Java Applet to Javascript Communication

There is a Java Applet which digitally signs files after taking
private key from a smart card.This applet takes external files.
I want to do this "Generate digital signature of a web page with the
help of an applet of which the applet is itself a part"
I am trying using Java Applet to Javascript Communication.
I am able to access the object which represents the HTML document.
That abject is represented by document itself.
Now I have to somehow generate the whole webpage i.e. like we view in a
notepad like this:
<HTML>
<Title>my page</title>
Then write into a file and then that file can be signed.
This is what I feel.
In C#.net there is a method .innerhtml.
Does such kind of a method exists in Java.???
I m searching but cudn't get till now.
Will serialization work??

Kindly forget the previous post. Read the following:
JSObject browserWindow = JSObject.getWindow(this);
JSObject doc = (JSObject)browserWindow.getMember("document");
Here doc represents the object of the HTML document.
This is accessed using Java Applet JavaScript Communication.
I want to serialize the object represented by doc.
Then write it into a file and generate it's digital signature.
In the below written line the parameter fileName is passed.
CertificationChainAndSignatureBase64 signingResult = signFile(fileName);
For this I have added few lines in the code written below.
see first 10-30 lines. Though this code gets compiled but it is not running. When I want to sign the file , it throws an error
"Unexpected error:sun.plugin.javascript.ocx.JSObject"
This code is just one class. Two other classes are needed to completely test the code.
Should I post them ??
Kindly see what is the error.
I will be highly grateful and Sorry for confusing in the previous mail...
private void signSelectedFile() {
try {
// Get the file name to be signed from the form in the HTML document
JSObject browserWindow = JSObject.getWindow(this);
JSObject mainForm = (JSObject) browserWindow.eval("document.forms[0]");
String fileNameFieldName = this.getParameter(FILE_NAME_FIELD_PARAM);
JSObject fileNameField = (JSObject) mainForm.getMember(fileNameFieldName);
//This is another modification
//String fileName = (String) fileNameField.getMember("value");
               //here we get the document......
JSObject doc = (JSObject)browserWindow.getMember("document");
//String docum = doc.toString();
String thePage = "as";
               FileOutputStream out = new FileOutputStream(thePage);
               ObjectOutputStream s = new ObjectOutputStream(out);
               s.writeObject(doc);
               String fileName = thePage;
               JOptionPane.showMessageDialog(this, fileName); //"Unexpected error: " + e.getMessage());
// Perform the actual file signing
CertificationChainAndSignatureBase64 signingResult = signFile(fileName);
if (signingResult != null) {
// Document signed. Fill the certificate and signature fields
String certChainFieldName = this.getParameter(CERT_CHAIN_FIELD_PARAM);
JSObject certChainField = (JSObject) mainForm.getMember(certChainFieldName);
certChainField.setMember("value", signingResult.mCertificationChain);
String signatureFieldName = this.getParameter(SIGNATURE_FIELD_PARAM);
JSObject signatureField = (JSObject) mainForm.getMember(signatureFieldName);
signatureField.setMember("value", signingResult.mSignature);
} else {
// User canceled signing
catch (DocumentSignException dse) {
// Document signing failed. Display error message
String errorMessage = dse.getMessage();
JOptionPane.showMessageDialog(this, errorMessage);
catch (SecurityException se) {
se.printStackTrace();
JOptionPane.showMessageDialog(this,
"Unable to access the local file system.\n" +
"This applet should be started with full security permissions.\n" +
"Please accept to trust this applet when the Java Plug-In ask you.");
catch (JSException jse) {
jse.printStackTrace();
JOptionPane.showMessageDialog(this,
"Unable to access some of the fields of the\n" +
"HTML form. Please check the applet parameters.");
catch (Exception e) {
e.printStackTrace();
JOptionPane.showMessageDialog(this, "Unexpected error: " + e.getMessage());
}

Similar Messages

Signed applet and javascript communication

Hi All,
I have an (jar) signed applet which I use to access system properties (e.g user.home). I also have a javascript code that communicates (call to a public function) with the applet to get the property "user.home" from the applet. Everything works fine in Java plugin 1.3 but since I have installed the latest plugin 1.4.2_01 from http://www.java.com/en/download/windows_automatic.jsp website I can not access the system properties even though everything in the code is same.
I can however still access public functions/variables from the same applet which do not access system properties in the new plugin 1.4.2_01.
The browser I am using is IE and OS is Windows 2000.
Does anybody know if Sun has changed the security policy for 1.4.2_01, in the new plugin for java-javascript communication to block access to functions which uses system property,fileIO, socket etc. even if they are signed applet??
Thanks in advance..

