Develop Reference

Making the "Calling method" wait for the "Return" of data

I have 2 classes, one class is a JFrame (MainUIHolder.java) and the other class is a JDialog (EditValuationsDialog.java). MainUIHolder can call EditValuationsDialog on button click event.
Once EditValuationsDialog is open, user can enter data in its fields and press its "Add" button. OK, here is the issue now. Once the user press the "Add" button, the EditValuationsDialog should inform that to the MainUIHolder.
Below is the code.
MainUIHolder
Action edit = new AbstractAction()
{
public void actionPerformed(ActionEvent e)
{
JTable table = (JTable)e.getSource();
int rowNum = Integer.valueOf(e.getActionCommand());
Object valueAt = table.getModel().getValueAt(rowNum, 0);
EditValuationsDialog edit = new EditValuationsDialog(null,true);
edit.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
edit.setTitle("Edit Valuations");
edit.setClientName(portfolioViewClientName.getText());
edit.setPortfolioType(portfolioViewInvestmentTypeCombo.getSelectedItem().toString());
edit.setPortfolioId(id);
edit.setOngoingValuationsId(Integer.parseInt(String.valueOf(valueAt)));
edit.setLocationRelativeTo(table);
edit.setVisible(true);
//CATCH THE CALL FROM EditValuationsDialog HERE!!!!//
}
};
EditValuationsDialog
//Action Listeners
private class AddBtnAction implements ActionListener
{
#Override
public void actionPerformed(ActionEvent e)
{
if(someCondition)
{
return String / int to MainUIHolder (See where I want to catch it in MainUIHolder)
}
else
{
do nothing
}
}
}
In my code I have indicated from where the call to MainUIHolder should be generated and in what place I must catch that call in MainUIHolder. How can I do this call back work?

You could...
Add a static method to EditValuationsDialog that shows the dialog, evaluates the results and returns the value you are expecting...
public void actionPerformed(ActionEvent e)
{
int result = EditValuationsDialog.showDialog();
}
public class EditValuationsDialog ... {
//...
private int result = -1;
//...
public int getResult() {
return result;
}
//...
public static int showDialog(Component source, int rowNum, Object valueAt) {
EditValuationsDialog edit = null;
Window parent = SwingUtilities.windowFor(source);
if (parent instanceof Frame) {
edit = new EditValuationsDialog((Frame)parent,true);
} else if (parent instanceof Dialog) {
edit = new EditValuationsDialog((Dialog)parent,true);
} else {
edit = new EditValuationsDialog(null,true);
}
edit.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
edit.setTitle("Edit Valuations");
edit.setClientName(portfolioViewClientName.getText());
edit.setPortfolioType(portfolioViewInvestmentTypeCombo.getSelectedItem().toString());
edit.setPortfolioId(id);
edit.setOngoingValuationsId(Integer.parseInt(String.valueOf(valueAt)));
edit.setLocationRelativeTo(source);
edit.setVisible(true);
return edit.getResult();
}
//...
private class AddBtnAction implements ActionListener
{
#Override
public void actionPerformed(ActionEvent e)
{
if(someCondition)
{
result = 0;
}
else
{
result = 1;
}
EditValuationsDialog.this.dispose();
}
}
}
Or you could...
Simply evaluate the results of getResult() from the above example directly...
Side note: Because I don't like extending from top level containers like JDialog, I tend to create some of my panels/components with static showDialog methods, thing something along the lines of a login panel for example. It means I could re-use the panel else where, but provides me with the convenience of been able to popup a dialog when I need to. I've also used JOptionPane from time to time to show these panels, but it depends on the complexity of the available actions...

Make the dialog modal (setModal(true)). Then the code after dialog.setVisible(true) is executed after the dialog is closed.
BTW it's better to pass the MainUIHolder JFrame instance as parent of the dialog.

You could add an interface to the EditValuationsDialog something like this:
Interface EditValuationsDialogInterface {
public void onAddClicked(addedVlue);
}
and then add it as such:
edit.setOnAddButtonCallback(new EditValuationsDialogInterface () {
#Override
onAddClicked(addedVlue){
//DO SOMETHING
}
});
in your EditValuationsDialog's add button onclick call add this:
onAddButtonClickedCallback.onAddClicked(retunrValue);
This allows you to have a direct link back to the original calling class.

How force the program wait a Task and show Progress Bar to user?

