Attaching a JOptionFrame to an Applet
Is it possible to attach a JOptionPane to an applet? If so how can this be done?
Thanks.
I already have Null in but it still does not seem to work. Bellow I have giving an example of what my JOptionPane looks like.
Any other suggestions?
Code:
JOptionPane.showMessageDialog(null, "The remote password has expired! Contact System Administrator to re-activate account", "Tacacs+ Error", JOptionPane.WARNING_MESSAGE);
Similar Messages
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Emailing attached HTML file with embedded applet
Are there any mail servers that could reject emails with attached HTML file that includes embedded applet in a Java Plug-in Object tags? It has an absolute path to a server where the applet resides.
I have seen very few cases where Symantec Anti Virus filter is dropping the messages because of a mime problem. It appears that only two workarounds are to upgrade the Symantec product and to bypass our domain.
Is there anything I could do to prevent the mime problem issue? I hope the Java applet is not an issue.
Johnpberardi1,
I hope you get better soon from the accident you must have had. Surely you must be in the hospital or something, otherwise by now surely you'd have had the courtesy to say a simple
"Thank you".
So,
"You're welcome". -
Java Attach API - Installing Agents on Applets - Problem?
When I attempt to install an agent on a signed applet and try to start a thread I get a SecurityException, any solutions?
Hello,
I suspect you got zero replies because:
1) A vast majority of readers here don't know what the Attach APi is. I didn't either, until I took the endeavour to search what it was (and I still know very little about this now)
The form of your post is guilty here: you didn't take into account that your question was quite specific on a quite specific point of the Java ecosystem, and you haven't provided references for people who might want to help on this little-known area.
For those interested:
http://publib.boulder.ibm.com/infocenter/realtime/v2r0/index.jsp?topic=/com.ibm.rt.doc.20/user/attachapi.html
http://blogs.oracle.com/sundararajan/entry/using_mustang_s_attach_api
2) As far as I could tell after traversing the first couple of links returned by a quick search, the (Java) Attach API is not a part of the JVM specifications, and is left to JVM implementors to provide; apparently Sun and IBM do provide one proprietary API each. Note that there is the
Again the form of your post is questioned: exactly which VM/API are you using?
3) Your posts gives little details about what you are doing, little detail about what you get (a SecurityException generally comes loaded with an informative message), and no detail at all about what you have tried so far to investigate this issue. This doesn't help making people want to dig.
This article comes to mind: http://www.catb.org/~esr/faqs/smart-questions.html#id443939 -
Static variable, a bug in applet classloader, Java plug-in?
I found a potential bug in java plug-in.
Environment,
1. IE 6.0
2. Windows XP
3. JRE 1.3.1.06 and JRE 1.4.1.01
Steps,
1. build a very simple applet (attached below)
2. embed the applet into a .html page.
3. enable java plug-in for IE and Netscape.
4. launch the .html page in either of the two browsers.
5. for the 1st time, I can see 'tmp = 0' in the java console window.
6. keep the browser open, browse to 'www.google.com'
7. click 'Back' button of the browser.
8. I notice 'tmp = 1' in the java console window.
9. if I browse to google.com and back again, it will display 'tmp = 2'. and the number will keep on increasing if I repeat those steps.
10. But if I press F5 to refresh the page, the log message will go back to 'tmp = 0'. and if I press 'x' inthe console window to clean up the classloader cache, I will get 'tmp = 0'. If I close the browser and open a new one, I will still get 'tmp = 0', which is what the applet should output.
11. If I click 't' in the console window to list the thread while I am in the 'google' page, I can't see the applet thread, which means the applet should have been destroyed.
12. No matter I try 'g' to do garbage collect, or 'f' to finalize objects, the problem still happens. the only solution is what I did in the step 10.
Is it a bug in the classloader or the JRE itself? Why the value of the static variable won't be cleaned up along with the applet?
----------- HERE IS THE APPLET --------------------
import java.applet.Applet;
public class AA extends Applet
private static long tmp = 0;
public void init() {
System.out.println("tmp value = " + tmp);
tmp++;
public void start() {}
public void stop() {}
public void destroy() {}Static values are stored in the class. Once a class is loaded into a classloader, it cannot be unloaded (the only thing you can do is use another classloader).
Apparently, the classloader cache allows sharing of classloaders between applet instances. Perhaps F5 (reload) causes the classloader cache to be cleared.
I don't see any bug. When developing applications or applets that must run in the same JVM, you should program defensively and avoid using static values which can change over time. -
Plugin login appears after initial weblogic everytime applet makes http request
When I visit a page I get the initial login to the page via the realm followed
by a java plugin loging (shown in attached pictures) every time the applet makes
an http request. This stops the applet working, any idea how I can solve this?
[pictures.doc]Any idea how to do thisn not really sure what you mean. I already inclued the session
Id in the URL. Code we use to open connection is
URL url = new URL(serverProtocol + "://" + serverName + ":" + serverPort + "/"
+ servlet + ((sessionId==null)?"":"?sessionid=" + sessionId));
URLConnection uc = url.openConnection();
uc.setDoOutput(true);
uc.setDoInput(true);
uc.setUseCaches(false);
uc.setRequestProperty("Content-type", "java-internal/" + object.getClass().getName());
Robert Patrick <[email protected]> wrote:
If you are making HTTP requests from within an applet, you will need
to provide the
right HTTP headers to correctly identify that each subsequent request
is from the
previously logged-in user (e.g., the cookie that contains the WLS session
ID
attached to the response from logging in).
andrea bates wrote:
When I visit a page I get the initial login to the page via the realmfollowed
by a java plugin loging (shown in attached pictures) every time theapplet makes
an http request. This stops the applet working, any idea how I cansolve this?
Name: pictures.doc
pictures.doc Type: WINWORD File (application/msword)
Encoding: base64 -
I probably cant see the wood for the trees, but no mater how hard I try, I cannot debug an applet class. Whenever I right-click and run I get
init:
deps-jar:
compile-single:
run-applet:
Warning: <param name=... value=...> tag requires name attribute.
Warning: <param name=... value=...> tag requires name attribute.
Warning: <param name=... value=...> tag requires name attribute.
Warning: <param name=... value=...> tag requires name attribute.
BUILD SUCCESSFUL (total time: 0 seconds)
I have followed the help guide and have the html file in the src directory. I can run the html file ok in a normal browser. but for the life of me I cannot see where or how to either attach the debugger to the applet process, or even run it and hit a breakpoint.
I canot run it like a normal application as there is no "Main Class" and trying to set that up is a nightmare in itself. I have only just started using the IDE and although it has similarities with .NET (hope thats not a bad word here) it does seem to be a lot more complex when youre trying to recall everything you forgot from years ago.
Can anyone explain is an easy straight foward basic language what I need to do ? I find the help files assume that one already has a vast amount of background. The learning curve for me is very steep at the moment.
Thanks for your time and help.
KessQuote:
Copy the MyApplet.html launcher file from the build folder to the package where the applet class lives in the src folder (in this case, to org.me.hello). Make sure that the MyApplet.html launcher file has the same name as the applet class.
Note that later it says....
Note that applets run in the virtual machine of the IDE's default web browser. The IDE uses a different virtual machine and therefore applets are not included in a web application's debug session. Debug the applet within the Java project, as explained above.
So, if you create the htm file and add in some parameters, it becomes a web application and the caveat is that no breakpoints can be set and you cant step into the code.
Which is the problem I am having.
Of course none of the examples or help pages only ever give the most simplest of the "Hello Word" examples, and it would appear that doing something a little more complex is beyond the help articles.......
I am still stuck, and would much prefer someone to state excatly how to debug an applet.....
I cant believe this beyond some of the experts here.
Thanks for your comments so far. -
Hi,
I need my code to have a scroll bar. Such that I can add more JTextAreas and they will only be displayed if the user scrolls vertically so they can see the content.
My code is attached.
Thanks
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt. Toolkit;
public class eg extends JFrame {
JPanel draw;
JLabel label;
JLabel img;
JLabel hse;
JLabel off;
JLabel pic1;
JTextArea sum;
JTextArea ln1;
JTextArea ln2;
public eg() {
JLabel img = new JLabel(new ImageIcon("flat.jpg"));
JLabel hse = new JLabel(new ImageIcon("house.gif"));
JLabel off = new JLabel(new ImageIcon("office.jpg"));
JTextArea sum=new JTextArea("",2,0);
JScrollPane pane= new JScrollPane(sum);
sum.setText("Pictures");
sum.setEditable(false);
JTextArea ln1=new JTextArea("",2,0);
ln1.setBackground(Color.white);
JScrollPane pane1= new JScrollPane(ln1);
ln1.setText("House");
ln1.setEditable(false);
JTextArea ln2=new JTextArea("",2,0);
ln2.setBackground(Color.white);
JScrollPane pane2= new JScrollPane(ln1);
ln2.setText("Office ");
ln2.setEditable(false);
addWindowListener(new WindowAdapter() {
public void windowClosing (WindowEvent e) {
System.exit(0);
Box b1 = Box.createVerticalBox();
Box b2 = Box.createHorizontalBox();
Box b3 = Box.createHorizontalBox();
Box b4 = Box.createHorizontalBox();
Box b5 = Box.createHorizontalBox();
Box b6 = Box.createHorizontalBox();
Box b7 = Box.createHorizontalBox();
Box b8 = Box.createHorizontalBox();
Box b9 = Box.createHorizontalBox();
Box b10 = Box.createHorizontalBox();
Box b11 = Box.createHorizontalBox();
Box b12 = Box.createHorizontalBox();
Box b13 = Box.createHorizontalBox();
Box b14 = Box.createHorizontalBox();
b1.add(b2);
b1.add(b10);
b10.add(Box.createRigidArea(new Dimension(8,8)));
b1.add(b4);
b4.add(Box.createRigidArea(new Dimension(8,8)));
b4.add(sum);
b4.add(Box.createRigidArea(new Dimension(8,8)));
b1.add(b11);
b11.add(Box.createRigidArea(new Dimension(8,8)));
b1.add(b5);
b5.add(Box.createRigidArea(new Dimension(8,8)));
b5.add(img);
b5.add(Box.createRigidArea(new Dimension(8,8)));
b5.add(ln1);
b5.add(Box.createRigidArea(new Dimension(8,8)));
b1.add(b12);
b12.add(Box.createRigidArea(new Dimension(8,8)));
b1.add(b7);
b7.add(Box.createRigidArea(new Dimension(8,8)));
b7.add(hse);
b7.add(Box.createRigidArea(new Dimension(8,8)));
b7.add(ln2);
b7.add(Box.createRigidArea(new Dimension(8,8)));
b1.add(b13);
b13.add(Box.createRigidArea(new Dimension(8,8)));
b1.add(b8);
b8.add(Box.createRigidArea(new Dimension(8,8)));
b8.add(off);
b8.add(Box.createRigidArea(new Dimension(8,8)));
b1.add(b14);
b14.add(Box.createRigidArea(new Dimension(8,8)));
this.setBackground(Color.yellow);
this.getContentPane().add(b1);
this.pack();
this.show();
public static void main(String [] args) {
eg e = new eg();
class PicturePanel extends JPanel {
public void paintComponent(Graphics g) {}}}The actual bar itself? No i dont beleive see so. This is all handled by the OS in one of he GUI kits devleopers use. IF on the otherhand you mean a way to make the columns wider in the Finder when in column view, thats a yes. Below he scroll down arro there is a little square with some line on it... click and drag this horizontally and it will increase the widht of a column.
