Java tutorial
/* * Copyright 2014 Artem Chikin * Copyright 2014 Artem Herasymchuk * Copyright 2014 Tom Krywitsky * Copyright 2014 Henry Pabst * Copyright 2014 Bradley Simons * * 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 ca.ualberta.cmput301w14t08.geochan.managers; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.lang.reflect.Type; import java.util.ArrayList; import android.content.Context; import android.graphics.Bitmap; import ca.ualberta.cmput301w14t08.geochan.helpers.GsonHelper; import ca.ualberta.cmput301w14t08.geochan.models.Comment; import ca.ualberta.cmput301w14t08.geochan.models.ThreadComment; import com.google.gson.Gson; import com.google.gson.reflect.TypeToken; /** * Class responsible for managing local saving of threadsList, threads, and * comments. As well as managing and saving the queues of comments and * threadComments which are to be posted when internet connection is acquired. * * @author Artem Chikin * */ public class CacheManager { private static CacheManager instance = null; private Context context; private Gson offlineGson; private Gson onlineGson; private static final String EXTENSION = ".sav"; // File for saving ThreadList private static final String FILENAME = "threads.sav"; private static final String IMAGE = "IMG"; // File for the Queue of Comments to post private static final String FILENAME2 = "commentq.sav"; // File for the Queue of ChreadComments to post private static final String FILENAME3 = "threadq.sav"; private ArrayList<Comment> commentQueue; private ArrayList<ThreadComment> threadCommentQueue; /** * Initializes the CacheManager fields, private because of the Singleton * pattern. * * @param context The Context the CacheManager is running in. */ private CacheManager(Context context) { this.context = context; this.offlineGson = GsonHelper.getOfflineGson(); // thread Gson is same as online - all the data except for the comments. this.onlineGson = GsonHelper.getOnlineGson(); commentQueue = deserializeCommentQueue(); threadCommentQueue = deserializeThreadCommentQueue(); } /** * Adds a comment to the Queue of comments to post when Internet connection * is acquired. Serializes the queue. * * @param comment The Comment to be added to the queue. */ public void addCommentToQueue(Comment comment) { commentQueue.add(comment); serializeCommentQueue(); } /** * Adds a threadComment to the Queue of threadComments to post when Internet * connection is acquired. Serializes the queue. * * @param thread The ThreadComment to be added to the queue. */ public void addThreadCommentToQueue(ThreadComment thread) { threadCommentQueue.add(thread); serializeThreadCommentQueue(); } /** * Using the ThreadManager, posts all the comments and threadComments in the * queue, called once internet connection is acquired. */ public void postAll() { for (Comment comment : commentQueue) { ThreadManager.startPost(comment, null, comment.getLocation(), null, false); commentQueue.remove(comment); } for (ThreadComment threadComment : threadCommentQueue) { Comment bodyComment = threadComment.getBodyComment(); ThreadManager.startPost(bodyComment, threadComment.getTitle(), bodyComment.getLocation(), null, false); threadCommentQueue.remove(threadComment); } serializeCommentQueue(); serializeThreadCommentQueue(); } public static CacheManager getInstance() { return instance; } public static void generateInstance(Context context) { instance = new CacheManager(context); } public ArrayList<Comment> getCommentQueue() { return commentQueue; } public void setCommentQueue(ArrayList<Comment> commentQueue) { this.commentQueue = commentQueue; } public ArrayList<ThreadComment> getThreadCommentQueue() { return threadCommentQueue; } public void setThreadCommentQueue(ArrayList<ThreadComment> threadCommentQueue) { this.threadCommentQueue = threadCommentQueue; } /** * Serializes the comment queue to JSON. */ public void serializeCommentQueue() { try { String json = offlineGson.toJson(getCommentQueue()); FileOutputStream f = context.openFileOutput(FILENAME2, Context.MODE_PRIVATE); BufferedWriter w = new BufferedWriter(new OutputStreamWriter(f)); w.write(json); w.close(); f.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * Deserializes the comment queue from JSON. * @return An ArrayList of the deserialized Comments. */ public ArrayList<Comment> deserializeCommentQueue() { ArrayList<Comment> list = new ArrayList<Comment>(); try { FileInputStream f = context.openFileInput(FILENAME2); BufferedReader r = new BufferedReader(new InputStreamReader(f)); String json = ""; String temp = ""; temp = r.readLine(); while (temp != null) { json = json + temp; temp = r.readLine(); } r.close(); f.close(); Type type = new TypeToken<ArrayList<Comment>>() { }.getType(); list = onlineGson.fromJson(json, type); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return list; } /** * Serializes the ThreadComment queue to JSON. */ public void serializeThreadCommentQueue() { try { String json = offlineGson.toJson(getThreadCommentQueue()); FileOutputStream f = context.openFileOutput(FILENAME3, Context.MODE_PRIVATE); BufferedWriter w = new BufferedWriter(new OutputStreamWriter(f)); w.write(json); w.close(); f.