Note

1. Start up the MIDlet.
2. Choose Update Token and put in username/password pair test01/pass01. Then click UPDATE. The MIDlet will contact the single sign-on server and obtain a new authentication token for future use.
3. Choose Add Course. Add in a new class survey nickname and endpoint URL. You can just accept the suggested values.
4. Now you should see CS 301 available for selection under the Choose Course menu item. If you want to add more class surveys, you can repeat the last step.
5. Choose a course. iFeedBack will fetch the current question and display it for you.
6. Choose the appropriate answer and put in any comments. Then click SAVE to save the time-stamped answer to the on-device persistent cache.
7. You can repeat the last two steps multiple times for different questions from different courses.
8. From the main menu, click Submit Answers to submit all cached answers to their corresponding endpoints. All successfully submitted answers will be deleted from the cache.
9. Now you can view the uploaded answers from the class survey server. Just point your HTML browser to the URL

              http://host:8080/iFeedBackSurvey/servlet/Server.

public abstract class MVCComponent implements CommandListener {

 // Set from outside at beginning

 public static Display display;

 // Returns the screen object from the derived class

 public abstract Displayable getScreen();

 public Displayable prepareScreen () throws Exception {

    if ( getScreen() == null ) {

      initModel();

      createView();

    } else {

      updateView();

    }

    getScreen().setCommandListener ( (CommandListener) this );

    return getScreen ();

 }

 public void showScreen() {

    try {

      display.setCurrent( prepareScreen() );

    } catch (Exception e) {

      e.printStackTrace();

      Alert a = new Alert("Error");

      a.setTimeout(Alert.FOREVER);

      display.setCurrent(a);

    }

 }

 // Initialize. If a data member is not backed by RMS,

 // make sure it is null before you put in values.

 protected abstract void initModel () throws Exception;

 protected abstract void createView () throws Exception;

 protected abstract void updateView () throws Exception;

 public abstract void commandAction(Command c, Displayable s);

}

public class UpdateToken extends MVCComponent {

 // MIDP UI components: Commands, TextFields etc.

 // ... ...

 // Model parameters

 private static String username;

 private static String password;

 private static String token;

 private static String endPointURL;

 // Bean-style methods to access data members

 // Event handler

 public void commandAction(Command c, Displayable s) {

    try {

      if (c == backCommand) {

        (new MainMenu()).showScreen();

      } else if (c == updateCommand) {

        username = usernameField.getString();

        password = passwordField.getString();

        UpdateTokenTask t =

          new UpdateTokenTask(endPointURL, display);

        t.go();

      }

    } catch (Exception e) {

      // Show some alerts

    }

 }

 public Displayable getScreen () {

    return screen;

 }

 // In initModel(), first check whether the

 // the data model is persistently saved.

 //

 // The use of persistent store is transparent

 // to this class's users.

 protected void initModel() throws Exception {

    try {

      securityInfoStore =

        RecordStore.openRecordStore("securityInfo", true);

      RecordEnumeration re =

        securityInfoStore.enumerateRecords(null, null, false);

      ByteArrayInputStream bais =

        new ByteArrayInputStream( re.nextRecord() );

      DataInputStream din = new DataInputStream(bais);

      username = din.readUTF();

      password = din.readUTF();

      token = din.readUTF();

      din.close();

      bais.close();

      securityInfoStore.closeRecordStore();

    } catch (Exception e) {

      username = Start.UsernameSugg;

      password = Start.PasswordSugg;

      token = "-1:-1";

    }

 }

 // createView() creates a view from the current

 // model into the screen object

 protected void createView() throws Exception {

    backCommand = new Command("MAIN", Command.SCREEN, 2);

    updateCommand = new Command("UPDATE", Command.SCREEN, 1);

    usernameField = new TextField("Username:",

                    username, 40, TextField.ANY);

    passwordField = new TextField("Password:",

                     password, 40, TextField.ANY);

    screen = new Form("Security Info");

    ((Form) screen).append( usernameField );

    ((Form) screen).append( passwordField );

    ((Form) screen).append( "Current Token is " + token );

    screen.addCommand( backCommand );

    screen.addCommand( updateCommand );

 }

 // updateView() updates the screen object when

 // the model changes.

 protected void updateView() throws Exception {

    // display updated username and password

    usernameField.setString( username );

    passwordField.setString( password );

    // Deletes the old token display

    ((Form) screen).delete(2);

    if ( "-1:-1".equals(token) ) {

      ((Form) screen).append("The current token is not valid");

