mobile datamanager.java

J2ME mobile application to upload data to a Java Servlet

/*--------------------------------------------------
* DataManager.java
*
* Use GET to communicate with a Java servlet. 
* The servlet will Submit Data to a database 
* 
* BIT-001-0141/2006 NJERU NGANATHA ANDREW
*-------------------------------------------------*/

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.io.*;
import java.io.*;

public class DataManager extends MIDlet implements CommandListener
{
  private Image splashLogo;	
  private boolean isSplash = true;
  private Display display;      // Reference to Display object
  private Form fmMain;         // The main form
  private Form fmMenu;         // The Menu form
  private Alert alError;       // Alert to error message
  private Command cmSubmit;       // Request method GET
  private Command cmHelp;
  private Command cmAboutUs;       
  private Command cmExit;      
  private TextField tfSur;    
  private TextField tfFst;     
  private TextField tfAge;
  private TextField tfGdr;
  private TextField tfRst;
  private StringItem siBalance;// Show account balance
  private StringItem siResult;
  private String errorMsg = null;
  private Thread th = null;
  Ticker t;
  public DataManager()
  {
    display = Display.getDisplay(this);

    // Create commands
    cmSubmit = new Command("Submit", Command.SCREEN, 2);
    cmHelp = new Command("Help", Command.SCREEN, 3);
    cmAboutUs = new Command("AboutUs", Command.SCREEN, 4);    
    cmExit = new Command("Exit", Command.EXIT, 1);

    // Textfields
    tfSur = new TextField("Surname:", "", 25, TextField.ANY | TextField.ANY);
    tfFst = new TextField("Firstname:", "", 25, TextField.ANY | TextField.ANY); 
    tfAge = new TextField("Age:", "", 2, TextField.NUMERIC); 
    tfGdr = new TextField("Gender: M-Male or F-Female:", "", 1, TextField.ANY | TextField.ANY);
    tfRst = new TextField("Favourite TV Channel:", "", 25, TextField.ANY | TextField.ANY);                                            


    // Create Form, add commands & componenets, listen for events
    fmMain = new Form("Data Upload Manager");    
    fmMain.addCommand(cmExit);
    fmMain.addCommand(cmSubmit);
    fmMain.addCommand(cmHelp);
    fmMain.addCommand(cmAboutUs);
    fmMain.append(tfSur);
    fmMain.append(tfFst);
    fmMain.append(tfAge);
    fmMain.append(tfGdr);
    fmMain.append(tfRst);
    fmMain.setCommandListener(this);

  }

  public void startApp()
  {
	t=new Ticker("Welcome, Enter Data and Click Submit..");
	fmMain.setTicker(t);
	
	if(isSplash) {
	isSplash = true;

	try {
		splashLogo = Image.createImage("/image/splash.png");
		new SplashScreen(display, fmMain, splashLogo,5000);
		} catch(Exception ex) {
		}
		}
		
	try {
            Image screen = Image.createImage("/image/screen.png");
            fmMain.append(screen);
        } catch (IOException e) {
        }
	
  }

    public void clearFields() throws IOException
	{
		tfSur.setString("");		
		tfFst.setString("");
		tfAge.setString("");
		tfGdr.setString("");
		tfRst.setString("");
	}


  public void pauseApp()
  { }
  public void destroyApp(boolean unconditional)
  { }

  public void commandAction(Command c, Displayable s)
  {
	
    if (c == cmSubmit || c == cmHelp || c == cmAboutUs)
    {
	
     try 
      	{
	
        if (c == cmSubmit)
	{
	Thread th = new Thread()
	{
	public void run()
	{
	try
	{
          lookupBalance_withGET();
          clearFields();
	}
	catch (Exception e)
      	{ 
        System.err.println("Msg: " + e.toString());
      	}
	}
	};
	th.start();
	}
		 
        else if (c == cmHelp)
	{
	Thread th = new Thread()
	{
	public void run()
	{
	try
	{

	splashLogo = Image.createImage("/image/Help.png");
	new SplashScreen(display, fmMain, splashLogo,9000);
        //lookupBalance_withPOST();
	}
	catch (Exception e)
      	{ 
        System.err.println("Msg: " + e.toString());
      	}
	}
	};
	th.start();
	}

	else
	{
	Thread th = new Thread()
	{
	public void run()
	{
	try
	{

	splashLogo = Image.createImage("/image/info.png");
	new SplashScreen(display, fmMain, splashLogo,9000);
        //lookupBalance_withPOST();
	}
	catch (Exception e)
      	{ 
        System.err.println("Msg: " + e.toString());
      	}
	}
	};
	th.start();
	}

      	}
      	catch (Exception e)
        { 
        System.err.println("Msg: " + e.toString());
        }
        }



    else if (c == cmExit)
    {
      destroyApp(false);
      notifyDestroyed();
    } 
   }

  /*--------------------------------------------------
  * Access servlet using GET
  *-------------------------------------------------*/    
  private void lookupBalance_withGET() throws IOException
  {
    HttpConnection http = null;
    InputStream iStrm = null;    
    boolean ret = false;

    // Data is passed at the end of url for GET
    String url = "http://localhost:8080/DataManager/DataManagerServlet" + "?" +
                 "surname=" + tfSur.getString() + "&" + 
                 "firstname=" + tfFst.getString() + "&" + 
		     "age=" + tfAge.getString() + "&" +
		     "gender=" + tfGdr.getString() + "&" + 
                 "results=" + tfRst.getString();
    try
    {
      http = (HttpConnection) Connector.open(url);
      //----------------
      // Client Request
      //----------------
      // 1) Send request method
      http.setRequestMethod(HttpConnection.GET);
      // 2) Send header information - none
      // 3) Send body/data -  data is at the end of URL

      //----------------
      // Server Response
      //----------------
      iStrm = http.openInputStream();      
      // Three steps are processed in this method call
      ret = processServerResponse(http, iStrm);
    }
    finally
    {
      // Clean up
      if (iStrm != null)
        iStrm.close();
      if (http != null)
        http.close();
    }

    // Process request failed, show alert    
    if (ret == false)
      showAlert(errorMsg);        
  }

  

  /*--------------------------------------------------
  * Process a response from a server
  *-------------------------------------------------*/
  private boolean processServerResponse(HttpConnection http, InputStream iStrm) throws IOException
  {
    //Reset error message
    errorMsg = null;
    // 1) Get status Line
    if (http.getResponseCode() == HttpConnection.HTTP_OK)
    {
      // 2) Get header information - none
      // 3) Get body (data)
      int length = (int) http.getLength();
      String str;
      if (length != -1)
      {
        byte servletData[] = new byte[length];
        iStrm.read(servletData);
        str = new String(servletData);
      }
      else  // Length not available...
      {
        ByteArrayOutputStream bStrm = new ByteArrayOutputStream();
        int ch;
        while ((ch = iStrm.read()) != -1)
          bStrm.write(ch);

        str = new String(bStrm.toByteArray());
        bStrm.close();
      }
     // Update the string item on the display
     siBalance.setText(str);
     return true;
    }
    else
      // Use message from the servlet
      errorMsg = new String( http.getResponseMessage());

    return false;      
  }

  /*--------------------------------------------------
  * Show an Alert
  *-------------------------------------------------*/
  private void showAlert(String msg)
  {
    // Create Alert, use message returned from servlet
    alError = new Alert("Successful Entry!", msg, null, AlertType.ERROR);

    // Set Alert to type Modal
    alError.setTimeout(Alert.FOREVER);

    // Display the Alert. Once dismissed, display the form
    display.setCurrent(alError, fmMain); 
    
               
  }
}