service

来源：互联网发布：java正则校验时间格式编辑：程序博客网时间：2024/06/02 12:35

/* * Copyright (C) 2009 Jeff Sharkey, http://jsharkey.org/ * * 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.jsharkey.sky; import java.util.LinkedList; import java.util.Queue; import org.jsharkey.sky.ForecastProvider.AppWidgets; import org.jsharkey.sky.ForecastProvider.AppWidgetsColumns; import org.jsharkey.sky.webservice.WebserviceHelper; import org.jsharkey.sky.webservice.Forecast.ParseException; import android.app.AlarmManager; import android.app.PendingIntent; import android.app.Service; import android.appwidget.AppWidgetManager; import android.appwidget.AppWidgetProviderInfo; import android.content.ComponentName; import android.content.ContentResolver; import android.content.ContentUris; import android.content.Context; import android.content.Intent; import android.database.Cursor; import android.net.Uri; import android.os.IBinder; import android.text.format.DateUtils; import android.text.format.Time; import android.util.Log; import android.widget.RemoteViews; /** * Background service to build any requested widget updates. Uses a single * background thread to walk through an update queue, querying * {@link WebserviceHelper} as needed to fill database. Also handles scheduling * of future updates, usually in 6-hour increments. */ public class UpdateService extends Service implements Runnable { private static final String TAG = "UpdateService"; private static final String[] PROJECTION_APPWIDGETS = new String[] { AppWidgetsColumns.CONFIGURED, AppWidgetsColumns.LAST_UPDATED, }; private static final int COL_CONFIGURED = 0; private static final int COL_LAST_UPDATED = 1; /** * Interval to wait between background widget updates. Every 6 hours is * plenty to keep background data usage low and still provide fresh data. */ private static final long UPDATE_INTERVAL = 6 * DateUtils.HOUR_IN_MILLIS; /** * When rounding updates to the nearest-top-of-hour, trigger the update * slightly early by this amount. This makes sure that we're already updated * when the user's 6AM alarm clock goes off. */ private static final long UPDATE_TRIGGER_EARLY = 10 * DateUtils.MINUTE_IN_MILLIS; /** * If we calculated an update too quickly in the future, wait this interval * and try rescheduling. */ private static final long UPDATE_THROTTLE = 30 * DateUtils.MINUTE_IN_MILLIS; /** * Specific {@link Intent#setAction(String)} used when performing a full * update of all widgets, usually when an update alarm goes off. */ public static final String ACTION_UPDATE_ALL = "org.jsharkey.sky.UPDATE_ALL"; /** * Length of time before we consider cached forecasts stale. If a widget * update is requested, and {@link AppWidgetsColumns#LAST_UPDATED} is inside * this threshold, we use the cached forecast data to build the update. * Otherwise, we first trigger an update through {@link WebserviceHelper}. */ private static final long FORECAST_CACHE_THROTTLE = 3 * DateUtils.HOUR_IN_MILLIS; /** * Number of days into the future to request forecasts for. */ private static final int FORECAST_DAYS = 4; /** * Lock used when maintaining queue of requested updates. */ private static Object sLock = new Object(); /** * Flag if there is an update thread already running. We only launch a new * thread if one isn't already running. */ private static boolean sThreadRunning = false; /** * Internal queue of requested widget updates. You must access * through {@link #requestUpdate(int[])} or {@link #getNextUpdate()} to make * sure your access is correctly synchronized. */ private static Queue sAppWidgetIds = new LinkedList(); /** * Request updates for the given widgets. Will only queue them up, you are * still responsible for starting a processing thread if needed, usually by * starting the parent service. */ public static void requestUpdate(int[] appWidgetIds) { synchronized (sLock) { for (int appWidgetId : appWidgetIds) { sAppWidgetIds.add(appWidgetId); } } } /** * Peek if we have more updates to perform. This method is special because * it assumes you're calling from the update thread, and that you will * terminate if no updates remain. (It atomically resets * {@link #sThreadRunning} when none remain to prevent race conditions.) */ private static boolean hasMoreUpdates() { synchronized (sLock) { boolean hasMore = !sAppWidgetIds.isEmpty(); if (!hasMore) { sThreadRunning = false; } return hasMore; } } /** * Poll the next widget update in the queue. */ private