Integer, ReleasedAction>();
public void install() {
Toolkit.getDefaultToolkit().addAWTEventListener(this, AWTEvent.KEY_EVENT_MASK);
}
public void remove() {
Toolkit.getDefaultToolkit().removeAWTEventListener(this);
}
#Override
public void eventDispatched(AWTEvent event) {
assert event instanceof KeyEvent : "Shall only listen to KeyEvents, so no other events shall come here";
assert assertEDT(); // REMEMBER THAT THIS IS SINGLE THREADED, so no need for synch.
// ?: Is this one of our synthetic RELEASED events?
if (event instanceof Reposted) {
// -> Yes, so we shalln't process it again.
return;
}
// ?: KEY_TYPED event? (We're only interested in KEY_PRESSED and KEY_RELEASED).
if (event.getID() == KeyEvent.KEY_TYPED) {
// -> Yes, TYPED, don't process.
return;
}
final KeyEvent keyEvent = (KeyEvent) event;
// ?: Is this already consumed?
// (Note how events are passed on to all AWTEventListeners even though a previous one consumed it)
if (keyEvent.isConsumed()) {
return;
}
// ?: Is this RELEASED? (the problem we're trying to fix!)
if (keyEvent.getID() == KeyEvent.KEY_RELEASED) {
// -> Yes, so stick in wait
/**
* Really just wait until "immediately", as the point is that the subsequent PRESSED shall already have been
* posted on the event queue, and shall thus be the direct next event no matter which events are posted
* afterwards. The code with the ReleasedAction handles if the Timer thread actually fires the action due to
* lags, by cancelling the action itself upon the PRESSED.
*/
final Timer timer = new Timer(2, null);
ReleasedAction action = new ReleasedAction(keyEvent, timer);
timer.addActionListener(action);
timer.start();
_map.put(Integer.valueOf(keyEvent.getKeyCode()), action);
// Consume the original
keyEvent.consume();
}
else if (keyEvent.getID() == KeyEvent.KEY_PRESSED) {
// Remember that this is single threaded (EDT), so we can't have races.
ReleasedAction action = _map.remove(Integer.valueOf(keyEvent.getKeyCode()));
// ?: Do we have a corresponding RELEASED waiting?
if (action != null) {
// -> Yes, so dump it
action.cancel();
}
// System.out.println("PRESSED: [" + keyEvent + "]");
}
else {
throw new AssertionError("All IDs should be covered.");
}
}
/**
* The ActionListener that posts the RELEASED {#link RepostedKeyEvent} if the {#link Timer} times out (and hence the
* repeat-action was over).
*/
private class ReleasedAction implements ActionListener {
private final KeyEvent _originalKeyEvent;
private Timer _timer;
ReleasedAction(KeyEvent originalReleased, Timer timer) {
_timer = timer;
_originalKeyEvent = originalReleased;
}
void cancel() {
assert assertEDT();
_timer.stop();
_timer = null;
_map.remove(Integer.valueOf(_originalKeyEvent.getKeyCode()));
}
#Override
public void actionPerformed(#SuppressWarnings ("unused") ActionEvent e) {
assert assertEDT();
// ?: Are we already cancelled?
// (Judging by Timer and TimerQueue code, we can theoretically be raced to be posted onto EDT by TimerQueue,
// due to some lag, unfair scheduling)
if (_timer == null) {
// -> Yes, so don't post the new RELEASED event.
return;
}
// Stop Timer and clean.
cancel();
// Creating new KeyEvent (we've consumed the original).
KeyEvent newEvent = new RepostedKeyEvent((Component) _originalKeyEvent.getSource(),
_originalKeyEvent.getID(), _originalKeyEvent.getWhen(), _originalKeyEvent.getModifiers(),
_originalKeyEvent.getKeyCode(), _originalKeyEvent.getKeyChar(), _originalKeyEvent.getKeyLocation());
// Posting to EventQueue.
Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(newEvent);
// System.out.println("Posted synthetic RELEASED [" + newEvent + "].");
}
}
/**
* Marker interface that denotes that the {#link KeyEvent} in question is reposted from some
* {#link AWTEventListener}, including this. It denotes that the event shall not be "hack processed" by this class