I use Swing Application Framework in my program. And I have some long-time work. I use org.jdesktop.application.Task for it. Another programmer wrote two Tasks before I took this project (I can not ask him about the programm). When Tasks are executing user sees progress bar without showing percent complete, but what shows "Wait" message and user can not click to a main window while Task does not ended. It is fine! But I could not find place where ProgressBars was created. May be it is described in some xml-file or property-file?
Also I wrote another Tasks and when they run, progress bar which I created is not displayed or displayed incorrectly. I read about ProgressBar and ProgressMonitor, but it does not help me.
Programm continue to run after someTask.execute(), but I want to it displays ProgressBar, ProgressMonitor or something else and user can not click the main window and window will display correctly. Now window has black "blocks" when user change it.
May be I need use org.jdesktop.application.TaskMonitor. I try to use it as here https://kenai.com/projects/bsaf/sources/main/content/other/bsaf_nb/src/examples/StatusBar.java?rev=235 , but my main window is displayed incorrectly and my ProgressBar is not displayed.
I need to when Task is running program waits it, but user can see ProgressBar, can cancel the operation and can not click to the main window. How can I do it?
Here my code:
public class A{
#Action(name = "ActionName", block = Task.BlockingScope.APPLICATION)
public RequestInfoTask requestInfo() {
RequestInfoTask task = new RequestInfoTask(Application.getInstance());
isSuccessedGetInfo=false;
task.addTaskListener(new TaskListener.Adapter<List<InfoDTO>, Void>() {
#Override
public void succeeded(TaskEvent<List<InfoDTO>> listTaskEvent) {
isSuccessedGetResources=true;
}
});
//Here I want to the program shows ProgressMonitor and user can not click to the main window.
//But small window with message "Progress..." is displayed for several seconds and disappear.
ProgressMonitor monitor = new ProgressMonitor(getMainView(), "Wait! Wait!", "I am working!", 0, 100);
int progress = 0;
monitor.setProgress(progress);
while(!task.isDone()){
monitor.setProgress(progress+=5);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
}
monitor.setProgress(100);
//This code must run after "task" finishes.
if(isSuccessedGetInfo){
MyTask2 task2 = new MyTask2(Application.getInstance());
isSuccessedTask2=false;
task2.addTaskListener(new TaskListener.Adapter<Map<?,?>, Void>(){
#Override
public void succeeded(TaskEvent<Map<String, ICredential>> arg0) {
isSuccessedTask2=true;
}
});
//Do something with results of task2.
}
return task;
}
}
public class RequestInfoTask extends Task<List<InfoDTO>, Void> {
public RequestInfoTask(Application application) {
super(application);
}
#Override
protected List<InfoDTO> doInBackground() throws Exception {
List<InfoDTO> result = someLongerLastingMethod();
return result;
}
}

Part of your problem sounds like it comes from not using the EDT correctly. Any long running task needs to be started in it's own thread to keep the GUI responsive and repainting.
Ideally you'd be following a MVC pattern. In that case you place your Progress Bar in the view, your flag (that indicates whether the task should be running still) in the control, and your long running task in in the Model.
From that point, if your model checks periodically if it should stop (Probably at good stopping points), you can reset everything.
Here's an example with MVC:
import java.awt.BorderLayout;
import java.awt.event.*;
import javax.swing.*;
public class ProgressBarDemo{
public static class View extends JPanel{
Controller control;
public JProgressBar progressBar = new JProgressBar(0, 100);
JButton button = new JButton("Start Long Running Task");
public View(Controller controlIn){
super();
this.control = controlIn;
setLayout(new BorderLayout());
button.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
//Toggle between running or not
if(control.isRunning){
control.isRunning = false;
button.setText("Canceling...");
button.setEnabled(false);
} else{
control.isRunning = true;
button.setText("Cancel Long Running Task");
control.startTask();
}
}});
progressBar.setStringPainted(true);
add(progressBar);
add(button, BorderLayout.SOUTH);
}
}
//Communications gateway
public static class Controller{
View view = new View(this);
boolean isRunning = false;
public void updateProgress(final int progress){
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run() {
view.progressBar.setValue(progress);
}});
}
public void reset(){
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run() {
isRunning = false;
view.button.setText("Start Long Running Task");
view.progressBar.setValue(0);
view.button.setEnabled(true);
}});
}
public void startTask(){
LongRunningClass task = new LongRunningClass(this);
new Thread(task).start();
}
}
public static class LongRunningClass implements Runnable{
Controller control;
public LongRunningClass(Controller reference){
this.control = reference;
}
#Override
public void run() {
try {
for(int i = 0; i < 11; i++){
//Monitor the is running flag to see if it should still run
if(control.isRunning == false){
control.reset();
break;
}
control.updateProgress(i * 10);
Thread.sleep(3000);
}
control.reset();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) throws InterruptedException {
// Create and set up the window.
JFrame frame = new JFrame("LabelDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Add content to the window.
frame.add(new Controller().view);
// Display the window.
frame.pack();
frame.setVisible(true);
}
}

