Applet -Servlet connection in JNLP

[alex antony]

Hi all,

I am seeking your help in my assignment.

I am launching an applet through JNLP.

The directory Structure i am following is like this

src/com/alex/MenuDemo.java
bin/com/alex/MenuDemo.class

The main code is here

package com.alex;

import java.awt.*;
import java.awt.event.*;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JCheckBoxMenuItem;
import javax.swing.JRadioButtonMenuItem;
import javax.swing.ButtonGroup;
import javax.swing.JMenuBar;
import javax.swing.KeyStroke;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;
import javax.swing.JFrame;
import javax.swing.table.*;
import javax.swing.*;
import javax.swing.JTable;
import java.awt.Dimension;
import java.util.StringTokenizer;
import java.net.*;
import javax.jnlp.*;
import java.io.*;
import java.util.*;
import java.net.URL;



public class MenuDemo implements ActionListener, ItemListener {
    JTextArea output;
    JScrollPane scrollPane;
    String newline = "\n";

    static BasicService basicService = null;
    private boolean DEBUG = false;


    public JMenuBar createMenuBar() {
        JMenuBar menuBar;
        JMenu menu, submenu;
        JMenuItem menuItem;
        JRadioButtonMenuItem rbMenuItem;
        JCheckBoxMenuItem cbMenuItem;

        //Create the menu bar.
        menuBar = new JMenuBar();

        //Build the first menu.
        menu = new JMenu("File");
        menu.setMnemonic(KeyEvent.VK_A);
        menu.getAccessibleContext().setAccessibleDescription(
                                                             "The only menu in this program that has menu items");
        menuBar.add(menu);

        //a group of JMenuItems
        menuItem = new JMenuItem("Related Commands",
                                 KeyEvent.VK_T);
        //menuItem.setMnemonic(KeyEvent.VK_T); //used constructor instead
        menuItem.setAccelerator(KeyStroke.getKeyStroke(
                                                       KeyEvent.VK_1, ActionEvent.ALT_MASK));
        menuItem.getAccessibleContext().setAccessibleDescription(
                                                                 "This doesn't really do anything");
        menuItem.addActionListener(this);
        menu.add(menuItem);

        menuItem = new JMenuItem("Ticket Commands");
        menuItem.setMnemonic(KeyEvent.VK_D);
        menuItem.addActionListener(this);
        menu.add(menuItem);

        //a group of radio button menu items
        menu.addSeparator();
        ButtonGroup group = new ButtonGroup();

        rbMenuItem = new JRadioButtonMenuItem("Acknowledged Action");
        rbMenuItem.setSelected(true);
        rbMenuItem.setMnemonic(KeyEvent.VK_R);
        group.add(rbMenuItem);
        rbMenuItem.addActionListener(this);
        menu.add(rbMenuItem);

        rbMenuItem = new JRadioButtonMenuItem("Deacknowledge");
        rbMenuItem.setMnemonic(KeyEvent.VK_O);
        group.add(rbMenuItem);
        rbMenuItem.addActionListener(this);
        menu.add(rbMenuItem);

        //a group of check box menu items
        menu.addSeparator();
        cbMenuItem = new JCheckBoxMenuItem("Online Advisor");
        cbMenuItem.setMnemonic(KeyEvent.VK_C);
        cbMenuItem.addItemListener(this);
        menu.add(cbMenuItem);

        cbMenuItem = new JCheckBoxMenuItem("Show Child Events");
        cbMenuItem.setMnemonic(KeyEvent.VK_H);
        cbMenuItem.addItemListener(this);
        menu.add(cbMenuItem);

        //a submenu
        menu.addSeparator();
        submenu = new JMenu("Filter");
        submenu.setMnemonic(KeyEvent.VK_S);

        menuItem = new JMenuItem("By Region");
        menuItem.setAccelerator(KeyStroke.getKeyStroke(
                                                       KeyEvent.VK_2, ActionEvent.ALT_MASK));
        menuItem.addActionListener(this);
        submenu.add(menuItem);

        menuItem = new JMenuItem("By Node");
        menuItem.addActionListener(this);
        submenu.add(menuItem);
        menu.add(submenu);

        //Build second menu in the menu bar.
        menu = new JMenu("Edit");
        menu.setMnemonic(KeyEvent.VK_N);
        menuBar.add(menu);

        menu = new JMenu("View");
        menu.setMnemonic(KeyEvent.VK_N);
        menuBar.add(menu);

        menu = new JMenu("Alerts");
        menu.setMnemonic(KeyEvent.VK_N);
        menuBar.add(menu);

        menu = new JMenu("Tools");
        menu.setMnemonic(KeyEvent.VK_N);
        menuBar.add(menu);

        menu = new JMenu("Help");
        menu.setMnemonic(KeyEvent.VK_N);
        menuBar.add(menu);

        return menuBar;
    }

    public Container createContentPane(){
        //Create the content-pane-to-be.
        JPanel contentPane = new JPanel(new BorderLayout());
        contentPane.setOpaque(true);

        //Create a scrolled text area.

