Java tutorial
/* * Copyright (c) 2012 Washington State Department of Transportation * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/> * */ package gov.wa.wsdot.android.wsdot.service; import gov.wa.wsdot.android.wsdot.provider.WSDOTContract.Caches; import gov.wa.wsdot.android.wsdot.provider.WSDOTContract.Cameras; import java.io.BufferedInputStream; import java.io.BufferedReader; import java.io.InputStreamReader; import java.net.URL; import java.net.URLConnection; import java.util.ArrayList; import java.util.List; import java.util.zip.GZIPInputStream; import org.json.JSONArray; import org.json.JSONObject; import android.app.IntentService; import android.content.ContentResolver; import android.content.ContentValues; import android.content.Intent; import android.database.Cursor; import android.text.format.DateUtils; import android.util.Log; public class CamerasSyncService extends IntentService { private static final String DEBUG_TAG = "CamerasSyncService"; private static final String CAMERAS_URL = "http://data.wsdot.wa.gov/mobile/Cameras.js.gz"; private String[] projection = { Caches.CACHE_LAST_UPDATED }; public CamerasSyncService() { super("CamerasSyncService"); } @Override protected void onHandleIntent(Intent intent) { ContentResolver resolver = getContentResolver(); Cursor cursor = null; long now = System.currentTimeMillis(); boolean shouldUpdate = true; String responseString = ""; /** * Check the cache table for the last time data was downloaded. If we are within * the allowed time period, don't sync, otherwise get fresh data from the server. */ try { cursor = resolver.query(Caches.CONTENT_URI, projection, Caches.CACHE_TABLE_NAME + " LIKE ?", new String[] { "cameras" }, null); if (cursor != null && cursor.moveToFirst()) { long lastUpdated = cursor.getLong(0); //long deltaDays = (now - lastUpdated) / DateUtils.DAY_IN_MILLIS; //Log.d(DEBUG_TAG, "Delta since last update is " + deltaDays + " day(s)"); shouldUpdate = (Math.abs(now - lastUpdated) > (7 * DateUtils.DAY_IN_MILLIS)); } } finally { if (cursor != null) { cursor.close(); } } // Ability to force a refresh of camera data. boolean forceUpdate = intent.getBooleanExtra("forceUpdate", false); if (shouldUpdate || forceUpdate) { List<Integer> starred = new ArrayList<Integer>(); starred = getStarred(); try { URL url = new URL(CAMERAS_URL); URLConnection urlConn = url.openConnection(); BufferedInputStream bis = new BufferedInputStream(urlConn.getInputStream()); GZIPInputStream gzin = new GZIPInputStream(bis); InputStreamReader is = new InputStreamReader(gzin); BufferedReader in = new BufferedReader(is); String jsonFile = ""; String line; while ((line = in.readLine()) != null) jsonFile += line; in.close(); JSONObject obj = new JSONObject(jsonFile); JSONObject result = obj.getJSONObject("cameras"); JSONArray items = result.getJSONArray("items"); List<ContentValues> cams = new ArrayList<ContentValues>(); int numItems = items.length(); for (int j = 0; j < numItems; j++) { JSONObject item = items.getJSONObject(j); ContentValues cameraData = new ContentValues(); cameraData.put(Cameras.CAMERA_ID, item.getString("id")); cameraData.put(Cameras.CAMERA_TITLE, item.getString("title")); cameraData.put(Cameras.CAMERA_URL, item.getString("url")); cameraData.put(Cameras.CAMERA_LATITUDE, item.getString("lat")); cameraData.put(Cameras.CAMERA_LONGITUDE, item.getString("lon")); cameraData.put(Cameras.CAMERA_HAS_VIDEO, item.getString("video")); cameraData.put(Cameras.CAMERA_ROAD_NAME, item.getString("roadName")); if (starred.contains(Integer.parseInt(item.getString("id")))) { cameraData.put(Cameras.CAMERA_IS_STARRED, 1); } cams.add(cameraData); } // Purge existing cameras covered by incoming data resolver.delete(Cameras.CONTENT_URI, null, null); // Bulk insert all the new cameras resolver.bulkInsert(Cameras.CONTENT_URI, cams.toArray(new ContentValues[cams.size()])); // Update the cache table with the time we did the update ContentValues values = new ContentValues(); values.put(Caches.CACHE_LAST_UPDATED, System.currentTimeMillis()); resolver.update(Caches.CONTENT_URI, values, Caches.CACHE_TABLE_NAME + " LIKE ?", new String[] { "cameras" }); responseString = "OK"; } catch (Exception e) { Log.e(DEBUG_TAG, "Error: " + e.getMessage()); responseString = e.getMessage(); } } else { responseString = "NOP"; } Intent broadcastIntent = new Intent(); broadcastIntent.setAction("gov.wa.wsdot.android.wsdot.intent.action.CAMERAS_RESPONSE"); broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT); broadcastIntent.putExtra("responseString", responseString); sendBroadcast(broadcastIntent); } /** * Check the camera table for any starred entries. If we find some, save them * to a list so we can re-star those cameras after we flush the database. */ private List<Integer> getStarred() { ContentResolver resolver = getContentResolver(); Cursor cursor = null; List<Integer> starred = new ArrayList<Integer>(); try { cursor = resolver.query(Cameras.CONTENT_URI, new String[] { Cameras.CAMERA_ID }, Cameras.CAMERA_IS_STARRED + "=?", new String[] { "1" }, null); if (cursor != null && cursor.moveToFirst()) { while (!cursor.isAfterLast()) { starred.add(cursor.getInt(0)); cursor.moveToNext(); } } } finally { if (cursor != null) { cursor.close(); } } return starred; } }