How to close javafx and swing window threads between subsequent calls? - javafx

Question

Below is a functioning class that simulates extracting data from a website. The question is how to close the window and threads after the data is retrieved? The error message is
Exception in thread "AWT-EventQueue-0" java.lang.IllegalStateException: Platform.exit has been called
On line: final JFXPanel fxPanel = new JFXPanel() {
Here is the code. When Platform.exit() is inserted at the indicated locations, the above error occurs. In the actual code, javafx is used for obtaining and scanning the html text. Also, javafx is used for setting attributes on the server and starting a program on the server, both done using java script. The javafx functionality was removed from this minimal example that demonstrates the error that occurs when using Platform.exit().
public class Step11a {
public static void main(String[] args) throws ParseException, InterruptedException {
Step11a st = new Step11a();
st.getData();
st.getData();
}
private JTable table;
private String url;
private WebView webView;
public Step11a() {
url = "https://www.tsp.gov/investmentfunds/shareprice/sharePriceHistory.shtml";
table = new JTable();
}
private Scene createScene(ArrayBlockingQueue<DefaultTableModel> platfromQueue) {
StackPane root = new StackPane();
Scene scene = new Scene(root);
webView = new WebView();
WebEngine webEngine = webView.getEngine();
Worker<Void> worker = webEngine.getLoadWorker();
worker.stateProperty().addListener((Observable o) -> {
if (worker.getState() == Worker.State.SUCCEEDED) {
DefaultTableModel tableDataModel = (DefaultTableModel) table.getModel();
// Following steps deleted for minimal example
// 1) Get html code from server
// 2) Locate elements to modify
// 3) Create javascript string to modify element values
// 4) Execute javascript to update elemetns
// 5) Execute javascript to start data retrieval on server
// 6) Get html and extract table of data
// For this example, we just set the rows and columns
// in the table
tableDataModel.setColumnCount(11);
tableDataModel.setRowCount(24);;
try {
platfromQueue.put(tableDataModel);
} catch (Exception e) {
e.printStackTrace();
}
}
});
webEngine.load(url);
root.getChildren().add(webView);
return scene;
}
private DefaultTableModel initAndShowGUI() { // This method is invoked on the EDT thread
JFrame frame = new JFrame("WebViewTable");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JFXPanel fxPanel = new JFXPanel() {
private static final long serialVersionUID = 1L;
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 400);
}
};
frame.add(fxPanel, BorderLayout.CENTER);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
ArrayBlockingQueue<DefaultTableModel> platformQueue = new ArrayBlockingQueue<DefaultTableModel>(5) ;
Platform.runLater(() -> {
initFX(fxPanel,platformQueue);
});
DefaultTableModel tspData = null;
try {
tspData = platformQueue.take();
} catch (Exception e) {
e.printStackTrace();
}
// Platform.exit(); // At this location causes error on next call
// error occurs on final JFXPanel fxPanel = new JFXPanel() {
return tspData;
}
private void initFX(JFXPanel fxPanel, ArrayBlockingQueue<DefaultTableModel> platformQueue) {
// This method is invoked on the JavaFX thread
// System.out.println("JavaFx thread name "+Thread.currentThread().getName());
Scene scene = createScene(platformQueue);
fxPanel.setScene(scene);
}
private DefaultTableModel getData() {
ArrayBlockingQueue<DefaultTableModel> swingQueue = new ArrayBlockingQueue<>(5);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
DefaultTableModel tspDataLocal = initAndShowGUI( );
swingQueue.put(tspDataLocal);
} catch (java.lang.ArrayIndexOutOfBoundsException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
DefaultTableModel tableJFrameData = null;
try {
tableJFrameData = swingQueue.take();
} catch (InterruptedException e) {
e.printStackTrace();
}
// Platform.exit(); // At this location causes error on next call
// error occurs on final JFXPanel fxPanel = new JFXPanel() {
return tableJFrameData;
}
}