When invokin applet methods via javascript, you are accessing privileged actions from an unsafe source.
Depending on your needs, you could either load the system variables in applet init into class variables and return the information contained in the class variables to javascript or wrap the method calls inside AccessController.doPrivileged() calls.

Java Applet call javascript problem

Hi I have a web page as follow and embedded a applet. The applet call the java script, and instead of showing an alarm, the browser show the javascript code. Is that strange ? Any suggestion for this problem.
HTML:
================================================================
<HTML>
     <HEAD>
     function ShowEmbd()
          alert("Test Applet call Javascript");
     </SCRIPT>
     </HEAD>
     <BODY>
     <FORM NAME="AppletEmbdStart">
          <OBJECT classid="clsid:48B2DD7B-6B52-4DB0-97C9-ECB940113B47" id="CIVON_DEmbdObj" width="0" height="0"></OBJECT>
          <APPLET code="MyApplet.class" width="0" height="0"></APPLET>
     </FORM>
     </BODY>
</HTML>MyApplet.java
=========================================================================
import netscape.javascript.*;
public class MyApplet extends javax.swing.JApplet
     private JSObject m_win = null;
     private JSObject m_doc = null;
     public void init()
          getJSWin().call("ShowEmbd", null);
     private getJSDoc()
          if(m_doc == bull)
               m_doc = (JSObject) getJSWin().getMember("document");
          return m_doc;
     private JSObject getJSWin()
          if (m_win == null)
               m_win = netscape.javascript.JSObject.getWindow(this);
          return m_win;
}The page was load and it should call the applet MyApplet. The MyApplet should do the init() method and call the Javascript "ShowEmbd()", BUT, instead of show alert from ShowEmbd(), the browser show the code of ShowEmbd() itself ...... It did not run the javascript and shows the alert ??
The browser shows a message from status bar "The applet not initial" ???? why ???
Can anyone help ?!

On first look:
I am not sure about the Object Tag, but the Applet Tag requires the MAYSCRIPT attribute before Java can call Javascript.

When Java applet invokes JavaScript which executes window.showModalDialog, get popup with about:blank

When using a Java applet that invokes a Javascript function that in turn calls window.showModalDialog, a pop-up dialog that only contains "about:blank" results. Selecting "show desktop" from the Windows 7 taskbar and then viewing the FireFox window results in the true dialog content being displayed. Everything worked properly until very recently (and old versions of FireFox work) and I suspect something was changed in FireFox as a result of the recent Java security failures.

Hello, I don't know about this specifically but this is what I would try.
Instead of the string "\u7834\u70C2\u7269\u7A0B\u5E8F\u5458..."
Set the encoding type in the String constructor first...
ie:
new String( "\u7834\u70C2\u7269\u7A0B\u5E8F\u5458...","GB18030");
Here is a little class I whipped up to show the CharSets that are available to you..
public class ShowAllCharSets
ShowAllCharSets()
Map myMap = Charset.availableCharsets();
Iterator iterator = myMap.keySet().iterator();
   while (iterator.hasNext())
      System.out.println("Char set name = "+((String)it.next()));
public static void main(String args[])
   new ShowAllCharSets();
}Then use the preset charset String with the specific encoding already set for your menu items.
GB18030 I picked arbitrarily because it is Chinese and you may have to try another.
Good Luck!
(T)

Java Applet vs JavaScript

Trying to find pros and cons for Applet and JavaScript. Anyone know any or a good place to look?
Thanks

I suppose it depends on what you ultimately want to see. In many ways (many) JavaScript and Applets are not comparable. And you can use Javascript with Applets and vice versa. I have a web application I work on that uses lots of JS with DHTML and it also communicates with an applet, and the applet calls JS stuff as well.
Trying to use JS/DHMTL for very complex GUIs is going to be slower performance then an applet, but probably faster download/start time. Applets also should be using the Java Plug-in which the user would have to pre-install. Netscape 7 has no built-in JVM anymore, and the built-in ones in Netscape 4.7 and IE are both old (JDK 1.8) and buggy.
I agree with your advantages. As for the disadvantages:
1. For non-programmers learning curve can be steep.Who is the target user? A developer? The client browser user wouldn't care about this.
2. Not standard support for Javascript across browsers esp. DOMYes, however, if you can restrict people to IE6 and Netscape 7, then you will find that the differences are minimal. Nothing at all like the difference between them and Netscape 4.7. I'm not up on the latest Opera's support, however.
3. Web page useless if script does not work!!"does not work" sounds like a development problem. Good, correct code will work.
4. Javascript may be disabled by browser reading HTML file no control over thisYes, but if you A) have proper checking you can be sure it's enabled, and B) applets can also be enabled.
5. Anyone can see the JavaScript source code by viewing the
HTML document source. Thus you could not create a secure
multiple-choice test in JavaScript; it would be very easy to
see the answers!While this is generally true, you can do some tricks to solve that type of problem. Lets take this example. You can find Javascript code for creating MD5 hashes, and you can then use that to store the hash of the answers in the page and use the MD5 code to compare the given answers to the real ones. This type of thing is not good for all, of course.
6.Even though JavaScript is a standard, different browsers
interpret JavaScript differently, and some commands that work
fine on one browser simply do not work on another. You must
carefully test your JavaScript code on all browsers to make
sure it runs correctly.This is basically the same type of problem as #2 above, and I would give the same answer. Ultimately, you have to limit yourself to certain browsers/versions. But if the user wants to see it, there's little you can do.
As Sue said, Flash is pretty robust and more secure, since it's easy enough to decompile applets. And server side things would be better security as well, if that's a big issue.

