ProgressProperty and isCancelled causing a bound value that cannot be set.

Question

I noticed that cancelling the following application causes errors since a bound value cannot be set. I tried to add some conditions to prevent this error from happening but to no avail.
The following is the main culprit:
pb.progressProperty().bind(serv.progressProperty());You can also notice that I tried to use progressProperty and ChangeListener instead of bind method. Unfortunately unsuccessfully. Can I make progressbar functioning without bind method (code above)?
Complete error message when cancel button is pressed is the following:
Service status: SCHEDULED
Let the download begin!
Service status: CANCELLED
Service status cancelled when progress was: 0.09582292038557658
java.lang.RuntimeException: A bound value cannot be set.
     at javafx.beans.property.DoublePropertyBase.set(Unknown Source)
     at javafx.scene.control.ProgressIndicator.setProgress(Unknown Source)
     at dm.Thr$2.handle(Thr.java:73)
     at dm.Thr$2.handle(Thr.java:1)
     at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
     at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
     at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
     at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
     at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
     at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
     at javafx.event.Event.fireEvent(Unknown Source)
Cancelling!
Finished/cancelled!
     at javafx.scene.Node.fireEvent(Unknown Source)
     at javafx.scene.control.Button.fire(Unknown Source)
     at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(Unknown Source)
     at com.sun.javafx.scene.control.skin.SkinBase$5.handle(Unknown Source)
     at com.sun.javafx.scene.control.skin.SkinBase$5.handle(Unknown Source)
     at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
     at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
     at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
     at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
     at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
     at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
     at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
     at javafx.event.Event.fireEvent(Unknown Source)
     at javafx.scene.Scene$MouseHandler.process(Unknown Source)
     at javafx.scene.Scene$MouseHandler.process(Unknown Source)
     at javafx.scene.Scene$MouseHandler.access$1300(Unknown Source)
     at javafx.scene.Scene.impl_processMouseEvent(Unknown Source)
     at javafx.scene.Scene$ScenePeerListener.mouseEvent(Unknown Source)
     at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(Unknown Source)
     at com.sun.glass.ui.View.handleMouseEvent(Unknown Source)
     at com.sun.glass.ui.View.notifyMouse(Unknown Source)
     at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
     at com.sun.glass.ui.win.WinApplication.access$100(Unknown Source)
     at com.sun.glass.ui.win.WinApplication$2$1.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)Application:
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import javafx.application.Application;
import javafx.concurrent.Service;
import javafx.concurrent.Task;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.ProgressBar;
import javafx.scene.control.TextArea;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
public class Thr extends Application {
     @Override
     public void start(Stage stage) throws Exception {
          final Group rootGroup = new Group();
           final Scene scene = new Scene(rootGroup, 500, 400, Color.GHOSTWHITE);
           stage.setScene(scene);
           stage.setTitle("Testing downloads from Spring");
           stage.show();
           setS(rootGroup);
     final VBox vbox = new VBox();
     final javafx.scene.control.Button btn = new javafx.scene.control.Button("START!");
     final TextArea tf = new TextArea();
     final javafx.scene.control.Button btnC = new javafx.scene.control.Button("CANCEL!");
     final ProgressBar pb = new ProgressBar();
     final FirstLineService serv = new FirstLineService();
     boolean cancelled = false;
     private void setS(Group rg) {
          tf.setPrefRowCount(5);
          vbox.getChildren().add(btn);
          vbox.getChildren().add(tf);
          vbox.getChildren().add(btnC);
          vbox.getChildren().add(pb);
          pb.setPrefWidth(450);
          rg.getChildren().add(vbox);
          btn.setOnAction(new EventHandler<ActionEvent>() {
               @Override
               public void handle(ActionEvent arg0) {
                    serv.start();
                    System.out.println("Service status: "+serv.getState());
                    tf.setText("STARTED!");
          btnC.setOnAction(new EventHandler<ActionEvent>() {
               @Override
               public void handle(ActionEvent arg0) {
                    serv.cancel();
                    System.out.println("Service status: "+serv.getState());
                    System.out.println("Service status cancelled when progress was: "+serv.getProgress());
                    tf.appendText("\nCANCELLED!");
                    pb.setProgress(serv.getProgress());
          //pb.setProgress(0);
          if (cancelled!=true) {
               pb.progressProperty().bind(serv.progressProperty());
          } else {
               pb.progressProperty().unbind();
          /*pb.progressProperty().addListener(new ChangeListener<Task>() {
               @Override
               public void changed(ObservableValue<? extends Task> arg0,
                         Task arg1, Task arg2) {
                    // TODO Auto-generated method stub
                    pb.setProgress(serv.getProgress());
     private class FirstLineService extends Service {
        protected Task createTask() {
            return new Task<Void>() {
                protected Void call() {
                     URL url;
                         try {
                              url = new URL("http://s3.amazonaws.com/dist.springframework.org/release/SPR/spring-framework-3.1.1.RELEASE.zip");
                           InputStream in = url.openStream();
                           int fileSize = url.openConnection().getContentLength()/1024;
                           File f = new File("spring.zip");
                           BufferedInputStream bin = new BufferedInputStream(in, 1024);
                           FileOutputStream fos = new FileOutputStream(f);
                           BufferedOutputStream bos = new BufferedOutputStream(fos, 1024);
                           int n=0;
                           int k=0;
                           System.out.println("Let the download begin!");
                           while(n !=-1){
                                if (isCancelled()) {
                                     cancelled = true;
                                        n=-1;
                                        System.out.println("Cancelling!");
                                   } else {
                                   k=k+1;
                                n=bin.read();
                                bos.write(n);
                                updateProgress(k/1024,fileSize);
                                //pb.progressProperty().bind(this.progressProperty());
                                //pb.setProgress(getProgress());
                           bos.close();
                           System.out.println("Finished/cancelled!");
                         } catch (MalformedURLException e) {
                              e.printStackTrace();
                         } catch (FileNotFoundException e) {
                              e.printStackTrace();
                         } catch (IOException e) {
                              e.printStackTrace();
                      return null;
     public static void main(final String[] arguments)
          Application.launch(arguments);
}

