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.DateTime; import com.google.gwt.gdata.client.GData; import com.google.gwt.gdata.client.GDataSystemPackage; import com.google.gwt.gdata.client.contacts.ContactEntry; import com.google.gwt.gdata.client.contacts.ContactFeed; import com.google.gwt.gdata.client.contacts.ContactFeedCallback; import com.google.gwt.gdata.client.contacts.ContactQuery; import com.google.gwt.gdata.client.contacts.ContactsService; import com.google.gwt.gdata.client.impl.CallErrorException; import com.google.gwt.user.client.ui.FlexTable; import com.google.gwt.user.client.ui.Label; import java.util.Date; /** * The following example demonstrates how to query for contacts * according to certain criteria. */ public class ContactsRetrieveContactsUsingQueryDemo 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 ContactsRetrieveContactsUsingQueryDemo(); } @Override public String getDescription() { return "<p>This sample demonstrates how to retrieve contact entries " + "using query parameters.</p>"; } @Override public String getName() { return "Contacts - Retrieving contacts using query parameters"; } }; } private ContactsService service; private FlexTable mainPanel; private final String scope = "http://www.google.com/m8/feeds/"; /** * Setup the Contacts service and create the main content panel. * If the user is not logged on to Contacts display a message, * otherwise start the demo by querying the user's contacts. */ public ContactsRetrieveContactsUsingQueryDemo() { mainPanel = new FlexTable(); initWidget(mainPanel); if (!GData.isLoaded(GDataSystemPackage.CONTACTS)) { showStatus("Loading the GData Contacts package...", false); GData.loadGDataApi(GDATA_API_KEY, new Runnable() { public void run() { startDemo(); } }, GDataSystemPackage.CONTACTS); } else { startDemo(); } } /** * Retrieves a contacts feed using a Query object. * In GData, feed URIs can contain querystring parameters. The * GData query objects aid in building parameterized feed URIs. * We query for contacts updated today, sorted descending. * Upon successfully receiving the contacts feed, the contact entries * are displayed to the user via the showData method. * The UpdatedMin and SortOrder parameters are used to limit * the number of contact entries retrieved and to specify how they * should sorted. * * @param contactsFeedUri The contacts feed uri. */ private void queryContacts(String contactsFeedUri) { showStatus("Querying contacts...", false); ContactQuery query = ContactQuery.newInstance(contactsFeedUri); Date today = new Date(); DateTime updatedMin = DateTime.newInstance(today, true); query.setUpdatedMin(updatedMin); query.setSortOrder(ContactQuery.SORTORDER_DESCENDING); service.getContactFeed(query, new ContactFeedCallback() { public void onFailure(CallErrorException caught) { showStatus("An error occurred while retrieving the Contacts feed: " + caught.getMessage(), true); } public void onSuccess(ContactFeed result) { ContactEntry[] entries = result.getEntries(); if (entries.length == 0) { showStatus("No contacts were found that were modified today.", false); } else { showData(entries); } } }); } /** * Displays a set of Google Contacts contact entries in a tabular * fashion with the help of a GWT FlexTable widget. The data fields * Title, Email and Updated are displayed. * * @param entries The Google Contacts contact entries to display. */ private void showData(ContactEntry[] entries) { mainPanel.clear(); String[] labels = new String[] { "Title", "Email", "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++) { ContactEntry 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 email = ""; if (entry.getEmailAddresses().length > 0) { email = entry.getEmailAddresses()[0].getAddress(); } mainPanel.setWidget(row, 1, new Label(email)); 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 = ContactsService.newInstance("HelloGData_Contacts_RetrieveContactsUsingQueryDemo_v2.0"); if (User.getStatus(scope) == AuthSubStatus.LOGGED_IN) { queryContacts("http://www.google.com/m8/feeds/contacts/default/full"); } else { showStatus("You are not logged on to Google Contacts.", true); } } }