How do I integrate Java Applet and JavaScript?

Hi:
This has been asked before, I have read the archives, yet I'm still left with some doubts, and some posts are VERY old and may not apply today. (sorry, some questions might seem stupid, this is my first applet). The purpose is to create a light weight application for managing certificates stored on a smart card, requesting certificate renewal from a server and installing the issued certificate on the card.
I need to create an applet (signed) to bridge the gab caused by the security limitations of JavaScript in order to access the smart card on the client. The applet will manage certificates on the card and do client-card interaction, while all client-server and user interaction is done by AJAX/JavaScript.
So, the applet is actually supposed to be an invisible object embedded on the page that is accessed by the JavaScript. How do I go about this?
- is there any reason to prefer JApplet over Applet?
- do the JavaScript need to invoke start() or init() or is this done on page load?
- are there limitations on data exchange with the applet (ie. only string types)?
- how do I throw exceptions from the applet to the calling script?
and: will is it better to let JavaScript do all http to keep the applet light, or to let the applet fetch files given a URL (to fetch the new certificate)?
If the applet is stored in a jar-file, how do I indicate which class/method to invoke? Do the JavaScript have access to public methods only?
Thanks for your advice and suggestions,
Erik

Hi,
Are you still interested?
I can work with you over this.
Adil

Java Scipt Calling Java Applet

how could i call java applet in my java script code as i'm going to build an applet for internet application server but i'm going to check user input validation in java script !?!?!!?

in javascript:
theApplet.someMethod()
in html: add a name attribute to the applet tag.
<APPLET CODE=MyApplet.class
NAME="theApplet"
MAYSCRIPT
HEIGHT=150
WIDTH=500>
</APPLET>
the mayscript attribute is added if you want to make applet to javascript communication possible. (and not only javascript to applet communication)

Run Priviliged Code in a Java Applet

I am calling a Java applet from Javascript. The Java code needs to run in privileged mode. Eventually it is going to display a file chooser which will display files from the local hard disk, but for now it just returns a simple dummy value. The problem I am having is that the call from JavaScript to Java returns PrivilegedActionException. The applet is in a signed Jar file. I'm running 8u25.
Here's the Java class:
    // Java code
    public class OHLib extends Applet {
        public String getFile() {
            String result;
            try {
                result = (String) AccessController.doPrivileged(new PrivilegedAction() {
                    public String run() {
                        // JFileChooser code will go here
                        return "xxx";
            } catch (Exception e) {
                e.printStackTrace();
            return result;
Can anybody tell me what's wrong with this code? I would also be interested to know why the above try/catch block is not catching the exception. The only place I see the exception is in the browser F12 developer tools.
Here's the JavaScript code:
    function BrowseForFile() {
        var x;
        try {
             // this code generates PrivilegedActionException
             x = ohApplet.getFile();
        } catch (e) {
             console.log(e);
The applet is deployed on my web page as follows:
<script src="/plugins/deployJava.js"></script>
<script>
     var attributes = {
         id:'ohApplet',
         code:'OHLib',
         codebase: 'java',
         archive: 'OHLib.jar',
         width:1,
         height:1,
     var parameters = {
      jnlp_href: 'OHLib.jnlp',
      classloader_cache: 'false',
     deployJava.runApplet(attributes, parameters, '1.8');
<script>
The applet is in a signed jar file, with the following manifest:
Application-Name: <appname>
Permissions: all-permissions
Codebase: <domain>.dev <domain>.com
Caller-Allowable-Codebase: <domain>.dev <domain>.com
Application-Library-Allowable-Codebase: <domain>.dev <domain>.com
The JNLP file is as follows:
    <?xml version="1.0" encoding="UTF-8"?>
    <jnlp spec="1.0+" codebase="" href="">
        <information>
            <title>title</title>
            <vendor>vendor</vendor>
        </information>
        <security>
            <all-permissions />
        </security>
        <resources>
            <j2se version="1.8+" href="http://java.sun.com/products/autodl/j2se" />
            <jar href="OHLib.jar" main="true" />
        </resources>
        <applet-desc
             main-class="OHLib"
             name="OHLib"
             width="1"
             height="1">
         </applet-desc>
    </jnlp>

