JavaFX progress bar component activated from Spring Listener Method - spring

Question

I have three layer(gui->services->dao) desktop application (JavaFX+Spring 4).
Some of my methods realized in my services layer (without fx dependency) have long time computing. I'd like to report their progress in gui.
But there is a problem. My service layer hasn't got direct access to gui, make a log of IO operations and returns only summarize of it. GUI layer, doesn't know about progress of intermediate operations.
I try to make a generic progress component. It could be realized as a Spring Bean with listener method located id GUI layer. My services can publish ApplicationEvent, which can be received via progress component in gui. When it gets the event, should activate progress bar and report next events.
In init methods I have started ProgressTask, and bind progressProperty with my gui progress bar control.
Call method of my ProgressTask runs while actual counter is less that max number of steps.
There is my component:
#Component
#Controller
public class ProgressBarComponent {
#FXML
private ProgressBar progressBar;
private ProgressTask actTask;
#FXML
public void initialize(){
}
private void initProgressBar(int aMax){
actTask=new ProgressTask();
actTask.initState(aMax);
progressBar.progressProperty().bind(actTask.progressProperty());
new Thread(actTask).start();
}
#EventListener
public void handleProgressEvent(ProgressEvent event) {
if(event.getGetActStep()==0){
initProgressBar(event.getMaxStep());
}
actTask.changeState(event.getGetActStep());
}
class ProgressTask extends Task<Object>{
private int max=100;
private int act=0;
private volatile boolean cancelled;
public void initState(int aMax){
this.max=aMax;
}
public void changeState(int newVal){
act=newVal;
updateProgress(act, max);
updateMessage("progress: " + act);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
throw new IllegalArgumentException(e);
}
}
#Override
protected Object call() throws Exception {
while(act<max){
}
return null;
}
}
}
But it doesn't work.
Progress bar control is activated but in one step and at once it has a 100 percent value.
I have found a lot of examples Progress Bar FX control, but all of them assume that main logic is computed inside call() method of ProgressTask. In my case it isn't possible.
It is possible to make a ProgressBar Component, which is activated from listener method ? If yes, what code should be in ProgressTask.call() method ?

Answer 1

The point of a Task is to define some functionality that should be run on a background thread. So if this functionality is already implemented elsewhere, there is no need for a task.
Assuming the service is being invoked on a background thread (i.e. not on the FX Application Thread), you should just be able to do:
#Component
#Controller
public class ProgressBarComponent {
private int max ;
#FXML
private ProgressBar progressBar;
#FXML
public void initialize(){
}
private void initProgressBar(int aMax){
this.max = aMax ;
}
#EventListener
public void handleProgressEvent(ProgressEvent event) {
if(event.getGetActStep()==0){
Platform.runLater(() -> initProgressBar(event.getMaxStep()));
}
Platform.runLater(() ->
progressBar.setProgress(1.0 * event.getGetActStep() / max));
}
}
Here's a complete SSCCE:
ProgressViewer.java:
package springevent;
import org.springframework.context.event.EventListener;
import javafx.application.Platform;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.ProgressBar;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class ProgressViewer {
private Stage stage = new Stage();
private Scene scene ;
private ProgressBar progressBar ;
public ProgressViewer() {
progressBar = new ProgressBar();
StackPane root = new StackPane(progressBar);
root.setPadding(new Insets(20));
scene = new Scene(root);
stage.setScene(scene);
}
#EventListener
public void progressUpdate(ProgressEvent event) {
if (event.getCurrent() < event.getMax()) {
Platform.runLater(stage::show);
} else {
Platform.runLater(stage::hide);
}
final double progress = 1.0 * event.getCurrent() / event.getMax() ;
Platform.runLater(() -> progressBar.setProgress(progress));
}
}
Service.java:
package springevent;
import javax.inject.Inject;
import org.springframework.context.ApplicationContext;
public class Service {
#Inject
private ApplicationContext context ;
public void runService() {
context.publishEvent(new ProgressEvent(0, 100));
try {
for (int i = 1 ; i <= 100; i++) {
Thread.sleep(200);
context.publishEvent(new ProgressEvent(i, 100));
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
}
}
ProgressEvent.java
package springevent;
public class ProgressEvent {
private final int current ;
private final int max ;
public ProgressEvent(int current, int max) {
this.current = current ;
this.max = max ;
}
public int getCurrent() {
return current ;
}
public int getMax() {
return max ;
}
}
MainController.java
package springevent;
import java.util.concurrent.Executor;
import javax.inject.Inject;
import org.springframework.context.event.EventListener;
import javafx.fxml.FXML;
import javafx.scene.control.Button;
public class MainController {
#Inject
private Executor exec ;
#Inject
private Service service ;
#FXML
private Button startButton ;
public void startProcess() {
exec.execute(service::runService);
}
#EventListener
public void progressUpdate(ProgressEvent event) {
startButton.setDisable(event.getCurrent() < event.getMax());
}
}
Main.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.StackPane?>
<?import javafx.scene.control.Button?>
<?import javafx.geometry.Insets?>
<StackPane xmlns:fx="http://javafx.com/fxml/1" fx:controller="springevent.MainController">
<padding>
<Insets top="20" bottom="20" left="20" right="20"/>
</padding>
<Button fx:id="startButton" text="Start process" onAction="#startProcess" />
</StackPane>
Main.java
package springevent;
import java.io.IOException;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
private AbstractApplicationContext context ;
#Override
public void start(Stage primaryStage) throws IOException {
context = new AnnotationConfigApplicationContext(AppConfig.class);
FXMLLoader loader = new FXMLLoader(getClass().getResource("Main.fxml"));
loader.setControllerFactory(context::getBean);
Scene scene = new Scene(loader.load());
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
and AppConfig.java:
package springevent;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
#Configuration
public class AppConfig {
#Bean
public Service service() {
return new Service();
}
#Bean
public MainController mainController() {
return new MainController();
}
#Bean
public ProgressViewer progressViewer() {
return new ProgressViewer();
}
#Bean
public Executor exec() {
return Executors.newCachedThreadPool(runnable -> {
Thread t = new Thread(runnable);
t.setDaemon(true);
return t ;
});
}
}