-
Number of Files in same copied DIR Differs
any ideas why when i copy a dir from one drive to another, both formatted with OS Extended Journalled, tat the file numbering differs? One drive had the DIR on, i copied across to another which didn't have it on, thus a clean copy, no overwriting, and source drive says 45 items, destination says 50, as per the image attached..
Im running the applet from the webserver.
So it is not possible?An applet is always run client-side. The Java plugin for the browser you're using downloads the applet from the browser and runs it locally.
Don't let the fact that your client and server might be the same machine confuse you, they are still seperate entities.
If however you're not running this with a browser, but with an applet viewer I don't know. The general rule is that applets can't get access to the client filesystem, I guess that still holds true when using viewers other than browsers. -
How to attach files using an applet
hi,
i want to know how can i use an applet to upload or attach files in my application
help meHallo there,
I am intrested on the same topic but I am not so good to modify the sound sdk demo. Is there anyone willing to share some code?
Thanks
Matteo -
JavaMail Applet with sending attachment
hello everybody,
Do u have any samples about sending attachment by using JavaMail Applet?
You will be very appreciated if u can send me the Java source code.
Thanks very much!
Best rgds.~
AlphaIf you are going to run this from a webpage I would suggest that you change your approach and look into doing this server side. The security restrictions placed on applets will cause all kinds of problems. Just to name two:
1. An applet can only communicate with the server it came from. This means that the SMTP server and the web server must be on the same machine.
2. An applet cannot access the file system on the local machine. Just imagine the security holes that would be there if it could.
One solution for these problems is to sign the applet, but after working on this approach for several days I decided to do everything with servlets instead. -
How can I attach a policy file to a applet in IE55?
I want to use jdbc in applet, so I had to run IE55 with a policy file, how can I set it?
thant u very much.Search the JDBC forum. It has been explained in there.
-
Hi;
Could anyone help me to convert my example code from applet to swing,please, thank
import java.awt.*;
import java.applet.*;
import java.lang.Math;
import java.awt.Font;
import java.lang.Integer;
/*** Main class == Applet ***/
public class Suffix extends Applet implements Runnable {
private Thread main;
public s_tree _tree=null;
public node nd=null;
public boolean userPause=false,resumed=false;
private String str[]={"GOOGOL$","Paused","Resumed","Compacting","Done"};
public Color bl=Color.blue,rd=Color.red;
public Font fnt;
public int mode=3,delay=3000;
private char alph[]={'$','Q','W','E','R','T','Y','U','I','O',
'P','A','S','D','F','G','H','J','K','L',
'Z','X','C','V','B','N','M'};
/*** initialisation function. It is the first Funct to be called ***/
public void init() {
// Temp data
int temp=0,nxx=30;
// Ini. of fnt , the font size + style used by this applet.
fnt=new Font("Denis",1,25);
/*** parsing command parameters ***/
// try {
//DELAY VALUE PARAM
String param=getParameter("DELAY");
if (param!=null) {
temp=Integer.parseInt(param);
if ((temp>500)&&(temp<6000)) delay=temp;
//x LEFTMOST coordinate
param=getParameter("X");
if (param!=null) {
temp=Integer.parseInt(param);
nxx=temp;
//Base String parameter
param=getParameter("STRING");
if ((param!=null)&&(param.length()<15)) {
str[0]=param;
// } catch (ParseException e) { showParseError(e); }
// Allocating mem for _tree + initialize it .
_tree=new s_tree(str[0],fnt);
// Override xx (left_bound) by the caller's or the default value
_tree.xx=nxx;
/*** "animation loop is controled here" ***/
public void run() {
while(true) {
try {
//delay the process for time==delay
Thread.sleep(delay);
} catch (InterruptedException e) {}
//controls animation loop
repaint();
/*** override APPLET's paint function ***/
public void paint (Graphics g) {
//Output graphics
update(g);
/*** Updates the graphics ***/
public void update (Graphics g) {
// Set font
if (g.getFont()!=fnt) g.setFont(fnt);
if ((userPause==false)&&(resumed==false)) // Is the applet paused ?
g.clearRect(0,0,1024,768); //clears the screen
if (_tree==null) { // if tree is not initialised
init();
//_tree.show(g);
} else {
if (mode==3) { // if graphics output mode is 3
if (nd!=null) nd._to_rd(false);
nd=_tree.step_compact(nd); //compacts the tree one step further
if (nd==null) // if tree is totally compacted ...
mode=4; //change the ani. mode to 4 (don't call compact)
else
nd._to_rd(true); //colors the next node to compact in red
// Draw the "titleviewport's" comment
g.setColor(bl);
g.drawString(str[mode],10,15);
_tree.show(g); //show tree
} else {
g.clearRect(0,0,200,25); //clears the "titleviewport to update it"
g.setColor(rd);
if (resumed==true){
resumed=false;
g.drawString(str[2],10,15);
else g.drawString(str[1],10,15);
/*** restart the animation process ***/
public void start() {
main=new Thread(this);
main.start();
/*** stops the animation ***/
public void stop() {
main.stop();
main=null;
/*** Handles the user's events (mouse , kbd , ... ***/
public boolean handleEvent(Event evt) {
if (evt.id==Event.MOUSE_DOWN) { //if mouse button have been pushed ...
if (main!=null && main.isAlive()) {
if (userPause) {
main.start();
resumed=true;
} else {
main.stop();
userPause= !userPause;
} else {
main= new Thread(this);
main.start();
userPause=false;
resumed=true;
repaint();
return true;
} else {
return super.handleEvent(evt);
/*** Linked List of node(s) ***/
class nodelist{
nodelist next=null;
node ptr=null;
public void nodelist(){};
/*** node of a structure tree ***/
class node {
// Relatives
public nodelist children=null;
public node parent=null;
// variables
public int maxchild=12,childnum=0,level=0;
public int center[]={0,0};
public int xlen=20,ylen=10,vspace=15,hspace=8;
public int x[]={0,0};
public boolean _ishidden=false;
private Color bk=Color.black,wh=Color.white,rd=Color.red;
// Node==red toggle variable
public boolean to_rd=false;
// node's text
public String label=null;
/*** initialisation of the node ***/
public node(int nx,int ny,int nxl,int nyl,node nparent,int nlevel,String nstr){
x[0]=nx; x[1]=ny;
xlen=nxl; ylen=nyl;
parent=nparent;
level=nlevel;
label=new String(nstr);
children=new nodelist();
/*** destroys the node ***/
public void destruct() {
// NOTE : not like C++ destructors . Do not confuse .
delete_subtree();
children=null;
parent=null;
bk=wh=rd=null;
label=null;
/*** Node to red toggle switch ***/
public void _to_rd(boolean b) {to_rd=b;};
/*** Adds a child to this node ***/
public void add_child(int nx,int ny,int nxl,int nyl,node nparent,int nlevel,
String nstr) {
if (childnum<maxchild) { // if 'legal' space left ...
if (children==null) { // if no nodelist attached ...
children=new nodelist(); //init. children
children.ptr=new node(nx,ny,nxl,nyl,nparent,nlevel,nstr); //create node
childnum++;
} else {
nodelist dummy=children;
// search for the last nodelist
while (dummy.next!=null) dummy=dummy.next;
dummy.next=new nodelist(); //adds a nodelist
dummy=dummy.next;
dummy.ptr=new node(nx,ny,nxl,nyl,nparent,nlevel,nstr); //create child
childnum++;
// Tree needs to be realigned
/*** adds a child and returns its address ***/
public node add_child_ret(int nx,int ny,int nxl,int nyl,node nparent,int nlevel,
String nstr) {
if (childnum<maxchild) {
if (children==null) {
children=new nodelist();
children.ptr=new node(nx,ny,nxl,nyl,nparent,nlevel,nstr);
childnum++;
return(children.ptr);
} else {
nodelist dummy=children;
// search for the last child
while (dummy.next!=null) dummy=dummy.next;
dummy.next=new nodelist();
dummy=dummy.next;
dummy.ptr=new node(nx,ny,nxl,nyl,nparent,nlevel,nstr);
childnum++;
return(dummy.ptr);
return(null);
// Tree needs to be realigned
/*** adds the node nchild as a new children ***/
public void add_child(node nchild) {
nodelist dummy=null;
dummy=children;
if (childnum<maxchild) {
if (children==null) {
children=new nodelist();
children.ptr=nchild;
childnum++;
} else {
while (dummy.next!=null) dummy=dummy.next;
dummy.next=new nodelist();
dummy=dummy.next;
dummy.ptr=nchild;
childnum++;
//Tree needs to restructured.
/*** deletes all childrens ***/
public void delete_subtree() {
while (childnum>0 && children!=null) { //while child exists , kill it
if (children.ptr!=null) {
children.ptr.destruct();
children.ptr=null;
children=children.next;
} else children=null;
childnum--;
/*** moves this node and its children horizontally ***/
public void move_tree(int nx) {
nodelist dummy=children;
x[0]+=nx;
while (childnum>0 && dummy!=null) {
if (dummy.ptr!=null) {
dummy.ptr.move_tree(nx);
dummy=dummy.next;
/*** removes the node from the tree (do not preserve order of ordered tree ) ***/
public void remove_node() {
nodelist dummy=children;
while(dummy!=null) {
if (dummy.ptr!=null){
parent.add_child(dummy.ptr);
dummy=dummy.next;
children=null;
//could call restructure tree here .
//don't forget to change the node's levels !!!
