Asynchronous Tasks using JavaFX 2.1???

Can somebody help me with sample code for creating asynchronous Tasks using JavaFX 2.1.
In this request, I need to make a call to server and get certain required information.

Look at the Task and Service classes. There are examples in the javadoc.

Similar Messages

Cannot start JavaFX Task using Thread.start()

Well I am currently studying JavaFX and as a total beginner(but not in Java) I started reading the official tutorials in Java and I'm currently studying Concurrency in JavaFX. and I tried to create my first JavaFx Task Object and start it. This what I have tried so far
package concurrency;
import javafx.concurrent.Task;
public class JavaTaskClass {
      * @param args
     public static void main(String[] args) {
          //create task object
          Task<Integer> task = new Task<Integer>(){
               @Override
               protected Integer call() throws Exception{
                    System.out.println("Background task started...");
                    int iterations;
                    for(iterations = 0; iterations < 10000; iterations++){
                         if(isCancelled()){
                              break;
                         System.out.println("Iteration " + iterations);
                         Thread.sleep(3000);
                    return iterations;
          //start the background task
          Thread th = new Thread(task);
          th.setDaemon(true);
          System.out.println("Starting background task...");
          th.start();
but the task doesn't start. I don't see any messages in my console. Is there something I missed?
Edited by: 979420 on Jan 1, 2013 10:02 PM
Edited by: 979420 on Jan 1, 2013 10:02 PM
Edited by: 979420 on Jan 1, 2013 10:03 PM
Edited by: 979420 on Jan 1, 2013 10:49 PM

Tasks are meant to be run in the context of a JavaFX application, like in the example below:
import javafx.application.Application;
import javafx.concurrent.Task;
import javafx.scene.Scene;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import java.io.IOException;
public class TaskApp extends Application {
public static void main(String[] args) { launch(args); }
@Override public void start(final Stage stage) throws IOException {
    //create task object
    Task<Integer> task = new Task<Integer>(){
      @Override
      protected Integer call() throws Exception{
        System.out.println("Background task started...");
        int iterations;
        for(iterations = 0; iterations < 10000; iterations++){
          if(isCancelled()){
            break;
          System.out.println("Iteration " + iterations);
          Thread.sleep(3000);
        return iterations;
    //start the background task
    Thread th = new Thread(task);
    th.setDaemon(true);
    System.out.println("Starting background task...");
    th.start();
    stage.setScene(new Scene(new StackPane(), 200, 100, Color.BLANCHEDALMOND));
    stage.show();
}Also your code was setting the task thread as a daemon thread. The Java Virtual Machine exits when the only threads running are all daemon threads. So once your main routine finished (which would be really quickly), the program would just exit without doing anything much. Note that, in your example, even if you made the Task thread a non-daemon thread, it still doesn't work (likely because the Task class has some reliance on the JavaFX system being initialized). For your simple background process you could skip Task and just use a Runnable or a Callable (which doesn't require JavaFX and hence would work in a non-daemon thread invoked from main), but I guess it's just an experiment.

How do i use multiple threads( very much real time), using JavaFX?

I'm creating an application, using JavaFX because one can create awesome GUI using JavaFX. I need to know how to create real time multiple threads using javafx.
JavaFX doesn't support creation of multiple threads, but i think there is another way of doing it. I need it work in real time as my application works with an hardware (wacom intous 3 tablet), and i need mutiple threads to get all the parameters from the stylus of the tablet simultaneously...
any code which will help me out or explaination on how to go about this is appreciated...
Help required quickly...

See example at
[http://jfxstudio.wordpress.com/2009/06/09/asynchronous-operations-in-javafx/|http://jfxstudio.wordpress.com/2009/06/09/asynchronous-operations-in-javafx/]

Help me with some question about Worker/Service/Task in JavaFx 2

I have read some articles in the forum adout mutithreading in JavaFx2, and now I know if I want to do some long-run jobs, i should use Service/Task.
But my application needs a function like this:
1. here is a long-run job(something like getting data from database or other resources);
2. If I clicked a button, then the job started and get the data.
3. When the job is done, I show the data in the tableview of my JavaFx application.
4. then the job waiting some random time(such as 100 seconds).
5. then the job started again automaticlly.
so, the steps are 2->3->4->5->3->4->5->3->4->5->........
so, the important things is that the job runs many times automaticlly.
I know I should implements the job as a Service or Task in javaFx, But where should I put my "while(true){ job.start();sleep(random_time);}" loop code to make the job start automaticlly after some random sleep time.
I wonder what is the best practice for this use case.
My english is poor, but i hope you can understand what i'm dealing with.
Thank you very much!
Edited by: user9529194 on 2011-12-18 下午8:20