static int getNextUpdate() { synchronized (sLock) { if (sAppWidgetIds.peek() == null) { return AppWidgetManager.INVALID_APPWIDGET_ID; } else { return sAppWidgetIds.poll(); } } } /** * Start this service, creating a background processing thread, if not * already running. If started with {@link #ACTION_UPDATE_ALL}, will * automatically add all widgets to the requested update queue. */ @Override public void onStart(Intent intent, int startId) { super.onStart(intent, startId); // If requested, trigger update of all widgets if (ACTION_UPDATE_ALL.equals(intent.getAction())) { Log.d(TAG, "Requested UPDATE_ALL action"); AppWidgetManager manager = AppWidgetManager.getInstance(this); requestUpdate(manager.getAppWidgetIds(new ComponentName(this, MedAppWidget.class))); requestUpdate(manager.getAppWidgetIds(new ComponentName(this, TinyAppWidget.class))); } // Only start processing thread if not already running synchronized (sLock) { if (!sThreadRunning) { sThreadRunning = true; new Thread(this).start(); } } } /** * Main thread for running through any requested widget updates until none * remain. Also sets alarm to perform next update. */ public void run() { Log.d(TAG, "Processing thread started"); AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(this); ContentResolver resolver = getContentResolver(); long now = System.currentTimeMillis(); while (hasMoreUpdates()) { int appWidgetId = getNextUpdate(); Uri appWidgetUri = ContentUris.withAppendedId(AppWidgets.CONTENT_URI, appWidgetId); // Check if widget is configured, and if we need to update cache Cursor cursor = null; boolean isConfigured = false; boolean shouldUpdate = false; try { cursor = resolver.query(appWidgetUri, PROJECTION_APPWIDGETS, null, null, null); if (cursor != null && cursor.moveToFirst()) { isConfigured = cursor.getInt(COL_CONFIGURED) == AppWidgetsColumns.CONFIGURED_TRUE; long lastUpdated = cursor.getLong(COL_LAST_UPDATED); long deltaMinutes = (now - lastUpdated) / DateUtils.MINUTE_IN_MILLIS; Log.d(TAG, "Delta since last forecast update is " + deltaMinutes + " min"); shouldUpdate = (Math.abs(now - lastUpdated) > FORECAST_CACHE_THROTTLE); } } finally { if (cursor != null) { cursor.close(); } } if (!isConfigured) { // Skip this update if not configured yet Log.d(TAG, "Not configured yet, so skipping update"); continue; } else if (shouldUpdate) { // Last update is outside throttle window, so update again try { WebserviceHelper.updateForecasts(this, appWidgetUri, FORECAST_DAYS); } catch (ParseException e) { Log.e(TAG, "Problem parsing forecast", e); } } // Process this update through the correct provider AppWidgetProviderInfo info = appWidgetManager.getAppWidgetInfo(appWidgetId); String providerName = info.provider.getClassName(); RemoteViews updateViews = null; if (providerName.equals(MedAppWidget.class.getName())) { updateViews = MedAppWidget.buildUpdate(this, appWidgetUri); } else if (providerName.equals(TinyAppWidget.class.getName())) { updateViews = TinyAppWidget.buildUpdate(this, appWidgetUri); } // Push this update to surface if (updateViews != null) { appWidgetManager.updateAppWidget(appWidgetId, updateViews); } } // Schedule next update alarm, usually just before a 6-hour block. This // triggers updates at roughly 5:50AM, 11:50AM, 5:50PM, and 11:50PM. Time time = new Time(); time.set(System.currentTimeMillis() + UPDATE_INTERVAL + UPDATE_TRIGGER_EARLY); time.hour -= (time.hour % 6); time.minute = 0; time.second = 0; long nextUpdate = time.toMillis(false) - UPDATE_TRIGGER_EARLY; long nowMillis = System.currentTimeMillis(); // Throttle our updates just in case the math went funky if (nextUpdate - nowMillis < UPDATE_THROTTLE) { Log.d(TAG, "Calculated next update too early, throttling for a few minutes"); nextUpdate = nowMillis + UPDATE_THROTTLE; } long deltaMinutes = (nextUpdate - nowMillis) / DateUtils.MINUTE_IN_MILLIS; Log.d(TAG, "Requesting next update at " + nextUpdate + ", in " + deltaMinutes + " min"); Intent updateIntent = new Intent(ACTION_UPDATE_ALL); updateIntent.setClass(this, UpdateService.class); PendingIntent pendingIntent = PendingIntent.getService(this, 0, updateIntent, 0); // Schedule alarm, and force the device awake for this update AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE); alarmManager.set(AlarmManager.RTC_WAKEUP, nextUpdate, pendingIntent); // No updates remaining, so stop service stopSelf(); } @Override public IBinder onBind(Intent intent) { return null; } }