Return to thread

Hi there!
I am writing a program which monitors a set of user specified directorys every minute. The set of directories is then copied over to another location on the hard disk. When a file is updated it is also copied. The first time the thread detects a change, it calls a GUI which allows the user to specify which folders to backup. There is then a button which should start the process running and close the GUI, returning to the monitoring thread. The GUI and the thread are different classes and I need the button to return to the thread which created the GUI. Does anybody have any suggestions on how I can do this??

Can't tell you the exact coding right now. But I can give you some hint.
You are actually using two threads and they are from two different classes. The wait() and notify() or notifyAll() methods works on the same object monitor only. That's why you are getting such kind of exception. I guess the best solution is to use ThreadGroups. Using the threadgroup can solve your problem withouth much more changing the program logic. Just explore in javadoc or tutorial. If can't get the stuff then tell I'll take out some time for my friend.
(Dhananjay Singh)

Similar Messages

What a victory: failed installs due to "shared technology" errors returns endless threads via Google

I purchased PSE 10 (download) and lit up an install. It failed. I searched Google and oddly, the moment I hit the terms "photoshop elements 10 install fail" I got 40-50 results for "shared technology" failures. You guys are failure stars!
By the way, I cannot thank you enough for wasting my day like this. Back in the old days one had to visit microsoft.com to waste an entire ******** day trying to get their poorly engineered product installed, after it's failed endlessly to do as expected. Bill would be proud, if he weren't busy out there earning billions of dollars by giving away millions...which is nicer than what I have to say about you right now. Who needs time with their kids? Install PSE!!! It's a great time soak!
So, with that, I beg of you to please start sending me the usual asinine, nonworking fixes-in-a-box to get this product installed on my machine, even though we both know it won't work. Meanwhile, I have purchased downloaded, installed, and started using the Corel's latest version of PSP, which nearly FLEW into my hard drive and immediately worked right out of the box. Boy, they suck, huh? No. They don't. You do.
I've followed the hilariously funny and equally useless advice on your help forums (my favorite: " If you are using a downloaded installer, or running the installation from the hard drive, the Shared Technologies can fail because of the installation path. Copy the installation files to a folder to the root of the drive." Really? So you're saying "to install this stupid product, first you must fix our stupid mistake." Love you. Truly, I do.) and nothing has worked. I assume you will end up pointing at Microsoft and calling them bad, since every other app on my computer works without this moronic, yet remarkably popular, failure.
And even if we get this (endlessly) failed implementation to work - emphasis on IF - I will probably de-install it and demand a refund, depending on whether PSP has their product up to par, which is far more likely than Adobe having a working fix.
Now, I will say for the record that I have been harsh, and snide, and nasty. I am tired, and frustrated, and it's been four hours, and I have had enough. Having said that, deal with it. I am your customer (for the moment). Why do I need to ask you to make your product work? Isn't that the point? Is it? Helloooo?

