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Java - Can't access arraylist in another class

I have a runnable class "TemperatureSensor" which is periodically adding a new randomized floating point value to an array list TemperatureList as an object Temperature. The last added object in the array (index 0) is then sent from RMI client to RMI server - this happens without problems.
However, when I click a button on GUI to display the size of this object array, I always get a 0. If I print out the size of the array from RMI client class, it shows a correct size.
My question is, how do I access the same array from multiple classes correctly?
Here is the UML:
TemperatureSensor:
import java.text.DecimalFormat;
import java.util.Random;
public class TemperatureSensor implements Runnable
{
private int waitingTime;
private Model model;
public TemperatureSensor(Model model, int waitingTime)
{
this.model = model;
this.waitingTime = waitingTime;
}
#Override
public void run()
{
float temperature = 25.0f;
while(true)
{
temperature = measureTemperature(temperature);
model.addTemperatureData(temperature);
System.out.println("Sending: " + temperature);
waiting();
}
}
private float measureTemperature(float temperature)
{
Random rand = new Random();
float minTempFloat = 0.1f;
float maxTempFloat = 0.2f;
int incrementSwitch = rand.nextInt(3-0) + 0;
if (incrementSwitch == 0)
{
temperature += minTempFloat + rand.nextFloat() * (maxTempFloat - minTempFloat);
}
else if(incrementSwitch == 1)
{
//Do nothing
}
else if (incrementSwitch == 2)
{
temperature -= minTempFloat + rand.nextFloat() * (maxTempFloat -
minTempFloat);
}
return temperature;
}
private void waiting()
{
try
{
Thread.sleep(waitingTime);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
}
Model:
public interface Model
{
public void addTemperatureData(float value);
public Temperature getLatestTemperatureData();
public int getTempListSize();
}
ModelManager:
public class ModelManager implements Model
{
private TemperatureList temperatureList;
public ModelManager()
{
temperatureList = new TemperatureList();
}
#Override
public void addTemperatureData(float value)
{
Temperature temperature = new Temperature(value);
//this.temperatureList.clearTemperatureDataList();
this.temperatureList.addTemperatureDataToList(temperature);
}
#Override
public Temperature getLatestTemperatureData()
{
return temperatureList.getLatestTemperatureDataFromList();
}
#Override
public int getTempListSize()
{
return temperatureList.size();
}
}
RMIsensorClient:
import java.rmi.Naming;
import java.rmi.RemoteException;
public class RMIsensorClient
{
private RMIserverInterface serverInterface;
private static Model model = new ModelManager();
public static void main(String[] args) throws RemoteException, InterruptedException
{
TemperatureSensor tempSensor = new TemperatureSensor(model, 5000);
Thread tempThread = new Thread(tempSensor, "TempSensor");
tempThread.start();
RMIsensorClient sensorClient = new RMIsensorClient();
}
public RMIsensorClient() throws RemoteException
{
super();
try
{
serverInterface = (RMIserverInterface) Naming.lookup("rmi://localhost:1099/rmiServer");
while(true)
{
serverInterface.getTemperature(model.getLatestTemperatureData());
System.out.println(model.getTempListSize());
Thread.sleep(5000);
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
Controler:
public class Controller
{
private static Model model;
public Controller ()
{
this.model = new ModelManager();
}
public int getNumberOfListElements()
{
return model.getTempListSize();
}
}
GUI:
public class GUItemperatureController implements Initializable
{
private Controller controller = new Controller();
#FXML
private Label tlTemperature;
#FXML
private Pane mainPane;
#FXML
private TextField tfTemperature;
#FXML
private Button btnUpdate;
#Override
public void initialize(URL arg0, ResourceBundle arg1)
{
tfTemperature.setEditable(false);
}
#FXML
void showArraySize(ActionEvent event)
{
tfTemperature.setText(Integer.toString(controller.getNumberOfListElements()));
}
}
TemperatureList:
import java.io.Serializable;
import java.util.ArrayList;
public class TemperatureList implements Serializable
{
private ArrayList<Temperature> temperatureList;
public TemperatureList()
{
this.temperatureList = new ArrayList<>();
}
public void addTemperatureDataToList(Temperature temperature)
{
temperatureList.add(0,temperature);
}
public Temperature getLatestTemperatureDataFromList()
{
return this.temperatureList.get(0);
}
public void clearTemperatureDataList()
{
temperatureList.clear();
}
public int size()
{
return temperatureList.size();
}
}
Here is where I launch the GUI:
import java.rmi.RemoteException;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class userMain extends Application
{
public FXMLLoader loader;
public static void main(String[] args)
{
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception
{
loader = new FXMLLoader();
loader.setLocation(getClass().getResource("FXML/FXMLtemperature.fxml"));
loader.setController(new GUItemperatureController());
Parent root = loader.load();
Scene scene = new Scene(root);
primaryStage.setTitle("GEMS - Test");
primaryStage.setScene(scene);
primaryStage.show();
}
}