* again. (The problem is that it is not possible to state "inject this event from this point in the pipeline" - one
* have to inject it to the event queue directly, thus it will come through this {#link AWTEventListener} too.
*/
public interface Reposted {
// marker
}
/**
* Dead simple extension of {#link KeyEvent} that implements {#link Reposted}.
*/
public static class RepostedKeyEvent extends KeyEvent implements Reposted {
public RepostedKeyEvent(#SuppressWarnings ("hiding") Component source, #SuppressWarnings ("hiding") int id,
long when, int modifiers, int keyCode, char keyChar, int keyLocation) {
super(source, id, when, modifiers, keyCode, keyChar, keyLocation);
}
}
private static boolean assertEDT() {
if (!EventQueue.isDispatchThread()) {
throw new AssertionError("Not EDT, but [" + Thread.currentThread() + "].");
}
return true;
}
}
I can't be the only one who still runs into this - meanwhile 15 y.o. - problem and don't want to use timers...
EDIT: What this code is doing is fix the known problem on any Linux distri, where you add a simple KeyListener, which handles keyDowns, but invokes keyReleased Event repeatedly. To clearify my problem here a simple example
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
public class Test5 extends JFrame{
public Test5() {
addKeyListener(new KeyListener() {
boolean keydown = false;
#Override
public void keyTyped(KeyEvent arg0) {
// TODO Auto-generated method stub
}
#Override
public void keyReleased(KeyEvent arg0) {
keydown = false;
System.out.println("keyup");
}
#Override
public void keyPressed(KeyEvent arg0) {
if (keydown){
System.out.println("key is down");
} else {
System.out.println("key not down");
}
keydown = true;
}
});
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(400, 400);
setVisible(true);
//new RepeatingReleasedEventsFixer().install(); // This line will fix it for one key pressed
}
public static void main(String[] args) {
new Test5();
}
}
The output without the line being commented out:
key not down
keyup
key not down
keyup
key not down
keyup
key not down
keyup
key not down
keyup
otherwise:
key not down
key is down
key is down
key is down
key is down
key is down
key is down
key is down
key is down
key is down
keyup
Btw. How come, that it's not beeing fixed by now?
EDIT:
I tried the KeyBindings, as suggested, where it comes to these problems:
public class Test5 extends JFrame{
long timestamp = 0;
public Test5() {
((JComponent)getComponent(0)).getInputMap().put(KeyStroke.getKeyStroke('a'), "a");
((JComponent)getComponent(0)).getActionMap().put("a", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("time: "+(System.currentTimeMillis()-timestamp));
timestamp = System.currentTimeMillis();
}
});
((JComponent)getComponent(0)).getInputMap().put(KeyStroke.getKeyStroke('s'), "s");
((JComponent)getComponent(0)).getActionMap().put("s", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
System.out.println("s");
}
});
((JComponent)getComponent(0)).getInputMap().put(KeyStroke.getKeyStroke('d'), "d");
((JComponent)getComponent(0)).getActionMap().put("d", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent arg0) {
System.out.println("d");
}
});
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(400, 400);
setVisible(true);
new RepeatingReleasedEventsFixer().install(); // This line will fix it for one key pressed
}
/**
* #param args
*/
public static void main(String[] args) {
new Test5();
}
Holding down "a" will give me following output:
time: 4171
time: 501
time: 30
time: 30
time: 30
Where the second time is the actual problem. It takes about 470ms too long.
Holding down "s" and then somewhne pressing "d" will give me that output:
s
s
s
s
d
d
d
d
d
So I can't process two actions as the same time, so I can't use KeyBindings

