I am developing a payment gateway of a vending machine. My gateway connects to the vending machine successfully using socket. I am able to receive messages on the required price successfully process it but sending back my approval messages to machines gives java.lang.NullPointerException . My UI is on JavaFX
below is my code on 1st Controller
@FXML
public void handleButtonAction(ActionEvent event)throws UnknownHostException, IOException {
LOGGER.info("Connect button Clicked");
status.setWrapText(true);
status.appendText("Connect button Clicked \n");
// getting localhost ip
InetAddress ip = InetAddress.getByName("localhost");
// establish the connection
s = new Socket(ip, ServerPort);
status.appendText("connected to " + s.toString() + "\n" );
LOGGER.info("connected to " + s.toString() + "\n" );
//start a scanning thread
receivemessage();
}
receive message method
public void receivemessage()
{
LOGGER.info("Receive message thread started");
status.setWrapText(true);
status.appendText("Receive message thread started \n");
// readMessage thread
Thread readMessage = new Thread(new Runnable()
{
// Platform.setImplicitExit(false);
public void run(){
InputStream input = null;
try {
input = s.getInputStream();
status.appendText("Scanning thread started.");
//scanning always running
while(true) {
String dataString = "";
byte buffer[] = new byte[1024];
// read all received bytes
while (input.available() > 0) {
int i = input.read(buffer, 0, 1024);
if (i < 0) {
break;
}
dataString += new String(buffer, 0, i);
}
if(!dataString.isEmpty()) {
status.appendText("Server respond: \"" +dataString +"\"");
LOGGER.info("Server respond: \"" +dataString +"\"");
String VendRequest_input="External PC Plugin;Vend Request;add_on_variable=&required_price=50#";
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
Logger.getLogger(BritsConnectController.class.getName()).log(Level.SEVERE, null, ex);
}
final String data=dataString;
Platform.runLater(() ->{
try {
loadPhoneInput(data);
} catch (IOException ex) {
Logger.getLogger(BritsConnectController.class.getName()).log(Level.SEVERE, null, ex);
}
});
/*for (int x=0; x<result.length; x++) {
System.out.println(result[x]);
}*/
}
}
} catch (IOException ex) {
Logger.getLogger(BritsConnectController.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
input.close();
} catch (IOException ex) {
Logger.getLogger(BritsConnectController.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
});
readMessage.start();
}
public void loadPhoneInput( String dataString) throws IOException
{
//Parse String and Capture
String Capture = dataString;
String[] tokens = Capture.split("#");
System.out.println(tokens.length);
for(int i=0; i<tokens.length; i++)
{
String prefix = "External PC Plugin;Vend Request;add_on_variable=&required_price=";
if(tokens[i].contains(prefix))
{
//fetch total Amount
System.out.println(tokens[i]);
String Command=tokens[i];
String[] price = Command.split("&");
String exact_Price=price[1]; //required_price=50
String[] total_Amount =exact_Price.split("=");
System.out.println();
String totalAmount=total_Amount[1];
//Load phone Input and Pass Prices
FXMLLoader loader = new FXMLLoader(getClass().getResource("PhoneInput.fxml"));
Parent root = (Parent) loader.load();
//transfer totalAmount
PhoneInputController phonecontoller=loader.<PhoneInputController>getController();
phonecontoller.setDispenseAmount(totalAmount);
//load phone input
Stage stage=new Stage();
Scene scene = new Scene(root);
stage.setScene(scene);
stage.initStyle(StageStyle.UNDECORATED);
stage.show();
stage.centerOnScreen();
stage.setAlwaysOnTop(true);
//close current pane
//ConnectorStage = (Stage)ConnectorPane.getScene().getWindow();// pane you are ON
//ConnectorStage.hide();
}
}
}
Send approval message method
@FXML
public void sendVendronApproveResponse()
{
System.out.println("Sending Initiated....");
String msg ="External PC Plugin;Vend Request Respond;status=approve#";
try {
PrintWriter output= new PrintWriter(s.getOutputStream(),true);
output.printf(msg);
output.flush();
status.appendText("\nSending to server: " +msg);
} catch (Exception e) {
LOGGER.info(e.toString());
e.printStackTrace();
System.out.println( e.getCause());
}
}
This is code on second controller calling send message
private void postUsingRawJSON(WebTarget target) throws IOException {
String payment = paymentUtil.createPaymentInJSON(phoneNumberInput
, amountInput
, "1");
ProviderResponse response = target.request()
.post(Entity.entity(payment, MediaType.APPLICATION_JSON)
, ProviderResponse.class);
System.out.println(response.getCode());
//Response message option to Vendron
String Vend_Request_Respond_APPROVE="External PC Plugin;Vend Request Respond;status=approve#";
String Vend_Request_Respond_DENIED="External PC Plugin;Vend Request Respond;status=denied#";
String code=response.getCode();
switch (code){
case "0":
{
//send Vendron Dispense Command
try
{
FXMLLoader loader1 = new FXMLLoader(getClass().getResource("FXMLDocument.fxml"));
BritsConnectController britsContoller = loader1.getController();
britsContoller.sendMessage(Vend_Request_Respond_APPROVE);
}
catch (Exception ex) {
ex.getCause();
ex.printStackTrace();
}
FXMLLoader loader = new FXMLLoader(getClass().getResource("successTransaction.fxml"));
Parent root = loader.load();
Stage stage=new Stage();
Scene scene = new Scene(root);
stage.setScene(scene);
stage.initStyle(StageStyle.UNDECORATED);
stage.show();
stage.centerOnScreen();
stage.setAlwaysOnTop(true);
confirmStage = (Stage)confirmPane.getScene().getWindow();// pane you are ON
confirmStage.hide();
PauseTransition delay = new PauseTransition(Duration.seconds(10));
delay.setOnFinished( event -> stage.close() );
delay.play();
break;
}
}
//get the new customer
//getCustomerById(target, response);
}