/*** show all nodes ***/
public void show_all(Graphics g) {
if (_ishidden==false) { //if not hidden
if (children!=null) { //if child exist
nodelist dummy=children; //temp var.
while(dummy!=null) { //while there is a child...
if (dummy.ptr!=null)
dummy.ptr.show_all(g);
dummy=dummy.next;
show_node(g);
/*** show nodes in preorder ***/
public int preorder_show(Graphics g,int label){
if (_ishidden==false) {
show_node(g/*,label++*/);
if (children!=null) {
nodelist dummy=children;
while(dummy!=null) {
if (dummy.ptr!=null) label=dummy.ptr.preorder_show(g,label);
dummy=dummy.next;
return(label);
/** show nodes in postorder ***/
public int postorder_show(Graphics g,int label){
if (_ishidden==false) {
if (children!=null) {
nodelist dummy=children;
while(dummy!=null) {
if (dummy.ptr!=null) label=dummy.ptr.postorder_show(g,label);
dummy=dummy.next;
show_node(g/*,label++*/);
return(label);
/*** show nodes in inorder ***/
public int inorder_show(Graphics g,int label){
if (_ishidden==false) {
if (children!=null) {
nodelist dummy=children;
if (dummy.ptr!=null) label=dummy.ptr.inorder_show(g,label);
dummy=dummy.next;
show_node(g/*,label++*/);
while(dummy!=null) {
if (dummy.ptr!=null) label=dummy.ptr.inorder_show(g,label);
dummy=dummy.next;
} else show_node(g/*,label++*/);
return(label);
/*** Restructure the coordinates of all nodes ***/
public int align(int min,Font fnt,int lev,Graphics g){
int i=min; //left bound
FontMetrics fntm=g.getFontMetrics(fnt); //used to know the text size
level=lev;
// node x and y radius are computed here
xlen=4+(int)(fntm.stringWidth(label)/2);
ylen=4+(int)(fntm.getHeight()/2);
if (children!=null) { //if child present ...
nodelist dummy=children;
while(dummy!=null) {
if (dummy.ptr!=null) i=dummy.ptr.align(i,fnt,lev+1,g); //align them
dummy=dummy.next;
x[0]=min+(int)((i-min)/2); //could be underflow so will be checked
x[1]=lev*(vspace+(ylen*2))+26;
// overflow should happen only when the parent node is larger than its children
if ((x[0]-xlen)<min) { //check uf underflow occurs.
move_tree(min+xlen-x[0]+1);
i=x[0]+xlen+5;
if (childnum==0) x[0]+=2;
return(i);
/*** returns the child following nd ***/
/*** if nd==null -> return 1st child ***/
/*** if nd==last children -> return null***/
public node next_child(node nd) {
nodelist dummy=null;
if (children==null) return(null);
if (nd==null) return(children.ptr);
dummy=children;
while (dummy.ptr!=nd) {
if (dummy.next!=null)
dummy=dummy.next;
else
return(null);
dummy=dummy.next;
if (dummy!=null) return(dummy.ptr);
else return(null);
/*** returns child with first letter==nh ***/
public node get_childd(char ch) {
nodelist dummy=null;
dummy=children;
while (dummy!=null) {
if (dummy.ptr!=null) {
if (dummy.ptr.label.charAt(0)==ch)
return(dummy.ptr);
dummy=dummy.next;
return(null);
/*** returns the nodelist containing nd ***/
public nodelist get_child(node nd) {
nodelist dummy=children;
while (dummy!=null) {
if (dummy.ptr==nd) return(dummy);
dummy=dummy.next;
return(null);
/*** outputs the node to Screen ***/
public void show_node(Graphics g) {
if (_ishidden==false) {
if (level>0) { //if it is not a root then draw link-line
g.setColor(bk);
g.drawLine(x[0],x[1]-ylen,parent.x[0],parent.x[1]+parent.ylen); //from this node to parent node
if (to_rd==false)
g.setColor(wh);
else
g.setColor(rd);
g.fillOval(x[0]-xlen,x[1]-ylen,xlen*2,ylen*2); //draws an oval
g.setColor(bk);
g.drawString(label,x[0]-xlen+4,x[1]+ylen-12); //output the text
/*** class which uses nodes to create a SUFFIX TREE ***/
class s_tree {
node root=null; // root node.
String str=null; // 'search' string
Font fnt=null; // font type
int xx=30; // left limit for graphics
/*** initialize a SUFFIX TREE with string==nstr and Font==nfnt ***/
public s_tree(String nstr,Font nfnt) {
str=new String(nstr);
fnt=nfnt;
create();
/*** uninitialize the structure **/
public void destruct() {
root.destruct();
str=null;
fnt=null;
/*** show the tree ***/
public void show(Graphics g) {
root.align(xx,fnt,0,g); // restructure node's coordinates
root.show_all(g); //show tree
/*** creates a tree structure from String=str ***/
public void create() {
node dummy=null;
root=new node(0,0,0,0,dummy,0," "); //create root
root.parent=null; //just to make sure ...
for (int i=0;i<str.length();i++) {
// Create subtree of root in the following way :
// create subtree ("ASDF$");
// " " ("aSDF$");
// " " ("asDF$"); ...
// where : the UPPERCASE letters is the part of the string sent to insert_string
insert_string(str.substring(i));
//root.align(0,fnt,0); //align root now ?
/*** creates a subtree of ROOT with String=nstr ***/
public void insert_string(String nstr) {
node dummy2=null,dummy=null;
int i=0;
dummy=root;
dummy2=root;
// As long as a children of dummy2 have the letter nstr[i] , dummy==thischildren
// It is used to make sure that a node does not have two children with the
// same letter
while (dummy2!=null) {
dummy2=dummy2.get_childd(nstr.charAt(i));
if (dummy2!=null) {
i++;
dummy=dummy2;
//create the nodes for the rest of the string
for(;i<nstr.length();i++) {
if (dummy!=null) dummy=dummy.add_child_ret(0,0,0,0,dummy,1,nstr.substring(i,i+1));
// Compacts the tree node by node and returns the next node to compact
// if node==null , compacts the first node ...
//Works in POST-ORDER
public node step_compact(node nd) {
node dummy=nd,dummy2=null;
nodelist ndlst=null;
// GOES TO THE LOWER LEFT CHILDREN
if (nd==null) { //first call !
dummy=root;
while(dummy.children!=null) {
if (dummy.children.ptr==null)
dummy.children=dummy.children.next;
else
dummy=dummy.children.ptr;
//*** tries to find a 'compactable' node ***
//*** It uses the POST-ORDER method ***
// if this node is not the last children then try to find next compactable node
// in the next children.
if (dummy.parent.childnum!=1) dummy=next_chain(dummy);
if (dummy==null) return(null); //fully optimized
//remove parent node.
/*** THIS IS WHERE COMPACTING TAKES PLACE **/
dummy2=dummy.parent.parent;
ndlst=dummy2.get_child(dummy.parent);
if (ndlst==null) return(null); //we've got a beeeeg problem if this happens ...
//*** merges the parent string with this one and delete parent .
dummy.label=dummy.parent.label.concat(dummy.label);
ndlst.ptr=dummy;
//delete parent .
dummy.parent=null;
dummy.parent=dummy2;
// root.align(0,fnt,0);
return(dummy);
/*** finds the next chain in the tree (i.e. the next compactable node) ***/
public node next_chain(node nd){
node dummy=null;
if (nd.parent==null) return(null); //finished ! This is the root
if (nd.parent.childnum==1) return(nd); //can be optimized
// finds the nd.parent's child following nd
dummy=nd.parent.next_child(nd);
if (dummy==null) // if OLD_nd==last child
return(next_chain(nd.parent)); //tries to find a chain upwards
else {
// OLD_nd was not the last child . nd==OLD_nd's next brother
// GOES TO THE LOWER LEFT most child of nd's subtree.
while(dummy.children!=null) {
if (dummy.children.ptr==null)
dummy.children=dummy.children.next;
else
dummy=dummy.children.ptr;
return(next_chain(dummy)); // returns the next compactable node
};First, show me the rupees! Show me the rupees!
-
Floating boxes applet with drag events need click event
I Have an applet cobbled from the net & modified. Is works but needs one major event added. It draws "Graphics.drawline" boxes with a text "String" inside each box ( the text string represents an URL location). These "boxes" are objects which are "draggable to other locations on canvas & therefore can be independently positioned by user. Each box redraws itself periodically to a slightly different screen location & becomes stationary after a 5 or 6 seconds. The point is, all of this "drag & mobility" behavior must remain intact & is not part of the "problem task".
Task: Need to have an "event" behavior added in one of two ways ( or a 3rd way if there is another ) whichever is quickest/ easiest. "Clickable mouse events" must be added to each box. ( boxes are built in a loop so adding to one will add to other locations & create as many "buttons" as there are boxes) . At each box's location, clicking one box should be an event which fires & clicking a different box should be a separate event which fires. Separate , so that URL location can be "hotlinked" to each box. That URL is currently displayed in the boxes (visible when running applet).
1st possible solution: Exchange these "boxes" which appear on canvas into clickable event "Graph panel.buttons" ( for example or some other clickable object) which maintains existing "drag" behavior of boxes. These buttons must each have "clickability" with mouse events to enable placing "getAppletContext. showDocument()" code with these events ( e.g., "hotlinked" to http locations).
or
2nd possible solution:. The drawstring boxes are currently dead string text with no event model other than the "drag" feature associated with each box. Must add an additional mouse event behavior to existing boxes so they are "clickable" ( or text inside is clickable) and can then execute "showDocument()" URL when clicked independently.
Maybe there is a #3. I don't know what that would be. Open to try anything without losing the drag & placement mobility of existing boxes.
These "boxes" could be images, or event buttons - doesnt matter.
Not sure if #2 is possible & have not been able to accomplish #1. Must stay within existing AWT framework so IE browsers can run it natively ( which of course IE cannot run Swing graphics unless a Sun plugin loaded ).
Applet is a single file ( creating 4 classes).
html file (which invokes it) passes a string param which is broken into above noted URL strings in each box.
Running this applet, you see a "button" event ( at base of canvas labeled "NewUrl" ) which pops up an url location when clicked ( using "showdocument"). This button is not attached to locations or text of each box object ( which is the "task" to accomplish) . The button does represent the kind of event behavior which each "box" should have when task is achieved. So the box can be exchanged with buttons or the boxes can be imbued with events to hyperlink like a button.
In spirit of solution #1, here is the bonehead attempt I tried which did not work: copied entire "if" block of logic from the button event (sited in preceding paragraph) into region of code which builds boxes ( "for" loop of "drawstring" method).