Your problem is not about classes.
You run two separate applications. One runs your RMIsensorClient and one runs your GUI. They know nothing about each other, your RMIsensorClient and your Controller have their own separate instances of ModelManager and you have no code anywhere that would share any data between them.
You need to make the data you want to show in your GUI accessible somehow.
One solution could be to use a network interface for that. Create two different ModelManagers, one that opens and listens to a ServerSocket, and one that uses a Socket in getLatestTemperatureData() to connect to the other one.
Use the former in your RMIsensorClient and the latter in your GUI's Controller.
Research networking in Java.
This is a very crude solution, but there are plenty of great tutorials for networking and sharing data between multiple Java applications.

You haven't included your TemperatureList implementation, but if as you say it's an ArrayList it's likely you're not properly synchronizing access across threads. It's imperative that you properly synchronize cross-thread work otherwise you'll wind up with some sort of undefined behavior, such as changes not propagating or data structures winding up broken.
There are a number of thread-safe collections in java.util.collect.concurrent that you might consider, otherwise you'll need to ensure you use synchronized blocks or methods anywhere you're working with this list.

The most obvious problem that I found(and this might not be all) is that your array list is method specific. it is not static. Meaning that it can only be accessed by the method it originates in. the easiest fix for this is to add a static modifier to your array list when it is created and create it outside of the methods.

Know when a different class is exited

I'm currently coding a project Java in eclipse which has two classes. The first class (open) I use to send a specific string to my second class (viewer) and then run my second class. The second class (viewer) I have imported into my program in the form of a jar file. I have done it this way as class viewer is a pdf viewer that i created using apache PDFBox and class open sends the file to the viewer to use, but the file will be different depending on many conditions (that are not relevant) in class open. The point is that class open needs to be separate from class viewer and can not simply be two different methods in one class. I would like to know if there is a way for class open to know when class viewer has been closed, as currently I am using a while loop, which just eats up memory and is very inefficient. The code I have does currently work, but I feel there is a better way, perhaps using listeners. This is the code for closing class viewer:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
//and import swing components ect
Public class viewer extends javax.swing.JFrame
implements KeyListener,
ActionListener{
private javax.swing.JButton zoomIn;
private javax.swing.JButton zoomOut;
//and a bunch more swing components
public static boolean closed = false;
public static String fileName = "";
public viewer()
{
}
private void initComponents() throws IOException
{
addWindowListener(new java.awt.event.WindowAdapter()
{
#Override
public void windowClosing(java.awt.event.WindowEvent evt)
{
exitApplication();
}
});
}
private void exitMenuItemActionPerformed(ActionEvent evt)
{
if( document != null )
{
try
{
document.close();
}
catch( IOException e )
{
throw new RuntimeException(e);
}
}
closed = true;
System.exit(0);
}
public static void main(String filename) throws Exception
{
fileName = filename;
viewer mainViewer = new viewer();
String[] splittedStr = fileName.split("/");
BASETITLE = splittedStr[splittedStr.length - 1];
if (fileName != null)
{
mainViewer.openPDFFile(fileName);
}
mainViewer.setVisible(true);
}
This is my code from class open:
public static void main(String[] args) throws Exception {
String fileName = "C:/Files/Test.pdf";
viewer.main(fileName);
while(viewer.closed == false)
{
if(viewer.closed == true)
{
System.out.print("The Viewer Has Been Closed");
}
}
}
I want to know when it is closed so I can delete the file on the local drive. Thanks for your help!