The problem was that I was not including the anonymous inner class (OHLib$1.class) in the jar file. My original jar command looked like this:
jar cfmv OHLib.jar "../../jar_manifest.txt" OHLib.class
Changing it to below fixed the problem:
jar cfmv OHLib.jar "../../jar_manifest.txt" OHLib.class OHLib$1.class
Credits go to this page for the solution.

COMMUNICATION BETWEEN JAVASCRIPT AND JAVA APPLET: US$20 AWARD FOR SOLUTION!

COMMUNICATION BETWEEN JAVASCRIPT AND JAVA APPLET PROBLEM (Easy Filter Java Applet) -
US$20 TO ANYONE WHO CAN RESOLVE THE PROBLEM
To forum visitors:
I am prepared to pay a standard shareware fee of US$20 to a user who can resolve this technical problem.
If your advice resolves the problem, I'll forward the payment to your postal address (include your
address with your reply, and also your email address)
I am attempting to enable a HTML button (using Javascript's onClick command) to directly input a number into one of the parameter text boxes in the Easy Filter Java applet (ie, enter a new color value number in the text field of the standard Colors Multiplicator Filter interface).
The applet is Freeware and can be downloaded at: http://www.javazoom.net/applets/easyfilter10/EasyFilter10.html
(It is a very effective bitmap display and editing utility)
To achieve this, I am trying to access the part of the applet that defines and sets the textbox. The text box is defined in the .class file by accessing the parameter details in the genericfilter.txt file (accompanies the .class files). I need to access 'private String appletInitialize()' and then one of the 'textFieldParameters' which sets the textbox.
I understand the basic syntax for referencing the applet:
document.appletname.setString("An example"). However, accessing the text fields in this applet is more complex!!
Please can you recommend the correct Javascript syntax to achieve communication with the applet.
Thank you for your kind assistance.
JM Graham
[email protected]
The Java source code for the applet: EasyFilter.class
# Easy Filter - E.B/JavaZOOM 1999 #
# Contact: [email protected] #
# http://javazoom.hypermart.net #
/* Originally compiled from EasyFilter.java */
import java.awt.*;
import java.io.*;
import java.net.*;
import java.applet.Applet;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.MemoryImageSource;
import java.awt.image.PixelGrabber;
import java.util.Vector;
public synchronized class EasyFilter extends Applet implements KeyListener
private String paramFileName;
private Color bgColor;
private Color fgColor;
private Color parColor;
private Color sepColor;
private Color titleColor;
private Color helpColor;
private int WinWidth;
private int WinHeight;
private String title;
private String logoFileName;
private String originalImageFileName;
private String filteredCaption;
private String originalCaption;
private Vector paramsName;
private Vector paramsValue;
private Vector paramsComment;
private Panel panelParameters[];
private Label labelParameters[];
private TextField textFieldParameters[];
private Label labelComments[];
private int nbParameters;
private ScrollPane scrollPaneParams;
private Panel panelParams;
private Image theLogo;
private Image theOriginalImage;
private Image theFilteredImage;
private int theOriginalPixelArray[];
private int logoWidth;
private int logoHeight;
private int imageWidth;
private int imageHeight;
private drawCanvas canvasTitle;
private Panel panelTitle;
private Label labelTitle;
private Panel panelImages;
private Panel panelOriginalImage;
private drawCanvas canvasOriginalImage;
private Label labelOriginalImage;
private Panel panelFilteredImage;
private drawCanvas canvasFilteredImage;
private Label labelFilteredImage;
private Panel panelHelp;
private Label labelHelp;
private int Yspc;
private FilterImplementation theFilter;
public void init()
String string = null;
string = appletInitialize();
setBackground(bgColor);
if (string != null)
removeAll();
setBackground(Color.white);
setForeground(Color.black);
Label label = new Label(new StringBuffer("Error: ").append(string).toString(), 1);
Panel panel = new Panel();
panel.add(label);
add(panel);
setLayout(new FlowLayout(1, 5, Yspc));
public void keyPressed(KeyEvent keyEvent)
panelHelp.removeAll();
boolean flag = true;
if (KeyEvent.getKeyText(keyEvent.getKeyCode()).equals("Enter"))
for (int i = 0; i < nbParameters; )
try
paramsValue.setElementAt(new Double(textFieldParameters.getText()), i);
i++;
catch (NumberFormatException e)
labelHelp.setText(labelParameters[i].getText() + ": Not a Number");
flag = false;
break;
if (flag == 1)
labelHelp.setText(" .... Running, please wait .... ");
labelHelp.setAlignment(1);
panelHelp.add(labelHelp);
panelHelp.doLayout();
theFilter.updateParameters(paramsValue);
theFilter.computeFilter();
theFilteredImage = createImage(new MemoryImageSource(theFilter.getFinalImageWidth(), theFilter.getFinalImageHeight(), theFilter.getFinalImageBuffer(), 0, theFilter.getFinalImageWidth()));
