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.PostalAddress; import com.google.gwt.gdata.client.atom.Text; import com.google.gwt.gdata.client.impl.CallErrorException; import com.google.gwt.gdata.client.maps.FeatureEntry; import com.google.gwt.gdata.client.maps.FeatureEntryCallback; import com.google.gwt.gdata.client.maps.KmlContent; import com.google.gwt.gdata.client.maps.MapEntry; import com.google.gwt.gdata.client.maps.MapFeed; import com.google.gwt.gdata.client.maps.MapFeedCallback; import com.google.gwt.gdata.client.maps.MapsService; 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 create a map feature. */ public class MapsCreateMapFeatureDemo 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 MapsCreateMapFeatureDemo(); } @Override public String getDescription() { return "<p>This sample code demonstrates how to create and insert " + "a new map feature. It retrieves a list of the user's maps and " + "inserts a feature with a title that starts with " + "'GWT-Maps-Client'.</p>"; } @Override public String getName() { return "Maps - Creating a map feature"; } }; } private MapsService service; private FlexTable mainPanel; private final String scope = "http://maps.google.com/maps/feeds/maps/"; /** * Setup the Google Maps service and create the main content panel. * If the user is not logged on to Google Maps display a message, * otherwise start the demo by retrieving the user's maps. */ public MapsCreateMapFeatureDemo() { mainPanel = new FlexTable(); initWidget(mainPanel); if (!GData.isLoaded(GDataSystemPackage.MAPS)) { showStatus("Loading the GData Maps package...", false); GData.loadGDataApi(GDATA_API_KEY, new Runnable() { public void run() { startDemo(); } }, GDataSystemPackage.MAPS); } else { startDemo(); } } /** * Retrieve the maps feed using the Maps service and * the maps 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 obtains the first map entry with a title * starting with "GWT-Maps-Client" and calls insertMapFeature to * insert a map feature into the map. * If no map is found, a message is displayed. * * @param mapsFeedUri The uri of the map feed */ private void getMaps(String mapsFeedUri) { showStatus("Loading maps feed...", false); service.getMapFeed(mapsFeedUri, new MapFeedCallback() { public void onFailure(CallErrorException caught) { showStatus("An error occurred while retrieving the maps feed: " + caught.getMessage(), true); } public void onSuccess(MapFeed result) { MapEntry[] entries = result.getEntries(); MapEntry targetMap = null; for (MapEntry entry : entries) { if (entry.getTitle().getText().startsWith("GWT-Maps-Client")) { targetMap = entry; break; } } if (targetMap == null) { showStatus("No map found that contains 'GWT-Maps-Client' in the title.", false); } else { String mapEntryUri = targetMap.getId().getValue(); insertMapFeature(mapEntryUri); } } }); } /** * Create a feature by inserting a feature entry into * a feature feed for a given map. * Set the feature's title to an arbitrary string. Here * we prefix the title with 'GWT-Maps-Client' so that * we can identify which features were created by this demo. * A value is also provided for the feature's postal address * along with the KML content which defines the placemarks * for this feature. * On success and failure, display a status message. * * @param mapId The id of the map into which to insert the * new feature entry */ private void insertMapFeature(String mapId) { showStatus("Creating map feature...", false); FeatureEntry entry = FeatureEntry.newInstance(); entry.setTitle(Text.newInstance()); entry.getTitle().setText("GWT-Maps-Client - inserted feature"); PostalAddress address = PostalAddress.newInstance(); address.setLabel("Google Headquarters"); address.setRel(PostalAddress.REL_WORK); address.setValue("1600 Amphitheatre Parkway\nMountain View, CA 94043"); entry.setPostalAddress(address); KmlContent kml = KmlContent.newInstance(); kml.setType(KmlContent.TYPE_APPLICATION_VND_GOOGLE_EARTH_KML_XML); kml.setText("<Placemark xmlns=\"http://www.opengis.net/kml/2.2\">" + "<name>Faulkner's Birthplace</name>" + "<description/><Point><coordinates>-89.520753,34.360902,0.0" + "</coordinates></Point><" + "/Placemark>"); entry.setContent(kml); String featuresFeedUri = mapId.replace("/feeds/maps/", "/feeds/features/") + "/full"; service.insertEntry(featuresFeedUri, entry, new FeatureEntryCallback() { public void onFailure(CallErrorException caught) { showStatus("An error occurred while creating a map feature: " + caught.getMessage(), true); } public void onSuccess(FeatureEntry result) { showStatus("Created a map feature.", false); } }); } /** * 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 = MapsService.newInstance("HelloGData_Maps_CreateMapFeatureDemo_v2.0"); if (User.getStatus(scope) == AuthSubStatus.LOGGED_IN) { Button startButton = new Button("Create a map feature"); startButton.addClickHandler(new ClickHandler() { public void onClick(ClickEvent event) { getMaps("http://maps.google.com/maps/feeds/maps/default/full"); } }); mainPanel.setWidget(0, 0, startButton); } else { showStatus("You are not logged on to Google Maps.", true); } } }