It has occurred to me that Adobe's support people may be cowards. Then again, I am being a jerk, and it's probable they may have read my comments and said "screw this guy." I might say that. Then again, if I worked for a world-class company like Adobe I might step up and defend my product.
Then again, I might not, because they fell off the tracks some time ago and failed to stay in sync with the technologies they need to work with (read: Microsoft) to the degree they have Google reflecting:
a.) Adobe's level of failure in compatibility given the immediate and numerous responses to the simple keywords "elements fail" returning an astonishing number of responses (mine at the top lately) and...
b.) Adobe's own technical staff offering roughly a dozen differing, non-working fixes to the issue and...
c.) Adobe's studied and intentional avoidance of my emails, this thread, and hilariously worthless chat support.
It is very likely the source of the issue is an administrator profile glitch on the MS side, or perhaps an MSI issue, but good luck getting that clarified from Adobe.
They!
Don't!!
Know!!!
And they don't care. All I can say about that is I am glad I only dropped sixty-odd bucks on this product rather than seven-odd hundred for CS6. Maybe I'd get support if I had, but these snotty threads would be YouTubed, Reddited, and published in the local paper.
Next: there has been a breakthrough! An amazing breakthrough!
Among the many useless and stupid bits of advice Adobe's staff throw around on the support site, there is a great recommendation to try to load the product in safe mode. Last night I booted into safe mode and tried to run the installer, which of course immediately popped a dialog box stating it couldn't run in safe mode, so there's Adobe's great advice for you. While I was laughing and taking screen shots for posterity I glanced at my desktop, and there it was: the Photoshop Elements 10 icon. What are you doing there? I double clicked, and viola! It was loaded all along! Opened right up with that blue screen with a thousand names of the dev team.
Wait. What? I thought it rolled back? It SAID it rolled back the install. No? That 5 minutes it spends “rolling back” it just pretends to roll back, deletes the icon, leaving my computer polluted with a product I already got a refund on from Amazon? Really?
Anyway I rebooted back into my normal state and lo and behold, the PSE 10 icon is still there on my desktop. It did not install from safe mode. It had been installed from the beginning, and for whatever reason booting into safe mode and rebooting back seems to fix whatever idiotic and mindless failure Adobe built into this thing which they couldn't otherwise help me fix. Plain reboots did not do this: only booting into and back out of safe mode.
Thinking I was imagining things, I got up this morning and checked. Yep. There it is on my desktop, working as if it had been there all along and I hadn't been ignored, avoided, led astray, given stupid advice, or sold a product that clearly wasn't ready for sale. PSE 10. Working. Seemingly fully functional. Glory be.
Now, since I am the one who fixed it, I was thinking Adobe should pay me. I spent about 10 hours fuming over this thing, and I bill $65 an hour as a consultant. I realize that I am not an Adobe coder or support specialist, but I fixed it and should be compensated for my time at my rate. A bonus is in order as well - call it pain and suffering. 10X$65 plus a little sweetener, let's call it a thousand bucks. What do you say, Adobe? Are you going to award my ingeniousness and brilliance? You couldn't handle it, and still can't, but I did it. Me. The bitchy, whiny one infesting your support board with angry hate. You owe me.
Yeah, I didn’t think so. Anyway, I have always liked PSE and have used past versions to great success. I think I will like PSE10 just as much, regardless the fact my view of Adobe is that much dimmer for the shamefully bad experience of late. This has been a pretty sucky couple of days, and from the boards and complaints I have found out it's the exception rather than the rule, but exceptional nonetheless.
Now I shall screenshot this thread and publish it everywhere I can find a place for it. I will call out the responses I received from Adobe (none) and the great support I received from Adobe (none) and the quality service I received from Adobe (none). Then I will do my level best to remember what the heck I was doing that made me want to buy PSE in the first place: there was a photo of...something, and I wanted to...do something. What was it? I've spent so much time in Adobe FailShop I have forgotten what I was doing here in this bottomless abyss of fail...
Ta taa, Adobe Support. Love you, really I do. True story.

Return of thread starting new method

hi,
I have an application that runs a thread pool, each thread builds up a linklist. what I need to know is that I Need to get this linklist only when the thread is done and pass it to another method in another object where all of these linklists are kept.
How do I do this, I dont have a huge knowledge on threads :(
I believe I can add this new objective ( to keep all the linklists ) to be run in the same thread pool as well or should I make a new seperate thread to run it.
Other thing is I believe I can synchronize that method so it waits until one link list is finished, but is this an efficient way I mean the threads in my thread pool changes fast, so is it ok to make the method synchronized. I mean does that decrease the performance, say each thread takes about 1 sec to finish...
Thank you.

thanks
each thread is for obtaining information from network
stream which takes up time. one thread handles one
IP. If I use only 1 thread It takes a hell of a long
time.. I said 1 sec for 1 thread as just a measure
but practically it takes more than that ...Okay. I just wanted to make sure you had a good reason to use multiple threads, rather than thinking that multithreading a CPU-intensive operation would magically make it go faster.
I'll try the join method, the main thread which
starts the thread pool execution waits until
everything is done.That can work, depending on your requirements. If you want the main thread to stop and do nothing until ALL the other threads are done, that's fine. But if you want something to happen as soon as each thread finishes, join is not a good way to go.
so is it OK if I run the linklist
processing method in the mainthread's stack or shall
I use a thread in the thread pool for that..I don't understand enough about what you're trying to do to answer that.

