I am returning the result of an API under the form ModelAndView which is basically an excel file. Due to long processing of this api, I want to move the processing "process" in the background using the help of threads. Is there any way you can help me out to rewrite this controller method in order to activate a background thread that performs the processing? Thank you so much.
My controller class looks like this:
#RestController
#RequestMapping("/api/background")
public class BackgroundController {
private final BackgroundService backgroundService;
public BackgroundController(BackgroundService backgroundService) {
this.backgroundService = backgroundService;
}
#ApiOperation("Get excel file from processing")
#GetMapping("/headers/export-excel")
private ModelAndView getExcelFile(Principal principal,
#RequestParam(name = "reqId", required = false) BigDecimal reqId) {
return new ModelAndView(new ExcelView(), ExcelView.EXPORT_LIST_NAME, backgroundService.getExcelFile(reqId));
}
}
Related
I've got a customization to the Invoice & Memo screen where I execute some custom code (web service calls) when the Release action is activated. This works fine - I knew how to replace the PXAction code and proceeded from there. Now I want to use the Release AR Documents processing screen to do the same thing, but I'm having trouble understanding where / what to override, or where to place my code.
I see the ARDocumentRelease graph constructor with the SetProcessDelegate in the source code, but I'm not sure how to proceed - whether this is where I need to be looking or not. I need to execute my code for each line being released, using the RefNbr in my code.
Since it's an static method, you can't override it. Also, you can't do like it's done in the T300, because you are in processing graph and you can't override the release button with your own. I was able to achieve it by passing callback for each AR document that have been processed.
You can call the Initialize method of the ARDocumentRelease graph to override the logic like you said. After you just have to call ReleaseDoc that uses a callback parameter instead of using the default one.
Here's the code that I came with:
public class ARDocumentRelease_Extension : PXGraphExtension<ARDocumentRelease>
{
public override void Initialize()
{
ARSetup setup = Base.arsetup.Current;
Base.ARDocumentList.SetProcessDelegate(
delegate (List<BalancedARDocument> list)
{
List<ARRegister> newlist = new List<ARRegister>(list.Count);
foreach (BalancedARDocument doc in list)
{
newlist.Add(doc);
}
AddAdditionalLogicToRelease(newlist);
}
);
Base.ARDocumentList.SetProcessCaption("Release");
Base.ARDocumentList.SetProcessAllCaption("Release All");
}
public delegate void PostPorcessing(ARRegister ardoc, bool isAborted);
private void AddAdditionalLogicToRelease(List<ARRegister> newlist)
{
ARDocumentRelease.ReleaseDoc(newlist, true, null, delegate(ARRegister ardoc, bool isAborted) {
//Add your logic to handle each document
//Test to check if it was not aborted
});
}
}
Please note that you must always call static methods from within long running process and create necessary objects there.
Processing delegate logic is implemented as long running process which creates worker thread to execute the processing logic.
You have AddAdditionalLogicToRelease() method which requires object instance in order to call and will fail during thread context switches and hence the issue. So, you must have create object instance inside the thread context and then call instance method.
In general, method that gets called from long running processes are declared static and required objects/graphs are created inside this static method to do some work. See below example how to properly override ARDocumentRelease graph for this purpose:
public class ARDocumentRelease_Extension : PXGraphExtension<ARDocumentRelease>
{
public override void Initialize()
{
Base.ARDocumentList.SetProcessDelegate(
delegate (List<BalancedARDocument> list)
{
List<ARRegister> newlist = new List<ARRegister>(list.Count);
foreach (BalancedARDocument doc in list)
{
newlist.Add(doc);
}
// use override that allows to specify onsuccess routine
ARDocumentRelease.ReleaseDoc(newlist, true, null, (ardoc, isAborted) =>
{
//Custom code here, such as create your GL
});
}
);
}
}
I think it's the function
public static void ReleaseDoc(List<ARRegister> list, bool isMassProcess, List<Batch> externalPostList, ARMassProcessDelegate onsuccess)
under ARDocumentRelease businesss logic.