        String[] columnNames = {"Ticket Number","Node","NodeType","Region","Alert","Date","Severity"};
        Object data[][] =new Object [10][7];

        String h=httptext();

        StringTokenizer st=new StringTokenizer(h,"%");
        int p=0;
        while(st.hasMoreTokens())
            {
                String hello=st.nextToken();
                StringTokenizer st1=new StringTokenizer(hello,"@");
                int q=0;
                while(st1.hasMoreTokens())
                    {
                        if(q==6)
                            {
                                data[p][q]=Integer.parseInt(st1.nextToken());
                            }
                        else
                            {
                                data[p][q]=st1.nextToken();
                            }
                        q++;
                    }
                p++;
            }

        DefaultTableModel myModel = new DefaultTableModel(data, columnNames);
        final JTable table = new JTable(myModel);
        table.setDefaultRenderer(Object.class, new MyTableCellRender());

        table.setPreferredScrollableViewportSize(new Dimension(500, 70));
        table.setFillsViewportHeight(true);
        table.setCellSelectionEnabled(true);
        //table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        new PopupManager(table);


        //Add the text area to the content pane.
        contentPane.add(table, BorderLayout.CENTER);
        scrollPane = new JScrollPane(table);
        contentPane.add(scrollPane, BorderLayout.CENTER);



        return contentPane;
    }


    private String httptext() {

        try {
            // Construct a URL referring to the servlet
            URL url = new URL("/opt/Abhishek/software/tomcat/webapps/innovation/DaytimeServlet");

            // Create a com.oreilly.servlet.HttpMessage to communicate with that URL
            HttpMessage msg = new HttpMessage(url);

            // Send a GET message to the servlet, with no query string
            // Get the response as an InputStream
            InputStream in = msg.sendGetMessage();

            // Wrap the InputStream with a DataInputStream
      DataInputStream result =
          new DataInputStream(new BufferedInputStream(in));

      // Read the first line of the response, which should be
      // a string representation of the current time
      String date = result.readLine();

      // Close the InputStream
      in.close();

      // Return the retrieved time
      return date;
        }
        catch (Exception e) {
            // If there was a problem, print to System.out
            // (typically the Java console) and return null
            e.printStackTrace();
            return null;
        }


    }


    private AbstractTableModel getModel() {
        return new AbstractTableModel() {
                public int getColumnCount() { return 3; }
                public int getRowCount() { return 4;}
                public Object getValueAt(int row, int col) {
                    return String.valueOf(row) + col;
                }
            };
    }


    class MyTableCellRender extends DefaultTableCellRenderer
    {
        public MyTableCellRender()
        {
            super();
            setOpaque(true);
        }
        public Component getTableCellRendererComponent(JTable table, Object value,
                                                       boolean isSelected, boolean hasFocus, int row, int column)
        {
            if(table.getValueAt(row, 6).equals(1))
                {
                    setForeground(Color.black);
                    setBackground(Color.red);
                }
            else if(table.getValueAt(row, 6).equals(2))
                {
                    setBackground(Color.yellow);
                    setForeground(Color.black);
                }

            else
                {
                    setBackground(Color.green);
                    setForeground(Color.black);
                }
            setText(value !=null ? value.toString() : "");
            return this;
        }
    }



    private void printDebugData(JTable table) {
        int numRows = table.getRowCount();
        int numCols = table.getColumnCount();
        javax.swing.table.TableModel model = table.getModel();

        System.out.println("Value of data: ");
        for (int i=0; i < numRows; i++) {
            System.out.print("    row " + i + ":");
            for (int j=0; j < numCols; j++) {
                System.out.print("  " + model.getValueAt(i, j));
            }
            System.out.println();
        }
        System.out.println("--------------------------");
    }


    public void actionPerformed(ActionEvent e) {
        JMenuItem source = (JMenuItem)(e.getSource());
        String s = "Action event detected."
                   + newline
            + "    Event source: " + source.getText()
            + " (an instance of " + getClassName(source) + ")";
        output.append(s + newline);
        output.setCaretPosition(output.getDocument().getLength());
    }

    public void itemStateChanged(ItemEvent e) {
        JMenuItem source = (JMenuItem)(e.getSource());
        String s = "Item event detected."
                   + newline
            + "    Event source: " + source.getText()
            + " (an instance of " + getClassName(source) + ")"
                   + newline
                   + "    New state: "
            + ((e.getStateChange() == ItemEvent.SELECTED) ?
               "selected":"unselected");
        output.append(s + newline);
        output.setCaretPosition(output.getDocument().getLength());
    }