Random returning same values for all threads?

I "translated" an Applet example from a book to a MIDlet (as part of my learning process). However the MIDlet does not react as it should, and when the particles are all moving independently in the Applet, they are stuck together (as one) in the MIDlet.
So far, only one possibility was suggested to me: if the Random object are created one after the other, they could end up based on the same seed (which is the clock by default) and will generate the same numbers.
I tried to delay between the creation of the threads with no result. And the fact that the applet runs properly makes me wonder...
Does anyone have a clue?
In the MIDlet:
protected Thread makeThread(final Particle p) { // utility
 Runnable runloop = new Runnable() {
 public void run() {
 try {
 for(;;) {
 p.move();
 canvas.repaint();
 Thread.sleep(100); // 100msec is arbitrary
 catch (InterruptedException e) { return; }
 return new Thread(runloop);
}In the particle:
protected final Random rng = new Random();
public synchronized void move() {
 x += rng.nextInt(step) - (step/2);
 y += rng.nextInt(step) - (step/2);
 //returns exactly the same 10 times in a row
}

You might try justing just one static Random object.
Also note that als long as your using CLDC 1.0, you don't have any floating point support.

Is there a way to figure out what the current thread is?

I've got the following snippet of code:
// create a new thread. If the current thread is not this new thread, return
Thread CountDownThread = new Thread("CountDownThread");
CountDownThread.start();
if (/*CURRENT THREAD*/.getName() != CountDownThread.getName()) {
     System.out.println ("I'm not CountDownThread. I'm leaving.");
     return;
// current thread should be new thread. Therefore start the countdown
CurrTime = InitTime;
while(CurrTime.charAt(0) != '-') {      // go until current time is negative
     CurrTime = C.countDown();       // returns the current time based on the difference between the initial and elapsed time
     setText(CurrTime);                   // display current time in JLabel
C.reset();
setText(C.getCurrTime());What I'm trying to do is get a clock (C) to count down and display the time remaining in a JLabel (this snippet is taken from a method within that very JLabel which I'm extending from javax.swing.JLabel). While it's counting down, I'd like for the program to go off and do other things. Therefore, I'm trying to create a new thread that carries out the task of counting down while the original/main thread moves on to do other things.
Please have a look at the above code and tell me if I'm on the right track. The one thing I don't know how to do is figure out how to tell which thread the current thread is. I'm assuming that both the new thread and original/main one will execute the if statement, the new one after it returns from start() (which I haven't defined). The original/main one will detect that it is not the new thread and return, whereas the new thread will and go on to the while loop. In the while loop, it will count down the clock until it reaches 0, after which point it will reset it and die.
If I'm on the right track, all I need to know is how to detect which thread is currently executing. If I'm not on the right track, what would be the best way to do this?

What? No! No Thread terminates on the return of start(). Those two events are unrelated!Uh... I think you misunderstood what I said.
I didn't say that CountDownThread terminates upon returning from start() (which is what it sounds like you interpreted from me); I said that the thread that CountDownThread creates terminates once CountDownThread returns from start() (i.e. like any other local variable/object). This, of course, assumes that CountDownThread has a Runnable object on which to call its run() method (am I right?), in which case my code above doesn't create a new thread at all (i.e. CountDownThread.start() is executed within the main/original thread) - am I right?
No, run() doesn't call start()! That would be stupid.Again, you misunderstood. I shouldn't need to explain this one. A simple reference to an ordinary dictionary on the words 'former' and 'latter' should suffice :)
Anyway, all joking aside, I have now improved my code and it works! Here's what it looks like:
ClockJLabel.java
package MazeMania.clock;
public class ClockJLabel extends javax.swing.JLabel {
private Clock C;
private ClockJLabelsRunnable CJLR;
public ClockJLabel() {
C = new Clock();
CJLR = new ClockJLabelsRunnable();
setText(C.getCurrTime()); // should be 00:00:00:00
setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
// need to figure out how to set the size so that it sticks
setForeground(new java.awt.Color(255, 0, 0));
setBackground(new java.awt.Color(0, 0, 0));
setOpaque(true);
// starts the clock counting up indefinitely from 0
public void start() {
(new Thread(new Runnable() {
    public void run() {
     while(true) setText(C.getElapsedTime());
   })).start();
//System.out.println("Started clock...");
// starts the clock counting down from an initial time and runs this count down in a separate thread
public void countDown(String InitTime) {
// initialize the clock
try {C.initClock(InitTime);}
catch(java.text.ParseException PE) {
   System.out.println(PE.getMessage());
// initialize JLabel's display
setText(C.getCurrTime());
// prepare Runnable and give it to new Thread. New Thread starts count down.
CJLR.task = CJLR.COUNTDOWN;
CJLR.CJL = this;
Thread CountDownThread = new Thread(CJLR);
CountDownThread.start();
public Clock getClock() {
return C;
}ClockJLabelsRunnable
package MazeMania.clock;
import java.lang.Runnable;
class ClockJLabelsRunnable implements Runnable {
public static int COUNTDOWN = 1;
public static int COUNTUP = 2;
// NOTE: this Runnable doesn't test for the proper setting of these variables
public int task = 0;
public ClockJLabel CJL = null;
public void run() {
Clock C = CJL.getClock();
while(C.countDown().charAt(0) != '-') {CJL.setText(C.getCurrTime());}
C.reset();
CJL.setText(C.getCurrTime());