Answer 1

The following is the main culprit:
pb.progressProperty().bind(serv.progressProperty());I think your problem is the following line:
   pb.setProgress(serv.getProgress())  //bound value cannot be setAdd a listener to a serv. progressProperty()
  serv.progressProperty().addListener(new ChangeListener() {
                   @Override
                   public void changed(ObservableValue o, Object oldVal,
                           Object newVal) {
                      pb.progressProperty().setValue(serv.getProgress());
               });Here is the modified code:
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import javafx.beans.value.*;
import javafx.application.Application;
import javafx.concurrent.Service;
import javafx.concurrent.Task;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.ProgressBar;
import javafx.scene.control.TextArea;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
public class Thr extends Application {
     @Override
     public void start(Stage stage) throws Exception {
          final Group rootGroup = new Group();
           final Scene scene = new Scene(rootGroup, 500, 400, Color.GHOSTWHITE);
           stage.setScene(scene);
           stage.setTitle("Testing downloads from Spring");
           stage.show();
           setS(rootGroup);
     final VBox vbox = new VBox();
     final javafx.scene.control.Button btn = new javafx.scene.control.Button("START!");
     final TextArea tf = new TextArea();
     final javafx.scene.control.Button btnC = new javafx.scene.control.Button("CANCEL!");
     final ProgressBar pb = new ProgressBar();
     final FirstLineService serv = new FirstLineService();
     boolean cancelled = false;
     private void setS(Group rg) {
          tf.setPrefRowCount(5);
          vbox.getChildren().add(btn);
          vbox.getChildren().add(tf);
          vbox.getChildren().add(btnC);
          vbox.getChildren().add(pb);
          pb.setPrefWidth(450);
          rg.getChildren().add(vbox);
          btn.setOnAction(new EventHandler<ActionEvent>() {
               @Override
               public void handle(ActionEvent arg0) {
                    serv.start();
                    System.out.println("Service status: "+serv.getState());
                    tf.setText("STARTED!");
                 serv.progressProperty().addListener(new ChangeListener() {
                   @Override
                   public void changed(ObservableValue o, Object oldVal,
                           Object newVal) {
                      pb.progressProperty().setValue(serv.getProgress());
          btnC.setOnAction(new EventHandler<ActionEvent>() {
               @Override
               public void handle(ActionEvent arg0) {
                    serv.cancel();
                    System.out.println("Service status: "+serv.getState());
                    System.out.println("Service status cancelled when progress was: "+serv.getProgress());
                    tf.appendText("\nCANCELLED!");
                    //pb.setProgress(serv.getProgress());n
          //pb.setProgress(0);
     //     if (cancelled!=true) {
//               pb.progressProperty().bind(serv.progressProperty());//
//          } else {
//               pb.progressProperty().unbind();
          pb.progressProperty().addListener(new ChangeListener<Task>() {
               @Override
               public void changed(ObservableValue<? extends Task> arg0,
                         Task arg1, Task arg2) {
                    // TODO Auto-generated method stub
                    pb.setProgress(serv.getProgress());
     private class FirstLineService extends Service {
        protected Task createTask() {
            return new Task<Void>() {
                protected Void call() {
                     URL url;
                         try {
                              url = new URL("http://s3.amazonaws.com/dist.springframework.org/release/SPR/spring-framework-3.1.1.RELEASE.zip");
                           InputStream in = url.openStream();
                           int fileSize = url.openConnection().getContentLength()/1024;
                           File f = new File("spring.zip");
                           BufferedInputStream bin = new BufferedInputStream(in, 1024);
                           FileOutputStream fos = new FileOutputStream(f);
                           BufferedOutputStream bos = new BufferedOutputStream(fos, 1024);
                           int n=0;
                           int k=0;
                           System.out.println("Let the download begin!");
                           while(n !=-1){
                                if (isCancelled()) {
                                     cancelled = true;
                                        n=-1;
                                        System.out.println("Cancelling!");
                                   } else {
                                   k=k+1;
                                n=bin.read();
                                bos.write(n);
                                updateProgress(k/1024,fileSize);
                                //pb.progressProperty().bind(this.progressProperty());
                                //pb.setProgress(getProgress());
                           bos.close();
                           System.out.println("Finished/cancelled!");
                         } catch (MalformedURLException e) {
                              e.printStackTrace();
                         } catch (FileNotFoundException e) {
                              e.printStackTrace();
                         } catch (IOException e) {
                              e.printStackTrace();
                      return null;
     public static void main(final String[] arguments)
          Application.launch(arguments);
}