This is not an answer, it is a long comment with a picture and some explanations.
I used your Test5 (without RepeatingReleasedEventsFixer) to hold down a and measure the time responses. The output is of the form
time: t1
time: t2
time: t3
time: t3
time: t3
...
t1 is meaningless since it depends on the current time and has nothing to do with response time (you also seem to ignore it).
t2 is the time it takes for the OS to realize that you're holding the key for repeated input.
t3 is the "sample time" of the held key, or a discretization of the input.
I'm using Windows where I have the following control panel options:
Repeat delay allows me to set t2 between ~257 (short) and ~1050 (long).
Repeat rate allows me to set t3 between ~407 (slow) and ~37 (fast).
For Linux, you'll have to consult someone / somewhere on how to change these values if you don't already know how to.
As for using multiple keys, see this question and answer and the excellent link within (especially the "Motion With Multiple Keys Pressed" section). It's a short tutorial and analysis of key bindings and key listeners, similar to the one I sent you to on this site.
Key bindings will always be preferred over key listeners unless maybe there is some very low level thing you want to do.

After days of researching and putting stuff together, I ended up writing my own Listener combined with a KeyEventDispatcher, here is the code for someone running into the same problem. It can and should be optimized, but is working for now:
Klass to test if a specific key is pressed:
import java.awt.KeyEventDispatcher;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyEvent;
import java.util.HashMap;
public class IsKeyPressed {
private static boolean wPressed = false;
private HashMap<Integer, Boolean> keys = new HashMap<Integer, Boolean>();
public IsKeyPressed() {
KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventDispatcher(new KeyEventDispatcher() {
#Override
public boolean dispatchKeyEvent(KeyEvent ke) {
synchronized (IsKeyPressed.class) {
switch (ke.getID()) {
case KeyEvent.KEY_PRESSED:
keys.put(ke.getKeyCode(), true);
break;
case KeyEvent.KEY_RELEASED:
keys.put(ke.getKeyCode(), false);
break;
}
return false;
}
}
});
}
public static boolean isWPressed() {
synchronized (IsKeyPressed.class) {
return wPressed;
}
}
public boolean isPressed(int keyCode){
synchronized (IsKeyPressed.class) {
if (keys == null)
return false;
if (keys.get(keyCode) == null)
return false;
return keys.get(keyCode);
}
}
}
Abstract class, thats beeing used for the actions.
public abstract class KeyActionListener {
protected int keyCode;
public KeyActionListener(int keyCode) {
this.keyCode = keyCode;
}
public void setKeyCode(int keyCode){
this.keyCode = keyCode;
}
public int getKeyCode(){
return this.keyCode;
}
public abstract void onKeyDown();
public abstract void onKeyUp();
public abstract void onKeyHolding();
}
Start listening to the keys and run the actions.
import java.util.ArrayList;
import java.util.HashMap;
public class KeyThread extends Thread{
private int sleep = 3;
ArrayList<KeyActionListener> listener = new ArrayList<KeyActionListener>();
IsKeyPressed isPressed = new IsKeyPressed();
HashMap<KeyActionListener, Boolean> pressed = new HashMap<KeyActionListener, Boolean>();
public KeyThread() {
this.start();
}
public void run() {
while (true){
for (int i = 0; i < listener.size(); i++) {
KeyActionListener curListener = listener.get(i);
if (isPressed.isPressed(curListener.getKeyCode()) && !pressed.get(curListener)){
curListener.onKeyDown();
pressed.put(curListener, true);
} else if(!isPressed.isPressed(curListener.getKeyCode()) && pressed.get(curListener)) {
curListener.onKeyUp();
pressed.put(curListener, false);
}
if(isPressed.isPressed(curListener.getKeyCode())){
curListener.onKeyHolding();
}
try{
Thread.sleep(sleep);
} catch(InterruptedException e){
}
}
}
}
public void addKeyActionListener(KeyActionListener l){
listener.add(l);
pressed.put(l, false);
}
}

Using timer to count as a stopwatch in Java Applet

I'm wanting to create a stopwatch so to speak in order to score my game. Lets say I have a variable: int sec = 0. When the game starts I want a g.drawString to draw the time to the applet. So for example each second, sec will increment by 1.
How do I go about making it g.drawString(Integer.toString(sec), 40, 400) increment by 1 and draw each second?
Thanks.
EDIT:
I've figured out how to increment it and print it to the screen by using ActionListener and putting g.drawString in there but it prints ontop of each other. If I put g.drawString into the paint method and only increment sec by 1 in the ActionListener there is a a flicker. Should I use Double Buffering? If so how do I go about doing this?