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * Deserializes the ThreadComment queue from JSON. * @return An ArrayList of the deserialized ThreadComments. */ public ArrayList<ThreadComment> deserializeThreadCommentQueue() { ArrayList<ThreadComment> list = new ArrayList<ThreadComment>(); try { FileInputStream f = context.openFileInput(FILENAME3); BufferedReader r = new BufferedReader(new InputStreamReader(f)); String json = ""; String temp = ""; temp = r.readLine(); while (temp != null) { json = json + temp; temp = r.readLine(); } r.close(); f.close(); Type type = new TypeToken<ArrayList<ThreadComment>>() { }.getType(); list = onlineGson.fromJson(json, type); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return list; } /** * Serializes a Bitmap into JSON and stores it in the cache. * @param image The Bitmap to be serialized. * @param id The ID of the image being serialized. */ public void serializeImage(Bitmap image, String id) { try { String json = onlineGson.toJson(image); FileOutputStream f = context.openFileOutput(IMAGE + id + EXTENSION, Context.MODE_PRIVATE); BufferedWriter w = new BufferedWriter(new OutputStreamWriter(f)); w.write(json); w.close(); f.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * Deserializes an image from the cache and returns it. * @param id The ID of the comment to retrieve. * @return The deserialized Bitmap. */ public Bitmap deserializeImage(String id) { Bitmap image = null; try { FileInputStream f = context.openFileInput(IMAGE + id + EXTENSION); BufferedReader r = new BufferedReader(new InputStreamReader(f)); String json = ""; String temp = ""; temp = r.readLine(); while (temp != null) { json = json + temp; temp = r.readLine(); } r.close(); f.close(); image = onlineGson.fromJson(json, Bitmap.class); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return image; } /** * Serialize the list of threads with all the data with the exception of all * the comment children of the Thread body comment. * * @param list The ArrayList of ThreadComments to serialize. */ public void serializeThreadList(ArrayList<ThreadComment> list) { try { String json = onlineGson.toJson(list); FileOutputStream f = context.openFileOutput(FILENAME, Context.MODE_PRIVATE); BufferedWriter w = new BufferedWriter(new OutputStreamWriter(f)); w.write(json); w.close(); f.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * Deserialize a list of ThreadComment objects without comments. * * @return The ArrayList of ThreadComments. */ public ArrayList<ThreadComment> deserializeThreadList() { ArrayList<ThreadComment> list = new ArrayList<ThreadComment>(); try { FileInputStream f = context.openFileInput(FILENAME); BufferedReader r = new BufferedReader(new InputStreamReader(f)); String json = ""; String temp = ""; temp = r.readLine(); while (temp != null) { json = json + temp; temp = r.readLine(); } r.close(); f.close(); Type type = new TypeToken<ArrayList<ThreadComment>>() { }.getType(); list = onlineGson.fromJson(json, type); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return list; } /** * Serialize ThreadComment object into a file with the file's name being * ThreadComment's id. * * @param thread The ThreadComment to serialize. */ public void serializeThreadCommentById(ThreadComment thread) { try { String json = offlineGson.toJson(thread); FileOutputStream f = context.openFileOutput(thread.getId() + EXTENSION, Context.MODE_PRIVATE); BufferedWriter w = new BufferedWriter(new OutputStreamWriter(f)); w.write(json); w.close(); f.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * Retrieve ThreadComment object by id and return the children of its body * comment. This is done because we already have ThreadComment object and * its BodyComment from the ThreadComment Deserializers. This deserializer * runs when a thread is opened and we need to retrieve comments only from * the cache. * * @param id The id of the ThreadComment to deserialize. * @return An ArrayList of the ThreadComment's body comment's children. */ public ArrayList<Comment> deserializeThreadCommentById(String id) { ThreadComment thread = null; try { FileInputStream f = context.openFileInput(id + EXTENSION); BufferedReader r = new BufferedReader(new InputStreamReader(f)); String json = ""; String temp = ""; temp = r.readLine(); while (temp != null) { json = json + temp; temp = r.readLine(); } r.close(); f.close(); thread = offlineGson.fromJson(json, ThreadComment.class); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } if (thread != null) { return thread.getBodyComment().getChildren(); } else { return null; } } }