canvasFilteredImage.setImage(theFilteredImage);
canvasFilteredImage.setBounds(0, 0, theFilter.getFinalImageWidth(), theFilter.getFinalImageHeight());
canvasFilteredImage.repaint();
panelHelp.removeAll();
labelHelp.setText("- Done -");
else
labelHelp.setText("- Press Enter to run the Filter -");
labelHelp.setAlignment(1);
panelHelp.add(labelHelp);
panelHelp.doLayout();
public void keyReleased(KeyEvent keyEvent)
public void keyTyped(KeyEvent keyEvent)
private String appletInitialize()
WinWidth = size().width;
WinHeight = size().height;
if (getParameter("bgcolor") == null)
bgColor = new Color(0, 0, 40);
else
bgColor = new Color(Integer.parseInt(getParameter("bgcolor"), 16));
if (getParameter("fgcolor") == null)
fgColor = new Color(255, 255, 255);
else
fgColor = new Color(Integer.parseInt(getParameter("fgcolor"), 16));
if (getParameter("sepcolor") == null)
sepColor = new Color(158, 128, 128);
else
sepColor = new Color(Integer.parseInt(getParameter("sepcolor"), 16));
if (getParameter("parcolor") == null)
parColor = new Color(24, 24, 24);
else
parColor = new Color(Integer.parseInt(getParameter("parcolor"), 16));
if (getParameter("titlecolor") == null)
titleColor = new Color(255, 255, 0);
else
titleColor = new Color(Integer.parseInt(getParameter("titlecolor"), 16));
if (getParameter("helpcolor") == null)
helpColor = new Color(0, 255, 255);
else
helpColor = new Color(Integer.parseInt(getParameter("helpcolor"), 16));
paramsName = new Vector();
paramsValue = new Vector();
paramsComment = new Vector();
paramFileName = getParameter("paramfile");
String string = readParams(paramFileName);
if (string != null)
return string;
MediaTracker mediaTracker = new MediaTracker(this);
theOriginalImage = getImage(getDocumentBase(), originalImageFileName);
mediaTracker.addImage(theOriginalImage, 0);
if (logoFileName != null)
theLogo = getImage(getDocumentBase(), logoFileName);
mediaTracker.addImage(theLogo, 1);
try
mediaTracker.waitForAll();
catch (InterruptedException e1)
return "Error while loading image";
if (mediaTracker.isErrorAny())
return "Error while loading image";
if (logoFileName != null)
logoWidth = theLogo.getWidth(this);
logoHeight = theLogo.getHeight(this);
imageWidth = theOriginalImage.getWidth(this);
imageHeight = theOriginalImage.getHeight(this);
theOriginalPixelArray = new int[imageWidth * imageHeight];
PixelGrabber pixelGrabber = new PixelGrabber(theOriginalImage, 0, 0, imageWidth, imageHeight, theOriginalPixelArray, 0, imageWidth);
try
pixelGrabber.grabPixels();
panelTitle = new Panel();
canvasTitle = new drawCanvas();
labelTitle = new Label();
panelTitle.setLayout(new FlowLayout(1, 10, Yspc));
add(panelTitle);
panelTitle.setBackground(bgColor);
panelTitle.add(canvasTitle);
canvasTitle.setImage(theLogo);
canvasTitle.setBounds(0, 0, logoWidth, logoHeight);
labelTitle.setText(title);
catch (InterruptedException e2)
return "Internal Error, Try RELOAD !";
if (title != null)
panelTitle.add(labelTitle);
labelTitle.setForeground(titleColor);
labelTitle.setFont(new Font("Dialog", 1, 14));
panelImages = new Panel();
panelOriginalImage = new Panel();
canvasOriginalImage = new drawCanvas();
labelOriginalImage = new Label();
panelFilteredImage = new Panel();
canvasFilteredImage = new drawCanvas();
labelFilteredImage = new Label();
panelImages.setLayout(new FlowLayout(1, 10, Yspc));
add(panelImages);
panelImages.setBackground(bgColor);
panelOriginalImage.setLayout(new BorderLayout(0, 2));
panelImages.add(panelOriginalImage);
panelOriginalImage.setBackground(Color.black);
panelOriginalImage.add("Center", canvasOriginalImage);
canvasOriginalImage.setImage(theOriginalImage);
canvasOriginalImage.setBounds(0, 0, imageWidth, imageHeight);
labelOriginalImage.setText(originalCaption);
labelOriginalImage.setAlignment(1);
panelOriginalImage.add("South", labelOriginalImage);
labelOriginalImage.setBackground(Color.lightGray);
labelOriginalImage.setForeground(Color.black);
labelOriginalImage.setFont(new Font("SansSerif", 0, 10));
panelFilteredImage.setLayout(new BorderLayout(0, 2));
panelImages.add(panelFilteredImage);
panelFilteredImage.setBackground(Color.black);
panelFilteredImage.add("Center", canvasFilteredImage);
theFilter = new FilterImplementation(paramsValue, theOriginalPixelArray, imageWidth, imageHeight);
theFilter.computeFilter();
theFilteredImage = createImage(new MemoryImageSource(theFilter.getFinalImageWidth(), theFilter.getFinalImageHeight(), theFilter.getFinalImageBuffer(), 0, theFilter.getFinalImageWidth()));
canvasFilteredImage.setImage(theFilteredImage);
canvasFilteredImage.setBounds(0, 0, theFilter.getFinalImageWidth(), theFilter.getFinalImageHeight());
labelFilteredImage.setText(filteredCaption);
labelFilteredImage.setAlignment(1);
panelFilteredImage.add("South", labelFilteredImage);
labelFilteredImage.setBackground(Color.lightGray);