"g.drawString(doit, x - (w-10)/2, (y - (h-4)/2) + fm.getAscent());"
I copied all the "if" block of logic for button creation into the area immediately after the above line ( for loop which builds the boxes). Hoping that I could create buttons with events, along with all the boxes (which are getting created using "drawstring" above in a "for" loop). These "buttons" must also have positioning info of each box to appear in different locations on the canvas. Positioning data is not in that "if" block of code but it would have been a start to get the multiple buttons created ( even if all drawn in one spot). The "if" code block I've provieded for an example begins with the line:
" if ("NewUrl".equals(arg)) { "
and ends with with lines:
" return true; "
" } " //< -- end of above if block
This full "if" block can be seen in the listing below:
This "if" block creates the "NewUrl" button. Of course, I got a bunch of errors when I tried to copy this block to the above location:
variable: "arg" "not found in class GraphPanel".
methods: "getcodebase, showstatus, getappletcontext()"
"not found in class GraphPanel".
----------- The applet code in total follows next
Here are both the java & htm complete source.
import java.net.MalformedURLException;
import java.net.URL;
import java.net.*;
import java.util.*;
import java.awt.*;
import java.applet.Applet;
import java.applet.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.*;
class Node {
double x;
double y;
double dx;
double dy;
boolean fixed;
String lbl;
class Edge {
int from;
int to;
double len;
} // eEdgeCla
class GraphPanel extends Panel implements Runnable {
Box box;
int nnodes;
Node nodes[] = new Node[100];
int nedges;
Edge edges[] = new Edge[200];
Thread relaxer;
boolean showit;
boolean random;
GraphPanel(Box box) {
this.box = box;
} //ebox
int findNode(String lbl) {
for (int i = 0 ; i < nnodes ; i++) {
if (nodes.lbl.equals(lbl)) {
return i;
return addNode(lbl);
int addNode(String lbl) {
Node n = new Node();
n.x = 10 + 380*Math.random();
n.y = 10 + 380*Math.random();
n.lbl = lbl;
nodes[nnodes] = n;
return nnodes++;
void addEdge(String from, String to, int len) {
Edge e = new Edge();
e.from = findNode(from);
e.to = findNode(to);
e.len = len;
edges[nedges++] = e;
public void run() {
int i3=0;
while (true) {
relax();
if (random && (Math.random() < 0.03)) {
Node n = nodes[(int) (1 * nnodes) ]; // no
if (!n.fixed) {
n.x += (100*0.02) - 50;
n.y += (100*0.02) - 50; //
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
break;
i3++;
} //ew
} // epublrun()
synchronized void relax() {
for (int i = 0 ; i < nedges ; i++) {
Edge e = edges;
double vx = nodes[e.to].x - nodes[e.from].x;
double vy = nodes[e.to].y - nodes[e.from].y;
double len = Math.sqrt(vx * vx + vy * vy);
double f = (edges.len - len) / (len * 3) ;
double dx = f * vx;
double dy = f * vy;
nodes[e.to].dx += dx;
nodes[e.to].dy += dy;
nodes[e.from].dx += -dx;
nodes[e.from].dy += -dy;
} //efo
for (int i = 0 ; i < nnodes ; i++) {
Node n1 = nodes;
double dx = 0;
double dy = 0;
for (int j = 0 ; j < nnodes ; j++) {
if (i == j) {
continue;
Node n2 = nodes[j];
double vx = n1.x - n2.x;
double vy = n1.y - n2.y;
double len = vx * vx + vy * vy;
if (len == 0) {
dx += 0.02;
dy += 0.02;
} else if (len < 100*100) {
dx += vx / len;
dy += vy / len;
} //ef3a
double dlen = dx * dx + dy * dy;
if (dlen > 0) {
dlen = Math.sqrt(dlen) / 2;
n1.dx += dx / dlen;
n1.dy += dy / dlen;
} //ef3
Dimension d = size();
// f4
for (int i = 0 ; i < nnodes ; i++) {
Node n = nodes;
if (!n.fixed) {
n.x += Math.max(-5, Math.min(5, n.dx));
n.y += Math.max(-5, Math.min(5, n.dy));
if (n.x < 0) {
n.x = 0;
} else if (n.x > d.width) {
n.x = d.width;
if (n.y < 0) {
n.y = 0;
} else if (n.y > d.height) {
n.y = d.height;
n.dx /= 2;
n.dy /= 2;
repaint();
Node pick;
boolean pickfixed;
Image offscreen;
Dimension offscreensize;
Graphics offgraphics;
final Color fixedColor = Color.green;
final Color selectColor = Color.gray;
final Color edgeColor = Color.black;
final Color nodeColor = new Color(200, 90, 50);
final Color showitColor = Color.gray;
final Color arcColor1 = Color.black;
final Color arcColor2 = Color.orange;
final Color arcColor3 = Color.blue;
public void paintNode( Graphics g, Node n, FontMetrics fm) {
int x = (int)n.x;
int y = (int)n.y;
g.setColor((n == pick) ? selectColor : (n.fixed ? fixedColor : nodeColor));
int w = fm.stringWidth(n.lbl) + 10;
int h = fm.getHeight() + 4;
g.fillRect(x - w/2, y - h / 2, w, h);
g.setColor(Color.black);
g.drawRect(x - w/2, y - h / 2, w-1, h-1);
String doit = n.lbl.replace('x','/');
g.drawString(doit, x - (w-10)/2, (y - (h-4)/2) + fm.getAscent());
} // epa
public synchronized void update(Graphics g) {
Dimension d = size();
if ((offscreen == null) || (d.width != offscreensize.width) || (d.height != offscreensize.height)) {
offscreen = createImage(d.width, d.height);
offscreensize = d;
offgraphics = offscreen.getGraphics();
offgraphics.setFont(getFont());
offgraphics.setColor(getBackground());
offgraphics.fillRect(0, 0, d.width, d.height);
for (int i = 0 ; i < nedges ; i++) {
Edge e = edges;
int x1 = (int)nodes[e.from].x;
int y1 = (int)nodes[e.from].y;
int x2 = (int)nodes[e.to].x;
int y2 = (int)nodes[e.to].y;
int len = (int)Math.abs(Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)) - e.len);
offgraphics.setColor((len < 10) ? arcColor1 : (len < 20 ? arcColor2 : arcColor3)) ;
offgraphics.drawLine(x1, y1, x2, y2);
if (showit) {
String lbl = String.valueOf(len);
offgraphics.setColor(showitColor);
offgraphics.drawString("href= http://localhost:"+lbl, x1 + (x2-x1)/2, y1 + (y2-y1)/2);
offgraphics.setColor(edgeColor);
} //ef5
FontMetrics fm = offgraphics.getFontMetrics();
for (int i = 0 ; i < nnodes ; i++) {
paintNode( offgraphics, nodes, fm); //or
g.drawImage(offscreen, 0, 0, null);
public synchronized boolean mouseDown(Event evt, int x, int y) {
double bestdist = Double.MAX_VALUE;
for (int i = 0 ; i < nnodes ; i++) {
Node n = nodes;
double dist = (n.x - x) * (n.x - x) + (n.y - y) * (n.y - y);
if (dist < bestdist) {
pick = n;
bestdist = dist;
pickfixed = pick.fixed;
pick.fixed = true;
pick.x = x;
pick.y = y;
repaint();
return true;
public synchronized boolean mouseDrag(Event evt, int x, int y) {
pick.x = x;
pick.y = y;
repaint();
return true;
} //e-pubsyncmousedrag
public synchronized boolean mouseUp(Event evt, int x, int y) {
pick.x = x;
pick.y = y;
pick.fixed = pickfixed;
pick = null;
repaint();
return true;
public void start() {
relaxer = new Thread(this);
relaxer.start();
public void stop() {
relaxer.stop();
public class Box extends Applet {
GraphPanel panel;
public void init() {
setLayout(new BorderLayout());
panel = new GraphPanel(this);
add("Center", panel);
Panel p = new Panel();
add("South", p);
p.add(new Button("Reposition"));
p.add(new Button("NewUrl"));
p.add(new Checkbox("Showit"));
String edges = getParameter("edges"); // putinli
for (StringTokenizer t = new StringTokenizer(edges, ",") ; t.hasMoreTokens() ; ) {
String str = t.nextToken();
int i = str.indexOf('-');
if (i > 0) { int len = 50;
int j = str.indexOf('/');
if (j > 0) {
len = Integer.valueOf(str.substring(j+1)).intValue();
str = str.substring(0, j);
panel.addEdge(str.substring(0,i), str.substring(i+1), len);
} //ef8
Dimension d = size();
String center = getParameter("center");
if (center != null){
Node n = panel.nodes[panel.findNode(center)];
n.x = d.width / 2;
n.y = d.height / 2;
n.fixed = true;
} // eif
} // ep
public void start() {
panel.start();
public void stop() {
panel.stop();
public boolean action(Event evt, Object arg) {
if (arg instanceof Boolean) {
if (((Checkbox)evt.target).getLabel().equals("Showit")) {
panel.showit = ((Boolean)arg).booleanValue();
}// e-
else {
panel.random = ((Boolean)arg).booleanValue();
return true;
} // e-if instof bool
if ("Reposition".equals(arg)) {
Dimension d = size();
for (int i = 0 ; i < panel.nnodes ; i++) {
Node n = panel.nodes;
if (!n.fixed) {
n.x = 10 + (d.width-20)*Math.random();
n.y = 10 + (d.height-20)*Math.random();
} //ei
} //ef9
return true;
} //eif scram
if ("NewUrl".equals(arg)) {
Dimension d = size();
URL url = getCodeBase();
try {
getAppletContext().showDocument( new URL(url+"main.htm"), "_blank" );
try {
Thread.sleep(1000);
} catch (InterruptedException e) { }
} catch(MalformedURLException e) {
showStatus("814 URL not found");
for (int i = 0 ; i < panel.nnodes ; i++) {
Node n = panel.nodes;
if (!n.fixed) {
n.x += (80*0.02) - 40;
n.y += (80*0.02) - 40;
return true;
} //ei
return false;
-----------------------htm file to launch------------------------------
<html>
<head>
<title>R
</title>
</head>
<body>
<h3>
<center>
R
</center>
</h3>
I
<b>
</b>
<table border = 1>
<td>De<td>Test List<tr>
<td>N <td><tr>
<td>N <td><tr>
</table>
<b>view </b>
<applet code="Box.class" CODEBASE=. width=1000 height=600
ALT="Test ">
<param name=edges value="http:xxabc.htm-http:xxnet.htm,http:xxthis.htm-http:xx.comet.htm,http:xxnewsighting.htm-http:xxstar.htm,http:xxmoon.htm-http:xxNeptune.htm">
<hr>
</applet>
</b>
<p>
<table border = 1>
<tr>
<tr>
</table>
</html>
</body>
instructions to compile :
0 : The discussion becomes easy to follow after 1st compiling
& viewing the applet.
1. : cut out applet code.
2. : the post somehow deleted all references to "" <--- HERE
see, the data has been deleted again as I preview this post.
