Java tutorial
/* * Copyright 2008 Google Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package com.google.gwt.gdata.sample.hellogdata.client; import com.google.gwt.accounts.client.AuthSubStatus; import com.google.gwt.accounts.client.User; import com.google.gwt.gdata.client.GData; import com.google.gwt.gdata.client.GDataSystemPackage; import com.google.gwt.gdata.client.calendar.CalendarEventEntry; import com.google.gwt.gdata.client.calendar.CalendarEventFeed; import com.google.gwt.gdata.client.calendar.CalendarEventFeedCallback; import com.google.gwt.gdata.client.calendar.CalendarService; import com.google.gwt.gdata.client.impl.CallErrorException; import com.google.gwt.user.client.ui.FlexTable; import com.google.gwt.user.client.ui.HTML; import com.google.gwt.user.client.ui.Label; /** * The following example demonstrates how to retrieve a list of a * user's calendar events. */ public class CalendarRetrieveEventsDemo extends GDataDemo { /** * This method is used by the main sample app to obtain * information on this sample and a sample instance. * * @return An instance of this demo. */ public static GDataDemoInfo init() { return new GDataDemoInfo() { @Override public GDataDemo createInstance() { return new CalendarRetrieveEventsDemo(); } @Override public String getDescription() { return "<p>This sample demonstrates how to retrieve all " + "primary calendar events for the authenticated user. The " + "private/full feed is used to obtain the events from the " + "private calendar with full projection. The sample iterates " + "through the list of events and prints out each event's " + "title.</p>"; } @Override public String getName() { return "Calendar - Retrieving events"; } }; } private CalendarService service; private FlexTable mainPanel; private final String scope = "http://www.google.com/calendar/feeds/"; /** * Setup the Calendar service and create the main content panel. * If the user is not logged on to Calendar display a message, * otherwise start the demo by retrieving the user's calendars. */ public CalendarRetrieveEventsDemo() { mainPanel = new FlexTable(); initWidget(mainPanel); if (!GData.isLoaded(GDataSystemPackage.CALENDAR)) { showStatus("Loading the GData Calendar package...", false); GData.loadGDataApi(GDATA_API_KEY, new Runnable() { public void run() { startDemo(); } }, GDataSystemPackage.CALENDAR); } else { startDemo(); } } /** * Retrieve the Calendar events feed using the Calendar service and * the events feed uri. In GData all get, insert, update and delete methods * always receive a callback defining success and failure handlers. * Here, the failure handler displays an error message while the * success handler calls showData to display the event entries. * * @param eventsFeedUri The uri of the events feed */ private void getEvents(String eventsFeedUri) { showStatus("Loading events feed...", false); service.getEventsFeed(eventsFeedUri, new CalendarEventFeedCallback() { public void onFailure(CallErrorException caught) { showStatus("An error occurred while retrieving the Events feed: " + caught.getMessage(), true); } public void onSuccess(CalendarEventFeed result) { CalendarEventEntry[] entries = (CalendarEventEntry[]) result.getEntries(); if (entries.length == 0) { showStatus("There are no Calendar events.", false); } else { showData(entries); } } }); } /** * Displays a set of Calendar event entries in a tabular fashion with * the help of a GWT FlexTable widget. The data fields Title, URL * and Updated are displayed. * * @param entries The Calendar event entries to display. */ private void showData(CalendarEventEntry[] entries) { mainPanel.clear(); String[] labels = new String[] { "Title", "URL", "Updated" }; mainPanel.insertRow(0); for (int i = 0; i < labels.length; i++) { mainPanel.addCell(0); mainPanel.setWidget(0, i, new Label(labels[i])); mainPanel.getFlexCellFormatter().setStyleName(0, i, "hm-tableheader"); } for (int i = 0; i < entries.length; i++) { CalendarEventEntry entry = entries[i]; int row = mainPanel.insertRow(i + 1); mainPanel.addCell(row); mainPanel.setWidget(row, 0, new Label(entry.getTitle().getText())); mainPanel.addCell(row); String link = entry.getHtmlLink().getHref(); mainPanel.setWidget(row, 1, new HTML("<a href=\"" + link + "\">" + link + "</a>")); mainPanel.addCell(row); mainPanel.setWidget(row, 2, new Label(entry.getUpdated().getValue().getDate().toString())); } } /** * Displays a status message to the user. * * @param message The message to display. * @param isError Indicates whether the status is an error status. */ private void showStatus(String message, boolean isError) { mainPanel.clear(); mainPanel.insertRow(0); mainPanel.addCell(0); Label msg = new Label(message); if (isError) { msg.setStylePrimaryName("hm-error"); } mainPanel.setWidget(0, 0, msg); } /** * Starts this demo. */ private void startDemo() { service = CalendarService.newInstance("HelloGData_Calendar_RetrieveEventsDemo_v2.0"); if (User.getStatus(scope) == AuthSubStatus.LOGGED_IN) { getEvents("http://www.google.com/calendar/feeds/default/private/full"); } else { showStatus("You are not logged on to Google Calendar.", true); } } }