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

Question

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;
    }

}

Answer 1

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);

    }
}