( that "" should contain an "i" array increment argument:
"open square bracket" "i" "close square bracket" ) array
so "javac Box.java" will get 10 errors. These "[" "i" "]"
array args must be replaced to compile the code.
3. : All array variables inside the 10 "for" loops ( the bare words
"edges" and "nodes" ) without array increment "i" should
read "edges" "[" "i" "]" & "nodes" "[" "i" "]".
The 10 location lines are approx:
line #65, #129, #136, #149, #195, #283, #311, #331, #477, #522
4. : These 10 edits reqresent a missing "i" to all 10 for loop arrays.
for eddges & nodes. fix this & javac Box.java" will get
4 class files.
5. : cut "Box.htm" from post & do "appletviewer Box.htm"
or put in an apache "htdoc" or tomcat "servlet" http delivered
directory & call "http://localhost/Box.htm.
6. : of course, selecting the event button "NewUrl" will not
work in appletviewer but will work in an http web location.
7. : post your questions to problem or fixes to problem as I'm
monitoring closely. TIA.Thanks for code post tip to fix array deletion problem.
Here is code reposted using delimiters with will
compile straight out of cut/paste.import java.net.MalformedURLException;
import java.net.URL;
import java.net.*;
import java.util.*;
import java.awt.*;
import java.applet.Applet;
import java.applet.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.*;
class Node {
double x;
double y;
double dx;
double dy;
boolean fixed;
String lbl;
class Edge {
int from;
int to;
double len;
} // eEdgeCla
class GraphPanel extends Panel implements Runnable {
Box box;
int nnodes;
Node nodes[] = new Node[100];
int nedges;
Edge edges[] = new Edge[200];
Thread relaxer;
boolean showit;
boolean random;
GraphPanel(Box box) {
this.box = box;
} //ebox
int findNode(String lbl) {
for (int i = 0 ; i < nnodes ; i++) {
//if (nodes.lbl.equals(lbl)) {
if (nodes.lbl.equals(lbl)) {
return i;
return addNode(lbl);
int addNode(String lbl) {
Node n = new Node();
n.x = 10 + 380*Math.random();
n.y = 10 + 380*Math.random();
n.lbl = lbl;
nodes[nnodes] = n;
return nnodes++;
void addEdge(String from, String to, int len) {
Edge e = new Edge();
e.from = findNode(from);
e.to = findNode(to);
e.len = len;
edges[nedges++] = e;
public void run() {
int i3=0;
while (true) {
relax();
if (random && (Math.random() < 0.03)) {
Node n = nodes[(int) (1 * nnodes) ]; // no
if (!n.fixed) {
n.x += (100*0.02) - 50;
n.y += (100*0.02) - 50; //
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
break;
i3++;
} //ew
} // epublrun()
synchronized void relax() {
for (int i = 0 ; i < nedges ; i++) {
//Edge e = edges;
Edge e = edges[i];
double vx = nodes[e.to].x - nodes[e.from].x;
double vy = nodes[e.to].y - nodes[e.from].y;
double len = Math.sqrt(vx * vx + vy * vy);
//double f = (edges.len - len) / (len * 3) ;
double f = (edges[i].len - len) / (len * 3) ;
double dx = f * vx;
double dy = f * vy;
nodes[e.to].dx += dx;
nodes[e.to].dy += dy;
nodes[e.from].dx += -dx;
nodes[e.from].dy += -dy;
} //efo
for (int i = 0 ; i < nnodes ; i++) {
//Node n1 = nodes[i];
Node n1 = nodes[i];
double dx = 0;
double dy = 0;
for (int j = 0 ; j < nnodes ; j++) {
if (i == j) {
continue;
Node n2 = nodes[j];
double vx = n1.x - n2.x;
double vy = n1.y - n2.y;
double len = vx * vx + vy * vy;
if (len == 0) {
dx += 0.02;
dy += 0.02;
} else if (len < 100*100) {
dx += vx / len;
dy += vy / len;
} //ef3a
double dlen = dx * dx + dy * dy;
if (dlen > 0) {
dlen = Math.sqrt(dlen) / 2;
n1.dx += dx / dlen;
n1.dy += dy / dlen;
} //ef3
Dimension d = size();
// f4
for (int i = 0 ; i < nnodes ; i++) {
//Node n = nodes;
Node n = nodes[i];
if (!n.fixed) {
n.x += Math.max(-5, Math.min(5, n.dx));
n.y += Math.max(-5, Math.min(5, n.dy));
if (n.x < 0) {
n.x = 0;
} else if (n.x > d.width) {
n.x = d.width;
if (n.y < 0) {
n.y = 0;
} else if (n.y > d.height) {
n.y = d.height;
n.dx /= 2;
n.dy /= 2;
repaint();
Node pick;
boolean pickfixed;
Image offscreen;
Dimension offscreensize;
Graphics offgraphics;
final Color fixedColor = Color.green;
final Color selectColor = Color.gray;
final Color edgeColor = Color.black;
final Color nodeColor = new Color(200, 90, 50);
final Color showitColor = Color.gray;
final Color arcColor1 = Color.black;
final Color arcColor2 = Color.orange;
final Color arcColor3 = Color.blue;
public void paintNode( Graphics g, Node n, FontMetrics fm) {
int x = (int)n.x;
int y = (int)n.y;
g.setColor((n == pick) ? selectColor : (n.fixed ? fixedColor : nodeColor));
int w = fm.stringWidth(n.lbl) + 10;
int h = fm.getHeight() + 4;
g.fillRect(x - w/2, y - h / 2, w, h);
g.setColor(Color.black);
g.drawRect(x - w/2, y - h / 2, w-1, h-1);
String doit = n.lbl.replace('x','/');
g.drawString(doit, x - (w-10)/2, (y - (h-4)/2) + fm.getAscent());
} // epa
public synchronized void update(Graphics g) {
Dimension d = size();
if ((offscreen == null) || (d.width != offscreensize.width) || (d.height != offscreensize.height)) {
offscreen = createImage(d.width, d.height);
offscreensize = d;
offgraphics = offscreen.getGraphics();
offgraphics.setFont(getFont());
offgraphics.setColor(getBackground());
offgraphics.fillRect(0, 0, d.width, d.height);
for (int i = 0 ; i < nedges ; i++) {
//Edge e = edges;
Edge e = edges[i];
int x1 = (int)nodes[e.from].x;
int y1 = (int)nodes[e.from].y;
int x2 = (int)nodes[e.to].x;
int y2 = (int)nodes[e.to].y;
int len = (int)Math.abs(Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)) - e.len);
offgraphics.setColor((len < 10) ? arcColor1 : (len < 20 ? arcColor2 : arcColor3)) ;
offgraphics.drawLine(x1, y1, x2, y2);
if (showit) {
String lbl = String.valueOf(len);
offgraphics.setColor(showitColor);
offgraphics.drawString("href= http://localhost:"+lbl, x1 + (x2-x1)/2, y1 + (y2-y1)/2);
offgraphics.setColor(edgeColor);
} //ef5
FontMetrics fm = offgraphics.getFontMetrics();
for (int i = 0 ; i < nnodes ; i++) {
//paintNode( offgraphics, nodes, fm); //or
paintNode( offgraphics, nodes[i], fm); //or
g.drawImage(offscreen, 0, 0, null);
public synchronized boolean mouseDown(Event evt, int x, int y) {
double bestdist = Double.MAX_VALUE;
for (int i = 0 ; i < nnodes ; i++) {
//Node n = nodes;
Node n = nodes[i];
double dist = (n.x - x) * (n.x - x) + (n.y - y) * (n.y - y);
if (dist < bestdist) {
pick = n;
bestdist = dist;
pickfixed = pick.fixed;
pick.fixed = true;
pick.x = x;
pick.y = y;
repaint();
return true;
public synchronized boolean mouseDrag(Event evt, int x, int y) {
pick.x = x;
pick.y = y;
repaint();
return true;
} //e-pubsyncmousedrag
public synchronized boolean mouseUp(Event evt, int x, int y) {
pick.x = x;
pick.y = y;
pick.fixed = pickfixed;
pick = null;
repaint();
return true;
public void start() {
relaxer = new Thread(this);
relaxer.start();
public void stop() {
relaxer.stop();
public class Box extends Applet {
GraphPanel panel;
public void init() {
setLayout(new BorderLayout());
panel = new GraphPanel(this);
add("Center", panel);
Panel p = new Panel();
add("South", p);
p.add(new Button("Reposition"));
p.add(new Button("NewUrl"));
p.add(new Checkbox("Showit"));
String edges = getParameter("edges"); // putinli
for (StringTokenizer t = new StringTokenizer(edges, ",") ; t.hasMoreTokens() ; ) {
String str = t.nextToken();
int i = str.indexOf('-');
if (i > 0) { int len = 50;
int j = str.indexOf('/');
if (j > 0) {
len = Integer.valueOf(str.substring(j+1)).intValue();
str = str.substring(0, j);
panel.addEdge(str.substring(0,i), str.substring(i+1), len);
} //ef8
Dimension d = size();
String center = getParameter("center");
if (center != null){
Node n = panel.nodes[panel.findNode(center)];
n.x = d.width / 2;
n.y = d.height / 2;
n.fixed = true;
} // eif
} // ep
public void start() {
panel.start();
public void stop() {
panel.stop();
public boolean action(Event evt, Object arg) {
if (arg instanceof Boolean) {
if (((Checkbox)evt.target).getLabel().equals("Showit")) {
panel.showit = ((Boolean)arg).booleanValue();
}// e-
else {
panel.random = ((Boolean)arg).booleanValue();
return true;
} // e-if instof bool
if ("Reposition".equals(arg)) {
Dimension d = size();
for (int i = 0 ; i < panel.nnodes ; i++) {
//Node n = panel.nodes;
Node n = panel.nodes[i];
if (!n.fixed) {
n.x = 10 + (d.width-20)*Math.random();
n.y = 10 + (d.height-20)*Math.random();
} //ei
} //ef9
return true;
} //eif scram
if ("NewUrl".equals(arg)) {
Dimension d = size();
URL url = getCodeBase();
try {
getAppletContext().showDocument( new URL(url+"main.htm"), "_blank" );
try {
Thread.sleep(1000);
} catch (InterruptedException e) { }
} catch(MalformedURLException e) {
showStatus("814 URL not found");
for (int i = 0 ; i < panel.nnodes ; i++) {
//Node n = panel.nodes;
Node n = panel.nodes[i];
if (!n.fixed) {
n.x += (80*0.02) - 40;
n.y += (80*0.02) - 40;
return true;
} //ei
return false; -
Floating "boxes" applet with drag events need ckick events
I Have an applet cobbled from the net & modified. Is works but needs one major event added. It draws "Graphics.drawline" boxes with a text "String" inside each box ( the text string represents an URL location). These "boxes" are objects which are "draggable to other locations on canvas & therefore can be independently positioned by user. Each box redraws itself periodically to a slightly different screen location & becomes stationary after a 5 or 6 seconds. The point is, all of this "drag & mobility" behavior must remain intact & is not part of the "problem task".
