Java tutorial
/* * Copyright 2013 Abid Hasan Mujtaba * * 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.abid_mujtaba.fetchheaders.models; import android.util.Log; import android.util.SparseArray; import com.abid_mujtaba.fetchheaders.Resources; import com.abid_mujtaba.fetchheaders.Settings; import com.sun.mail.imap.IMAPFolder; import com.sun.mail.util.MailConnectException; import javax.mail.AuthenticationFailedException; import javax.mail.FetchProfile; import javax.mail.Flags; import javax.mail.Folder; import javax.mail.Message; import javax.mail.MessagingException; import javax.mail.NoSuchProviderException; import javax.mail.Session; import javax.mail.Store; import java.io.IOException; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileWriter; import java.util.*; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; /** * Model representing an email account. It encapsulates the various methods which connect to an email account and interact with it */ public class Account { private String mName; private String mHost; private String mUsername; private String mPassword; private int mId; private static ArrayList<Account> sInstances = new ArrayList<Account>(); private static int sNumOfInstances = 0; private Message[] mMessages; // Stores the Message objects fetched from the email account private Folder mInbox; // Stores reference to the Inbox object, will be used to delete emails. private Folder mTrash; // Trash Folder on the email account private boolean mUsesLabels = false; // This flag indicates that the email account uses Labels rather than Folders (Gmail being the most common example) private int mMaxNumOfEmails = 10; // Max number of emails fetched for any account SparseArray<Email> mEmails; private Account() // Default empty constructor used to track objects { mId = sNumOfInstances; sInstances.add(mId, this); // Add instance to the list and increment number of instances sNumOfInstances++; } public Account(String _name, String _host, String _username, String _password) { this(); mName = _name; mHost = _host; mUsername = _username; mPassword = _password; } public static Account newInstance() // creates and return an empty instance of Account. update() should be called immediately after to populate it. { return new Account(); } public String name() { return mName; } public String host() { return mHost; } public String username() { return mUsername; } public String password() { return mPassword; } public static Account get(int id) { return sInstances.get(id); } @Override public String toString() { return String.format("<Account - name: %s - host: %s - username: %s - password: %s>", mName, mHost, mUsername, mPassword); } public SparseArray<Email> emails() { return mEmails; } // Method to access the emails associated with an account. public void update(String _name, String _host, String _username, String _password) // Used to update account information { mName = _name; mHost = _host; mUsername = _username; mPassword = _password; writeAccountsToJson(); } public static int numberOfAccounts() { return sNumOfInstances; } public static void createAccountsFromJson() // Reads the specified json file and uses it to construct Account objects { try { File file = new File(Resources.INTERNAL_FOLDER, Settings.ACCOUNTS_JSON_FILE); if (!file.exists()) { createEmptyAccountsJsonFile(file); } FileInputStream fis = new FileInputStream(file); String content = Resources.getStringFromInputStream(fis); fis.close(); JSONObject root = new JSONObject(content); JSONArray accounts = root.getJSONArray("accounts"); for (int ii = 0; ii < accounts.length(); ii++) // Iterate over all accounts in the JSONArray and use each to construct an Account object { JSONObject account = accounts.getJSONObject(ii); new Account(account.getString("name"), account.getString("host"), account.getString("username"), account.getString("password")); } } catch (FileNotFoundException e) { Log.e(Resources.LOGTAG, "Unable to open " + Settings.ACCOUNTS_JSON_FILE, e); } catch (IOException e) { Log.e(Resources.LOGTAG, "Unable to close FileInputStream for " + Settings.ACCOUNTS_JSON_FILE, e); } catch (JSONException e) { Log.e(Resources.LOGTAG, "Exception thrown while working with JSON", e); } } private static void writeAccountsToJson() // Reads all Account objects (some of them updated) and uses them to write this data to accounts.json { try { JSONObject jRoot = new JSONObject(); JSONArray jAccounts = new JSONArray(); for (int ii = 0; ii < sNumOfInstances; ii++) { JSONObject jAccount = new JSONObject(); Account account = sInstances.get(ii); jAccount.put("name", account.name()); jAccount.put("host", account.host()); jAccount.put("username", account.username()); jAccount.put("password", account.password()); jAccounts.put(jAccount); } jRoot.put("accounts", jAccounts); // Save JSON to accounts.json FileWriter fw = new FileWriter(new File(Resources.INTERNAL_FOLDER, Settings.ACCOUNTS_JSON_FILE)); // Write root JSON object to file info.json fw.write(jRoot.toString()); fw.flush(); fw.close(); } catch (JSONException e) { Log.e(Resources.LOGTAG, "Exception raised while manipulate JSON objects.", e); } catch (IOException e) { Log.e(Resources.LOGTAG, "Exception raised while saving content to json file.", e); } } private