@Override
 public int getUnreadMessageCount() throws MessagingException {
   checkOpen();
   try {
     int unreadMessageCount = 0;
     List<ImapResponse> responses =
         mConnection.executeSimpleCommand(
             String.format(
                 ImapConstants.STATUS + " \"%s\" (" + ImapConstants.UNSEEN + ")",
                 ImapStore.encodeFolderName(mName, mStore.mPathPrefix)));
     // S: * STATUS mboxname (MESSAGES 231 UIDNEXT 44292)
     for (ImapResponse response : responses) {
       if (response.isDataResponse(0, ImapConstants.STATUS)) {
         unreadMessageCount =
             response
                 .getListOrEmpty(2)
                 .getKeyedStringOrEmpty(ImapConstants.UNSEEN)
                 .getNumberOrZero();
       }
     }
     return unreadMessageCount;
   } catch (IOException ioe) {
     throw ioExceptionHandler(mConnection, ioe);
   } finally {
     destroyResponses();
   }
 }
  @Override
  public boolean create(FolderType type) throws MessagingException {
    /*
     * This method needs to operate in the unselected mode as well as the selected mode
     * so we must get the connection ourselves if it's not there. We are specifically
     * not calling checkOpen() since we don't care if the folder is open.
     */
    ImapConnection connection = null;
    synchronized (this) {
      if (mConnection == null) {
        connection = mStore.getConnection();
      } else {
        connection = mConnection;
      }
    }
    try {
      connection.executeSimpleCommand(
          String.format(
              ImapConstants.CREATE + " \"%s\"",
              ImapStore.encodeFolderName(mName, mStore.mPathPrefix)));
      return true;

    } catch (MessagingException me) {
      return false;

    } catch (IOException ioe) {
      throw ioExceptionHandler(connection, ioe);

    } finally {
      connection.destroyResponses();
      if (mConnection == null) {
        mStore.poolConnection(connection);
      }
    }
  }
  /**
   * Selects the folder for use. Before performing any operations on this folder, it must be
   * selected.
   */
  private void doSelect() throws IOException, MessagingException {
    List<ImapResponse> responses =
        mConnection.executeSimpleCommand(
            String.format(
                ImapConstants.SELECT + " \"%s\"",
                ImapStore.encodeFolderName(mName, mStore.mPathPrefix)));

    // Assume the folder is opened read-write; unless we are notified otherwise
    mMode = OpenMode.READ_WRITE;
    int messageCount = -1;
    for (ImapResponse response : responses) {
      if (response.isDataResponse(1, ImapConstants.EXISTS)) {
        messageCount = response.getStringOrEmpty(0).getNumberOrZero();
      } else if (response.isOk()) {
        final ImapString responseCode = response.getResponseCodeOrEmpty();
        if (responseCode.is(ImapConstants.READ_ONLY)) {
          mMode = OpenMode.READ_ONLY;
        } else if (responseCode.is(ImapConstants.READ_WRITE)) {
          mMode = OpenMode.READ_WRITE;
        }
      } else if (response.isTagged()) { // Not OK
        throw new MessagingException(
            "Can't open mailbox: " + response.getStatusResponseTextOrEmpty());
      }
    }
    if (messageCount == -1) {
      throw new MessagingException("Did not find message count during select");
    }
    mMessageCount = messageCount;
    mExists = true;
  }
  @Override
  public boolean exists() throws MessagingException {
    if (mExists) {
      return true;
    }
    /*
     * This method needs to operate in the unselected mode as well as the selected mode
     * so we must get the connection ourselves if it's not there. We are specifically
     * not calling checkOpen() since we don't care if the folder is open.
     */
    ImapConnection connection = null;
    synchronized (this) {
      if (mConnection == null) {
        connection = mStore.getConnection();
      } else {
        connection = mConnection;
      }
    }
    try {
      connection.executeSimpleCommand(
          String.format(
              ImapConstants.STATUS + " \"%s\" (" + ImapConstants.UIDVALIDITY + ")",
              ImapStore.encodeFolderName(mName, mStore.mPathPrefix)));
      mExists = true;
      return true;

    } catch (MessagingException me) {
      // Treat IOERROR messaging exception as IOException
      if (me.getExceptionType() == MessagingException.IOERROR) {
        throw me;
      }
      return false;

    } catch (IOException ioe) {
      throw ioExceptionHandler(connection, ioe);

    } finally {
      connection.destroyResponses();
      if (mConnection == null) {
        mStore.poolConnection(connection);
      }
    }
  }
  /**
   * Appends the given messages to the selected folder. This implementation also determines the new
   * UID of the given message on the IMAP server and sets the Message's UID to the new server UID.
   */
  @Override
  public void appendMessages(Message[] messages) throws MessagingException {
    checkOpen();
    try {
      for (Message message : messages) {
        // Create output count
        CountingOutputStream out = new CountingOutputStream();
        EOLConvertingOutputStream eolOut = new EOLConvertingOutputStream(out);
        message.writeTo(eolOut);
        eolOut.flush();
        // Create flag list (most often this will be "\SEEN")
        String flagList = "";
        Flag[] flags = message.getFlags();
        if (flags.length > 0) {
          StringBuilder sb = new StringBuilder();
          for (int i = 0, count = flags.length; i < count; i++) {
            Flag flag = flags[i];
            if (flag == Flag.SEEN) {
              sb.append(" " + ImapConstants.FLAG_SEEN);
            } else if (flag == Flag.FLAGGED) {
              sb.append(" " + ImapConstants.FLAG_FLAGGED);
            }
          }
          if (sb.length() > 0) {
            flagList = sb.substring(1);
          }
        }

        mConnection.sendCommand(
            String.format(
                ImapConstants.APPEND + " \"%s\" (%s) {%d}",
                ImapStore.encodeFolderName(mName, mStore.mPathPrefix),
                flagList,
                out.getCount()),
            false);
        ImapResponse response;
        do {
          response = mConnection.readResponse();
          if (response.isContinuationRequest()) {
            eolOut = new EOLConvertingOutputStream(mConnection.mTransport.getOutputStream());
            message.writeTo(eolOut);
            eolOut.write('\r');
            eolOut.write('\n');
            eolOut.flush();
          } else if (!response.isTagged()) {
            handleUntaggedResponse(response);
          }
        } while (!response.isTagged());

        // TODO Why not check the response?