Task: Need to have an "event" behavior added in one of two ways ( or a 3rd way if there is another ) whichever is quickest/ easiest. "Clickable mouse events" must be added to each box. ( boxes are built in a loop so adding to one will add to other locations & create as many "buttons" as there are boxes) . At each box's location, clicking one box should be an event which fires & clicking a different box should be a separate event which fires. Separate , so that URL location can be "hotlinked" to each box. That URL is currently displayed in the boxes (visible when running applet).
1st possible solution: Exchange these "boxes" which appear on canvas into clickable event "Graph panel.buttons" ( for example or some other clickable object) which maintains existing "drag" behavior of boxes. These buttons must each have "clickability" with mouse events to enable placing "getAppletContext. showDocument()" code with these events ( e.g., "hotlinked" to http locations).
or
2nd possible solution:. The drawstring boxes are currently dead string text with no event model other than the "drag" feature associated with each box. Must add an additional mouse event behavior to existing boxes so they are "clickable" ( or text inside is clickable) and can then execute "showDocument()" URL when clicked independently.
Maybe there is a #3. I don't know what that would be. Open to try anything without losing the drag & placement mobility of existing boxes.
These "boxes" could be images, or event buttons - doesnt matter.
Not sure if #2 is possible & have not been able to accomplish #1. Must stay within existing AWT framework so IE browsers can run it natively ( which of course IE cannot run Swing graphics unless a Sun plugin loaded ).
Applet is a single file ( creating 4 classes).
html file (which invokes it) passes a string param which is broken into above noted URL strings in each box.
Running this applet, you see a "button" event ( at base of canvas labeled "NewUrl" ) which pops up an url location when clicked ( using "showdocument"). This button is not attached to locations or text of each box object ( which is the "task" to accomplish) . The button does represent the kind of event behavior which each "box" should have when task is achieved. So the box can be exchanged with buttons or the boxes can be imbued with events to hyperlink like a button.
In spirit of solution #1, here is the bonehead attempt I tried which did not work: copied entire "if" block of logic from the button event (sited in preceding paragraph) into region of code which builds boxes ( "for" loop of "drawstring" method).
"g.drawString(doit, x - (w-10)/2, (y - (h-4)/2) + fm.getAscent());"
I copied all the "if" block of logic for button creation into the area immediately after the above line ( for loop which builds the boxes). Hoping that I could create buttons with events, along with all the boxes (which are getting created using "drawstring" above in a "for" loop). These "buttons" must also have positioning info of each box to appear in different locations on the canvas. Positioning data is not in that "if" block of code but it would have been a start to get the multiple buttons created ( even if all drawn in one spot). The "if" code block I've provieded for an example begins with the line:
" if ("NewUrl".equals(arg)) { "
and ends with with lines:
" return true; "
" } " //< -- end of above if block
This full "if" block can be seen in the listing below:
This "if" block creates the "NewUrl" button. Of course, I got a bunch of errors when I tried to copy this block to the above location:
variable: "arg" "not found in class GraphPanel".
methods: "getcodebase, showstatus, getappletcontext()"
"not found in class GraphPanel".
----------- The applet code in total follows next
Here are both the java & htm complete source.
import java.net.MalformedURLException;
import java.net.URL;
import java.net.*;
import java.util.*;
import java.awt.*;
import java.applet.Applet;
import java.applet.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.*;
class Node {
double x;
double y;
double dx;
double dy;
boolean fixed;
String lbl;
class Edge {
int from;
int to;
double len;
} // eEdgeCla
class GraphPanel extends Panel implements Runnable {
Box box;
int nnodes;
Node nodes[] = new Node[100];
int nedges;
Edge edges[] = new Edge[200];
Thread relaxer;
boolean showit;
boolean random;
GraphPanel(Box box) {
this.box = box;
} //ebox
int findNode(String lbl) {
for (int i = 0 ; i < nnodes ; i++) {
if (nodes.lbl.equals(lbl)) {
return i;
return addNode(lbl);
int addNode(String lbl) {
Node n = new Node();
n.x = 10 + 380*Math.random();
n.y = 10 + 380*Math.random();
n.lbl = lbl;
nodes[nnodes] = n;
return nnodes++;
void addEdge(String from, String to, int len) {
Edge e = new Edge();
e.from = findNode(from);
e.to = findNode(to);
e.len = len;
edges[nedges++] = e;
public void run() {
int i3=0;
while (true) {
relax();
if (random && (Math.random() < 0.03)) {
Node n = nodes[(int) (1 * nnodes) ]; // no
if (!n.fixed) {
n.x += (100*0.02) - 50;
n.y += (100*0.02) - 50; //
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
break;
i3++;
} //ew
} // epublrun()
synchronized void relax() {
for (int i = 0 ; i < nedges ; i++) {
Edge e = edges;
double vx = nodes[e.to].x - nodes[e.from].x;
double vy = nodes[e.to].y - nodes[e.from].y;
double len = Math.sqrt(vx * vx + vy * vy);
double f = (edges.len - len) / (len * 3) ;
double dx = f * vx;
double dy = f * vy;
nodes[e.to].dx += dx;
nodes[e.to].dy += dy;
nodes[e.from].dx += -dx;
nodes[e.from].dy += -dy;
} //efo
for (int i = 0 ; i < nnodes ; i++) {
Node n1 = nodes;
double dx = 0;
double dy = 0;
for (int j = 0 ; j < nnodes ; j++) {
if (i == j) {
continue;
Node n2 = nodes[j];
double vx = n1.x - n2.x;
double vy = n1.y - n2.y;
double len = vx * vx + vy * vy;
if (len == 0) {
dx += 0.02;
dy += 0.02;
} else if (len < 100*100) {
dx += vx / len;
dy += vy / len;
} //ef3a
double dlen = dx * dx + dy * dy;
if (dlen > 0) {
dlen = Math.sqrt(dlen) / 2;
n1.dx += dx / dlen;
n1.dy += dy / dlen;
} //ef3
Dimension d = size();
// f4
for (int i = 0 ; i < nnodes ; i++) {
Node n = nodes;
if (!n.fixed) {
n.x += Math.max(-5, Math.min(5, n.dx));
n.y += Math.max(-5, Math.min(5, n.dy));
if (n.x < 0) {
n.x = 0;
} else if (n.x > d.width) {
n.x = d.width;
if (n.y < 0) {
n.y = 0;
} else if (n.y > d.height) {
n.y = d.height;
n.dx /= 2;
n.dy /= 2;
repaint();
Node pick;
boolean pickfixed;
Image offscreen;
Dimension offscreensize;
Graphics offgraphics;
final Color fixedColor = Color.green;
final Color selectColor = Color.gray;
final Color edgeColor = Color.black;
final Color nodeColor = new Color(200, 90, 50);
final Color showitColor = Color.gray;
final Color arcColor1 = Color.black;
final Color arcColor2 = Color.orange;
final Color arcColor3 = Color.blue;
public void paintNode( Graphics g, Node n, FontMetrics fm) {
int x = (int)n.x;
int y = (int)n.y;
g.setColor((n == pick) ? selectColor : (n.fixed ? fixedColor : nodeColor));
int w = fm.stringWidth(n.lbl) + 10;
int h = fm.getHeight() + 4;
g.fillRect(x - w/2, y - h / 2, w, h);
g.setColor(Color.black);
g.drawRect(x - w/2, y - h / 2, w-1, h-1);
String doit = n.lbl.replace('x','/');
g.drawString(doit, x - (w-10)/2, (y - (h-4)/2) + fm.getAscent());
} // epa
public synchronized void update(Graphics g) {
Dimension d = size();
if ((offscreen == null) || (d.width != offscreensize.width) || (d.height != offscreensize.height)) {
offscreen = createImage(d.width, d.height);
offscreensize = d;
offgraphics = offscreen.getGraphics();
offgraphics.setFont(getFont());
offgraphics.setColor(getBackground());
offgraphics.fillRect(0, 0, d.width, d.height);
for (int i = 0 ; i < nedges ; i++) {
Edge e = edges;
int x1 = (int)nodes[e.from].x;
int y1 = (int)nodes[e.from].y;
int x2 = (int)nodes[e.to].x;
int y2 = (int)nodes[e.to].y;
int len = (int)Math.abs(Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)) - e.len);
offgraphics.setColor((len < 10) ? arcColor1 : (len < 20 ? arcColor2 : arcColor3)) ;
offgraphics.drawLine(x1, y1, x2, y2);
if (showit) {
String lbl = String.valueOf(len);
offgraphics.setColor(showitColor);
offgraphics.drawString("href= http://localhost:"+lbl, x1 + (x2-x1)/2, y1 + (y2-y1)/2);
offgraphics.setColor(edgeColor);
} //ef5
FontMetrics fm = offgraphics.getFontMetrics();
for (int i = 0 ; i < nnodes ; i++) {
paintNode( offgraphics, nodes, fm); //or
g.drawImage(offscreen, 0, 0, null);
public synchronized boolean mouseDown(Event evt, int x, int y) {
double bestdist = Double.MAX_VALUE;
for (int i = 0 ; i < nnodes ; i++) {
Node n = nodes;
double dist = (n.x - x) * (n.x - x) + (n.y - y) * (n.y - y);
if (dist < bestdist) {
pick = n;
bestdist = dist;
pickfixed = pick.fixed;
pick.fixed = true;
pick.x = x;
pick.y = y;
repaint();
return true;
public synchronized boolean mouseDrag(Event evt, int x, int y) {
pick.x = x;
pick.y = y;
repaint();
return true;
} //e-pubsyncmousedrag
public synchronized boolean mouseUp(Event evt, int x, int y) {
pick.x = x;
pick.y = y;
pick.fixed = pickfixed;
pick = null;
repaint();
return true;
public void start() {
relaxer = new Thread(this);
relaxer.start();
public void stop() {
relaxer.stop();
public class Box extends Applet {
GraphPanel panel;
public void init() {
setLayout(new BorderLayout());
panel = new GraphPanel(this);
add("Center", panel);
Panel p = new Panel();
add("South", p);
p.add(new Button("Reposition"));
p.add(new Button("NewUrl"));
p.add(new Checkbox("Showit"));
String edges = getParameter("edges"); // putinli
for (StringTokenizer t = new StringTokenizer(edges, ",") ; t.hasMoreTokens() ; ) {
String str = t.nextToken();
int i = str.indexOf('-');
if (i > 0) { int len = 50;
int j = str.indexOf('/');
if (j > 0) {
len = Integer.valueOf(str.substring(j+1)).intValue();
str = str.substring(0, j);
panel.addEdge(str.substring(0,i), str.substring(i+1), len);
} //ef8
Dimension d = size();
String center = getParameter("center");
if (center != null){
Node n = panel.nodes[panel.findNode(center)];
n.x = d.width / 2;
n.y = d.height / 2;
n.fixed = true;
} // eif
} // ep
public void start() {
panel.start();
public void stop() {
panel.stop();
public boolean action(Event evt, Object arg) {
if (arg instanceof Boolean) {
if (((Checkbox)evt.target).getLabel().equals("Showit")) {
panel.showit = ((Boolean)arg).booleanValue();
}// e-
else {
panel.random = ((Boolean)arg).booleanValue();
return true;
} // e-if instof bool
if ("Reposition".equals(arg)) {
Dimension d = size();
for (int i = 0 ; i < panel.nnodes ; i++) {
Node n = panel.nodes;
if (!n.fixed) {
n.x = 10 + (d.width-20)*Math.random();
n.y = 10 + (d.height-20)*Math.random();
} //ei
} //ef9
return true;
} //eif scram
if ("NewUrl".equals(arg)) {
Dimension d = size();
URL url = getCodeBase();
try {
getAppletContext().showDocument( new URL(url+"main.htm"), "_blank" );
try {
Thread.sleep(1000);
} catch (InterruptedException e) { }
} catch(MalformedURLException e) {
showStatus("814 URL not found");
for (int i = 0 ; i < panel.nnodes ; i++) {
Node n = panel.nodes;
if (!n.fixed) {
n.x += (80*0.02) - 40;
n.y += (80*0.02) - 40;
return true;
} //ei
return false;
-----------------------htm file to launch------------------------------
<html>
<head>
<title>R
</title>
</head>
<body>
<h3>
<center>
R
</center>
</h3>
I
<b>
</b>
<table border = 1>
<td>De<td>Test List<tr>
<td>N <td><tr>
<td>N <td><tr>
</table>
<b>view </b>
<applet code="Box.class" CODEBASE=. width=1000 height=600
ALT="Test ">
<param name=edges value="http:xxabc.htm-http:xxnet.htm,http:xxthis.htm-http:xx.comet.htm,http:xxnewsighting.htm-http:xxstar.htm,http:xxmoon.htm-http:xxNeptune.htm">
<hr>
</applet>
</b>
<p>
<table border = 1>
<tr>
<tr>
</table>
</html>
</body>
instructions to compile :
0 : The discussion becomes easy to follow after 1st compiling
& viewing the applet.
