/**
 * The following MIDlet application demonstrates how to establish a
 * HttpConnection and uses it to send a GET request to Web server.
 */

/*************************************************

THIS CODE CAUSES A WARNING!  WHY?

**************************************************/

// include MIDlet class libraries
import javax.microedition.midlet.*;
// include networking class libraries
import javax.microedition.io.*;
// include GUI class libraries
import javax.microedition.lcdui.*;
// include I/O class libraries
import java.io.*;

public class HttpGET extends MIDlet implements CommandListener {

  // A default URL is used. User can change it from the GUI.
  private static String defaultURL =
  "http://www.brunel.ac.uk/~emstaam/home.htm";

  // GUI components for entering a Web URL.
  private Display myDisplay = null;
  private Form mainScreen;
  private TextField requestField;

  // GUI components for displaying server responses.
  private Form resultScreen;
  private StringItem resultField;

  // the "send" button used on mainScreen
  Command sendCommand = new Command("SEND", Command.OK, 1);
  // the "back" button used on resultScreen
  Command backCommand = new Command("BACK", Command.OK, 1);

  // Exit MIDlet Command
  Command cmExit = new Command("Exit", Command.EXIT, 1);

  public HttpGET(){

    // initialize the GUI components
    myDisplay = Display.getDisplay(this);
    mainScreen = new Form("Type in a URL:");
    requestField =
    new TextField(null, defaultURL,
    100, TextField.URL);
    mainScreen.append(requestField);
    mainScreen.addCommand(sendCommand);
    mainScreen.addCommand(cmExit);
    mainScreen.setCommandListener(this);
  }

  public void startApp() {
    myDisplay.setCurrent(mainScreen);
  }

  public void pauseApp() {
  }

  public void destroyApp(boolean unconditional) {
  }

  public void commandAction(Command c, Displayable s) {

    // when user clicks on the "send" button on mainScreen
    if (c == sendCommand) {

      // retrieve the Web url that user entered
      String urlstring = requestField.getString();

      // send a GET request to Web server
      String resultstring = "";
      try {
        resultstring = sendGetRequest(urlstring);
      } catch (IOException e) {
        resultstring = "ERROR";
      }

      // display the page content retrieved from Web server
      resultScreen = new Form("GET Result:");
      resultField =
      new StringItem(null, resultstring);
      resultScreen.append(resultField);
      resultScreen.addCommand(backCommand);
      resultScreen.setCommandListener(this);
      myDisplay.setCurrent(resultScreen);

    } else if (c == backCommand) {

      // do it all over again
      requestField.setString(defaultURL);
      myDisplay.setCurrent(mainScreen);
     }
    else if(c ==cmExit) {
      destroyApp(true);
      notifyDestroyed();
    }
  }

  // send a GET request to Web server
  public String sendGetRequest(String urlstring) throws IOException {

    HttpConnection hc = null;
    DataInputStream dis = null;

    String message = "";
    try {

      // open up an HttpConnection with the Web server
      // the default request method is GET.
      hc = (HttpConnection) Connector.open(urlstring);

      // obtain a DataInputStream from the HttpConnection
      dis = new DataInputStream(hc.openInputStream());

      // retrieve the contents of the requested page from Web server
      int ch;
      while ((ch = dis.read()) != -1) {
        message = message + (char) ch;
      }
    } finally {
      if (hc != null) hc.close();
      if (dis != null) dis.close();
    }
    return message;
  }
}