windowbuilder tutorial not functioning - gwt

Question

I am trying to do a tutorial that allows one to Add and Remove stocks and witness their price and change. This tutorial demonstrates how to use the GUI builder, GWT Designer, to create and design a Stock Watcher application based on the GWT tutorial.
http://code.google.com/webtoolkit/tools/gwtdesigner/tutorials/stockwatcher.html#design_ui
So far I have SW.java:
package edu.gatech.client;
import java.util.ArrayList;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.FlexTable;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.event.dom.client.KeyPressHandler;
import com.google.gwt.event.dom.client.KeyPressEvent;
/**
* Entry point classes define <code>onModuleLoad()</code>.
*/
public class SW implements EntryPoint {
private RootPanel rootPanel;
private FlexTable stocksFlexTable;
private HorizontalPanel addPanel;
private VerticalPanel mainWindow;
private TextBox newSymbolTextBox;
private Button addButton;
private Label lastUpdatedLabel;
private ArrayList <String> stocks = new ArrayList<String>(); //Add this line
public void onModuleLoad() {
rootPanel = RootPanel.get();
mainWindow = new VerticalPanel();
rootPanel.add(mainWindow, 10, 10);
mainWindow.setSize("267px", "175px");
FlexTable stocksFlexTable = new FlexTable();
//Add these lines
stocksFlexTable.setText(0, 0, "Symbol");
stocksFlexTable.setText(0, 1, "Price");
stocksFlexTable.setText(0, 2, "Change");
stocksFlexTable.setText(0, 3, "Remove");
mainWindow.add(stocksFlexTable);
addPanel = new HorizontalPanel();
rootPanel.add(addPanel, 10, 200);
addPanel.setSize("267px", "68px");
newSymbolTextBox = new TextBox();
newSymbolTextBox.addKeyPressHandler(new KeyPressHandler() {
public void onKeyPress(KeyPressEvent event) {
if (event.getCharCode() == KeyCodes.KEY_ENTER){
addStock();
}
}
});
addPanel.add(newSymbolTextBox);
newSymbolTextBox.setWidth("211px");
addButton = new Button("Add");
addButton.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
addStock();
}
});
addPanel.add(addButton);
lastUpdatedLabel = new Label("New Label");
rootPanel.add(lastUpdatedLabel, 48, 274);
}
private void addStock() {
final String symbol = newSymbolTextBox.getText().toUpperCase().trim();
newSymbolTextBox.setFocus(true);
// Stock code must be between 1 and 10 chars that are numbers, letters, or dots.
if (!symbol.matches("^[0-9A-Z\\.]{1,10}$")) {
Window.alert("'" + symbol + "' is not a valid symbol.");
newSymbolTextBox.selectAll();
return;
}
newSymbolTextBox.setText("");
// don't add the stock if it's already in the watch list
if (stocks.contains(symbol))
return;
// add the stock to the list
int row = stocksFlexTable.getRowCount();
stocks.add(symbol);
stocksFlexTable.setText(row, 0, symbol);
// add button to remove this stock from the list
Button removeStock = new Button("x");
removeStock.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
int removedIndex = stocks.indexOf(symbol);
stocks.remove(removedIndex);
stocksFlexTable.removeRow(removedIndex + 1);
}
});
stocksFlexTable.setWidget(row, 3, removeStock);
}
}
When I run the web application, I cannot Add a stock. The program does, however, distinguish between bad stock names and acceptable ones. Instead I get an "uncaught exception escaped" error and the program doesn't really do anything. How do I troubleshoot this?

Answer 1

Use the debugger and single step through the code. Set a breakpoint on addStock's first line and find which line crashes. Once you find which line you then instrument the line to find out what aspect is causing the problem - assuming you can't deduce the problem by looking at the line.