Having an huge customers profile page if two or more users start using same page and start editing big change will happen in my database so planing to implement Threads concept where only one user can use that customer page
i'm aware about threads concept but confused how to implement it
hope i need to use Singleton class as well
Any suggestion or Logic's will be helpful
I'm using Struts,Hibernate frame work
You may use application context to store a flag variable. Action will use its value to allow only one simultaneous execution.
public class TestAction extends ActionSupport implements ApplicationAware {
private static final String APP_BUSY_KEY = "APP_BUSY";
Map<String, Object> map;
#Override
public void setApplication(Map<String, Object> map) {
this.map = map;
}
#Override
public String execute() throws Exception {
if (map.containsKey(APP_BUSY_KEY)) {
return ERROR;
} else {
map.put(APP_BUSY_KEY, "1");
try {
// action logic here
} finally {
map.remove(APP_BUSY_KEY);
}
return SUCCESS;
}
}
}
If you plan to implement similar logic for two requests (lock after displaying values and release lock after submitting new values) then logic will be more complex and you will also need to handle lock release after timeout.
I have an MVC application in which I have a controller that receives data from the user and then uploads a file to Azure blob storage. The application is using Unity IoC to handle dependency injection.
During the workflow I have isolated the following code as demonstrating the problem
public class MvcController : Controller
{
private IDependencyResolver _dependencyResolver;
public MvcController() : this(DependencyResolver.Current)
{
}
public MvcController(IDependencyResolver dependencyResolver)
{
this._dependencyResolver = dependencyResolver;
}
public GetService<T>()
{
T resolved = _dependencyResolver.GetService<T>()
if (resolved == null)
throw new Exception(string.Format("Dependency resolver does not contain service of type {0}", typeof(T).Name));
return resolved;
}
}
public class MyController : MvcController
{
[NoAsyncTimeout]
public async Task<ActionResult> SaveFileAsync(/* A bunch of arguments */)
{
/* A bunch of code */
//This line gets a concrete instance from HttpContext.Current successfully...
IMyObject o = GetService<IMyObject>();
await SaveFileToAzure(/* A bunch of parameters */);
.
.
/* Sometime later */
Method2(/* A bunch of parameters */);
}
private Method2(/* A bunch of parameters */)
{
//This line fails because HttpContext.Current is null
IMyObject o = GetService<IMyObject>();
/* A bunch of other code */
}
private async Task SaveFileToAzure(/* A bunch of parameters */)
{
//Grab a blob container to store the file data...
CloudBlobContainer blobContainer = GetBlobContainer();
ICloudBlob blob = blobContainer.GetBlockBlobReference(somePath);
Stream dataStream = GetData();
System.Threading.CancellationToken cancelToken = GetCancellationToken();
//All calls to DependencyResolver.GetService<T>() after this line of code fail...
response = await blob.UploadStreamAsync(dataStream, cancelToken);
/* A bunch of other code */
}
}
Unity has a registration for my object:
container.RegisterType<IMyObject, MyObject>(new HttpLifetimeManager());
My lifetime manager is defined as follows:
public sealed class HttpRequestLifetimeManager : LifetimeManager
{
public Guid Key { get; private set; }
public HttpRequestLifetimeManager()
{
this.Key = Guid.NewGuid();
}
public override object GetValue()
{
return HttpContext.Current.Items[(object)this.Key];
}
public override void SetValue(object newValue)
{
HttpContext.Current.Items[(object)this.Key] = newValue;
}
public override void RemoveValue()
{
HttpContext.Current.Items.Remove((object)this.Key);
}
}
Nothing complicated.
Stepping into the HttpRequestLifetimeManager on the failing GetService() calls shows that after the UploadStreamAsync() call HttpContext.Current is null...
Has anyone else come across this problem? If so, is this a bug? Is this expected behaviour? Am I doing something out of the ordinary? What should I do to resolve it?
I can hack around it by storing a reference to HttpContext.Current prior to the offending call and restoring it after, but that doesn't seem like the right approach.
Any ideas?
To echo #Joachim - http context may not be available to your async thread. Compare the current thread id where you can see httpcontext is available, to the thread id where you can see that it isn't - i'm assuming you will see they are 2 different threads. If my assumption is correct this may be a sign that your main thread (the one with httpcontext) does not have a "synchronizationcontext". (you can see http://blogs.msdn.com/b/pfxteam/archive/2012/01/20/10259049.aspx for more details of how that works) If so, it may mean that the code immediately after your await statement is actually not running on the same thread as the code prior to the await statement! So from your perspective, one moment you have http context and the next you don't because execution has actually been switched to another thread! You should probably look at implementing / setting a synchronizationcontext on your main thread if that's the case and then control will be returned to your original thread with http context and that should fix your problem, or alternatively you could retrieve your object from http context on the original thread and find a way to pass it as a parameter to the async method/s so that they don't need to access http context to get their state.