How to display a modal message while processing in a thread.

I have difficulty in display a modal dialog while in processing in a background.
I have created the following class.
package fedex.screen.component;
import java.awt.*;
// This infobox is a modal dialog which display static text and stay
// on screen without blocking proceeding code from execution and can
// only close by issuing close method.
public class ProcessInfoBox implements Runnable
 // Display dialog box
 private InfoBox dialog = null;
 // Thread to enable showing of Dialog Box
 private Thread thread = new Thread(this);
 // Determine if to close dialogbox
 private boolean isFinish = false;
 public ProcessInfoBox(Frame frame) {
 dialog = new InfoBox(frame,"Performing Operation","Processing...");
thread.setPriority(Thread.MAX_PRIORITY);
 public void setTitle(String title) {
 dialog.setTitle(title);
 public void setText(String text) {
 dialog.getMessageLbl().setText(text);
 // The reference return will be ProcessInfoBox.InfoBox
 public InfoBox getInfoBox() {
 return dialog;
 // Thread method
 public void run() {
 dialog.setVisible(true);
 // If true return from thread and exit.
 while ( isFinish == false )
 try
 Thread.sleep(500); // 500 msec
 catch ( InterruptedException e )
 // Start showing dialog
 final public void show() {
 thread.start();
 isFinish = false;
 final public void hide() {
 isFinish = true;
 dialog.setVisible(false);
 // Dialog box which show text.
 public class InfoBox extends Dialog
 private Label messageLbl = new Label("Processing ...");
 public InfoBox(Frame frame, String title, String message) {
 super(frame,title,true);
 initInfoBox();
 public Label getMessageLbl() {
 return messageLbl;
 private void initInfoBox() {
 setLayout(new BorderLayout());
 add(messageLbl,BorderLayout.CENTER);
 setSize(250,150);
FormUtility.centerForm(this);
 public static void main(String[] args) {
 Frame frame = new Frame("BigMac");
 frame.setSize(600,600);
 frame.setVisible(true);
 ProcessInfoBox box = new ProcessInfoBox(frame);
 box.show();
 for ( int i = 1; i < 10000; i++ )
 System.out.println(i);
 box.hide();
To test the code I used the following section to test
The main method in the class is used. In the simple
example, the message did correctly update itself while
i is increment. However, when I try on more complex
application, the message just stalk there without
updating itself as it is hanging.
I have try to set piority to highest but without effect.
Is there anything to rectify the situation
thank

The "please wait" dialog is a modal dialog. When u
show it, the following code can not executed!
That's the problem