labelFilteredImage.setFont(new Font("SansSerif", 0, 10));
scrollPaneParams = new ScrollPane(0);
panelParams = new Panel();
nbParameters = paramsName.size();
int i = WinHeight - (33 + 7 * Yspc + logoHeight + imageHeight + 23);
if (i < Yspc + 2 + 24)
i = Yspc + 2 + 24;
scrollPaneParams.setBounds(0, 0, WinWidth - 10, i);
panelParams.setLayout(new GridLayout(nbParameters, 1, 5, Yspc / 2));
scrollPaneParams.add(panelParams);
panelParams.setBackground(sepColor);
panelParameters = new Panel[nbParameters];
labelParameters = new Label[nbParameters];
textFieldParameters = new TextField[nbParameters];
labelComments = new Label[nbParameters];
for (int j = 0; j < nbParameters; j++)
panelParameters[j] = new Panel();
panelParameters[j].setLayout(new FlowLayout(0, 5, 1));
panelParams.add(panelParameters[j]);
panelParameters[j].setBackground(parColor);
labelParameters[j] = new Label();
labelParameters[j].setText((String)paramsName.elementAt(j));
panelParameters[j].add(labelParameters[j]);
labelParameters[j].setForeground(fgColor);
labelParameters[j].setFont(new Font("Dialog", 1, 12));
textFieldParameters[j] = new TextField(8);
textFieldParameters[j].setText(paramsValue.elementAt(j).toString());
panelParameters[j].add(textFieldParameters[j]);
textFieldParameters[j].setBackground(fgColor);
textFieldParameters[j].addKeyListener(this);
labelComments[j] = new Label();
labelComments[j].setText((String)paramsComment.elementAt(j));
panelParameters[j].add(labelComments[j]);
labelComments[j].setForeground(fgColor);
add(scrollPaneParams);
panelHelp = new Panel();
labelHelp = new Label();
panelHelp.setLayout(new FlowLayout(1, 5, 0));
add(panelHelp);
panelHelp.setBackground(bgColor);
labelHelp.setText(" Change colour values and press enter ");
labelHelp.setAlignment(1);
panelHelp.add(labelHelp);
labelHelp.setForeground(helpColor);
return null;
private String readParams(String string1)
Object object1;
String string2;
if (string1 == null)
return "Filename of filter's parameters needed";
try
URL uRL = new URL(getDocumentBase(), string1);
URLConnection uRLConnection = uRL.openConnection();
uRLConnection.setDoInput(true);
uRLConnection.setUseCaches(false);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(uRLConnection.getInputStream()));
string2 = null;
catch ()
return object1.getMessage();
catch ()
return object1.getMessage();
catch ()
return object1.getMessage();
if (bufferedReader != null)
Object object2;
try
for (object2 = bufferedReader.readLine(); object2 != null && string2 == null; object2 = bufferedReader.readLine())
string2 = extractFormat(object2);
catch ()
string2 = object2.getMessage();
finally
bufferedReader.close();
if (string2 != null)
return string2;
else
return null;
private String extractFormat(String string1)
if (string1.length() == 0)
return null;
int i = 0;
int j = string1.indexOf(" ", i);
if (j == -1)
return "Bad format error (space missing)";
String string2 = string1.substring(i, j);
if (string2.equals("TITLE"))
i = j;
j = string1.indexOf(34, i);
if (j == -1)
return "Bad format (Double quote in TITLE missing)";
i = j + 1;
j = string1.indexOf(34, i);
if (j == -1)
return "Bad format (Double quote in TITLE missing)";
title = string1.substring(i, j);
return null;
if (string2.equals("ORIGINALCAPTION"))
i = j;
j = string1.indexOf(34, i);
if (j == -1)
return "Bad format (Double quote in ORIGINALCAPTION missing)";
i = j + 1;
j = string1.indexOf(34, i);
if (j == -1)
return "Bad format (Double quote in ORIGINALCAPTION missing)";
originalCaption = string1.substring(i, j);
return null;
if (string2.equals("FILTEREDCAPTION"))
i = j;
j = string1.indexOf(34, i);
if (j == -1)
return "Bad format (Double quote in FILTEREDCAPTION missing)";
i = j + 1;
j = string1.indexOf(34, i);
if (j == -1)
return "Bad format (Double quote in FILTEREDCAPTION missing)";
filteredCaption = string1.substring(i, j);
return null;
if (string2.equals("LOGO"))
i = j + 1;
j = string1.length();
logoFileName = string1.substring(i, j);
return null;
if (string2.equals("ORIGINALIMAGE"))
i = j + 1;
j = string1.length();
originalImageFileName = string1.substring(i, j);
return null;
if (!string2.equals("PARAM"))
return null;
i = j;
j = string1.indexOf(34, i);
if (j == -1)
return "Bad format in a PARAM line";
i = j + 1;
j = string1.indexOf(34, i);
if (j == -1)
return "Bad format in a PARAM line";
paramsName.addElement(string1.substring(i, j));
i = j + 2;
j = string1.indexOf(32, i);
if (j == -1)
return "Bad format in a PARAM line";
try
paramsValue.addElement(new Double(string1.substring(i, j)));
j = string1.indexOf(34, i);
catch (NumberFormatException e)
return "Bad format in a PARAM line";
if (j == -1)
return "Bad format (Double quote in PARAM comment missing)";
i = j + 1;
j = string1.indexOf(34, i);
if (j == -1)
return "Bad format (Double quote in PARAM comment missing)";
paramsComment.addElement(string1.substring(i, j));
return null;
public EasyFilter()
logoHeight = 33;
Yspc = 5;