Either you pass a callback (e.g. a Runnable) as argument to viewer.main, like viewer.main(fileName, () -> System.out.print("The Viewer Has Been Closed")) and make sure that it is called when the process is done, or you do as you've done except that you sleep your main thread a short time in the while loop, like Thread.sleep(100).

okay so I actually found an answer to my question and I'll just post it in case someone else had the same problem as me. I added a interface to the open class with the method close as shown:
import mainpackage.viewer;
public class Open implements closeInterface{
public Open() { }
public static String fileName;
public static void main(String[] args) throws Exception {
fileName = "C:/Files/Test.pdf";
run();
}
#Override
public void close() {
System.out.print("The Viewer Has Been Closed");
}
public static void run() throws Exception
{
viewer view = new viewer();
view.main(fileName);
view.addListener(new Open());
}
}
This was my code for my interface:
package mainpackage;
public interface closeInterface {
public void close();
}
And this was the snipit of code for my Viewer class
public class viewer extends javax.swing.JFrame {
private static closeInterface Closed;
private void initComponents() throws IOException
{
addWindowListener(new java.awt.event.WindowAdapter()
{
#Override
public void windowClosing(java.awt.event.WindowEvent evt)
{
exitApplication();
}
});
}
private void exitApplication()
{
try
{
if( document != null )
{
document.close();
}
}
catch( IOException io )
{
//do nothing because we are closing the application
}
Closed.close();
this.setVisible( false );
this.dispose();
}
public void addListener(closeInterface closed){
Closed = closed;
}
}
Thanks for everyone's help!

Item not working in minecraft mod - Minecraft Forge Mod Development [EDIT: FIXED]

I have started making a mod, it's not registering as an item. When i type /give Fidojj222 fcm:fuel_canister it should give me the item except it says it doesn't exist! I am using eclipse as my IDE I am suspecting it might be this warning when I compile it into a jar:
JAR export finished with warnings. See details for additional information.
Can not export external class folder at 'C:\Users\J.J\.gradle\caches\minecraft\net\minecraftforge\forge\1.8-11.14.3.1450\start'.
If that is the problem, then how can I fix it? If not here's my code:
CarsMod.java:
package com.fidojj222.carsmod;
import com.fidojj222.carsmod.init.CarsItems;
import com.fidojj222.carsmod.proxy.CommonProxy;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.common.SidedProxy;
import net.minecraftforge.fml.common.event.FMLInitializationEvent;
import net.minecraftforge.fml.common.event.FMLPostInitializationEvent;
import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
#Mod(modid = Reference.MOD_ID, name = Reference.MOD_NAME, version = Reference.VERSION)
public class CarsMod {
#SidedProxy(clientSide = Reference.CLIENT_PROXY_CLASS, serverSide = Reference.SERVER_PROXY_CLASS)
public static CommonProxy proxy;
public void PreInit(FMLPreInitializationEvent event){
CarsItems.init();
CarsItems.register();
}
public void Init(FMLInitializationEvent event){
proxy.registerRenders();
}
public void PostInit(FMLPostInitializationEvent event){
}
}
Reference.java:
package com.fidojj222.carsmod;
public class Reference {
public static final String MOD_ID = "fcm";
public static final String MOD_NAME = "Fidojj222\'s Cars Mod";
public static final String VERSION = "1.0";
public static final String CLIENT_PROXY_CLASS = "com.fidojj222.carsmod.proxy.ClientProxy";
public static final String SERVER_PROXY_CLASS = "com.fidojj222.carsmod.proxy.CommonProxy";
}
CarsItems.java:
package com.fidojj222.carsmod.init;
import com.fidojj222.carsmod.Reference;
import net.minecraft.client.Minecraft;
import net.minecraft.client.resources.model.ModelResourceLocation;
import net.minecraft.item.Item;
import net.minecraftforge.fml.common.registry.GameRegistry;
public class CarsItems {
public static Item fuel_canister;
public static void init(){
fuel_canister = new Item().setUnlocalizedName("fuel_canister");
}
public static void register(){
GameRegistry.registerItem(fuel_canister, fuel_canister.getUnlocalizedName().substring(5));
}
public static void registerRenders(){
registerRender(fuel_canister);
}
public static void registerRender(Item item){
Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(item, 0, new ModelResourceLocation(Reference.MOD_ID + ":" + item.getUnlocalizedName().substring(5), "inventory"));
}
}
CommonProxy.java:
package com.fidojj222.carsmod.proxy;
public class CommonProxy {
public void registerRenders(){
}
}
ClientProxy.java:
package com.fidojj222.carsmod.proxy;
import com.fidojj222.carsmod.init.CarsItems;
public class ClientProxy extends CommonProxy {
#Override
public void registerRenders(){
CarsItems.registerRenders();
}
}