    // Returns just the class name -- no package info.
    protected String getClassName(Object o) {
        String classString = o.getClass().getName();
        int dotIndex = classString.lastIndexOf(".");
        return classString.substring(dotIndex+1);
    }

    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) {
        java.net.URL imgURL = MenuDemo.class.getResource(path);
        if (imgURL != null) {
            return new ImageIcon(imgURL);
        } else {
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("Ericsson Smart Alert Management System");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        MenuDemo demo = new MenuDemo();
        frame.setJMenuBar(demo.createMenuBar());
        frame.setContentPane(demo.createContentPane());

        //Display the window.
        frame.setSize(450, 260);
        frame.setVisible(true);
    }

    public static void main(String[] args) {


        try {
            basicService = (BasicService)
                ServiceManager.lookup("javax.jnlp.BasicService");
        } catch (UnavailableServiceException e) {
            System.err.println("Lookup failed: " + e);
        }

        javax.swing.SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    createAndShowGUI();
                }
            });
    }

    class HttpMessage {

        URL servlet = null;
        String args = null;

        public HttpMessage(URL servlet) {
            this.servlet = servlet;
        }

        // Performs a GET request to the previously given servlet
        // with no query string.
        public InputStream sendGetMessage() throws IOException {
            return sendGetMessage(null);
        }

        // Performs a GET request to the previously given servlet.
        // Builds a query string from the supplied Properties list.
        public InputStream sendGetMessage(Properties args) throws IOException {
            String argString = "";  // default

            if (args != null) {
                argString = "?" + toEncodedString(args);
            }
            URL url = new URL(servlet.toExternalForm() + argString);

            // Turn off caching
            URLConnection con = url.openConnection();
            con.setUseCaches(false);

            return con.getInputStream();
        }

        // Performs a POST request to the previously given servlet
        // with no query string.
        public InputStream sendPostMessage() throws IOException {
            return sendPostMessage(null);
        }

        // Performs a POST request to the previously given servlet.
        // Builds post data from the supplied Properties list.
        public InputStream sendPostMessage(Properties args) throws IOException {
            String argString = "";  // default
            if (args != null) {
                argString = toEncodedString(args);  // notice no "?"
            }

            URLConnection con = servlet.openConnection();

            // Prepare for both input and output
            con.setDoInput(true);
            con.setDoOutput(true);

            // Turn off caching
            con.setUseCaches(false);

            // Work around a Netscape bug
            con.setRequestProperty("Content-Type","application/x-www-form-urlencoded");

            // Write the arguments as post data
            DataOutputStream out = new DataOutputStream(con.getOutputStream());
            out.writeBytes(argString);
            out.flush();
            out.close();

            return con.getInputStream();
        }

        // Converts a Properties list to a URL-encoded query string
        private String toEncodedString(Properties args) {
            StringBuffer buf = new StringBuffer();
            Enumeration names = args.propertyNames();
            while (names.hasMoreElements()) {
                String name = (String) names.nextElement();
                String value = args.getProperty(name);
                buf.append(URLEncoder.encode(name) + "=" + URLEncoder.encode(value));
                if (names.hasMoreElements()) buf.append("&");
            }
            return buf.toString();
        }
    }


}


class PopupManager extends MouseAdapter implements ActionListener {
    JTable table;
    JPopupMenu popupMenu;
    JDialog dialog;

    public PopupManager(JTable table) {
        this.table = table;
        this.table.addMouseListener(this);
        initPopup();
        initDialog();
    }

    public void actionPerformed(ActionEvent e) {
        showDialog();
    }

    private void showDialog() {
        int row = table.getSelectedRow();
        int col = table.getSelectedColumn();
        Rectangle r = table.getCellRect(row, col, true);
        JList list = (JList)dialog.getContentPane().getComponent(0);
        DefaultListModel model = (DefaultListModel)list.getModel();
        model.removeAllElements();
        model.addElement("You selected row " + row);
        model.addElement("You selected column " + col);
        dialog.pack();
        Point p = r.getLocation();
        SwingUtilities.convertPointToScreen(p, table);
        dialog.setLocation(p.x, p.y+r.height);
        dialog.setVisible(true);
    }