import java.awt.event.*;
import javax.swing.*;
public class StopWatch extends JLabel
implements MouseListener, ActionListener {
private long startTime; // Start time of stopwatch.
// (Time is measured in milliseconds.)
private boolean running; // True when the stopwatch is running.
private Timer timer; // A timer that will generate events
// while the stopwatch is running
public StopWatch() {
// Constructor.
super(" Click to start timer. ", JLabel.CENTER);
addMouseListener(this);
}
public void actionPerformed(ActionEvent evt) {
// This will be called when an event from the
// timer is received. It just sets the stopwatch
// to show the amount of time that it has been running.
// Time is rounded down to the nearest second.
long time = (System.currentTimeMillis() - startTime) / 1000;
setText("Running: " + time + " seconds");
}
public void mousePressed(MouseEvent evt) {
// React when user presses the mouse by
// starting or stopping the stopwatch. Also start
// or stop the timer.
if (running == false) {
// Record the time and start the stopwatch.
running = true;
startTime = evt.getWhen(); // Time when mouse was clicked.
setText("Running: 0 seconds");
if (timer == null) {
timer = new Timer(100,this);
timer.start();
}
else
timer.restart();
}
else {
// Stop the stopwatch. Compute the elapsed time since the
// stopwatch was started and display it.
timer.stop();
running = false;
long endTime = evt.getWhen();
double seconds = (endTime - startTime) / 1000.0;
setText("Time: " + seconds + " sec.");
}
}
public void mouseReleased(MouseEvent evt) { }
public void mouseClicked(MouseEvent evt) { }
public void mouseEntered(MouseEvent evt) { }
public void mouseExited(MouseEvent evt) { }
} // end StopWatchRunner
A small applet to test the component:
/*
A trivial applet that tests the StopWatchRunner component.
The applet just creates and shows a StopWatchRunner.
*/
import java.awt.*;
import javax.swing.*;
public class Test1 extends JApplet {
public void init() {
StopWatch watch = new StopWatch();
watch.setFont( new Font("SansSerif", Font.BOLD, 24) );
watch.setBackground(Color.white);
watch.setForeground( new Color(180,0,0) );
watch.setOpaque(true);
getContentPane().add(watch, BorderLayout.CENTER);
}
}

how to pause program until a button press?

i use from a class that extended from jframe and it has a button(i use from it in my program)
i want when run jframe in my program the whole of my program pause
until i press the button.
how can i do it
in c++ getch() do this.
i want a function like that.

Pausing Execution with Sleep, although I doubt that is the mechanism that you'll want to use. So, as others have suggested, I believe you'll need to implement wait-notify logic. Here's an extremely contrived example:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.concurrent.atomic.AtomicBoolean;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
#SuppressWarnings("serial")
public class PanelWithButton extends JPanel
{
// Field members
private AtomicBoolean paused;
private JTextArea textArea;
private JButton button;
private Thread threadObject;
/**
* Constructor
*/
public PanelWithButton()
{
paused = new AtomicBoolean(false);
textArea = new JTextArea(5, 30);
button = new JButton();
initComponents();
}
/**
* Initializes components
*/
public void initComponents()
{
// Construct components
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
add( new JScrollPane(textArea));
button.setPreferredSize(new Dimension(100, 100));
button.setText("Pause");
button.addActionListener(new ButtonListener());
add(button);
// Runnable that continually writes to text area
Runnable runnable = new Runnable()
{
#Override
public void run()
{
while(true)
{
for(int i = 0; i < Integer.MAX_VALUE; i++)
{
if(paused.get())
{
synchronized(threadObject)
{
// Pause
try
{
threadObject.wait();
}
catch (InterruptedException e)
{
}
}
}
// Write to text area
textArea.append(Integer.toString(i) + ", ");
// Sleep
try
{
Thread.sleep(500);
}
catch (InterruptedException e)
{
}
}
}
}
};
threadObject = new Thread(runnable);
threadObject.start();
}
#Override
public Dimension getPreferredSize()
{
return new Dimension(400, 200);
}
/**
* Button action listener
* #author meherts
*
*/
class ButtonListener implements ActionListener
{
#Override
public void actionPerformed(ActionEvent evt)
{
if(!paused.get())
{
button.setText("Start");
paused.set(true);
}
else
{
button.setText("Pause");
paused.set(false);
// Resume
synchronized(threadObject)
{
threadObject.notify();
}
}
}
}
}
And here's your main class:
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class MainClass
{
/**
* Main method of this application
*/
public static void main(final String[] arg)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new PanelWithButton());
frame.pack();
frame.setVisible(true);
frame.setLocationRelativeTo(null);
}
});
}
}
As you can see, this example application will continually write to the text area until you click the button that reads 'Pause', whereupon to resume you'll need to click that same button which will now read 'Start'.