Java swing - when cancel button clicked don't loop

I have a gui, that is having a Login prompt added.
while(notValidLogIn){
LoginPrompt.getDetails() //a static method that
}
Hwoever, the loginPrompt is a Jdialog, with a parent JFrame. How can I stop looping of cancel clicked, I could put System.exit(0) in cancel action performed. But don't want to stop everything, I want something like :
while(notValidLogIn && LoginPrompt.isNotCancelled()){
LoginPrompt.getDetails(); //a static method that creates an instance of login JDialog()
}

In a recent project I was working on, I've implemented an event based solution. The idea is JDialog notify to its parent JFrame how the login process went and this last one may or may not continue its execution. This way I have no loops and keep separate responsibilities: The schema would be something like this:
LoginEvent:
This is the event itself. Not that complicated:
class LoginEvent extends EventObject {
public static final int LOGIN_SUCCEEDED = 0;
public static final int LOGIN_FAILED = 1;
public static final int LOGIN_DIALOG_CLOSED = 2;
private int id;
public LoginEvent(Object source, int id) {
super(source);
this.id = id;
}
public int getId() {
return id;
}
}
LoginListener
An interface to handle these LoginEvents:
public interface LoginListener extends EventListener {
public void handleLoginEvent(LoginEvent evt);
}
Login Dialog
This class has to mantain a List with subscribed LoginListeners:
class LoginDialog {
List<LoginListener> listeners = new ArrayList<>();
JDialog dialog;
JButton accept;
JButton cancel;
public void show() {
//create and show GUI components
}
public void close() {
if(dialog != null) {
dialog.dispose();
}
}
...
public void addLoginListener(LoginListener loginEventListener) {
if(!listeners.contains(loginEventListener)) {
listeners.add(loginEventListener);
}
}
public void removeLoginListener(LoginListener loginEventListener) {
listeners.remove(loginEventListener);
}
public void dispatchLoginEvent(LoginEvent evt) {
for(LoginListener loginListener: listeners) {
loginListener.handleLoginEvent(evt);
}
}
}
Adding action listeners to accept and cancel buttons:
accept.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// validate login data
if(loginValid) {
dispatchLoginEvent(new LoginEvent(dialog, LoginEvent.LOGIN_SUCCEEDED));
} else {
dispatchLoginEvent(new LoginEvent(dialog, LoginEvent.LOGIN_FAILED));
}
}
});
cancel.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
dispatchLoginEvent(new LoginEvent(dialog, LoginEvent.LOGIN_DIALOG_CLOSED));
}
});
Subscribing a LoginListener
In your JFrame:
final LoginDialog dialog = new LoginDialog();
dialog.addLoginListener(new LoginListener() {
#Override
public void handleLoginEvent(LoginEvent evt) {
if(evt.getId() == LoginEvent.LOGIN_SUCCEEDED {
dialog.close();
//continue execution
return;
}
if(evt.getId() == LoginEvent.LOGIN_FAILED) {
JOptionPane.showMessageDialog(null, "Login failed!");
return;
}
if(evt.getId() == LoginEvent.CLOSE_LOGIN_DIALOG) {
dialog.close();
// do something when this dialog is closed
}
}
};
dialog.show();

while(notValidLogIn && LoginPrompt.isNotCancelled()){
LoginPrompt.getDetails(); //a static method that creates an instance of login JDialog()
}
If this loop is inside another thread other than the EDT(event dispatch thread), then you can use SwingUtilities.invokeAndWait(new Runnable()) function: invokeAndWait() blocks the current thread until the EDT is done executing the task given by it. This option is particularly used while we want to await an execution of a thread for taking confirmation from user or other input using JDialogue/JFileChooser etc
while(notValidLogIn && LoginPrompt.isNotCancelled()){
SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
LoginPrompt.getDetails() ;
}
});
}
Note: re-stating for emphasizing: you should ensure that this loop is executing inside another Thread: such as using an extended class of Runnable, or by means of anonymous class:
new Thread()
{
// other code of your context
public void run()
{
while(notValidLogIn && LoginPrompt.isNotCancelled()){
SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
LoginPrompt.getDetails() ;
}
});
}
}
}.start();

How to create a delay between button click (to prevent button spamming)