Addition to my above submission
To clarify, I'll offer the US$20 to the FIRST person who offers me a workable solution to the problem, not to everyone!!!
JMGRAHAM

Socket communication failure between Java applet and C++ application

I have a java applet that connects to a C++ application via Java's ServerSocket and Socket objects. THe C++ application is using the Winsock 2 API. The applet and application are running on an NT workstation (SP 6) and using IE (5.5) For a very simple C++ test applications the communictions work fine. Once more code gets added to the C++ application the portion of the socket that C++ listens to seems to close. Upon performing a recv call the return value is a zero. Microsoft insists this is a sign the Java side has shut down the socket. The Java applet can still receive messages from the C++ app but C++ cannot receive responses from the Java side. Java throws no exceptions and an explicit check of the socket shows no errors. Again, what puzzles me is that it works for simple C++ applications. Are there any known conflicts between Java and C++ in this regard?
I have inlcuded the basic java code segments below.
/ run Method.
* This method is called by the Thread.start() method. This
* method is required for the implementation of the Runnable interface
* This method sets up the server side socket communication and
* contiuously loops looking for requests from a external
* socket.
* @author Chris Duke
public void run(){
     // create socket connections
     boolean success = false;
     try {
         cServerSocket = new ServerSocket(cPortID);
         System.out.println("Waiting for client to connect...");
         cClientSocket = cServerSocket.accept();
         System.out.println("Client connected");
         // Create a stream to read from the client
         cInStream = new BufferedReader(new InputStreamReader(
           cClientSocket.getInputStream()));
         // Create a stream to write to the client
         cOutStream = new PrintWriter(
           cClientSocket.getOutputStream(), true);
         success = true;
     }catch (IOException e) {
         System.out.println("CommSocket:Run - Socket Exception(1) " + e);
         success = false;
     // if the socket was successfully created, keep the thread running
     while (success){
         try{
            // check socket to see if it is still available for reading
            if (cInStream != null && cInStream.ready()){
                // check for an incoming message
                String message = ReceiveMessage();
                // Send message to listeners
                Event(message);
            if (cInStream == null){
                success = false;
                System.out.println("CommSocket:Run - shutdown");
         }catch (IOException e){
            System.out.println("CommSocket:Run - Socket not ready exception");
            break;
// SendMessage method -
* Sends a text message to a connected listener through port specified by portID
* @author Chris Duke
* @param String message - This will be the message sent out through the server
* socket's port specified by portID.
   public void SendMessage(String message){
      cOutStream.println(message);
      if (cOutStream.checkError() == true)
        System.out.println("SendMessage : Flush = Error");
      else{
        System.out.println("SendMessage : Flush - No Error");
   }