Hi,
Based on the response from John,
I think you can acheive the functionality as below.
// Creating the tableview.
TableView<Person> personTable = new TableView<Person>()
// Instantiating the personlist.
ObservableList<Person> persons = FXCollections.observableArrayList();
// Setting the list to the table.
personTable .setItems(persons)
final Button button = new Button("Refresh");
final Timeline repeatTimeLine = new Timeline(
      new KeyFrame(Duration.seconds(100), new EventHandler<ActionEvent>() {
            @Override
         public void handle(ActionEvent event) {
                // Call the service method to update the list.
                   PersonService.updatepersons(persons );
button.setOnAction(new EventHandler<ActionEvent>() {
     @Override
     public void handle(ActionEvent arg0) {
             repeatTimeLine.setCycleCount(Timeline.INDEFINITE);
             repeatTimeLine.play();
});And in the Service class...
public void updatepersons(final ObservableList<Person> persons){
          final Task<List<Person>> getPersonTask = new Task<List<Person>>() {
          @Override
          protected List<Person> call() throws Exception {
               return getPersonService().getPersons();
     getPersonTask .stateProperty().addListener(new ChangeListener<State>() {
          @Override
          public void changed(ObservableValue<? extends State> arg0, State arg1, State newState) {
               switch (newState) {
               case SUCCEEDED:
                    persons.clear();
                    persons.addAll(getPersonTask .getValue());
                    break;
               case FAILED:
                    break;
     ThreadManager.getInstance().schedule(this.getClass(), getPersonTask );
}I hope this code can give you some idea.
Happy Coding !! :)

Cannot trigger exception in an asynchronous task

I am trying to get an asynchonous task to follow a control path that it should go down when an exception is raised, but it isn't working.
Brief description of task: it is a method that creates a sales order in the background. It is asynchronous because I need the sales order to exist in the database before the next step in the workflow, which uses the order as a reference.
The exception that I want to raise should happen if I cannot get a sales order number returned from the code (the number is assigned before the order exists in the database); in that case, I want the exception to be raised.
In the exception path, I want to use a process flow step that marks the current workflow task obsolete, and executes the obsolete path to create a sales order in the foreground.
Problem is, whenever I try to raise the exception, the asynchronous task just stays in state STARTED. I wonder if this is because the event for completing the task has not been triggered.
So is it possible to raise exceptions in asynchronous tasks, and make the task obsolete before the terminating event has been received?

Thanks for the clarification; I must admit that sounds like a bad architectural design flaw to me.
This case is exactly why; the task uses a method that calls VA01 in background mode. It will not return a value of sales order number if it cannot create the sales order. However, since the task is asynchronous, and the terminating event is to receive the order created event from the BUS2032 sales order business object, it will wait forever to finish this step.
That's why I want to raise an exception if the sales order could not be created, but as you say, in an asynchronous task, that is not possible.
So what could be a better alternative? One possibility that I can think of is for the sales order creation task to be synchronous, and then have a follow-up task that checks that the sales order exists in the database before going forward. Does that sound reasonable?

Warning: "No terminating events defined for the task used"

Dear all,
I created a task with ABAP class and method as its object method. This task is a background task. The ABAP class inherits the IF_WORKFLOW interface but doesn't implement any method of the interface.
When I try to confirm the task settings in transaction SWDD, a message shows up "No terminating events defined for the task used" and I cannot continue the work. Does anybody have any idea what I should do?
Thanks + Best Regards
Jerome

Hi Jerome,
If you set a background task in your workflow, and if it is asynchronous, then you need some way to tell the template if it is finished and what happened. In this case you set terminating events - that is events which are published in the system as a result of your method (ie document.posted etc).
Either use a synchronous method for your task or set appropriate terminating events in your task setup.
Regards
Gareth

I use javaFx WebViewBrowser to download ZIP file, the page no action

I use javaFx WebViewBrowser to download ZIP file, the page no action; other tools example chrome ,ie can download the zip file .
so can you writer a download zip file example for me ?
thanks ,my english is so bad ,sorry !!! :)

