Java tutorial
/******************************************************************************* * Copyright (c) 2014 Ricki Hirner (bitfire web engineering). * All rights reserved. This program and the accompanying materials * are made available under the terms of the GNU Public License v3.0 * which accompanies this distribution, and is available at * http://www.gnu.org/licenses/gpl.html * * Contributors: * Richard Hirner (bitfire web engineering) - initial API and implementation ******************************************************************************/ package at.bitfire.davdroid.mirakel.syncadapter; import java.io.Closeable; import java.io.IOException; import java.util.Map; import java.util.concurrent.locks.ReentrantReadWriteLock; import lombok.Getter; import org.apache.http.HttpStatus; import android.accounts.Account; import android.accounts.AccountManager; import android.content.AbstractThreadedSyncAdapter; import android.content.ContentProviderClient; import android.content.ContentResolver; import android.content.Context; import android.content.SharedPreferences; import android.content.SyncResult; import android.os.AsyncTask; import android.os.Bundle; import android.preference.PreferenceManager; import android.provider.Settings; import android.util.Log; import at.bitfire.davdroid.mirakel.Constants; import at.bitfire.davdroid.mirakel.resource.LocalCollection; import at.bitfire.davdroid.mirakel.resource.LocalStorageException; import at.bitfire.davdroid.mirakel.resource.RemoteCollection; import at.bitfire.davdroid.mirakel.webdav.DavException; import at.bitfire.davdroid.mirakel.webdav.DavHttpClient; import at.bitfire.davdroid.mirakel.webdav.HttpException; import ch.boye.httpclientandroidlib.impl.client.CloseableHttpClient; public abstract class DavSyncAdapter extends AbstractThreadedSyncAdapter implements Closeable { private final static String TAG = "davdroid.DavSyncAdapter"; @Getter private static String androidID; protected AccountManager accountManager; /* We use one static httpClient for * - all sync adapters (CalendarsSyncAdapter, ContactsSyncAdapter) * - and all threads (= accounts) of each sync adapter * so that HttpClient's threaded pool management can do its best. */ protected static CloseableHttpClient httpClient; /* One static read/write lock pair for the static httpClient: * Use the READ lock when httpClient will only be called (to prevent it from being unset while being used). * Use the WRITE lock when httpClient will be modified (set/unset). */ private final static ReentrantReadWriteLock httpClientLock = new ReentrantReadWriteLock(); public DavSyncAdapter(Context context) { super(context, true); synchronized (this) { if (androidID == null) androidID = Settings.Secure.getString(context.getContentResolver(), Settings.Secure.ANDROID_ID); } accountManager = AccountManager.get(context); } @Override public void close() { Log.d(TAG, "Closing httpClient"); // may be called from a GUI thread, so we need an AsyncTask new AsyncTask<Void, Void, Void>() { @Override protected Void doInBackground(Void... params) { try { httpClientLock.writeLock().lock(); if (httpClient != null) { httpClient.close(); httpClient = null; } httpClientLock.writeLock().unlock(); } catch (IOException e) { Log.w(TAG, "Couldn't close HTTP client", e); } return null; } }.execute(); } protected abstract Map<LocalCollection<?>, RemoteCollection<?>> getSyncPairs(Account account, ContentProviderClient provider); @Override public void onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult) { Log.i(TAG, "Performing sync for authority " + authority); // set class loader for iCal4j ResourceLoader Thread.currentThread().setContextClassLoader(getContext().getClassLoader()); // create httpClient, if necessary httpClientLock.writeLock().lock(); if (httpClient == null) { Log.d(TAG, "Creating new DavHttpClient"); SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(getContext()); httpClient = DavHttpClient.create(settings.getBoolean(Constants.SETTING_DISABLE_COMPRESSION, false), settings.getBoolean(Constants.SETTING_NETWORK_LOGGING, false)); } // prevent httpClient shutdown until we're ready by holding a read lock // acquiring read lock before releasing write lock will downgrade the write lock to a read lock httpClientLock.readLock().lock(); httpClientLock.writeLock().unlock(); // TODO use VCard 4.0 if possible AccountSettings accountSettings = new AccountSettings(getContext(), account); Log.d(TAG, "Server supports VCard version " + accountSettings.getAddressBookVCardVersion()); try { // get local <-> remote collection pairs Map<LocalCollection<?>, RemoteCollection<?>> syncCollections = getSyncPairs(account, provider); if (syncCollections == null) Log.i(TAG, "Nothing to synchronize"); else try { for (Map.Entry<LocalCollection<?>, RemoteCollection<?>> entry : syncCollections.entrySet()) new SyncManager(entry.getKey(), entry.getValue()) .synchronize(extras.containsKey(ContentResolver.SYNC_EXTRAS_MANUAL), syncResult); } catch (DavException ex) { syncResult.stats.numParseExceptions++; Log.e(TAG, "Invalid DAV response", ex); } catch (HttpException ex) { if (ex.getCode() == HttpStatus.SC_UNAUTHORIZED) { Log.e(TAG, "HTTP Unauthorized " + ex.getCode(), ex); syncResult.stats.numAuthExceptions++; } else if (ex.isClientError()) { Log.e(TAG, "Hard HTTP error " + ex.getCode(), ex); syncResult.stats.numParseExceptions++; } else { Log.w(TAG, "Soft HTTP error " + ex.getCode() + " (Android will try again later)", ex); syncResult.stats.numIoExceptions++; } } catch (LocalStorageException ex) { syncResult.databaseError = true; Log.e(TAG, "Local storage (content provider) exception", ex); } catch (IOException ex) { syncResult.stats.numIoExceptions++; Log.e(TAG, "I/O error (Android will try again later)", ex); } } finally { // allow httpClient shutdown httpClientLock.readLock().unlock(); } Log.i(TAG, "Sync complete for " + authority); } }