1. : cut out applet code.
2. : the post somehow deleted all references to "" <--- HERE
see, the data has been deleted again as I preview this post.
( that "" should contain an "i" array increment argument:
"open square bracket" "i" "close square bracket" ) array
so "javac Box.java" will get 10 errors. These "[" "i" "]"
array args must be replaced to compile the code.
3. : All array variables inside the 10 "for" loops ( the bare words
"edges" and "nodes" ) without array increment "i" should
read "edges" "[" "i" "]" & "nodes" "[" "i" "]".
The 10 location lines are approx:
line #65, #129, #136, #149, #195, #283, #311, #331, #477, #522
4. : These 10 edits reqresent a missing "i" to all 10 for loop arrays.
for eddges & nodes. fix this & javac Box.java" will get
4 class files.
5. : cut "Box.htm" from post & do "appletviewer Box.htm"
or put in an apache "htdoc" or tomcat "servlet" http delivered
directory & call "http://localhost/Box.htm.
6. : of course, selecting the event button "NewUrl" will not
work in appletviewer but will work in an http web location.
7. : post your questions to problem or fixes to problem as I'm
monitoring closely. TIA.Thanks for code post tip to fix array index deletion problem.
Here is code reposted using "code" delimiters which will
compile straight out of cut/paste.
import java.net.MalformedURLException;
import java.net.URL;
import java.net.*;
import java.util.*;
import java.awt.*;
import java.applet.Applet;
import java.applet.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.*;
class Node {
double x;
double y;
double dx;
double dy;
boolean fixed;
String lbl;
class Edge {
int from;
int to;
double len;
} // eEdgeCla
class GraphPanel extends Panel implements Runnable {
Box box;
int nnodes;
Node nodes[] = new Node[100];
int nedges;
Edge edges[] = new Edge[200];
Thread relaxer;
boolean showit;
boolean random;
GraphPanel(Box box) {
this.box = box;
} //ebox
int findNode(String lbl) {
for (int i = 0 ; i < nnodes ; i++) {
//if (nodes.lbl.equals(lbl)) {
if (nodes.lbl.equals(lbl)) {
return i;
return addNode(lbl);
int addNode(String lbl) {
Node n = new Node();
n.x = 10 + 380*Math.random();
n.y = 10 + 380*Math.random();
n.lbl = lbl;
nodes[nnodes] = n;
return nnodes++;
void addEdge(String from, String to, int len) {
Edge e = new Edge();
e.from = findNode(from);
e.to = findNode(to);
e.len = len;
edges[nedges++] = e;
public void run() {
int i3=0;
while (true) {
relax();
if (random && (Math.random() < 0.03)) {
Node n = nodes[(int) (1 * nnodes) ]; // no
if (!n.fixed) {
n.x += (100*0.02) - 50;
n.y += (100*0.02) - 50; //
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
break;
i3++;
} //ew
} // epublrun()
synchronized void relax() {
for (int i = 0 ; i < nedges ; i++) {
//Edge e = edges;
Edge e = edges[i];
double vx = nodes[e.to].x - nodes[e.from].x;
double vy = nodes[e.to].y - nodes[e.from].y;
double len = Math.sqrt(vx * vx + vy * vy);
//double f = (edges.len - len) / (len * 3) ;
double f = (edges[i].len - len) / (len * 3) ;
double dx = f * vx;
double dy = f * vy;
nodes[e.to].dx += dx;
nodes[e.to].dy += dy;
nodes[e.from].dx += -dx;
nodes[e.from].dy += -dy;
} //efo
for (int i = 0 ; i < nnodes ; i++) {
//Node n1 = nodes[i];
Node n1 = nodes[i];
double dx = 0;
double dy = 0;
for (int j = 0 ; j < nnodes ; j++) {
if (i == j) {
continue;
Node n2 = nodes[j];
double vx = n1.x - n2.x;
double vy = n1.y - n2.y;
double len = vx * vx + vy * vy;
if (len == 0) {
dx += 0.02;
dy += 0.02;
} else if (len < 100*100) {
dx += vx / len;
dy += vy / len;
} //ef3a
double dlen = dx * dx + dy * dy;
if (dlen > 0) {
dlen = Math.sqrt(dlen) / 2;
n1.dx += dx / dlen;
n1.dy += dy / dlen;
} //ef3
Dimension d = size();
// f4
for (int i = 0 ; i < nnodes ; i++) {
//Node n = nodes;
Node n = nodes[i];
if (!n.fixed) {
n.x += Math.max(-5, Math.min(5, n.dx));
n.y += Math.max(-5, Math.min(5, n.dy));
if (n.x < 0) {
n.x = 0;
} else if (n.x > d.width) {
n.x = d.width;
if (n.y < 0) {
n.y = 0;
} else if (n.y > d.height) {
n.y = d.height;
n.dx /= 2;
n.dy /= 2;
repaint();
Node pick;
boolean pickfixed;
Image offscreen;
Dimension offscreensize;
Graphics offgraphics;
final Color fixedColor = Color.green;
final Color selectColor = Color.gray;
final Color edgeColor = Color.black;
final Color nodeColor = new Color(200, 90, 50);
final Color showitColor = Color.gray;
final Color arcColor1 = Color.black;
final Color arcColor2 = Color.orange;
final Color arcColor3 = Color.blue;
public void paintNode( Graphics g, Node n, FontMetrics fm) {
int x = (int)n.x;
int y = (int)n.y;
g.setColor((n == pick) ? selectColor : (n.fixed ? fixedColor : nodeColor));
int w = fm.stringWidth(n.lbl) + 10;
int h = fm.getHeight() + 4;
g.fillRect(x - w/2, y - h / 2, w, h);
g.setColor(Color.black);
g.drawRect(x - w/2, y - h / 2, w-1, h-1);
String doit = n.lbl.replace('x','/');
g.drawString(doit, x - (w-10)/2, (y - (h-4)/2) + fm.getAscent());
} // epa
public synchronized void update(Graphics g) {
Dimension d = size();
if ((offscreen == null) || (d.width != offscreensize.width) || (d.height != offscreensize.height)) {
offscreen = createImage(d.width, d.height);
offscreensize = d;
offgraphics = offscreen.getGraphics();
offgraphics.setFont(getFont());
offgraphics.setColor(getBackground());
offgraphics.fillRect(0, 0, d.width, d.height);
for (int i = 0 ; i < nedges ; i++) {
//Edge e = edges;
Edge e = edges[i];
int x1 = (int)nodes[e.from].x;
int y1 = (int)nodes[e.from].y;
int x2 = (int)nodes[e.to].x;
int y2 = (int)nodes[e.to].y;
int len = (int)Math.abs(Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2)) - e.len);
offgraphics.setColor((len < 10) ? arcColor1 : (len < 20 ? arcColor2 : arcColor3)) ;
offgraphics.drawLine(x1, y1, x2, y2);
if (showit) {
String lbl = String.valueOf(len);
offgraphics.setColor(showitColor);
offgraphics.drawString("href= http://localhost:"+lbl, x1 + (x2-x1)/2, y1 + (y2-y1)/2);
offgraphics.setColor(edgeColor);
} //ef5
FontMetrics fm = offgraphics.getFontMetrics();
for (int i = 0 ; i < nnodes ; i++) {
//paintNode( offgraphics, nodes, fm); //or
paintNode( offgraphics, nodes[i], fm); //or
g.drawImage(offscreen, 0, 0, null);
public synchronized boolean mouseDown(Event evt, int x, int y) {
double bestdist = Double.MAX_VALUE;
for (int i = 0 ; i < nnodes ; i++) {
//Node n = nodes;
Node n = nodes[i];
double dist = (n.x - x) * (n.x - x) + (n.y - y) * (n.y - y);
if (dist < bestdist) {
pick = n;
bestdist = dist;
pickfixed = pick.fixed;
pick.fixed = true;
pick.x = x;
pick.y = y;
repaint();
return true;
public synchronized boolean mouseDrag(Event evt, int x, int y) {
pick.x = x;
pick.y = y;
repaint();
return true;
} //e-pubsyncmousedrag
public synchronized boolean mouseUp(Event evt, int x, int y) {
pick.x = x;
pick.y = y;
pick.fixed = pickfixed;
pick = null;
repaint();
return true;
public void start() {
relaxer = new Thread(this);
relaxer.start();
public void stop() {
relaxer.stop();
public class Box extends Applet {
GraphPanel panel;
public void init() {
setLayout(new BorderLayout());
panel = new GraphPanel(this);
add("Center", panel);
Panel p = new Panel();
add("South", p);
p.add(new Button("Reposition"));
p.add(new Button("NewUrl"));
p.add(new Checkbox("Showit"));
String edges = getParameter("edges"); // putinli
for (StringTokenizer t = new StringTokenizer(edges, ",") ; t.hasMoreTokens() ; ) {
String str = t.nextToken();
int i = str.indexOf('-');
if (i > 0) { int len = 50;
int j = str.indexOf('/');
if (j > 0) {
len = Integer.valueOf(str.substring(j+1)).intValue();
str = str.substring(0, j);
panel.addEdge(str.substring(0,i), str.substring(i+1), len);
} //ef8
Dimension d = size();
String center = getParameter("center");
if (center != null){
Node n = panel.nodes[panel.findNode(center)];
n.x = d.width / 2;
n.y = d.height / 2;
n.fixed = true;
} // eif
} // ep
public void start() {
panel.start();
public void stop() {
panel.stop();
public boolean action(Event evt, Object arg) {
if (arg instanceof Boolean) {
if (((Checkbox)evt.target).getLabel().equals("Showit")) {
panel.showit = ((Boolean)arg).booleanValue();
}// e-
else {
panel.random = ((Boolean)arg).booleanValue();
return true;
} // e-if instof bool
if ("Reposition".equals(arg)) {
Dimension d = size();
for (int i = 0 ; i < panel.nnodes ; i++) {
//Node n = panel.nodes;
Node n = panel.nodes[i];
if (!n.fixed) {
n.x = 10 + (d.width-20)*Math.random();
n.y = 10 + (d.height-20)*Math.random();
} //ei
} //ef9
return true;
} //eif scram
if ("NewUrl".equals(arg)) {
Dimension d = size();
URL url = getCodeBase();
try {
getAppletContext().showDocument( new URL(url+"main.htm"), "_blank" );
try {
Thread.sleep(1000);
} catch (InterruptedException e) { }
} catch(MalformedURLException e) {
showStatus("814 URL not found");
for (int i = 0 ; i < panel.nnodes ; i++) {
//Node n = panel.nodes;
Node n = panel.nodes[i];
if (!n.fixed) {
n.x += (80*0.02) - 40;
n.y += (80*0.02) - 40;
return true;
} //ei
return false; -
ActionPerformed method not working when applet is loaded in browser window.