WebView doesn't have a built in file downloader - you have to implement it yourself.
You can find a sample implementation for file downloads in JavaFX here =>
http://www.zenjava.com/2011/11/14/file-downloading-in-javafx-2-0-over-http/
That sample does not include the hooks into WebView to trigger the downloads.
You will need to trigger off the mime type or the file extension in the url.
A rudimentary sample trigger a download off of webview is provided in the code below.
For a nice solution, you would probably want to spin the downloader off with it's own UI similar and manage the download itself as a JavaFX Task similar to how the zenjava component works.
Code adapted from => http://code.google.com/p/willow-browser/source/browse/src/main/java/org/jewelsea/willow/BrowserWindow.java
// monitor the location url, and if it is a pdf file, then create a pdf viewer for it, if it is downloadable, then download it.
view.getEngine().locationProperty().addListener(new ChangeListener<String>() {
@Override public void changed(ObservableValue<? extends String> observableValue, String oldLoc, String newLoc) {
    if (newLoc.endsWith(".pdf")) {
      try {
        final PDFViewer pdfViewer = new PDFViewer(false); // todo try icepdf viewer instead...
        pdfViewer.openFile(new URL(newLoc));
      } catch (Exception ex) {
        // just fail to open a bad pdf url silently - no action required.
    String downloadableExtension = null; // todo I wonder how to find out from WebView which documents it could not process so that I could trigger a save as for them?
    String[] downloadableExtensions = { ".doc", ".xls", ".zip", ".tgz", ".jar" };
    for (String ext: downloadableExtensions) {
      if (newLoc.endsWith(ext)) {
        downloadableExtension = ext;
        break;
    if (downloadableExtension != null) {
      // create a file save option for performing a download.
      FileChooser chooser = new FileChooser();
      chooser.setTitle("Save " + newLoc);
      chooser.getExtensionFilters().add(new FileChooser.ExtensionFilter("Downloadable File", downloadableExtension));
      int filenameIdx = newLoc.lastIndexOf("/") + 1;
      if (filenameIdx != 0) {
        File saveFile = chooser.showSaveDialog(view.getScene().getWindow());
        if (saveFile != null) {
          BufferedInputStream is = null;
          BufferedOutputStream os = null;
          try {
            is = new BufferedInputStream(new URL(newLoc).openStream());
            os = new BufferedOutputStream(new FileOutputStream(saveFile));
            int b = is.read();
            while (b != -1) {
              os.write(b);
              b = is.read();
          } catch (FileNotFoundException e) {
            System.out.println("Unable to save file: " + e);
          } catch (MalformedURLException e) {
            System.out.println("Unable to save file: " + e);
          } catch (IOException e) {
            System.out.println("Unable to save file: " + e);
          } finally {
            try { if (is != null) is.close(); } catch (IOException e) { /** no action required. */ }
            try { if (os != null) os.close(); } catch (IOException e) { /** no action required. */ }
        // todo provide feedback on the save function and provide a download list and download list lookup.
});

Workflow is not moving to next incase of asynchronous task

Hi Gurus,
I have a requirement to use asynchronous method and tasks in my workflow. For completing the asynchronous tasks, I am calling SWE_EVENT_CREATE with an event to complete the task from Web Dynpro Application. However, Event Linkage has benn deactivated automatically and the task remains in InProcess status.
Please provide your suggestions ASAP.
Thanks in Advance
Gopal.

For completing the asynchronous tasks, I am calling SWE_EVENT_CREATE
with an event to complete the task from Web Dynpro Application
Make sure that after calling the above Funciton module you have defined a COMMIT WORK statement. But before this as you were saying that the event linkage got deactivated, so please make sure that the event linkage is active......

Asynchronous task workitem

Hi ,
I have defined a terminating event " PROCESSED" for element "_WORKITEM " in "Terminating events" tab of task definition.
when ever my Asynchronous task workitem is opened and closed without procesing, the workitem disappears from
SAP Inbox .
but the wokitem should be in inbox until the workitem is processed ( that means invoice gets posted from workitem ).
please let me know the solution to resolve this issue.
Note : only the folllowing terminating events availble . a) Processed b) created c) Deleted for element "_WORKITEM "
Thanks ,
Sarath.