What do you mean by not showing? The item isn't found at all in the creative search menu, or it is an untextured (purple/black checkered) block?
If it is untextured, you need to make sure these 2 things are done:
Make sure you have this texture in place src/main/resources/assets/fcm/textures/items/fuel_canister.png it needs to be 16x16 pixels.
Create a fuel_canister.json file at src/main/resources/assets/fcm/models/item/fuel_canister.json This file defines how the image should be rendered ingame.
The contents of that file should be
{
"parent": "builtin/generated",
"textures":{
"layer0":"fcm:items/fuel_canister"
},
"display":{
"thirdperson":{
"rotation":[-90, 0, 0],
"translation":[0, 1, -3],
"scale":[0.55,0.55,0.55]
},
"firstperson":{
"rotation":[0,-135,25],
"translation":[0,4,2],
"scale":[1.7,1.7,1.7]
}
}
}

How to get text from JTextField, convert to a string, and use this string in a different java public class

I have a GUI that has 2 JTextFields- EmailLoginField and jPasswordField1. Ill just discuss the EmailLoginField and just duplicate what is recommended on jPasswordField1 too.
So heres some GUI code:
package p;
imports ...
public class EmailLoginGUI extends javax.swing.JFrame {
public EmailLoginGUI() {
initComponents();
}
private void initComponents() {
...
EmailLoginField = new javax.swing.JTextField();
}
...
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
EmailMainGUI open = new EmailMainGUI();
open.setVisible(true);
This next code snippet is what I have tried to do to get the text from the JTextField EmailLoginField in EmailLoginGUI.java
public String getEmailLoginField(){
return EmailLoginField.getText();
}
public String getjPasswordField(){
return jPasswordField1.getText();
}
Here is the next part (not assuming the code immediately above is correct). This next code is an entirely different public class, which same package of course. Here is what I have tried it should look at the EmailLoginGUI class and get the JTextField content, eventually storing it as a String.
PLEASE NOTE: the final strings that contain the JTextField content MUST NOT be inside the SendEmail(EmailLoginGUI c1, EmailLoginGUI c2){. They should be just outside of it just inside public class SendEmail { this is so that they can be used by other code later.
package p;
imports ...
public class SendEmail {
JTextField userTF;
JPasswordField passPF;
SendEmail(EmailLoginGUI c1, EmailLoginGUI c2){
userTF.setText(c1.getEmailLoginField());
passPF.setText(c2.getjPasswordField());
}
public String user(){
return userTF.getText();
}
public String pass() {
return passPF.getText();
}
...
SendEmail(...) {
Properties props = new Properties();
...
Session session = Session.getInstance(props, new javax.mail.Authenticator()
{
protected javax.mail.PasswordAuthentication getPasswordAuthentication()
{
return new javax.mail.PasswordAuthentication(user(), pass()); //This is where the final strings need to go.
}
});
Hopefully what I am trying to do is clear:
Get the content from JTextField created in EmailLoginGUI.java. Get this into SendEmail.java. Its final type should be String and is 'just on the inside' of the public class SendEmail. I have had everything from NullPointerException to Cannot find symbol for hours! Think I've been attempting it for so long that I could benefit from some fresh eyes!
Help would be greatly appreciated.

In SendEmail class create Constructor which has an argument of user input
SendEmail(String userInput) {
//Your Code
}
In EmailLoginGUI create
String userInput = EmailLoginField.getText().toString();
SendEmail sendemail = new SendEmail(userInput);
This method works I have used it. Hope it helps.

I realised both the security risk and how a dialogue would be easier, however I don't have time to go back to change it really. I have already coded the listener too so that's not a problem. But yes that's what I want to do! Where am I going wrong?
Then you need to implement some kind of Observer Pattern.
Start by defining the expected operations that the login view might generate, for example, it's reasonable to expect that the user can either accept or cancel the view
public interface EmailLoginListener {
public void emailLoginWasAccepted(EmailLoginGUI gui);
public void emailLoginWasCanceled(EmailLoginGUI gui);
}
Update the view to provide support for the listener
public class EmailLoginGUI extends javax.swing.JFrame {
private List<EmailLoginListener> listeners;
public EmailLoginGUI() {
initComponents();
listeners = new ArrayList<>(25);
}
//...
public void addEmailLoginListener(EmailLoginListener listener) {
listeners.add(listener);
}
public void removeEmailLoginListener(EmailLoginListener listener) {
listeners.add(listener);
}
protected void fireLoginWasAccepted() {
for (EmailLoginListener listener : listeners) {
listener.emailLoginWasAccepted(this);
}
}
protected void fireLoginWasCanceled() {
for (EmailLoginListener listener : listeners) {
listener.emailLoginWasCanceled(this);
}
}
}
In your action handlers for your buttons on the EmailLoginGUI view, trigger the required event...
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
fireLoginWasAccepted();
}
Remember, you should also do this for the cancel operation if you have one.
Now, when you create an instance of EmailLoginGUI, make sure you also register a EmailLoginListener with it
EmailLoginGUI loginView = new EmailLoginGUI();
loginView.addEmailLoginListener(new EmailLoginListener() {
#Override
public void emailLoginWasAccepted(EmailLoginGUI gui) {
gui.dispose();
String email = gui.getEmailLoginField();
String password = gui.getjPasswordField();
EmailMainGUI open = new EmailMainGUI();
open.setCredentials(email, password);
//...
open.setVisible(true);
}
#Override
public void emailLoginWasCanceled(EmailLoginGUI gui) {
// Exit the program?
gui.dispose();
}
});
//...
loginView.setVisible(true);
This will require you to either change the constructor of EmailMainGUI to accept the email and password or a method to pass that information to the class (as I've demonstrated above)
Finally change SendEmail to accept String values instead of your gui components
public class SendEmail {
String email;
String password;
SendEmail(String email, String password) {
this.email = email;
this.password = password;
}
public String user() {
return email;
}
public String pass() {
return password;
}
}