        /*
         * Try to recover the UID of the message from an APPENDUID response.
         * e.g. 11 OK [APPENDUID 2 238268] APPEND completed
         */
        final ImapList appendList = response.getListOrEmpty(1);
        if ((appendList.size() >= 3) && appendList.is(0, ImapConstants.APPENDUID)) {
          String serverUid = appendList.getStringOrEmpty(2).getString();
          if (!TextUtils.isEmpty(serverUid)) {
            message.setUid(serverUid);
            continue;
          }
        }

        /*
         * Try to find the UID of the message we just appended using the
         * Message-ID header.  If there are more than one response, take the
         * last one, as it's most likely the newest (the one we just uploaded).
         */
        String messageId = message.getMessageId();
        if (messageId == null || messageId.length() == 0) {
          continue;
        }
        // Most servers don't care about parenthesis in the search query [and, some
        // fail to work if they are used]
        String[] uids = searchForUids(String.format("HEADER MESSAGE-ID %s", messageId));
        if (uids.length > 0) {
          message.setUid(uids[0]);
        }
        // However, there's at least one server [AOL] that fails to work unless there
        // are parenthesis, so, try this as a last resort
        uids = searchForUids(String.format("(HEADER MESSAGE-ID %s)", messageId));
        if (uids.length > 0) {
          message.setUid(uids[0]);
        }
      }
    } catch (IOException ioe) {
      throw ioExceptionHandler(mConnection, ioe);
    } finally {
      destroyResponses();
    }
  }
 @Override
 public void copyMessages(Message[] messages, Folder folder, MessageUpdateCallbacks callbacks)
     throws MessagingException {
   checkOpen();
   try {
     List<ImapResponse> responseList =
         mConnection.executeSimpleCommand(
             String.format(
                 ImapConstants.UID_COPY + " %s \"%s\"",
                 ImapStore.joinMessageUids(messages),
                 ImapStore.encodeFolderName(folder.getName(), mStore.mPathPrefix)));
     // Build a message map for faster UID matching
     HashMap<String, Message> messageMap = new HashMap<String, Message>();
     boolean handledUidPlus = false;
     for (Message m : messages) {
       messageMap.put(m.getUid(), m);
     }
     // Process response to get the new UIDs
     for (ImapResponse response : responseList) {
       // All "BAD" responses are bad. Only "NO", tagged responses are bad.
       if (response.isBad() || (response.isNo() && response.isTagged())) {
         String responseText = response.getStatusResponseTextOrEmpty().getString();
         throw new MessagingException(responseText);
       }
       // Skip untagged responses; they're just status
       if (!response.isTagged()) {
         continue;
       }
       // No callback provided to report of UID changes; nothing more to do here
       // NOTE: We check this here to catch any server errors
       if (callbacks == null) {
         continue;
       }
       ImapList copyResponse = response.getListOrEmpty(1);
       String responseCode = copyResponse.getStringOrEmpty(0).getString();
       if (ImapConstants.COPYUID.equals(responseCode)) {
         handledUidPlus = true;
         String origIdSet = copyResponse.getStringOrEmpty(2).getString();
         String newIdSet = copyResponse.getStringOrEmpty(3).getString();
         String[] origIdArray = ImapUtility.getImapSequenceValues(origIdSet);
         String[] newIdArray = ImapUtility.getImapSequenceValues(newIdSet);
         // There has to be a 1:1 mapping between old and new IDs
         if (origIdArray.length != newIdArray.length) {
           throw new MessagingException(
               "Set length mis-match; orig IDs \""
                   + origIdSet
                   + "\"  new IDs \""
                   + newIdSet
                   + "\"");
         }
         for (int i = 0; i < origIdArray.length; i++) {
           final String id = origIdArray[i];
           final Message m = messageMap.get(id);
           if (m != null) {
             callbacks.onMessageUidChange(m, newIdArray[i]);
           }
         }
       }
     }
     // If the server doesn't support UIDPLUS, try a different way to get the new UID(s)
     if (callbacks != null && !handledUidPlus) {
       ImapFolder newFolder = (ImapFolder) folder;
       try {
         // Temporarily select the destination folder
         newFolder.open(OpenMode.READ_WRITE);
         // Do the search(es) ...
         for (Message m : messages) {
           String searchString = "HEADER Message-Id \"" + m.getMessageId() + "\"";
           String[] newIdArray = newFolder.searchForUids(searchString);
           if (newIdArray.length == 1) {
             callbacks.onMessageUidChange(m, newIdArray[0]);
           }
         }
       } catch (MessagingException e) {
         // Log, but, don't abort; failures here don't need to be propagated
         Log.d(Logging.LOG_TAG, "Failed to find message", e);
       } finally {
         newFolder.close(false);
       }
       // Re-select the original folder
       doSelect();
     }
   } catch (IOException ioe) {
     throw ioExceptionHandler(mConnection, ioe);
   } finally {
     destroyResponses();
   }
 }