Hi Sarath,
I have used follwing setting for terminating event used in a task
Element : WIOBJECT_ID
Object Category :ABAP Class
Object Type :ZITEM
Event : APPROVED
This works for me.
Please check "Synchronous Object Mehod " must not be checked in Basic data tab of tha task.
Thanks and regards,
SNJY

Creating a Scheduled Task using PowerShell v4

So here is my question. I'm trying/wanting to create a scheduled task using PowerShell v4 on Server 2012R2. I want to task to run on the 1st day of every month. The parameter for -Monthly -Day is not available. I need to use PowerShell
to create the Scheduled Task because the Task will be running with a group Managed Service Account credentials so the Scheduled Task can not be created via the Task Scheduler GUI.
Thanks in Advance

Here is a functioning task It can be easily edited in PowerShell or in notepad to alter the timing
<?xml version="1.0" encoding="UTF-16"?>
<Task version="1.1" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
<RegistrationInfo>
<Author>W8TEST\user01</Author>
</RegistrationInfo>
<Triggers>
<CalendarTrigger>
<StartBoundary>2014-06-04T21:31:32.0459499</StartBoundary>
<Enabled>true</Enabled>
<ScheduleByMonth>
<DaysOfMonth>
<Day>1</Day>
<Day>12</Day>
<Day>24</Day>
</DaysOfMonth>
<Months>
<January />
<February />
<March />
<April />
<May />
<June />
<July />
<August /
<September />
<October />
<November />
<December />
</Months>
</ScheduleByMonth>
</CalendarTrigger>
</Triggers>
<Principals>
<Principal id="Author">
<RunLevel>LeastPrivilege</RunLevel>
<UserId>W8TEST\jvierra</UserId>
<LogonType>InteractiveToken</LogonType>
</Principal>
</Principals>
<Settings>
<DisallowStartIfOnBatteries>true</DisallowStartIfOnBatteries>
<StopIfGoingOnBatteries>true</StopIfGoingOnBatteries>
<IdleSettings>
<StopOnIdleEnd>true</StopOnIdleEnd>
<RestartOnIdle>false</RestartOnIdle>
</IdleSettings>
<Enabled>true</Enabled>
<Hidden>false</Hidden>
<RunOnlyIfIdle>false</RunOnlyIfIdle>
<WakeToRun>false</WakeToRun>
<ExecutionTimeLimit>P3D</ExecutionTimeLimit>
<Priority>7</Priority>
</Settings>
<Actions Context="Author">
<Exec>
<Command>notepad.exe</Command>
<Arguments>test.txt</Arguments>
<WorkingDirectory>c:\temp</WorkingDirectory>
</Exec>
</Actions>
</Task>
I have edited and reloaded the XML many, many times. It works very nicely.
¯\_(ツ)_/¯

How to use a multiple boards (6321/6323) analogical acquisition task with simultaneous analogical generation task using the same boards (Labwindows CVI10)

Subject : it seems impossible to run a multiple boards analogical acquisition task with one or several analogical generation task using the same boards.
NI Configuration : Dev1 = Dev2 = 6321 boards
Development environnement : LabWindows CVI 10
Source code for analogical acquisitino task :
       DAQmxCreateTask("",&AIRecordingtaskHandle);
       DAQmxCreateAIVoltageChan(AIRecordingtaskHandle,chan,"",DAQmx_Val_NRSE,min,max,DAQmx_Val_Volts,NULL);
       DAQmxCfgSampClkTiming (AIRecordingtaskHandle, "", rate, DAQmx_Val_Rising, DAQmx_Val_FiniteSamps, sampsPerChan);
       DAQmxGetTaskAttribute(AIRecordingtaskHandle,DAQmx_Task_NumChans,&gNumChannels);
Chan = "Dev1/ai0, Dev1/ai1, Dev1/ai2, Dev2/ai1"
Source code for analogical generation taskS :
       DAQmxErrChk (DAQmxCreateTask("",&AOtaskHandle_C1_DAC0));
       DAQmxErrChk (DAQmxCreateAOVoltageChan (AOtaskHandle_C1_DAC0, chan, "", min, max,DAQmx_Val_Volts, "")); // chan vaut Dev1/ao0
       DAQmxErrChk (DAQmxCreateTask("",&AOtaskHandle_C1_DAC1));
       DAQmxErrChk (DAQmxCreateAOVoltageChan (AOtaskHandle_C1_DAC1, chan, "", min, max,DAQmx_Val_Volts, "")); // chan vaut Dev1/ao1
       DAQmxErrChk (DAQmxCreateTask("",&AOtaskHandle_C2_DAC0));
       DAQmxErrChk (DAQmxCreateAOVoltageChan (AOtaskHandle_C2_DAC0, chan, "", min, max,DAQmx_Val_Volts, "")); // chan vaut Dev2/ao0
At the first DAQmxReadBinary call attempt, the system shows an error (see attached document)
What we understand about that error : it is impossible to run the two set of tasks (ai and ao) using ressources from both Dev1 and Dev2 in the set of tasks because it is not allowed to use the same Reference Clock for that.
The question is : is there a way to to that without having that kind of message?
We tried different combinations :
- Using only one ao task (on Dev1/Dac0) : same error
- Not using any ao task (only the ai task) : no error
- configuring the ai task with only channel from Dev1 : no error
- Using "/Dev1/ai/SampleClock" as internal clock for the ai task and "/Devk/ao/SampleClock" for each ao task (k standing for "1" or "2" depending of the ao task we consider) : error
Thanks a lot.
Pièces jointes :
MsgErreur NIDAQmx.JPG ‏38 KB