static void createEmptyAccountsJsonFile(File file) { try { // We start by creating the JSON tree for an empty accounts.json file. JSONObject root = new JSONObject(); JSONArray accounts = new JSONArray(); root.put("accounts", accounts); // Save JSON to accounts.json FileWriter fw = new FileWriter(file); // Write root JSON object to file info.json fw.write(root.toString()); fw.flush(); fw.close(); } catch (JSONException e) { Log.e(Resources.LOGTAG, "Exception raised while manipulate JSON objects.", e); } catch (IOException e) { Log.e(Resources.LOGTAG, "Exception raised while saving content to json file.", e); } } public SparseArray<Email> fetchEmails() throws MessagingException // Fetches messages from account and uses them to create an array of Email objects. Catches connection exception and re-throws them up the chain. { Properties props = new Properties(); props.setProperty("mail.store.protocol", "imaps"); props.setProperty("mail.imaps.host", mHost); props.setProperty("mail.imaps.port", "993"); props.setProperty("mail.imaps.socketFactory.class", "javax.net.ssl.SSLSocketFactory"); // Uses SSL to secure communication props.setProperty("mail.imaps.socketFactory.fallback", "false"); Session imapSession = Session.getInstance(props); try { Store store = imapSession.getStore("imaps"); // Connect to server by sending username and password: store.connect(mHost, mUsername, mPassword); mInbox = store.getFolder("Inbox"); mInbox.open(Folder.READ_WRITE); // Open Inbox as read-write since we will be deleting emails later mTrash = store.getFolder("Trash"); if (!mTrash.exists()) { mTrash = store.getFolder("[Gmail]/Trash"); // If a folder labelled "Trash" doesn't exist we attempt to check if it is a Gmail account whose trash folder is differently named mUsesLabels = true; // Set flag to indicate that this account uses Labels rather than folders a la Gmail if (!mTrash.exists()) { mTrash = null; // No trash folder found. Emails will be deleted directly mUsesLabels = false; } } int num = mInbox.getMessageCount(); // Get number of messages in the Inbox if (num > mMaxNumOfEmails) { mMessages = mInbox.getMessages(num - mMaxNumOfEmails + 1, num); // Fetch latest mMaxNumOfEmails emails (seen and unseen both). The oldest email is indexed as 1 and so on. } else { mMessages = mInbox.getMessages(); } FetchProfile fp = new FetchProfile(); fp.add(IMAPFolder.FetchProfileItem.HEADERS); // Fetch header data fp.add(FetchProfile.Item.FLAGS); // Fetch flags mInbox.fetch(mMessages, fp); // Now that the messages have been fetched using the FetchProfile (that is the necessary information has been fetched with them) we sort the message in reverse chronological order Arrays.sort(mMessages, new MessageComparator()); // The sort is accomplished using an instance of a custom comparator that compares messages using DateSent mEmails = new SparseArray<Email>(); for (int ii = 0; ii < mMessages.length; ii++) { Email email = new Email(mMessages[ii]); mEmails.put(ii, email); } return mEmails; } catch (MessagingException e) { Resources.Loge("Exception while attempting to connect to mail server", e); throw e; } // The two above exceptions are caught by this one if they are not explicitly stated above. } public void delete(ArrayList<Email> emails) // Delete emails with the specified ids { if (emails.size() > 0) { Message[] messages = new Message[emails.size()]; try { for (int ii = 0; ii < emails.size(); ii++) { messages[ii] = emails.get(ii).message(); } if (mTrash != null) { mInbox.copyMessages(messages, mTrash); } if (!mUsesLabels) // For Gmail-type accounts (that use Labels rather than folders) copying the message to Trash is enough to carry out deletion. { mInbox.setFlags(messages, new Flags(Flags.Flag.DELETED), true); } mInbox.expunge(); // Forces INBOX to actually delete the emails flagged for deletion } catch (MessagingException e) { Resources.Loge("Exception raised while attempting to delete emails.", e); } } } public static void deleteAccount(int id) // Method for deleting account (with the specified id) and updating the json file accordingly { sInstances.remove(id); // Remove the specified Account object from the list sNumOfInstances--; // Update the count of num of instances writeAccountsToJson(); // Update the json file } private class MessageComparator implements Comparator<Message> // Used to order Messages by date { @Override public int compare(Message message, Message message2) { try { if (message.getSentDate().after(message2.getSentDate())) { return -1; } // Return -1 if message is NEWER then message2 in terms of the SentDate. The -1 indicates that message < message2 (this gives reverse chronological order in Arrays.sort) since the sort order from lesser to greater return 1; } catch (MessagingException e) { Resources.Loge("Error while comparing messages.", e); return -1; } } } private static void printMessages(Message[] messages) // Debugging method { try { for (Message message : messages) { Resources.Logd("" + message.getSentDate()); } } catch (MessagingException e) { } } public int num_unseen_emails() // Method for returning the number of unseen emails pulled for this account { int num = 0; for (int ii = 0; ii < mEmails.size(); ii++) { if (!mEmails.get(ii).seen()) { num++; } } return num; } }