Custom Event in GWT widget is not working

I am working on application in Vaadin for my classes.
I have to draw some map on the screen so I'm using gwt-graphics lib.
I have also some servlet which is waiting for requests.
When some specific request will come view of the map should be changed.
It lead me to prepare custom event:
// class NewModulePositionHandler
package com.example.locator;
import com.google.gwt.event.shared.EventHandler;
public interface NewModulePositionHandler extends EventHandler {
void onNewModulePosition(NewModulePositionEvent event);
}
Below implementation of my custom event:
import com.google.gwt.event.shared.GwtEvent;
public class NewModulePositionEvent extends GwtEvent<NewModulePositionHandler> {
private static final Type<NewModulePositionHandler> TYPE = new Type<NewModulePositionHandler>();
private final String m_Color;
public NewModulePositionEvent(String color) {
m_Color = color;
}
public static Type<NewModulePositionHandler> getType() {
return TYPE;
}
public String getColor() {
return m_Color;
}
#Override
public com.google.gwt.event.shared.GwtEvent.Type<NewModulePositionHandler> getAssociatedType() {
// TODO Auto-generated method stub
return TYPE;
}
#Override
protected void dispatch(NewModulePositionHandler handler) {
handler.onNewModulePosition(this);
}
}
And it's time for implementation of my custom widget:
a) MyComp.java
import com.google.gwt.event.shared.GwtEvent;
public class NewModulePositionEvent extends GwtEvent<NewModulePositionHandler> {
private static final Type<NewModulePositionHandler> TYPE = new Type<NewModulePositionHandler>();
private final String m_Color;
public NewModulePositionEvent(String color) {
m_Color = color;
}
public static Type<NewModulePositionHandler> getType() {
return TYPE;
}
public String getColor() {
return m_Color;
}
#Override
public com.google.gwt.event.shared.GwtEvent.Type<NewModulePositionHandler> getAssociatedType() {
// TODO Auto-generated method stub
return TYPE;
}
#Override
protected void dispatch(NewModulePositionHandler handler) {
handler.onNewModulePosition(this);
}
}
b) MyCompClientRpc.java
import com.vaadin.shared.communication.ClientRpc;
public interface MyCompClientRpc extends ClientRpc {
// TODO example API
public void alert(String message);
public void changeColor(String color);
}
c) MyCompConnector.java
package com.example.locator.widgetset.client.mycomp;
import com.google.gwt.core.client.GWT;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Widget;
import com.vaadin.client.ui.AbstractComponentConnector;
import com.vaadin.shared.ui.Connect;
import com.example.locator.MyComp;
import com.example.locator.NewModulePositionEvent;
import com.example.locator.NewModulePositionHandler;
import com.example.locator.widgetset.client.mycomp.MyCompWidget;
import com.example.locator.widgetset.client.mycomp.MyCompServerRpc;
import com.vaadin.client.communication.RpcProxy;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.vaadin.shared.MouseEventDetails;
import com.vaadin.client.MouseEventDetailsBuilder;
import com.example.locator.widgetset.client.mycomp.MyCompClientRpc;
import com.example.locator.widgetset.client.mycomp.MyCompState;
import com.vaadin.client.communication.StateChangeEvent;
#Connect(MyComp.class)
public class MyCompConnector extends AbstractComponentConnector {
MyCompServerRpc rpc = RpcProxy
.create(MyCompServerRpc.class, this);
public MyCompConnector() {
registerRpc(MyCompClientRpc.class, new MyCompClientRpc() {
public void alert(String message) {
// TODO Do something useful
Window.alert(message);
}
public void changeColor(String color) {
getWidget().InitMap(color);
}
});
// TODO ServerRpc usage example, do something useful instead
getWidget().addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
final MouseEventDetails mouseDetails = MouseEventDetailsBuilder
.buildMouseEventDetails(event.getNativeEvent(),
getWidget().getElement());
rpc.clicked(mouseDetails);
}
});