You don't say what you mean by pause. What is your app doing?
As a rule of thumb you CAN'T pause a UI app. User interface applications run from a message processing loop. Message comes in, message is dispatched, loop waits for another message. An app still needs to handles things like the user clicking on buttons, resizing the window, closing the app and so forth so this loop runs continuously.
If you want your application to "pause" in the sense of prevent the user doing something, just grey out whatever button or menu it is you don't want users to be doing.
If your app is running a thread in the background and wish it to suspend that action until you resume it, you can do so fairly easily like this.
MyThread mythread = new MyThread();
// Main thread
void pause() {
mythread.pause = true;
}
void resume() {
synchronized (mythread) {
mythread.pause = false;
mythread.notify();
}
}
class MyThread extends Thread {
public boolean pause = false;
public void run() {
while (someCondition) {
synchronized (this) {
if (pause) {
wait();
}
}
doSomething();
}
}
}
It is also possible to use Thread.suspend(), Thread.resume() to accomplish similar but these are inherently dangerous because you have no idea where the thread is when you suspend it. It could have a file open, be half way through sending a message over a socket etc. Putting a test in whatever loop controls your thread allows you do suspend at a point when it is safe to do so.

This answer entirely depends on whether I understand your question correctly, please give a bit more info if you want better answers. Here goes:
Pausing in a loop scenario
boolean paused;
while(true ) {
if(paused)
{
Thread.sleep(1000); // or do whatever you want in the paused state
} else {
doTask1
doTask2
doTask3
}
}
Threads:
You can also put those tasks into a seperate thread and not on the GUI thread which is typically what you would do for long running operations.
Pausing a thread is very easy. Just call suspend() on it. When you want to unpause call resume(). These methods however are dangerous and have been deprecated. Better or rather safer way to do it would be similar to the above by checking a pause flag.Here is a short example I had lying around in my snippets. Cant exactly remember where I got it in the first place:
// Create and start the thread
MyThread thread = new MyThread();
thread.start();
while (true) {
// Do work
// Pause the thread
synchronized (thread) {
thread.pleaseWait = true;
}
// Do work
// Resume the thread
synchronized (thread) {
thread.pleaseWait = false;
thread.notify();
}
// Do work
}
class MyThread extends Thread {
boolean pleaseWait = false;
// This method is called when the thread runs
public void run() {
while (true) {
// Do work
// Check if should wait
synchronized (this) {
while (pleaseWait) {
try {
wait();
} catch (Exception e) {
}
}
}
// Do work
}
}
} // Create and start the thread
MyThread thread = new MyThread();
thread.start();
while (true) {
// Do work
// Pause the thread
synchronized (thread) {
thread.pleaseWait = true;
}
// Do work
// Resume the thread
synchronized (thread) {
thread.pleaseWait = false;
thread.notify();
}
// Do work
}
class MyThread extends Thread {
boolean pleaseWait = false;
// This method is called when the thread runs
public void run() {
while (true) {
// Do work
// Check if should wait
synchronized (this) {
while (pleaseWait) {
try {
wait();
} catch (Exception e) {
}
}
}
// Do work
}
}
}
Hope this helps

try my java pause button:
package drawFramePackage;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame;
import javax.swing.Timer;
public class Milliseconds2 implements ActionListener, MouseListener{
JFrame j;
Timer t;
Integer onesAndZeros, time, time2, placeHolder2;
Boolean hasFired;
/**
* #param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
new Milliseconds2();
}
public Milliseconds2(){
j = new JFrame();
j.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
j.setSize(new Dimension(300, 300));
j.setVisible(true);
j.addMouseListener(this);
onesAndZeros = new Integer(0);
time = new Integer(0);
time2 = new Integer(0);
placeHolder2 = new Integer(0);
hasFired = new Boolean(true);
t = new Timer(2400, this);
time = (int) System.currentTimeMillis();
t.start();
}
#Override
public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub
if (onesAndZeros.equals(0)){
t.stop();
if (hasFired){
time2 = t.getDelay() - ((int) System.currentTimeMillis() - time);
}
else{
time2 -= (int) System.currentTimeMillis() - placeHolder2;
}
if (hasFired){
hasFired = false;
}
onesAndZeros = -1;
}
if (onesAndZeros.equals(1)){
//System.out.println(time2);
t.setInitialDelay(time2);
t.start();
placeHolder2 = (int) System.currentTimeMillis();
onesAndZeros = 0;
}
if (onesAndZeros.equals(-1)){
onesAndZeros = 1;
}
}
#Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
time = (int) System.currentTimeMillis();
hasFired = true;
System.out.println("Message");
}
}

