Java tutorial
package com.google.gwt.sample.userwatcher.client; import java.util.ArrayList; import java.util.Date; import java.util.Iterator; import com.google.gwt.core.client.GWT; import com.google.gwt.core.client.JsArray; import com.google.gwt.core.client.JsonUtils; import com.google.gwt.event.dom.client.ChangeEvent; import com.google.gwt.event.dom.client.ChangeHandler; 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.KeyDownEvent; import com.google.gwt.event.dom.client.KeyDownHandler; import com.google.gwt.http.client.Request; import com.google.gwt.http.client.RequestBuilder; import com.google.gwt.http.client.RequestCallback; import com.google.gwt.http.client.RequestException; import com.google.gwt.http.client.Response; import com.google.gwt.http.client.URL; 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.Composite; 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.user.client.ui.TextBox; import com.google.gwt.user.client.ui.VerticalPanel; public class PageWithPhoto extends Composite { 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 Label lastUpdatedLabel = new Label(); private ArrayList<String> stocks = new ArrayList<String>(); private StockPriceServiceAsync stockPriceSvc = GWT.create(StockPriceService.class); private Label errorMsgLabel = new Label(); private static final String JSON_URL = GWT.getModuleBaseURL() + "stockPrices?q="; public PageWithPhoto() { // 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"); stocksFlexTable.setCellPadding(6); // Add styles to elements in the stock list table. 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"); ClientPersistence cp = new ClientPersistence(); FileUploaderWidget_v2 fuw = new FileUploaderWidget_v2(cp); // Assemble Add Stock panel. addPanel.add(newSymbolTextBox); addPanel.add(addStockButton); addPanel.addStyleName("addPanel"); addPanel.add(fuw); fuw.draw(); fuw.addChangeHandler(new ChangeHandler() { public void onChange(ChangeEvent event) { FileUploaderWidget_v2 f = (FileUploaderWidget_v2) event.getSource(); int e = f.getChangeEvent(); processChange(e); } }); errorMsgLabel.setStyleName("errorMessage"); errorMsgLabel.setVisible(false); mainPanel.add(errorMsgLabel); // Assemble Main panel. mainPanel.add(stocksFlexTable); mainPanel.add(addPanel); mainPanel.add(lastUpdatedLabel); // Move cursor focus to the input box. newSymbolTextBox.setFocus(true); // Setup timer to refresh list automatically. Timer refreshTimer = new Timer() { @Override public void run() { refreshWatchList(); } }; refreshTimer.scheduleRepeating(REFRESH_INTERVAL); // Listen for mouse events on the Add button. addStockButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { addStock(); } }); // Listen for keyboard events in the input box. newSymbolTextBox.addKeyDownHandler(new KeyDownHandler() { public void onKeyDown(KeyDownEvent event) { if (event.getNativeKeyCode() == KeyCodes.KEY_ENTER) { addStock(); } } }); initWidget(mainPanel); } private void processChange(int e) { if (e == EventManager.FILE_UPLOADING) { //wLoading.show("Uploading in progress..."); } else if (e == EventManager.FILE_DONEUPLOADING) { //wLoading.hide(); } } /** * 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-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); // TODO Get the stock price. } private void refreshWatchList() { // Initialize the service proxy. if (stockPriceSvc == null) { stockPriceSvc = GWT.create(StockPriceService.class); } // Set up the callback object. AsyncCallback<StockPrice[]> callback = new AsyncCallback<StockPrice[]>() { public void onFailure(Throwable caught) { // If the stock code is in the list of delisted codes, display an error message. String details = caught.getMessage(); if (caught instanceof DelistedException) { details = "Company '" + ((DelistedException) caught).getSymbol() + "' was delisted"; } errorMsgLabel.setText("Error: " + details); errorMsgLabel.setVisible(true); } public void onSuccess(StockPrice[] result) { updateTable(result); } }; // 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())); // Clear any errors. errorMsgLabel.setVisible(false); } /** * 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); stocksFlexTable.setText(row, 2, changeText + " (" + changePercentText + "%)"); } /** * If can't get JSON, display error message. * @param error */ private void displayError(String error) { errorMsgLabel.setText("Error: " + error); errorMsgLabel.setVisible(true); } }