Java tutorial
/* * Copyright 2011 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 org.androidtitlan.estoesgoogle.service; import java.io.IOException; import java.io.InputStream; import java.util.zip.GZIPInputStream; import org.androidtitlan.estoesgoogle.io.LocalBlocksHandler; import org.androidtitlan.estoesgoogle.io.LocalExecutor; import org.androidtitlan.estoesgoogle.io.LocalRoomsHandler; import org.androidtitlan.estoesgoogle.io.LocalSearchSuggestHandler; import org.androidtitlan.estoesgoogle.io.LocalSessionsHandler; import org.androidtitlan.estoesgoogle.io.LocalSpeakersHandler; import org.androidtitlan.estoesgoogle.io.LocalTracksHandler; import org.androidtitlan.estoesgoogle.provider.ScheduleProvider; import org.apache.http.Header; import org.apache.http.HeaderElement; import org.apache.http.HttpEntity; import org.apache.http.HttpRequest; import org.apache.http.HttpRequestInterceptor; import org.apache.http.HttpResponse; import org.apache.http.HttpResponseInterceptor; import org.apache.http.client.HttpClient; import org.apache.http.entity.HttpEntityWrapper; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.params.BasicHttpParams; import org.apache.http.params.HttpConnectionParams; import org.apache.http.params.HttpParams; import org.apache.http.params.HttpProtocolParams; import org.apache.http.protocol.HttpContext; import android.app.IntentService; import android.app.Service; import android.content.ContentResolver; import android.content.Context; import android.content.Intent; import android.content.SharedPreferences; import android.content.pm.PackageInfo; import android.content.pm.PackageManager; import android.content.pm.PackageManager.NameNotFoundException; import android.content.res.Resources; import android.os.Bundle; import android.os.ResultReceiver; import android.text.format.DateUtils; import android.util.Log; import org.androidtitlan.estoesgoogle.R; /** * Background {@link Service} that synchronizes data living in * {@link ScheduleProvider}. Reads data from both local {@link Resources} and * from remote sources, such as a spreadsheet. */ public class SyncService extends IntentService { private static final String TAG = "SyncService"; public static final String EXTRA_STATUS_RECEIVER = "com.google.android.iosched.extra.STATUS_RECEIVER"; public static final int STATUS_RUNNING = 0x1; public static final int STATUS_ERROR = 0x2; public static final int STATUS_FINISHED = 0x3; private static final int SECOND_IN_MILLIS = (int) DateUtils.SECOND_IN_MILLIS; private static final String HEADER_ACCEPT_ENCODING = "Accept-Encoding"; private static final String ENCODING_GZIP = "gzip"; private static final int VERSION_CURRENT = 11; private LocalExecutor mLocalExecutor; public SyncService() { super(TAG); } @Override public void onCreate() { super.onCreate(); final ContentResolver resolver = getContentResolver(); mLocalExecutor = new LocalExecutor(getResources(), resolver); } @Override protected void onHandleIntent(Intent intent) { Log.d(TAG, "onHandleIntent(intent=" + intent.toString() + ")"); final ResultReceiver receiver = intent.getParcelableExtra(EXTRA_STATUS_RECEIVER); if (receiver != null) receiver.send(STATUS_RUNNING, Bundle.EMPTY); final SharedPreferences prefs = getSharedPreferences(Prefs.IOSCHED_SYNC, Context.MODE_PRIVATE); try { // Bulk of sync work, performed by executing several fetches from // local sources. // Load static local data mLocalExecutor.execute(R.xml.blocks, new LocalBlocksHandler()); mLocalExecutor.execute(R.xml.speakers, new LocalSpeakersHandler()); mLocalExecutor.execute(R.xml.rooms, new LocalRoomsHandler()); mLocalExecutor.execute(R.xml.tracks, new LocalTracksHandler()); mLocalExecutor.execute(R.xml.search_suggest, new LocalSearchSuggestHandler()); mLocalExecutor.execute(R.xml.sessions, new LocalSessionsHandler()); // Save local parsed version prefs.edit().putInt(Prefs.LOCAL_VERSION, VERSION_CURRENT).commit(); } catch (Exception e) { Log.e(TAG, "Problem while syncing", e); if (receiver != null) { // Pass back error to surface listener final Bundle bundle = new Bundle(); bundle.putString(Intent.EXTRA_TEXT, e.toString()); receiver.send(STATUS_ERROR, bundle); } } // Announce success to any surface listener Log.d(TAG, "sync finished"); if (receiver != null) receiver.send(STATUS_FINISHED, Bundle.EMPTY); } /** * Generate and return a {@link HttpClient} configured for general use, * including setting an application-specific user-agent string. */ public static HttpClient getHttpClient(Context context) { final HttpParams params = new BasicHttpParams(); // Use generous timeouts for slow mobile networks HttpConnectionParams.setConnectionTimeout(params, 20 * SECOND_IN_MILLIS); HttpConnectionParams.setSoTimeout(params, 20 * SECOND_IN_MILLIS); HttpConnectionParams.setSocketBufferSize(params, 8192); HttpProtocolParams.setUserAgent(params, buildUserAgent(context)); final DefaultHttpClient client = new DefaultHttpClient(params); client.addRequestInterceptor(new HttpRequestInterceptor() { public void process(HttpRequest request, HttpContext context) { // Add header to accept gzip content if (!request.containsHeader(HEADER_ACCEPT_ENCODING)) { request.addHeader(HEADER_ACCEPT_ENCODING, ENCODING_GZIP); } } }); client.addResponseInterceptor(new HttpResponseInterceptor() { public void process(HttpResponse response, HttpContext context) { // Inflate any responses compressed with gzip final HttpEntity entity = response.getEntity(); final Header encoding = entity.getContentEncoding(); if (encoding != null) { for (HeaderElement element : encoding.getElements()) { if (element.getName().equalsIgnoreCase(ENCODING_GZIP)) { response.setEntity(new InflatingEntity(response.getEntity())); break; } } } } }); return client; } /** * Build and return a user-agent string that can identify this application * to remote servers. Contains the package name and version code. */ private static String buildUserAgent(Context context) { try { final PackageManager manager = context.getPackageManager(); final PackageInfo info = manager.getPackageInfo(context.getPackageName(), 0); // Some APIs require "(gzip)" in the user-agent string. return info.packageName + "/" + info.versionName + " (" + info.versionCode + ") (gzip)"; } catch (NameNotFoundException e) { return null; } } /** * Simple {@link HttpEntityWrapper} that inflates the wrapped * {@link HttpEntity} by passing it through {@link GZIPInputStream}. */ private static class InflatingEntity extends HttpEntityWrapper { public InflatingEntity(HttpEntity wrapped) { super(wrapped); } @Override public InputStream getContent() throws IOException { return new GZIPInputStream(wrappedEntity.getContent()); } @Override public long getContentLength() { return -1; } } private interface Prefs { String IOSCHED_SYNC = "iosched_sync"; String LOCAL_VERSION = "local_version"; } }