    public void mousePressed(MouseEvent e) {
        Point p = e.getPoint();
        final int row = table.rowAtPoint(p);
        final int col = table.columnAtPoint(p);
        int selectedRow = table.getSelectedRow();
        int selectedCol = table.getSelectedColumn();
        if(dialog.isShowing())
            dialog.dispose();
        if(popupMenu.isVisible())
            popupMenu.setVisible(false);
        // Update the current selection for correct popupMenu behavior
        // in case a new selection is made with the right mouse button.
        if(row != selectedRow || col != selectedCol) {
            EventQueue.invokeLater(new Runnable() {
                    public void run() {
                        table.changeSelection(row, col, true, false);
                    }
                });
        }
        // Specify the condition(s) you want for popupMenu display.
        // For Example: show popupMenu only for view column index 1.
        //if(row != -1 && col == 3) {
        if(SwingUtilities.isRightMouseButton(e)) {
            Rectangle r = table.getCellRect(row, col, false);
            popupMenu.show(table, r.x, r.y+r.height);
        } else {
            e.consume();
        }
        //}
    }

    private void initPopup() {
        popupMenu = new JPopupMenu();

        JMenu item = new JMenu("Create Ticket");
        item.addActionListener(this);

        JMenuItem submenu = new JMenuItem("Queue 1");
        item.add(submenu);

        JMenuItem submenu1 = new JMenuItem("Queue 2");
        item.add(submenu1);

        JMenuItem submenu2 = new JMenuItem("Queue 3");
        item.add(submenu2);

        JMenuItem submenu3 = new JMenuItem("Queue 4");
        item.add(submenu3);

        popupMenu.add(item);

        JMenuItem item1 = new JMenuItem("Troubleshoot");
        item1.addActionListener(this);
        popupMenu.add(item1);

        JMenuItem item2 = new JMenuItem("View Statistics");
        item2.addActionListener(this);
        popupMenu.add(item2);

        JMenuItem item3 = new JMenuItem("Acknowledge");
        item3.addActionListener(this);
        popupMenu.add(item3);

        JMenuItem item4 = new JMenuItem("Deacknowledge");
        item4.addActionListener(this);
        popupMenu.add(item4);

        JMenuItem item5 = new JMenuItem("Clear Alarm");
        item5.addActionListener(this);
        popupMenu.add(item5);

        JMenuItem item6 = new JMenuItem("Add Journal");
        item6.addActionListener(this);
        popupMenu.add(item6);

        JMenuItem item7 = new JMenuItem("View Journal");
        item7.addActionListener(this);
        popupMenu.add(item7);
    }

    private void initDialog() {
        Frame owner = (Frame)table.getTopLevelAncestor();
        dialog = new JDialog(owner, "title", false);
        JList list = new JList(new DefaultListModel());
        dialog.add(list);
    }
}

This applet communicates with the servlet DaytimeServlet using the function httptext().The servlet connects to the database and returns back the values for filling the table.

When i am launching the applet via jnlp without the servlet it is launching fine.i.e i have hardcoded the values in the applet code only.But when i am trying to launch the applet with the servlet communication for getting the values from the database i am not able to launch it ..

i am not getting any errors ..i dont see anything

here is my jar file

META-INF/MANIFEST.MF
META-INF/MYSELF5.SF
META-INF/MYSELF5.DSA
META-INF/
com/
com/alex/
com/alex/MenuDemo$MyTableCellRender.class
com/alex/PopupManager$1.class
com/alex/MenuDemo.class
com/alex/MenuDemo$HttpMessage.class
com/alex/MenuDemo$1.class
com/alex/PopupManager.class
com/alex/MenuDemo$2.class
WEB-INF/
WEB-INF/web.xml
WEB-INF/lib/
WEB-INF/lib/jnlp-servlet.jar
WEB-INF/classes/
WEB-INF/classes/DaytimeServlet.java
WEB-INF/classes/DaytimeServlet.class

here is my jnlp file

<?xml version="1.0" encoding="utf-8"?>
<!-- JNLP File for SwingSet2 Demo Application -->
<jnlp spec="1.0+" codebase="http://150.236.9.70:8080/helloworld/" href="alertsys.jnlp">
<information>
<title>Smart Alert Management System</title>
<vendor>ericsson india global Services</vendor>
<homepage href="http://150.236.9.70:8080/helloworld/"/>
<description>Smart Alert Management System</description>
<description kind="short">IN Service Level Monitoring</description>
<offline-allowed/>
</information>
<security>
<all-permissions/>
</security>
<resources>
<j2se version="1.6+"/>
<jar href="alert.jar"/>
</resources>
<application-desc main-class="com.alex.MenuDemo"/>
</jnlp>

Anyone please suggest me where i am going wrong.Or please suggest me some atricles or link where i can get the communication going fine ..How to make this JNLP applet-Servlet Communication possible?

[sourabh girdhar]

I haven't looked into your code deeply but I have one suggestion.

Why don't you use RMI for this kind of communication. I have used RMI for similar kind of functionality and believe me it is much faster and wasier as compared to http or webservices.

Letme know if you need any help about setting up RMI in web start application.