encryptedsmsmidlet.java

J2ME MIDP_Example_Applications

// Copyright 2003 Nokia Corporation.
//
// THIS SOURCE CODE IS PROVIDED 'AS IS', WITH NO WARRANTIES WHATSOEVER,
// EXPRESS OR IMPLIED, INCLUDING ANY WARRANTY OF MERCHANTABILITY, FITNESS
// FOR ANY PARTICULAR PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE
// OR TRADE PRACTICE, RELATING TO THE SOURCE CODE OR ANY WARRANTY OTHERWISE
// ARISING OUT OF ANY PROPOSAL, SPECIFICATION, OR SAMPLE AND WITH NO
// OBLIGATION OF NOKIA TO PROVIDE THE LICENSEE WITH ANY MAINTENANCE OR
// SUPPORT. FURTHERMORE, NOKIA MAKES NO WARRANTY THAT EXERCISE OF THE
// RIGHTS GRANTED HEREUNDER DOES NOT INFRINGE OR MAY NOT CAUSE INFRINGEMENT
// OF ANY PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OWNED OR CONTROLLED
// BY THIRD PARTIES
//
// Furthermore, information provided in this source code is preliminary,
// and may be changed substantially prior to final release. Nokia Corporation
// retains the right to make changes to this source code at
// any time, without notice. This source code is provided for informational
// purposes only.
//
// Nokia and Nokia Connecting People are registered trademarks of Nokia
// Corporation.
// Java and all Java-based marks are trademarks or registered trademarks of
// Sun Microsystems, Inc.
// Other product and company names mentioned herein may be trademarks or
// trade names of their respective owners.
//
// A non-exclusive, non-transferable, worldwide, limited license is hereby
// granted to the Licensee to download, print, reproduce and modify the
// source code. The licensee has the right to market, sell, distribute and
// make available the source code in original or modified form only when
// incorporated into the programs developed by the Licensee. No other
// license, express or implied, by estoppel or otherwise, to any other
// intellectual property rights is granted herein.
import java.io.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
import javax.wireless.messaging.*;

// Main class which inits the connection and create the screens
// It owns the MessageConnection and Display
public class EncryptedSMSMIDlet
  extends MIDlet
  implements MessageListener, Runnable
{
  private final Image logo;
  private final SendScreen displayable;

  private int port;
  private MessageConnection conn;
  private Message nextMessage;


  public EncryptedSMSMIDlet()
  {
    // init basic parameters
    logo = makeImage("/logo.png");
    try
    {
      port = Integer.parseInt(getAppProperty("port"));
    }
    catch (Exception e)
    {
      // in case the property is missing or with a wrong format
      port = 6535;
    }
    ErrorScreen.init(logo, Display.getDisplay(this));
    displayable = new SendScreen(this);
  }


  public void startApp()
  {
    // Build the connection string
    String connection = "sms://:" + port;
    try
    {
      // Initiate the connection and add listener
      conn = (MessageConnection) Connector.open(connection);
      conn.setMessageListener(this);
    }
    catch (IOException e)
    {
      ErrorScreen.showError(
        "Exception creating message connection to "
        + connection, displayable);
    }

    Displayable current = Display.getDisplay(this).getCurrent();

    if (current == null)
    {
      // shows splash screen
      String text = getAppProperty("MIDlet-Name") + "\n" +
          getAppProperty("MIDlet-Vendor");
      Alert splashScreen = new Alert(null,
          text,
          logo,
          AlertType.INFO);
      splashScreen.setTimeout(3000);

      Display.getDisplay(this).setCurrent(splashScreen, displayable);
    }
    else
    {
      Display.getDisplay(this).setCurrent(current);
    }
  }


  public void pauseApp()
  {
  }


  public void destroyApp(boolean unconditional)
  {
    try
    {
      // Close the connection on exit
      if (conn != null)
      {
        conn.close();
      }
    }
    catch (IOException e)
    {
      // Ignore since we are closing anyway
    }
  }


  // Asynchronous callback for inbound message.
  public void notifyIncomingMessage(MessageConnection conn)
  {
    if (conn == this.conn)
    {
      try
      {
        // Create a ReceiveScreen upon message removal
        BinaryMessage incomingMessage =
          (BinaryMessage) conn.receive();
        ReceiveScreen handler =
          new ReceiveScreen(this, incomingMessage);
        Display.getDisplay(this).setCurrent(handler);
      }
      catch (IOException e)
      {
        ErrorScreen.showError(
          "Exception receiving message " + e.getMessage(),
          displayable);
      }
      catch (SecurityException e)
      {
        ErrorScreen.showError("Exception sending message(s) "
          + e.getMessage(),
          displayable);
      }
    }
  }


  // Send message in a different thread
  public void run()
  {
    if (nextMessage != null)
    {
      try
      {
        conn.send(nextMessage);
      }
      catch (IOException e)
      {
        ErrorScreen.showError("Exception sending message(s) "
          + e.getMessage(),
          displayable);
      }
      catch (SecurityException e)
      {
        ErrorScreen.showError("Sending message not allowed"
          + e.getMessage(),
          displayable);
      }
    }
    nextMessage = null;
  }


  // loads a given image by name
  static Image makeImage(String filename)
  {
    Image image = null;

    try
    {
      image = Image.createImage(filename);
    }
    catch (Exception e)
    {
      // use a null image instead
    }

    return image;
  }


  void showMessage(String message)
  {
    ErrorScreen.showError(message, displayable);
  }


  void sendMessage(String number,
           String plainText,
           String password,
           boolean addDigest)
  {
    if (conn != null)
    {
      // create a new message
      BinaryMessage binarySMS = (BinaryMessage) conn.newMessage(
          MessageConnection.BINARY_MESSAGE);
      String address = new StringBuffer("sms://")
        .append(number)
        .append(":")
        .append(port).toString();
      binarySMS.setAddress(address);

      // do encryption
      long difference = System.currentTimeMillis();
      try
      {
        byte[] messageContent = MessageCodec.encodeMessage(plainText,
                                                           password,
                                                           addDigest);
        // measire how long does it take to encrypt
        difference = System.currentTimeMillis() - difference;
        if (messageContent != null)
        {
          binarySMS.setPayloadData(messageContent);
          StringBuffer report = new StringBuffer(
              "Encryption succesful using cipher ")
              .append(MessageCodec.createEngine().getAlgorithmName());
          if (addDigest)
          {
            report.append(" and digest ")
              .append(MessageCodec.createDigest().
                getAlgorithmName());
          }
          report.append(" took ")
            .append(difference)
            .append(" ms. Overall message size is ")
            .append(messageContent.length)
            .append(" and uses ")
            .append(conn.numberOfSegments(binarySMS))
            .append(" segments");
          showReport(report.toString(), messageContent);
          nextMessage = binarySMS;
          // send the message in another thread
          new Thread(this).start();
        }
      }
      catch (Exception e)
      {
        showMessage(e.getMessage());
      }
    }
    else
    {
      showMessage("No connection available");
    }
  }


  // shows the main screen
  void showMain()
  {
    Display.getDisplay(this).setCurrent(displayable);
  }

  void showReport(String result, byte[] content) {
    Display.getDisplay(this).setCurrent(
      new ReportScreen(this, result, content, content.length));
  }

}