Java tutorial
package com.google.gwt.sample.stockwatcher_rpc.client; import java.util.ArrayList; import java.util.Date; import com.google.gwt.core.client.EntryPoint; import com.google.gwt.core.client.GWT; 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.event.dom.client.KeyPressEvent; import com.google.gwt.event.dom.client.KeyPressHandler; import com.google.gwt.i18n.client.DateTimeFormat; import com.google.gwt.i18n.client.NumberFormat; import com.google.gwt.user.client.Timer; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.rpc.AsyncCallback; import com.google.gwt.user.client.ui.Button; import com.google.gwt.user.client.ui.FlexTable; import com.google.gwt.user.client.ui.HTML; import com.google.gwt.user.client.ui.HorizontalPanel; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.RootPanel; import com.google.gwt.user.client.ui.TextBox; import com.google.gwt.user.client.ui.VerticalPanel; public class StockWatcherRPC implements EntryPoint { private static final int REFRESH_INTERVAL = 5000; // ms private VerticalPanel mainPanel = new VerticalPanel(); private FlexTable stocksFlexTable = new FlexTable(); private HorizontalPanel addPanel = new HorizontalPanel(); private TextBox newSymbolTextBox = new TextBox(); private Button addStockButton = new Button("Add"); private Button randomizeButton = new Button("Randomize"); private Label lastUpdatedLabel = new Label(); private Label randomizeLabel = new Label(); private ArrayList<String> stocks = new ArrayList<String>(); private StockPriceServiceAsync stockPriceSvc = GWT.create(StockPriceService.class); private RandomizeServiceAsync randomizeSvc = GWT.create(RandomizeService.class); private Label errorMsgLabel = new Label(); /** * Entry point method. */ public void onModuleLoad() { // Create table for stock data. stocksFlexTable.setText(0, 0, "Symbol"); stocksFlexTable.setText(0, 1, "Price"); stocksFlexTable.setText(0, 2, "Change"); stocksFlexTable.setText(0, 3, "Remove"); // Add styles to elements in the stock list table. stocksFlexTable.setCellPadding(6); stocksFlexTable.getRowFormatter().addStyleName(0, "watchListHeader"); stocksFlexTable.addStyleName("watchList"); stocksFlexTable.getCellFormatter().addStyleName(0, 1, "watchListNumericColumn"); stocksFlexTable.getCellFormatter().addStyleName(0, 2, "watchListNumericColumn"); stocksFlexTable.getCellFormatter().addStyleName(0, 3, "watchListRemoveColumn"); // Assemble Add Stock panel. addPanel.add(newSymbolTextBox); addPanel.add(addStockButton); addPanel.add(randomizeButton); addPanel.addStyleName("addPanel"); // Assemble Main panel. errorMsgLabel.setStyleName("errorMessage"); errorMsgLabel.setVisible(false); randomizeLabel.setVisible(false); mainPanel.add(errorMsgLabel); mainPanel.add(stocksFlexTable); mainPanel.add(addPanel); mainPanel.add(lastUpdatedLabel); mainPanel.add(new HTML("<br/>")); mainPanel.add(randomizeLabel); // Associate the Main panel with the HTML host page. RootPanel.get("stockList").add(mainPanel); // Move cursor focus to the input box. newSymbolTextBox.setFocus(true); // Setup timer to refresh list automatically. Timer refreshTimer = new Timer() { @Override public void run() { if (!stocks.isEmpty()) { refreshWatchList(); } } }; refreshTimer.scheduleRepeating(REFRESH_INTERVAL); // Listen for mouse events on the Add button. addStockButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { addStock(); } }); randomizeButton.addClickHandler(new ClickHandler() { @Override public void onClick(ClickEvent event) { randomizeNumber(); } }); // Listen for keyboard events in the input box. newSymbolTextBox.addKeyPressHandler(new KeyPressHandler() { public void onKeyPress(KeyPressEvent event) { if (event.getCharCode() == KeyCodes.KEY_ENTER) { addStock(); } } }); } private void randomizeNumber() { this.randomizeSvc.getRandomNumber(new AsyncCallback<Integer>() { @Override public void onFailure(Throwable caught) { randomizeLabel.setText(caught.getMessage()); randomizeLabel.setVisible(true); } @Override public void onSuccess(Integer result) { randomizeLabel.setText(result.toString()); randomizeLabel.setVisible(true); } }); this.randomizeLabel.setText(""); } /** * Add stock to FlexTable. Executed when the user clicks the addStockButton or presses enter in the newSymbolTextBox. */ 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-zA-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 table. if (stocks.contains(symbol)) return; // Add the stock to the table. int row = stocksFlexTable.getRowCount(); stocks.add(symbol); stocksFlexTable.setText(row, 0, symbol); stocksFlexTable.setWidget(row, 2, new Label()); stocksFlexTable.getCellFormatter().addStyleName(row, 1, "watchListNumericColumn"); stocksFlexTable.getCellFormatter().addStyleName(row, 2, "watchListNumericColumn"); stocksFlexTable.getCellFormatter().addStyleName(row, 3, "watchListRemoveColumn"); // Add a button to remove this stock from the table. Button removeStockButton = new Button("x"); removeStockButton.addStyleDependentName("remove"); removeStockButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { int removedIndex = stocks.indexOf(symbol); stocks.remove(removedIndex); stocksFlexTable.removeRow(removedIndex + 1); } }); stocksFlexTable.setWidget(row, 3, removeStockButton); // Get the stock price. refreshWatchList(); } /** * Generate random stock prices. */ private void refreshWatchList() { // Set up the callback object. AsyncCallback<StockPrice[]> callback = new AsyncCallback<StockPrice[]>() { public void onFailure(Throwable caught) { errorMsgLabel.setText("Error: " + caught.getMessage()); errorMsgLabel.setVisible(true); } public void onSuccess(StockPrice[] result) { updateTable(result); // Clear any errors. errorMsgLabel.setVisible(false); } }; // Make the call to the stock price service. stockPriceSvc.getPrices(stocks.toArray(new String[0]), callback); } /** * Update the Price and Change fields all the rows in the stock table. * * @param prices * Stock data for all rows. */ private void updateTable(StockPrice[] prices) { for (int i = 0; i < prices.length; i++) { updateTable(prices[i]); } // Display timestamp showing last refresh. lastUpdatedLabel.setText("Last update : " + DateTimeFormat.getMediumDateTimeFormat().format(new Date())); } /** * Update a single row in the stock table. * * @param price * Stock data for a single row. */ private void updateTable(StockPrice price) { // Make sure the stock is still in the stock table. if (!stocks.contains(price.getSymbol())) { return; } int row = stocks.indexOf(price.getSymbol()) + 1; // Format the data in the Price and Change fields. String priceText = NumberFormat.getFormat("#,##0.00").format(price.getPrice()); NumberFormat changeFormat = NumberFormat.getFormat("+#,##0.00;-#,##0.00"); String changeText = changeFormat.format(price.getChange()); String changePercentText = changeFormat.format(price.getChangePercent()); // Populate the Price and Change fields with new data. stocksFlexTable.setText(row, 1, priceText); Label changeWidget = (Label) stocksFlexTable.getWidget(row, 2); changeWidget.setText(changeText + " (" + changePercentText + "%)"); // Change the color of text in the Change field based on its value. String changeStyleName = "noChange"; if (price.getChangePercent() < -0.1f) { changeStyleName = "negativeChange"; } else if (price.getChangePercent() > 0.1f) { changeStyleName = "positiveChange"; } changeWidget.setStyleName(changeStyleName); } }