I have a requirement in JavaFX 2 to display the notifications on the header. These notifications are populated in the database through an external system.
When a new notification is inserted in the database, my JavaFX application should listen to the same and refresh the header.
One solution I can think about is to implement a timeline that triggers the code to retrieve the latest notification status once every fixed time period, may be once every 2 mins.
Other than this, is there any other way to achieve this? Any hints on this would be highly appreciated.
You can create a new Task that would be listening (or checking) for changes in your database. This Task would be running in a different Thread as not to block your UI. Once a change occurs, it can then update your UI.
Your code could look like this :
//... initialize your variables.
task = new DatabaseWatcher();
executor = Executors.newSingleThreadExecutor();
executor.execute(task);
And your DatabaseWatcher :
public class DatabaseWatcher extends Task<Object> {
public DatabaseWatcher() {
//initialize here
}
#Override
protected Object call() throws Exception {
//Get data from database
//if new update :
updateUI();
return null;
}
private void updateUI() {
Platform.runLater(new Runnable() {
#Override
public void run() {
//Set your new values in your UI
//Call the method in your UI to update values.
}
});
}
}
This should get you started on the right path.
See Also
Multiple FXML with Controllers, share object, more specifically this answer
javafx, update ui from another thread
Concurrency in JavaFX
In a multi form .NetCF 3.5 application I'm trying create the forms in the background while the user is occupied with the previous form.
We're using Orientation Aware Control in the project
We use a wrapper class (FormController) (please let me know if I'm using the wrong terminology) to keep static references to the different forms in our application. Since we only want to create them once.
At the moment the Forms are created the first time they are used. But since this is a time consuming operation we'd like to do this in the background while the user
Application.Run(new FormController.StartUI());
class FormController{
private static object lockObj = new object();
private static bool secIsLoaded = false;
private static StartForm startForm = new StartForm();
private static SecForm m_SecForm;
static SecForm FormWorkOrderList
{
get
{
CreateSecForm();
return m_SecForm;
}
}
private static void StartUI(){
startForm.Show();
ThreadStart tsSecForm = CreateSecForm;
Thread trSecForm = new Thread(tsSecForm);
trSecForm.Priority = ThreadPriority.BelowNormal;
trSecForm.IsBackground = true;
trSecForm.Start();
return startForm;
}
private static void CreateSecForm()
{
Monitor.Enter(lockObj);
if(!secIsLoaded){
m_SecForm = new SecForm();
secIsLoaded = true;
}
Monitor.Exit(lockObj);
}
private static void GotoSecForm()
{
SecForm.Show();
StartForm.Hide();
}
When I call GotoSecForm() the program throws an excepton on SecForm.Show() with an exection with hResult: 2146233067 and no other valuable information.
The stacktrace of the exception is:
on Microsoft.AGL.Common.MISC.HandleAr(PAL_ERROR ar)
on System.Windows.Forms.Control.SuspendLayout()
on b..ctor(OrientationAwareControl control)
on Clarius.UI.OrientationAwareControl.ApplyResources(CultureInfo cultureInfo, Boolean skipThis)
on Clarius.UI.OrientationAwareControl.ApplyResources()
on Clarius.UI.OrientationAwareControl.OnLoad(EventArgs e)
on Clarius.UI.OrientationAwareControl.c(Object , EventArgs )
on System.Windows.Forms.Form.OnLoad(EventArgs e)
on System.Windows.Forms.Form._SetVisibleNotify(Boolean fVis)
on System.Windows.Forms.Control.set_Visible(Boolean value)
on System.Windows.Forms.Control.Show()
I'm quite qlueless about what's going wrong here. Can anyone help me out?
Or are there some better ways to load the forms in the background?
Let me know if any more information is needed.
You can't create forms (or safely do any manipulation of controls or forms) in background threads. They need to be created on the same thread that the message pump is running on - its just the way that Windows Forms work.
Creating the form itself shouldn't be in itself an expensive task. My advice would be to perform any expensive computations needed to display the form in a background thread, and then pass the result of those computations back to the main message pump in order to create and display the form itself.
(Half way through writing this I realised that this question is about windows mobile, however I'm 99% sure that the above still applies in this situation)