I'm creating a java program that involves a button that gives a bunch of problems. I'm wondering how can I create a delay between the times a user can click a button (to prevent button spamming). Here is what I tried.
public void ButtonActionPerformed(java.awt.event.ActionEvent evt) {
Thread DelayTHREAD = new Delay();
if(DelayTHREAD.isAlive()) {
/*do nothing*/
}
else {
/*some other code*/
DelayTHREAD.start();
}
}
public static class Delay extends Thread /*Prevents user from spamming buttons*/ {
#Override
public void run() {
try {
Thread.sleep(5000); /*sleeps for the desired delay time*/
}catch(InterruptedException e){
}
}
}
OK so here is the problem, it doesn't matter whether or not the delay thread is started or not, the program still goes on and continues to perform the action performed as if the delay thread never even existed.
Someone please tell me how can I create a delay, so that a user cannot spam button in a program? Thanks :)

You might just create a little method that disables the button for a period of time after the user clicks on it, and then enables it afterward, like so:
static void disable(final AbstractButton b, final long ms) {
b.setEnabled(false);
new SwingWorker() {
#Override protected Object doInBackground() throws Exception {
Thread.sleep(ms);
return null;
}
#Override protected void done() {
b.setEnabled(true);
}
}.execute();
}
Then call it from your actionPerformed method like this:
disable(button, 5000);
Just make sure you call it from the EDT.

Use a SwingTimer to inject a delay between the button click and the activation of the associated action....
import javax.swing.Timer;
/*...*/
private Timer attackTimer;
/*...*/
attackTimer = new Timer(5000, new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// Do attack...
}
});
attackTimer.setRepeats(false);
/*...*/
public void ButtonActionPerformed(java.awt.event.ActionEvent evt) {
// Restart the timer each time the button is clicked...
// In fact, I would disable the button here and re-enable it
// in the timer actionPerformed method...
attackTimer.restart();
}

updating a JProgressBar while processing

I know the subject has already been seen on many Questions and has been answered, but still, I can't get trough it.
I just want to update a progressBar while extracting some stuff of a large xml file.
I thought it was enough to have the time-consuming loop in a different thread but ?..
All I managed to get is the progressBar either not showed at all, or updated at the end, just before it's closed.
Instanced somewhere near the launch of the application, I have:
public class SomeClass {
private SomeClass () {
myXMLParser reader = new myXMLParser();
CoolStuff fromXml = reader.readTheXml();
}
}
while showing and updating a JDialog with a JProgressBar:
public class LoadingDialog extends JDialog {
private JProgressBar progressBar;
/* ... */
public void progress() {
progressBar.setValue(progressBar.getValue() + 1);
}
}
So I have this myXMLParser:
public class myXMLParser {
private LoadingDialog loadingDialog = new LoadingDialog();
public CoolStuff readTheXml() {
CoolStuff fromXml = new CoolStuff();
while(manyIterations) {
loadingDialog.progress();
fromXml.add(some() + xml() + reading());
}
return fromXml;
}
}
I have seen many things with SwingWorker and using PropertyChange events update the progressBar, but examples are always given all-in-one, with the processing and the progressbar within the same class, and with classes within classes, and since I begin in Java, I wasn't able to translate that to my situation.
Any help ?.. Any (not too obvious) advices ?
Edit: So thanks to btantlinger it worked like that:
public class SomeClass {
private SomeClass () {
myXMLParser reader = new myXMLParser();
new Thread(new Runnable() {
#Override
public void run() {
CoolStuff fromXml = reader.readTheXml();
}
}).start();
}
}
public class LoadingDialog extends JDialog {
private JProgressBar progressBar;
/* ... */
public void progress() {
progressBar.setValue(progressBar.getValue() + 1);
}
}
public class myXMLParser {
private LoadingDialog loadingDialog = new LoadingDialog();
public CoolStuff readTheXml() {
CoolStuff fromXml = new CoolStuff();
while(manyIterations) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
loadingDialog.progress();
}
});
fromXml.add(some() + xml() + reading());
}
return fromXml;
}
}

You MUST update the JProgress bar on the Swing Event Dispatch Thread. You cannot modify Swing components on any other thread.
Your only other alternative would be to set the JProgress bar "indeterminate" before you start your thread where the progress bar will just go back and forth.
E.g
progBar.setIndeterminate(true);
See the SwingWorker javadoc:
http://docs.oracle.com/javase/6/docs/api/javax/swing/SwingWorker.html
If you don't want to use the SwingWorker, another option is the SwingUtilities.invokeLater method
//inside your long running thread when you want to update a Swing component
SwingUtilities.invokeLater(new Runnable() {
public void run() {
//This will be called on the EDT
progressBar.setValue(progressBar.getValue() + 1);
}
});

In addition to the code provided by #btantlinger, I found after testing that it required an additional line of code in order to update the progress bar on the UI thread while processing. See below.
SwingUtilities.invokeLater(new Runnable() {
public void run() {
progressBar.setValue((int)percentage);
//below code to update progress bar while running on thread
progressBar.update(progressBar.getGraphics());
}
});