doublon
Valentin
Certified TestStand Architect
Certified LabVIEW Developer
National Instruments France
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How to create a muli line text area using JavaFx

Hi all,
Since the preview SDK does not contain TextArea any more, I am wondering how to create a muli line text area using JavaFX. The behaviour of this text area/field should be somehow similar to JTextArea in Swing or StyledTextWidget in SWT.
Does JavaFX have any support for this? What would be a sensible approach to create such a widget?
Thanks for your suggestions,
br michael

This is a pretty old thread (I know I came across this while searching for something similar recently), but I figured I'd throw this out there in case other people might find this useful. As I write this, JavaFX's latest version is 1.3... which may have added the needed functionality since the last post.
You can now create a multi-line text area using a TextBox and by specifying the nubmer of lines and setting the "multiline" value to true. It may not offer all of the same functionality as JTextArea, but it did the job for what I needed... newlines by pressing enter, scrollbar if text surpasses height, etc.
Here's a simple example:
Group {
   content: [
      TextBox {
         text: "This is a multi-line textbox"
         lines: 10 // <-- this may/may not be necessary depending on your situation. Default is 5.
         multiline: true
}Edited by: loeschg on Jul 29, 2010 2:59 PM

Does anyone know if there is a way of getting a visual timeline for tasks using Mac like outlook offers?

I would like to organize my tasks using a programme that gives me a timeline of my tasks in a visual way like bars etc. I am using Toodledo at the moment and although it's brilliant it does not offer this option. I like outlook for this but can't find any other programms that do the same thing without having to re-insert all my tasks etc. Is there a way that ical can do this?

I'm a bit vague about what it is you wish to accomplish. Are you trying to capture video through an external box? If so, that's not posssible with any of the Canopus boxes I'm familar with. In fact I don't know of any external video capture solution that works with an iPad, though I can't state definitively that none exist. I really don't think an iPad would be well suited for this even if it's possible. I'd strongly suggest you look into a MacBook Air or one of the current MacBook Pros. Those are far better suited for on-the-fly video capture and editing.
If that's not what you mean, please post back and explain further what it is you wish to accomplish.
Regards.

If I Use JavaFX to Create a Game Do I Have to Release the Source Code?

Hello,
I've asked this question before, but I just thought I would try it again now
that version 1.0 is out.
If I Use JavaFX to Create a Game Do I Have to Release the Source Code?
Thanx in advance.

Could you please point me to a resource describing "the JavaFX Runtime license"? I'm trying to find answers to the following questions:
1. I'd like to use Scenario.jar from the JavaFX project in a desktop app that is not using Webstart and is not an applet. Will I be able to ship the jar with my software?
2. Can JavaFX applications be distributed as commercial software in the absence of a Web connection?
What's not clear to me is which is the real license for Scenario.jar (as shipped with JavaFX). Is it the one in openjfx-compiler's trunk, or the one that comes with the JavaFX SDK (which is very vague about redistribution)?

Adding custom field to Task using EEWB

Hi there,
I need to add 2 custom fields to a Task using the EEWB.
When I look at transaction CRMD_ORDER->Create, I see that the area I need to add to is categorized as a TASK.
But, following through the EEWB wizard, when asked for the EEW Bus. Object Type, TASK is not available on the dropdown.
My question is, is a TASK categorized as a BUSINESS_ACTIVITY ?
I've done a few of these already, for BUSINESS_ACTIVITY and SERVICE_PROCESS, and these were available in the EEB search help - not TASK though.
Any help would be greatly appreciated .
Thanks.

Hi Denis,
thanks for the quick response - I did the EEWB, choosing Business Activity, and then defined it as a Task
in a later step (Task was available on the later list, so I went with that).
Thanks again,
David.

Asynchronous Tasks using JavaFX 2.1???

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