a very simple C++ test applications the communictions work fine. Once more code gets added to the C++ application the portion of the socket that C++ listens to seems to close.
This quite strongly implicates the extra code in the C++ App. The firstly thing I would try would be telnet. Try connecting to both versions of the C++ Application and manually reproducing a proper exchange.
a recv call the return value is a zero. Microsoft insists this is a sign the Java side has shut down the socket.
A correct implementation of recv should return the number of bytes received, or -1 for an error. A zero return indicates no bytes received not a socket closed/error. This sounds like FUD to me.
Are there any known conflicts between Java and C++ in this regard?
I can see no obvious faults, though the code is incomplete, I don't think it's an sockets implementation issue, at either end, it sounds more likely to be a protocol/handshaking bug in the C++ App.

Call Javascript Function in my JAVA Applet

Hello every body,
I would like to be able to call a javascript function in my Java applet.
I know to call JAVA function with a javascript function but not inverse.
Someone can help me please ?

Look at chapters 25/26 (or so) in Sun's Plugin Developer's Guide.

Applet javascript communication

hi all,
I want my applet to flash the browser window, came to know that can be done
using applet javascript communication.
ne1 has ne idea how to do that.
thx in adv,
kiran

???

Calling a Java Applet - Javascript

Hey guys,
I'm still fairly new to Java. I'm having a hard time getting my Applet to run properly.
Basically, this is what I want it to do:
I have a web page with a series of fields on it (a form). I have a submit button. When the user clicks the submit button, it activates a Javascript function in a seperate file that validates ALL of these fields. The validation that it does is merely to determine whether or not the fields are blank.
Once it's accomplished this task, I THEN want it to run a Java applet.
Everything works up until the point at which it runs the Java applet. I'm not sure how exactly I'm supposed to call the applet from Javascript.
In every example of a web page that I see that has an applet, it has something that looks like this:
<APPLET CODE="classname.class >
</APPLET>That's all fine and good, but the problem is that it automatically calls the Applet then. I don't want it to do that. Is there a way that I can CALL the applet at the very end of a JS file? I mean, I don't want anything to load, no grey boxes or any of that stuff until I actually call it..
Any idea?
Thanks!
Todd

dude,
have you managed to call an applet method from firefox?
I'm not sure it is working at all.
I've read few articles and everyone is complaining about the same error:
Error: document.appl01 has no properties
in the case above the applet was called "appl01"
I've tried using
document.applets[0].<the applet method>
and I've got the same result..

Easy way to convert javascript to a java applet?

Hello all! I am relatively new to java and java programming and had a question about converting a JavaScript to a java applet or even a standalone application. I included the JavaScript code for a checkers game below and wanted to know what would be the easiest way to convert this code if at all possible?
Thanks in advance,
Bob
<SCRIPT language=JavaScript>

</SCRIPT>
<SCRIPT language=JavaScript1.1>

</SCRIPT>
<SCRIPT language=JavaScript>

</SCRIPT>
<SCRIPT language=JavaScript1.1>

</SCRIPT>

Well, you can get a free tutorial to Java at http://www.mindview.net/. It's the "Thinking In Java" book. You can download the whole book from that site, it's about a thousand pages. If you read that whole book, you'll know exactly where to start and probably how to finish it too.
As a gimmie, think about it -- you'll have to remove all of the browser-detect code, since browser-detection is only done to determine which version of JavaScript is supported by the browser.

Java Applet Communication

I have discovered that a Java Applet in a browser (Win or Mac) can talk to a Servlet on a server to access a database.
Is there anyway that a Java Applet in a browser (Win or Mac) can talk to a Java application running on the client system so that it can access local databases?
I was thinking something like writing cookies and then using the java application to read the contents and act accordingly. This would obviously be slow as far as feedback is concerned, is there a quicker or better way?
Thanks
James.

I had the same problem and i had to implement a server running on my local machine.
The servlet on the server allow me to access the local database.
As for trying to change the policy tool.....it's a nightmare.
I would recommend you to use a applet-servlet communication..

Java Applet to Javascript Communication

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