    } else {

      ((Form) screen).append("Current Token is token");

    }

 }

}

 

public abstract class BackgroundTask extends TimerTask {

 private Thread th;

 private boolean stopped;

 // Could be set in derived class

 // If the task is successfully completed

 protected Displayable nextScreen;

 // If the task is aborted

 protected Displayable prevScreen;

 // Display to draw-on

 protected Display display;

 // The gauge screen title

 protected String title;

 // Do we need to display an alert before

 // moving to the nextScreen?

 protected boolean needAlert = false;

 protected Alert alertScreen;

 public BackgroundTask (Display d) {

    display = d;

    th = new Thread(this);

 }

 public void go () {

    stopped = false;

    th.start();

 }

 public void stop () {

    stopped = true;

    th.setPriority(Thread.MIN_PRIORITY);

 }

 public void run() {

    ProgressGauge pg = null;

    try {

      pg = new ProgressGauge(this, title, display, prevScreen);

      runTask ();

    } catch (Exception e) {

      // elaborate error handling using alerts

    } finally {

      // Since pg could callback and reset

      // "stopped" when its

      // Cancel key is pressed on Gauge.

      if (!stopped) {

        if ( needAlert ) {

          pg.setNextScreen(alertScreen, nextScreen);

        } else {

          pg.setNextScreen(nextScreen);

        }

        pg.stop(); // notify progress guage to quit

      }

    }

 }

 // template method.

 public abstract void runTask () throws Exception;

}

public class UpdateTokenTask

       extends BackgroundTask {

 private String endPointURL;

 public UpdateTokenTask (String url, Display d) throws Exception {

    super (d);

    endPointURL = url;

    prevScreen =

      (new UpdateToken()).prepareScreen();

 }

 public void runTask () throws Exception {

    String username = UpdateToken.getUsername ();

    String password = UpdateToken.getPassword ();

    String token = getToken(username, password);

    if ( "-1:-1".equals(token) ) {

      needAlert = true;

      alertScreen = new Alert("Cannot update token");

      alertScreen.setString(

          "Authentication failed!");

      alertScreen.setTimeout(Alert.FOREVER);

      nextScreen = prevScreen;

    } else {

      UpdateToken.setAll( username, password, token );

      needAlert = true;

      alertScreen = new Alert("Success!");

      alertScreen.setString("The new token is token");

      alertScreen.setTimeout(Alert.FOREVER);

      nextScreen = (new MainMenu()).prepareScreen();

    }

 }

 // ... ...

}

Public class SubmitAllTask extends BackgroundTask {

 public SubmitAllTask (Display d) throws Exception {

    // Set up screens

 }

 public void runTask () throws Exception {

    RecordStore answerStore =

        RecordStore.openRecordStore("answer", true);

    RecordEnumeration re =

        answerStore.enumerateRecords(null, null, false);

    int recordNum = 0;

    while ( re.hasNextElement() ) {

      recordNum++;

      int recordid = re.nextRecordId();

      ByteArrayInputStream bais =

        new ByteArrayInputStream( answerStore.getRecord(recordid) );

      DataInputStream din = new DataInputStream(bais);

      String url = din.readUTF();

      int qid = din.readInt();

      long timestamp = din.readLong();

      String answer = din.readUTF();

      String comment = din.readUTF();

      HttpConnection conn = null;

      DataInputStream hdin = null;

      DataOutputStream hdout = null;

      try {

        conn = (HttpConnection) Connector.open( url );

        conn.setRequestMethod(HttpConnection.POST);

        hdout = conn.openDataOutputStream();

        hdout.writeInt(1); // Submit opcode

        hdout.writeUTF( UpdateToken.getToken () );

        hdout.writeLong( timestamp );

        hdout.writeInt( qid );

        hdout.writeUTF( answer );

        hdout.writeUTF( comment );

        hdout.flush();

        hdin = conn.openDataInputStream();

        boolean authsucc = hdin.readBoolean();

        if (authsucc) {

          boolean updatesucc = hdin.readBoolean();

          if ( updatesucc ) {

            answerStore.deleteRecord( recordid );

          } else {

            // Server error. Show alert

          }

          nextScreen = prevScreen;

        } else {

          // Auth error. Show Auth token screen

        }

      } finally {

        // Close all connections

      }

    }

    re.destroy();

    answerStore.closeRecordStore();

    // Setup the next screen and show the number of

    // records submitted

 }

}