getWidget().addNewModulePositionHandler(new NewModulePositionHandler() {
public void onNewModulePosition(NewModulePositionEvent event) {
// TODO Auto-generated method stub
rpc.newModulePosition(event.getColor());
}
});
}
#Override
protected Widget createWidget() {
return GWT.create(MyCompWidget.class);
}
#Override
public MyCompWidget getWidget() {
return (MyCompWidget) super.getWidget();
}
#Override
public MyCompState getState() {
return (MyCompState) super.getState();
}
#Override
public void onStateChanged(StateChangeEvent stateChangeEvent) {
super.onStateChanged(stateChangeEvent);
// TODO do something useful
final String color = getState().color;
getWidget().InitMap(color);
}
}
d) MyCompServerRpc.java
package com.example.locator.widgetset.client.mycomp;
import com.vaadin.shared.MouseEventDetails;
import com.vaadin.shared.communication.ServerRpc;
public interface MyCompServerRpc extends ServerRpc {
// TODO example API
public void clicked(MouseEventDetails mouseDetails);
public void newModulePosition(String color);
}
e) MyCompState.java
package com.example.locator.widgetset.client.mycomp;
public class MyCompState extends com.vaadin.shared.AbstractComponentState {
// TODO example state
public String color = "#000000";
}
And finally implementation of the widget:
f) MyCompWidget.java
package com.example.locator.widgetset.client.mycomp;
import org.vaadin.gwtgraphics.client.DrawingArea;
import org.vaadin.gwtgraphics.client.Line;
import org.vaadin.gwtgraphics.client.shape.Circle;
import org.vaadin.gwtgraphics.client.shape.Rectangle;
import com.example.locator.HasNewModulePositionHandlers;
import com.example.locator.NewModulePositionEvent;
import com.example.locator.NewModulePositionHandler;
import com.google.gwt.dev.util.collect.HashMap;
import com.google.gwt.event.shared.HandlerManager;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.touch.client.Point;
import com.example.locator.Module;
// TODO extend any GWT Widget
public class MyCompWidget extends DrawingArea implements HasNewModulePositionHandlers {
public static final String CLASSNAME = "mycomp";
public static double m_AreaWidth = 64.355;
public static double m_AreaHeight = 17.385;
public static int m_PictureWidth;
public static int m_PictureHeight;
public static double m_AreaToMapRatio;
public static double m_RouteWidth = 3.5;
public static double m_MainRouteCoordinateY = 8.0828;
public Circle circle;
//public HashMap<Integer, Module> ModuleMap = new HashMap<Integer, Module>();
public MyCompWidget(){
super(640, 320);
//ModuleMap.put(666, new Module(666, 30.0, 8.08, new Circle((int)TranslateCoordinate(30.0), (int)TranslateCoordinate(8.0), 7)));
//ModuleMap.put(15, new Module(15, 27.0, 8.08, new Circle((int)TranslateCoordinate(30.0), (int)TranslateCoordinate(8.0), 7)));
double xRatio = m_AreaWidth / 640;
double yRatio = m_AreaHeight / 320;
m_AreaToMapRatio = xRatio > yRatio ? xRatio : yRatio;
InitMap("#919491");
setStyleName(CLASSNAME);
}
public void InitMap(String color)
{
m_PictureWidth = (int)TranslateCoordinate(m_AreaWidth);
m_PictureHeight = (int)TranslateCoordinate(m_AreaHeight);
Rectangle rectangle = new Rectangle(0, 0, m_PictureWidth, m_PictureHeight);
rectangle.setFillColor(color);
add(rectangle);
Point point1Beg = new Point(0.0, 8.0828);
Point point1End = new Point(64.355, 8.0838);
Point point2Beg = new Point(20.2825, 8.0828);
Point point2End = new Point(20.2825, 17.385);
Point point3Beg = new Point(59.325, 0.0);
Point point3End = new Point(59.325, 8.0828);
point1Beg = TranslatePoint(point1Beg);
point1End = TranslatePoint(point1End);
point2Beg = TranslatePoint(point2Beg);
point2End = TranslatePoint(point2End);
point3Beg = TranslatePoint(point3Beg);
point3End = TranslatePoint(point3End);
Line line1 = new Line((int)point1Beg.getX(), (int)point1Beg.getY(), (int)point1End.getX(), (int)point1End.getY());
Line line2 = new Line((int)point2Beg.getX(), (int)point2Beg.getY(), (int)point2End.getX(), (int)point2End.getY());