Threads and blocking i/o

background i am building a multi-cliented server based on the model of one thread per client. client threads wait on a BufferedReader in the run() method for data over the network and take the appropriate action based on the input.
problem a client thread needs in certains circumstances to kill the thread of another client. since the run() method loops on the blocking input of BufferedReader, any flag or call to interrupt() will not be evaluated until the BufferedReader unblocks. this is bad since it means that the client who is to be killed will not return from run() until the client app talking to the thread sends some data to unblock BufferedReader. the result is a potential dos attack against this server. bad stuff.
example the current situation: client app one connects to the server spawning Thread-1. client app two connects to the server spawning Thread-2. app two triggers killSomeClient() on Thread-1. Thread-1 continues to linger until client app 1 transmits data to the server, whereupon Thread-1 dies.
example the required functionality: app one connects to Thread-1. app two connects to Thread-2. app two triggers killSomeClient() on Thread-1. Thread-1 returns from the run() loop and the thread dies immediately.
what i've tried well, obviously, stop() and destroy() are what i really want... but that's not an option. have tried setting a flag in the while loop to be set by killSomeClient() (ie while(keepRunning && (inputFromClient = in.readLine()) != null) ). have tried interrupt() in the same manner.
potential solutions i can think of a replacement for stop() or some effective non-blocking read allowing me to loop around the reader, grabbing one char at a time and continuing the loop even if the queue is empty.
the code example this is a very pared-down version of the code showing only the material necessary for this example (better for readability!). aside from this issue, the application runs.
someClient
public class someClient{
    private Socket socket;
    private BufferedReader in;
    private String inputFromClient;
    someClient(Socket socket){
        this.socket = socket;
        this.in = new BufferedReader(new InputStreamReader(theSocket.getInputStream()));
    public void run(){
        try{
            // waits on blocking input
            while((inputFromClient = in.readLine()) != null){
                System.out.println(inputFromClient);
        }catch(Exception e){}
    public void killSomeClient(someClient killme){
        // help!!
someServer
public class someServer{
    private ServerSocket ss;
    public someServer(){
        ss = new ServerSocket(9999);
    public startServer{
        Socket socket = ss.accept();
        someClient client = new someClient(socket);
        client.start();
}

problem a client thread needs in certains
circumstances to kill the thread of another client.
since the run() method loops on the blocking input of
BufferedReader, any flag or call to interrupt() will
not be evaluated until the BufferedReader unblocks.In general, the best approach to terminating a blocking operation is to invalidate the object on which that operation depends. In your case, closing the socket will terminate the read().
The following is a rather lengthy piece of code that's actually been tested :-)
import java.io.*;
import java.net.*;
public class SocketStopper
    private final static int PORTNUM = 10000;
    public static void main( String argv[] )
    throws Exception
        System.err.println("Starting server");
        Server server = new Server();
        (new Thread(server)).start();
        Thread.sleep(2000);
        System.err.println("Starting client");
        Client client = new Client();
        (new Thread(client)).start();
        Thread.sleep(2000);
        System.err.println("About to close server socket");
        server.closeSocket();
        Thread.sleep(2000);
        System.err.println("About to exit");
        System.exit(0);
    /** This object establishes a connection to the server port and then
     * sleeps for 10 minutes without writing anything. This should cause
     * the reader to block for input.
    public static class Client
    implements Runnable
        public void run()
            try
                Socket sock = new Socket(InetAddress.getLocalHost(), PORTNUM);
                System.err.println("Client established connection");
            catch (Exception e)
                System.err.println("Client unable to establish connection: " + e);
                return;
            try
                Thread.sleep(10 * 60000L);
            catch (InterruptedException ignored)
    /** This object sets up a server socket. It accepts the first connection
     * from that socket and attempts to read from it, which should block.
    public static class Server
    implements Runnable
        private Socket _sock;
        public void run()
            try
                ServerSocket srv = new ServerSocket(PORTNUM);
                _sock = srv.accept();
                System.err.println("Server accepted connection");
            catch (Exception e)
                System.err.println("Server unable to receive connection: " + e);
                return;
            try
                _sock.getInputStream().read();
                System.err.println("read() completed normally");
            catch (IOException e)
                System.err.println("read() terminated with exception: " + e);
        public void closeSocket()
            try
                _sock.close();
            catch (IOException ignored)
}

Very Urgent, files, threads, and swing !!!!

