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.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.gdata.client.GData; import com.google.gwt.gdata.client.GDataSystemPackage; import com.google.gwt.gdata.client.atom.Text; import com.google.gwt.gdata.client.contacts.ContactGroupEntry; import com.google.gwt.gdata.client.contacts.ContactGroupEntryCallback; import com.google.gwt.gdata.client.contacts.ContactGroupFeed; import com.google.gwt.gdata.client.contacts.ContactGroupFeedCallback; import com.google.gwt.gdata.client.contacts.ContactsService; import com.google.gwt.gdata.client.impl.CallErrorException; import com.google.gwt.user.client.ui.Button; import com.google.gwt.user.client.ui.FlexTable; import com.google.gwt.user.client.ui.Label; /** * The following example demonstrates how to update a contact group. */ public class ContactsUpdateContactGroupDemo 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 ContactsUpdateContactGroupDemo(); } @Override public String getDescription() { return "<p>This sample demonstrates how to update a contact group " + "entry. It obtains the first contact group entry that has a " + "title that starts with 'GWT-Contacts-Client' and updates its " + "title.</p>"; } @Override public String getName() { return "Contacts - Updating contact groups"; } }; } 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 retrieving the user's contact groups. */ public ContactsUpdateContactGroupDemo() { 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(); } } /** * Retrieve the contact groups feed using the Contacts service and * the contact groups feed uri. * On success, obtain the first group entry with a title starting * with "GWT-Contacts-Client", this is the group that will be updated. * If no contact group is found, display a message. * Otherwise call updateContactGroup to update the group. * * @param contactGroupsFeedUri The contact groups feed uri */ private void getContactGroups(String contactGroupsFeedUri) { showStatus("Loading contact groups feed...", false); service.getContactGroupFeed(contactGroupsFeedUri, new ContactGroupFeedCallback() { public void onFailure(CallErrorException caught) { showStatus( "An error occurred while retrieving the contact groups " + "feed: " + caught.getMessage(), true); } public void onSuccess(ContactGroupFeed result) { ContactGroupEntry[] entries = result.getEntries(); ContactGroupEntry targetGroup = null; for (ContactGroupEntry contact : entries) { String title = contact.getTitle().getText(); if (title.startsWith("GWT-Contacts-Client")) { targetGroup = contact; break; } } if (targetGroup == null) { showStatus( "No contacts groups were found with a title starting " + "with 'GWT-Contacts-Client'.", false); } else { updateContactGroup(targetGroup); } } }); } /** * 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); } /** * Update a contact group by making use of the updateEntry * method of the Entry class. * Set the group's title to an arbitrary string. Here * we prefix the title with 'GWT-Contacts-Client' so that * we can identify which groups were updated by this demo. * On success and failure, display a status message. * * @param targetGroup The contact group entry which to update */ private void updateContactGroup(ContactGroupEntry targetGroup) { showStatus("Updating a contact group...", false); targetGroup.setTitle(Text.newInstance()); targetGroup.getTitle().setText("GWT-Contacts-Client - updated group"); targetGroup.updateEntry(new ContactGroupEntryCallback() { public void onFailure(CallErrorException caught) { showStatus("An error occurred while updating a contact group: " + caught.getMessage(), true); } public void onSuccess(ContactGroupEntry result) { showStatus("Updated a contact group.", false); } }); } /** * Starts this demo. */ private void startDemo() { service = ContactsService.newInstance("HelloGData_Contacts_UpdateContactGroupDemo_v2.0"); if (User.getStatus(scope) == AuthSubStatus.LOGGED_IN) { Button startButton = new Button("Update a contact group"); startButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { getContactGroups("http://www.google.com/m8/feeds/groups/default/full"); } }); mainPanel.setWidget(0, 0, startButton); } else { showStatus("You are not logged on to Google Contacts.", true); } } }