Freezing your Main Thread will effectively freeze the entire program and could cause the operating system to think the application has crashed, not quite sure so correct me if I'm wrong. You could try to hide/disable the controls and enable them again when the user clicks on your button.

UI performs task using message driven mechanism.
If you have a button in your UI and you want to run something when that button is pressed, you should add an object of ActionListener to your button. Once the button is pressed, it fires the ActionListener object to perform a task, e.g.:
button.addActionListener(new ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
// do something
}
});
If you want to stop something when you press a pause button, you will defnitely need a Thread. This is more complicated than the former case.

How can I make a swing JButton repeat its action when it is held down?

I am creating an touch screen application using Swing and have a request to change one of buttons so that it will behave like a keyboard when the button is held down.
(First of all, I am not sure that the touch screen will allow the user to "hold down" the button, but pretend that they can for now)
I was going to go down the path of starting a loop when mousePressed was called and then ending the loop when mouseReleased was called. This will involve starting a thread and having to deal with synchronization as well as invokeLater() to get events back on the EventQueue.
Is there a very simple way to do what I want? I hope I am just not seeing the API to do it.

javax.swing.Timer is your friend. And here's an article with some more info.

I would do it like this:
Listen to mousePressed and schedule a java.util.Timer to be launched at a later time.
The Timer does the action and set itself to schedule again.
Listen to mouseReleased to cancel the Timer.

I went with the java.swing.Timer since it will automatically post back to the Swing EventQueue and that is what I am looking for. Thanks for the help.

Here's how you can do it by subclassing JButton:
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.Action;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.SwingUtilities;
public class TypomaticButton extends JButton implements MouseListener {
private boolean autotype = false;
private static Thread theThread = null;
private String myName = "unknown";
private int
speed = 150,
wait = 300,
decrement = (wait - speed) / 10;
TypomaticButton(Action action){
super(action);
myName = action.getValue(Action.NAME).toString();
addMouseListener(this);
}
TypomaticButton(String text){
super(text);
setBorder(BorderFactory.createEmptyBorder(6, 6, 6, 6));
myName = text;
addMouseListener(this);
}
#Override
public void mouseClicked(MouseEvent arg0) {}
#Override
public void mouseEntered(MouseEvent arg0) { }
#Override
public void mouseExited(MouseEvent arg0) { }
#Override
public void mousePressed(MouseEvent arg0) {
autotype = true;
theThread = new Thread(new Runnable() { // do it on a new thread so we don't block the UI thread
#Override
public void run() {
for (int i = 10000; i > 0 && autotype; i--) { // don't go on for ever
try {
Thread.sleep(wait); // wait awhile
} catch (InterruptedException e) {
break;
}
if(wait != speed){
wait = wait - decrement; // gradually accelerate to top speed
if(wait < speed)
wait = speed;
}
SwingUtilities.invokeLater(new Runnable() { // run this bit on the UI thread
public void run() {
if(!autotype) // it may have been stopped meanwhile
return;
ActionListener[] als = getActionListeners();
for(ActionListener al : als){ // distribute to all listeners
ActionEvent aevent = new ActionEvent(getClass(), 0, myName);
al.actionPerformed(aevent);
}
}
});
}
autotype = false;
}
});
theThread.start();
}
#Override
public void mouseReleased(MouseEvent arg0) {
autotype = false;
wait = 300;
}
void speed(int millisecs){
speed = millisecs;
decrement = (wait - speed) / 10;
}
void stop(){
autotype = false;
if(theThread != null){
theThread.interrupt();
}
}
}
It accelerates too.
Hope that helps.