Line line3 = new Line((int)point3Beg.getX(), (int)point3Beg.getY(), (int)point3End.getX(), (int)point3End.getY());
line1.setStrokeColor("#FFFFFF");
line2.setStrokeColor("#FFFFFF");
line3.setStrokeColor("#FFFFFF");
line1.setStrokeWidth((int)TranslateCoordinate(m_RouteWidth));
line2.setStrokeWidth((int)TranslateCoordinate(m_RouteWidth));
line3.setStrokeWidth((int)TranslateCoordinate(m_RouteWidth));
add(line1);
add(line2);
add(line3);
DrawWall(TranslateCoordinate(10.0));
DrawWall(TranslateCoordinate(20.0));
DrawWall(TranslateCoordinate(30.0));
DrawWall(TranslateCoordinate(40.0));
DrawWall(TranslateCoordinate(50.0));
DrawWall(TranslateCoordinate(60.0));
DrawDoor(3.0, 3.0);
DrawDoor(13.0, 3.0);
DrawDoor(23.0, 3.0);
DrawDoor(33.0, 3.0);
DrawDoor(43.0, 3.0);
DrawDoor(53.0, 3.0);
circle = new Circle((int)TranslateCoordinate(25.0), (int)TranslateCoordinate(8.0), 15);
add(circle);
}
public void DrawWall(double a_Place)
{
Line line = new Line((int)a_Place, 0, (int)a_Place, (int)TranslateCoordinate(m_AreaHeight));
line.setStrokeColor("#FFFFFF");
add(line);
}
public void DrawDoor(double a_Position, double a_Width)
{
double realDoorPositionY = m_MainRouteCoordinateY - (m_RouteWidth / 2);
int doorPositionYTop = (int)TranslateCoordinate(realDoorPositionY) - 1;
int doorPositionYBottom = (int)TranslateCoordinate(realDoorPositionY + m_RouteWidth) + 1;
Line line = new Line((int)TranslateCoordinate(a_Position), doorPositionYTop, (int)TranslateCoordinate(a_Position) + (int)TranslateCoordinate(a_Width), doorPositionYTop);
line.setStrokeColor("#000000");
line.setStrokeWidth(2);
add(line);
Line line2 = new Line((int)TranslateCoordinate(a_Position), doorPositionYBottom, (int)TranslateCoordinate(a_Position) + (int)TranslateCoordinate(a_Width), doorPositionYBottom);
line2.setStrokeColor("#000000");
line2.setStrokeWidth(2);
add(line2);
}
public Point TranslatePoint(Point a_Point)
{
Point translatedPoint = new Point(TranslateCoordinate(a_Point.getX()), TranslateCoordinate(a_Point.getY()));
return translatedPoint;
}
public double TranslateCoordinate(double a_Coordinate)
{
return (a_Coordinate) / (m_AreaToMapRatio);
}
public void Move(int id) {
//ModuleMap.get(id).GetCircle().setX(10 + circle.getX());
}
public HandlerRegistration addNewModulePositionHandler(
NewModulePositionHandler handler) {
return addHandler(handler, NewModulePositionEvent.TYPE);
}
private void someMethod() {
fireEvent(new NewModulePositionEvent("#000000"));
}
public void emulateEvent() {
someMethod();
}
}
g) HasNewModulesPositionHandlers.java
package com.example.locator;
import com.google.gwt.event.shared.HandlerRegistration;
public interface HasNewModulePositionHandlers {
// Attention! method returns HandlerRegistration, so that handler can be cancelled
public HandlerRegistration addNewModulePositionHandler(
NewModulePositionHandler handler);
}
If I compile the widgets set containing MyCompWidget and then run my application on glassfish I get the following message:
Widgetset 'com.example.locator.widgetset.LocatorWidgetset' does not contain implementation for com.example.locator.MyComp. Check its component connector's #Connect mapping, widgetsets GWT module description file and re-compile your widgetset. In case you have downloaded a vaadin add-on package, you might want to refer to add-on instructions.
If I cut
public void addNewModulePositionHandler(
NewModulePositionHandler handler) {
handlerManager.addHandler(NewModulePositionEvent.getType(), handler);
// TODO Auto-generated method stub
}
widget works properly (of course I have to comment out these lines from MyCompConnector as well):
getWidget().addNewModulePositionHandler(new NewModulePositionHandler() {
public void onNewModulePosition(NewModulePositionEvent event) {
// TODO Auto-generated method stub
rpc.newModulePosition(event.getColor());
}
});
Can anyone tell me where is the problem? It seems that compilation of the widget failes but I can't find any information about that.
Please, help me.
Thanks in advance.