Dear friends, i have a swing application, in that application i have a class that extends a thread, that thread will do nothing but read the contents of my data file and puts them in an array, but i am getting a NullpointerException in my thread, could any friend help me please, it is very urgent, i will post my code below.
import java.awt.*;
import java.awt.event.*;
import java.text.DateFormat;
import java.util.*;
import javax.swing.*;
import java.sql.*;
import java.net.URL;
import java.io.*;
public class FinalMachine extends JFrame
private JPanel MainPanel, ThicknessPanel, MainManager,fieldsPanel, sub_panel;
private Container c;
private CardLayout CardManager;
private String timezone;
private static final int ONE_SECOND = 1000;
private JLabel welcome_label, label1, label2, label3,field_label;
private JTextField data_entry;
private Connection connection;
public JPanel thick_figure;
public int num_of_hits, next_index, recCount;
public int dataBuffer[];
public FileReader data_file;
public BufferedReader b_data_file;
public File tem_file;
final int num_of_rec = 20;
public FinalMachine()
super("PHOENIX MACHINERY s.a.l");
/* Start all threads */
/* Start filling data file in global array */
 loadData dataFile = new loadData();
 dataFile.start();
/* Adding control to window application */
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowevent)
// setDefaultCloseOperation(0);
 System.exit(0);
public void windowDeiconified(WindowEvent eve)
setState(0);
addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent componentevent)
setSize(500, 500);
Dimension dimension1 = Toolkit.getDefaultToolkit().getScreenSize();
if(dimension1.width == 800 && dimension1.height == 600)
setLocation(150, 25);
else
if(dimension1.width == 1024 && dimension1.height == 768)
setLocation(200, 100);
/* Setting the location of the application on the screen */
Dimension dimension = Toolkit.getDefaultToolkit().getScreenSize();
if(dimension.width == 800 && dimension.height == 600)
setLocation(150, 25);
else
if(dimension.width == 1024 && dimension.height == 768)
setLocation(200, 100);
/* Constructing the main menu */
 JMenuBar bar = new JMenuBar();
 setJMenuBar( bar );
 JMenu fileMenu = new JMenu( "File");
 fileMenu.setMnemonic( 'F' );
 JMenuItem mainItem = new JMenuItem( "Main page" );
 mainItem.setMnemonic( 'M' );
 mainItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 CardManager.show(MainManager, "main");
 fileMenu.add( mainItem );
 JMenuItem dataItem = new JMenuItem( "Database page" );
 dataItem.setMnemonic( 'D' );
 dataItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 CardManager.show(MainManager, "data_base");
 fileMenu.add( dataItem );
 JMenuItem printItem = new JMenuItem( "Print" );
 printItem.setMnemonic( 'P' );
 printItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 PrintUtilities.printComponent(MainManager);
 fileMenu.add( printItem );
 JMenuItem exitItem = new JMenuItem( "Exit" );
 exitItem.setMnemonic( 'P' );
 exitItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 System.exit(0);
 fileMenu.add( exitItem );
 bar.add( fileMenu );
 JMenu figureMenu = new JMenu( "Figures");
 figureMenu.setMnemonic( 'G' );
 JMenuItem thicknessItem = new JMenuItem( "Thickness" );
 thicknessItem.setMnemonic( 'T' );
 thicknessItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 CardManager.show(MainManager, "thickness");
 figureMenu.add( thicknessItem );
 bar.add( figureMenu );
 JMenu helpMenu = new JMenu( "Help");
 helpMenu.setMnemonic( 'H' );
 JMenuItem aboutItem = new JMenuItem( "About us" );
 aboutItem.setMnemonic( 'A' );
 aboutItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 JOptionPane.showMessageDialog(null, "Engineer Bilal Haidar (Computer & "+ "Communication Engineering)\n\n All Rights Reserevd. @ 2002",
 "About me...", JOptionPane.PLAIN_MESSAGE);
 helpMenu.add( aboutItem );
 bar.add( helpMenu );
/* Intializing global values */
dataBuffer = new int[60];
/* Initializing the panels */