Hey there guys. I need urgent help from anybody who has experience in deploying websites whose code is in java.
I am having two problems as mentioned below...
first, I have made a simple login screen using java swing and JApplet. there is a single button to login. the action performed for this button accesses a private method to check the username and password which are there in atext file. the applet is working perfectly in appletviewer but when i load the applet in a Internet Explorer window using HTML's Applet tag, the button is giving no response at all even when i enter the correct username and password.
I guess it is either not calling the private function that is checking the username and password from the tes=xt file or it can not access the file. Please help as soon as possible as this is related to my college project.
I am attaching the code herewith. Suggestions to improve the coding are also welcome.
the second problem is that while writing my second program for generating a form which registers a user the html is not at all loading the applet into the browser and also if im trying to access a file to write all the details into the console is showing numerous amount of error after i press the button which i can't not understand. the only thing i can understand is that it is related to file access permissions. If anybody could put some light on the working of worker threads and thread safe activities of SwingUtilities.invokeandWait method it would be really appreciable.
import java.io.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.event.*;
import javax.swing.plaf.*;
<applet code = "UserLogin" width = 300 height = 150>
</applet>
public class UserLogin extends JApplet implements ActionListener, KeyListener {
private JLabel lTitle;
private JLabel lUsername, lPassword;
private JTextField tUsername;
private JPasswordField tPassword;
private JButton bLogin;
private JLabel lLinkRegister, lLinkForgot;
private JLabel lEmpty = new JLabel(" ", JLabel.CENTER);
private JPanel panel1, panel2;
public void init() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
LoginGUI();
catch(Exception e) {
e.printStackTrace();
public void start() {
setVisible(true);
public void stop() {
setVisible(false);
private void LoginGUI() {
super.setSize(300, 150);
super.setBackground(Color.white);
lTitle = new JLabel("<HTML><BODY><FONT FACE = \"COURIER NEW\" SIZE = 6 COLOR = BLUE>Login</FONT></BODY></HTML>", JLabel.CENTER);
lUsername = new JLabel("Username : ", JLabel.CENTER);
lPassword = new JLabel("Password : ", JLabel.CENTER);
tUsername = new JTextField(15);
tPassword = new JPasswordField(15);
bLogin = new JButton("LOGIN");
// bLogin.setEnabled(false);
bLogin.addActionListener(this);
bLogin.addKeyListener(this);
panel2 = new JPanel();
GridBagLayout gbag = new GridBagLayout();
GridBagConstraints gbc = new GridBagConstraints();
panel2.setLayout(gbag);
panel2.addKeyListener(this);
gbc.anchor = GridBagConstraints.CENTER;
panel2.setMinimumSize(new Dimension(300, 200));
panel2.setMaximumSize(panel2.getMinimumSize());
panel2.setPreferredSize(panel2.getMinimumSize());
gbc.gridx = 1;
gbc.gridy = 1;
gbag.setConstraints(lUsername,gbc);
panel2.add(lUsername);
gbc.gridx = 2;
gbc.gridy = 1;
gbag.setConstraints(tUsername,gbc);
panel2.add(tUsername);
gbc.gridx = 1;
gbc.gridy = 2;
gbag.setConstraints(lPassword,gbc);
panel2.add(lPassword);
gbc.gridx = 2;
gbc.gridy = 2;
gbag.setConstraints(tPassword,gbc);
panel2.add(tPassword);
gbc.gridx = 2;
gbc.gridy = 3;
gbag.setConstraints(lEmpty,gbc);
panel2.add(lEmpty);
gbc.gridx = 2;
gbc.gridy = 4;
gbag.setConstraints(bLogin,gbc);
panel2.add(bLogin);
panel1 = new JPanel(new BorderLayout());
panel1.add(lTitle, BorderLayout.NORTH);
panel1.add(panel2, BorderLayout.CENTER);
add(panel1);
setVisible(true);
public void keyReleased(KeyEvent ke) {}
public void keyTyped(KeyEvent ke) {}
public void keyPressed(KeyEvent ke) {
if(ke.getKeyCode() == KeyEvent.VK_ENTER){
String username = tUsername.getText();
String password = new String(tPassword.getPassword());
if(username.length() == 0 || password.length() == 0) {
JOptionPane.showMessageDialog(new JFrame(),"You must enter a username and password to login", "Error", JOptionPane.ERROR_MESSAGE);
else {
boolean flag = checkUsernamePassword(username, password);
if(flag)
JOptionPane.showMessageDialog(new JFrame(),"Username and Password Accepted", "Access Granted", JOptionPane.INFORMATION_MESSAGE);
else
JOptionPane.showMessageDialog(new JFrame(),"Username or password Incorrect", "Access Denied", JOptionPane.INFORMATION_MESSAGE);
public void actionPerformed(ActionEvent ae) {
String gotCommand = ae.getActionCommand();
if(gotCommand.equals("LOGIN")) {
String username = tUsername.getText();
String password = new String(tPassword.getPassword());
if(username.length() == 0 || password.length() == 0) {
JOptionPane.showMessageDialog(new JFrame(),"You must enter a username and password to login", "Error", JOptionPane.ERROR_MESSAGE);
else {
boolean flag = checkUsernamePassword(username, password);
if(flag)
JOptionPane.showMessageDialog(new JFrame(),"Username and Password Accepted", "Access Granted", JOptionPane.INFORMATION_MESSAGE);
else
JOptionPane.showMessageDialog(new JFrame(),"Username or password Incorrect", "Access Denied", JOptionPane.INFORMATION_MESSAGE);
private boolean checkUsernamePassword(String username, String password) {
String user = null, pswd = null;
try {
FileInputStream fin = new FileInputStream("@data\\userpass.txt");
DataInputStream din = new DataInputStream(fin);
BufferedReader brin = new BufferedReader(new InputStreamReader(din));
user = (String) brin.readLine();
pswd = (String) brin.readLine();
catch(IOException ioe) {
ioe.printStackTrace();
if(username.equals(user) && password.equals(pswd))
return true;
else
return false;
}PLEASE HELP ME GUYS......RockAsh wrote:
Hey Andrew, first of all sorry for that shout, it was un-intentional as i am new to posting topics on forums and didn't new that this kind of writing is meant as shouting. Cool.
Secondly thank you for taking interest in my concern.No worries.
Thirdly, as i mentioned before, I am reading i file for checking of username and password. the file is named as "userpass.txt" and is saved in the directory named "@data" which is kept in the same directory in which my class file resides.OK - server-side. That makes some sense, and makes things easier. The problem with your current code is that the applet will be looking for that directory on the end user's local file system. Of course the file does not exist there, so the applet will fail unless the the end user is using the same machine as the server is coming from.
To get access to a resource on the server - the place the applet lives - requires an URL. In applets, URLs are relatively easy to form. It might be something along the lines of
URL urlToPswrd = new URL(getCodeBase(), "@data/userpass.txt");
InputStream is = urlToPswrd.openStream();
DataInputStream din = new DataInputStream(is);
So the problem is that it is reading the file and showing the specific output dialog box when i run it through appletviewer.. Huhh. What version of the SDK are you using? More recent applet viewers should report security exceptions if the File exists.
..but the same is not happening when i launch the applet in my browser window using the code as written belowHave you discovered how to open the Java Console in the browser yet? It is important.
Also the answer to your second question
Also, the entire approach to storing/restoring the password is potentially wrong. For instance, where is it supposed to be stored, on the server, or on the client?is that, as of now it is just my college project so all the data files and the username and password wiles will be stored on my laptop only i.e. on the client only. no server involved.OK, but understand that an applet ultimately does not make much sense unless deployed through a server. And the entire server/client distinction becomes very important, since that code would be searching for a non-existent file on the computer of the end user.
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