Compilation problem is very clear: GWT compiler cannot fins source code for a specified java class. You add source files to GWT compiler scope in two steps:
*.java files must be accessible through classpath (eclipse gwt compiler automatically includes all source folders to classpath)
You need to tell GWT that it should consider your packages during compilation
Create .gwt.xml file in PARENT package (relative to your source files) with the following content (if your package is pkg1.pkg2.pkg3, then you should in package pkg1.pkg2 create file "Pkg3.gwt.xml", pkg = "pkg3", by convention pkg3 is typically named "client")
<module>
<source path="pkg3" />
</module>
!!!Be careful with letter cases, By convention those are the correct names.
Add to your widgetset.gwt.xml file "inherits" directive like that
<inherits name="pkg1.pkg2.Pkg3" />
!!! Pay attention to letter cases (P is capital in Pkg3, after file name Pkg3.gwt.xml), .gwt.xml is omitted here
Then, first of all, Vaadin uses GWT with a certain twist. I would recommend browsing through custom widgetset samples. You may need to understand how to propagate events to and from Vaadin-specific components. Below I explain how GWT event are supposed to be implemented and used. I'm not an expert in Vaadin, especially in advanced topics such as customizing widgetsets.
So, speaking of GWT.
Basically, you need to understand only two things to make (non-DOM, also knows as bitless) events work in GWT.
Code support
Event class. NewModulePositionEvent in your case.
Event Handler interface. NewModulePositionHandler in your case.
Feature interface (optional but advised). HasNewModulePositionHandlers in your case.
Usage pattern
Basically, the component that is supposed to fire event should create relevant Event object and pass it to the fireEvent method. All the logic to invoke necessary habdler is provided by EventBus (internally)
If you need to provide API to fire events externally (such as click() method for a Button), it should be done by providing special methods (do not expose internal stuff how exactly event is fired)
DOM events are special in details how they are created (by browser) and dispatched (they need to be explicitly enabled). Anyway, all the browser events are already implemented in GWT out of the box.
So, typical implementations for the above items: For the sake of clarity, I provide excerpts from our production code.
1) Event class
public class QuestionClickEvent extends GwtEvent<QuestionClickHandler> {
public QuestionClickEvent(SScript script, SQuestion question) {
super();
this.script = script;
this.question = question;
}
public static final Type<QuestionClickHandler> TYPE = new Type<QuestionClickHandler>();
// internal event state
private final SScript script;
private final SQuestion question;
#Override
public Type<QuestionClickHandler> getAssociatedType() {
return TYPE;
}
#Override
protected void dispatch(QuestionClickHandler handler) {
handler.onQuestionClicked(this);
}
// provide access to internal event state
public SScript getScript() {
return script;
}
public SQuestion getQuestion() {
return question;
}
}
2) Handler interface
public interface QuestionClickHandler extends EventHandler {
public void onQuestionClicked(QuestionClickEvent event);
}
3) Feature interface
public interface HasQuestionClickHandlers {
// Attention! method returns HandlerRegistration, so that handler can be cancelled
public HandlerRegistration addQuestionClickHandler(
QuestionClickHandler handler);
}
4) Your widget/component
public class SummaryPanel extends Widget implements HasQuestionClickHandlers {
// blah-blah-blah
// implement your handler registration method
#Override
public HandlerRegistration addQuestionClickHandler(
QuestionClickHandler handler) {
return addHandler(handler, QuestionClickEvent.TYPE);
}
// blah-blah-blah
private someMethod() {
// suddenly you realized that you need to to fire your event
fireEvent(new QuestionClickEvent(script, question));
}
// sample external API method
public void emulateEvent() {
someMethod();
}
}
And finally usage example:
SummaryPanel summary = new SummaryPanel();
summary.addQuestionClickHandler(new QuestionClickHandler() {
#Override
public void onQuestionClicked(QuestionClickEvent event) {
// your reaction goes here
}
});