Java tutorial
/* * Copyright 2014 sonaive.com. All rights reserved. * * 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.sonaive.v2ex.sync; import android.content.ContentProviderOperation; import android.content.ContentResolver; import android.content.Context; import android.content.OperationApplicationException; import android.net.Uri; import android.os.Bundle; import android.os.RemoteException; import com.google.gson.JsonParser; import com.google.gson.stream.JsonReader; import com.sonaive.v2ex.io.FeedsHandler; import com.sonaive.v2ex.io.JSONHandler; import com.sonaive.v2ex.io.MembersHandler; import com.sonaive.v2ex.io.NodesHandler; import com.sonaive.v2ex.io.ReviewsHandler; import com.sonaive.v2ex.provider.V2exContract; import java.io.IOException; import java.io.StringReader; import java.util.ArrayList; import java.util.HashMap; import static com.sonaive.v2ex.util.LogUtils.LOGD; import static com.sonaive.v2ex.util.LogUtils.LOGE; import static com.sonaive.v2ex.util.LogUtils.makeLogTag; /** * Created by liutao on 12/10/14. */ public class V2exDataHandler { private static final String TAG = makeLogTag(V2exDataHandler.class); public static final String ARG_DATA_KEY = "arg_data_key"; public static final String DATA_KEY_MEMBERS = "members"; public static final String DATA_KEY_FEEDS = "feeds"; public static final String DATA_KEY_NODES = "nodes"; public static final String DATA_KEY_REVIEWS = "reviews"; private static final String[] DATA_KEYS_IN_ORDER = { DATA_KEY_MEMBERS, DATA_KEY_FEEDS, DATA_KEY_NODES, DATA_KEY_REVIEWS }; Context mContext = null; // Handlers for each entity type: MembersHandler mMembersHandler = null; FeedsHandler mFeedsHandler = null; NodesHandler mNodesHandler = null; ReviewsHandler mReviewsHandler = null; // Convenience map that maps the key name to its corresponding handler (e.g. // "blocks" to mBlocksHandler (to avoid very tedious if-elses) HashMap<String, JSONHandler> mHandlerForKey = new HashMap<>(); // Tally of total content provider operations we carried out (for statistical purposes) private int mContentProviderOperationsDone = 0; public V2exDataHandler(Context ctx) { mContext = ctx; } /** * Parses the data in the given objects and imports the data into the * content provider. * * @param dataBodies The collection of JSON objects to parse and import. * @throws java.io.IOException If there is a problem parsing the data. */ public void applyData(Bundle[] dataBodies) throws IOException { LOGD(TAG, "Applying data from " + dataBodies.length + " files"); // create handlers for each data type mHandlerForKey.put(DATA_KEY_MEMBERS, mMembersHandler = new MembersHandler(mContext)); mHandlerForKey.put(DATA_KEY_FEEDS, mFeedsHandler = new FeedsHandler(mContext)); mHandlerForKey.put(DATA_KEY_NODES, mNodesHandler = new NodesHandler(mContext)); mHandlerForKey.put(DATA_KEY_REVIEWS, mReviewsHandler = new ReviewsHandler(mContext)); // process the jsons. This will call each of the handlers when appropriate to deal // with the objects we see in the data. LOGD(TAG, "Processing " + dataBodies.length + " JSON objects."); for (int i = 0; i < dataBodies.length; i++) { LOGD(TAG, "Processing json object #" + (i + 1) + " of " + dataBodies.length); String key = dataBodies[i].getString(V2exDataHandler.ARG_DATA_KEY); processDataBody(dataBodies[i], key); } // produce the necessary content provider operations ArrayList<ContentProviderOperation> batch = new ArrayList<ContentProviderOperation>(); for (String dataKey : DATA_KEYS_IN_ORDER) { LOGD(TAG, "Building content provider operations for: " + dataKey); mHandlerForKey.get(dataKey).makeContentProviderOperations(batch); LOGD(TAG, "Content provider operations so far: " + batch.size()); } LOGD(TAG, "Total content provider operations: " + batch.size()); // finally, push the changes into the Content Provider LOGD(TAG, "Applying " + batch.size() + " content provider operations."); try { int operations = batch.size(); if (operations > 0) { mContext.getContentResolver().applyBatch(V2exContract.CONTENT_AUTHORITY, batch); } LOGD(TAG, "Successfully applied " + operations + " content provider operations."); mContentProviderOperationsDone += operations; } catch (RemoteException ex) { LOGE(TAG, "RemoteException while applying content provider operations."); throw new RuntimeException("Error executing content provider batch operation", ex); } catch (OperationApplicationException ex) { LOGE(TAG, "OperationApplicationException while applying content provider operations."); throw new RuntimeException("Error executing content provider batch operation", ex); } // notify all top-level paths LOGD(TAG, "Notifying changes on all top-level paths on Content Resolver."); ContentResolver resolver = mContext.getContentResolver(); for (String path : V2exContract.TOP_LEVEL_PATHS) { Uri uri = V2exContract.BASE_CONTENT_URI.buildUpon().appendPath(path).build(); resolver.notifyChange(uri, null); } LOGD(TAG, "Done applying data."); } public int getContentProviderOperationsDone() { return mContentProviderOperationsDone; } /** * Processes data body and calls the appropriate data type handlers * to process each of the objects represented therein. * * @param dataBundle The body of data to process * @throws IOException If there is an error parsing the data. */ private void processDataBody(Bundle dataBundle, String key) throws IOException { if (mHandlerForKey.containsKey(key)) { String dataBody = mHandlerForKey.get(key).getBody(dataBundle); JsonReader reader = new JsonReader(new StringReader(dataBody)); JsonParser parser = new JsonParser(); // pass the value to the corresponding handler mHandlerForKey.get(key).process(parser.parse(reader)); } } }