c = getContentPane();
c.setLayout(new FlowLayout());
CardManager = new CardLayout();
MainManager = new JPanel(false);
MainManager.setLayout(CardManager);
c.add(MainManager);
javax.swing.border.Border border = BorderFactory.createEmptyBorder(10, 10, 5, 10);
MainPanel = new JPanel(false);
MainPanel.setLayout(new BoxLayout(MainPanel, 1));
MainPanel.setBorder(border);
ThicknessPanel = new JPanel(false);
ThicknessPanel.setLayout(new BoxLayout(ThicknessPanel, 1));
ThicknessPanel.setBorder(border);
fieldsPanel = new JPanel(false);
fieldsPanel.setLayout( new BoxLayout( fieldsPanel,1));
fieldsPanel.setBorder(border);
sub_panel = new JPanel(false);
sub_panel.setLayout( new BoxLayout(sub_panel,0) );
sub_panel.setBorder(border);
thick_figure = new JPanel(false);
thick_figure.setBorder(border);
/* Filling the main panel */
JLabel jlmain = new JLabel("Main Page");
MainPanel.add(jlmain);
timezone = showTime(new Locale("en", "US"));
JLabel jltime = new JLabel(" " + timezone);
MainPanel.add(jltime);
MainManager.add(MainPanel, "main");
/* Filling the thickness panel */
num_of_hits = 0;
next_index = 0;
/* fill in with ero values for everything*/
/*display the figure*/
ThicknessPanel.add(thick_figure);
JLabel blanklabel = new JLabel(" ");
ThicknessPanel.add(blanklabel);
JButton build_fig = new JButton("Draw Figure");
build_fig.addActionListener(
 new ActionListener() { // anonymous inner class
 public void actionPerformed( ActionEvent e )
if ( num_of_hits == 0 )
/* draw figure based on first 20 points in the array */
next_index = num_of_rec;
else
if ( num_of_hits > 3 )
JOptionPane.showMessageDialog(null,"No more data to draw","Error Drawing",JOptionPane.ERROR_MESSAGE);
else
/* draw the figure starting the data from index 20*/
next_index = next_index + num_of_rec;
num_of_hits += 1;
ThicknessPanel.add(build_fig);
MainManager.add(ThicknessPanel, "thickness");
/* filling the database panel */
label1 = new JLabel(" ",SwingConstants.CENTER);
welcome_label = new JLabel(" Database Page ",SwingConstants.CENTER);
label2 = new JLabel(" ",SwingConstants.CENTER);
fieldsPanel.add( label1 );
fieldsPanel.add( welcome_label );
fieldsPanel.add( label2 );
field_label = new JLabel(" Enter your name: ");
data_entry = new JTextField( 10 );
sub_panel.add( field_label );
sub_panel.add( data_entry );
fieldsPanel.add( sub_panel );
JButton add_data = new JButton( "Add me" );
add_data.addActionListener(
 new ActionListener() { // anonymous inner class
 public void actionPerformed( ActionEvent e )
// try {
// url = "jdbc:odbc:DataEntry";
// Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
// connection = DriverManager.getConnection( url );
// System.out.println( "Connection Suucessfull");
// Statement statement = connection.createStatement();
// String get_field;
// get_field = data_entry.getText();
// String query = "INSERT INTO data (anyField) VALUES ('get_field')";
// int result1 = statement.executeUpdate( query );
// if ( result1 == 1 )
// JOptionPane.showMessageDialog(null, "Thanks for the info..."," Data Entry Success",JOptionPane.INFORMATION_MESSAGE);
// else
// JOptionPane.showMessageDialog(null, "Sorry, your name was not added...","Data entry error",JOptionPane.ERROR_MESSAGE);
// catch ( ClassNotFoundException cnfex ) {
// // process ClassNotFoundExceptions here
// cnfex.printStackTrace();
// System.out.println( "Connection UN Suucessfull");
// catch ( SQLException sqlex ) {
// // process SQLExceptions here
// sqlex.printStackTrace();
// System.out.println( "Connection UN Suucessfull");
// catch ( Exception ex ) {
// // process remaining Exceptions here
// ex.printStackTrace();
// System.out.println( "Connection UN Suucessfull");
fieldsPanel.add(add_data);
MainManager.add(fieldsPanel, "data_base");
/* display time */
Timer timer = new Timer(1000, new ActionListener() {
public void actionPerformed(ActionEvent actionevent)
timezone = showTime(new Locale("en", "US"));
setTitle("PHOENIX MACHINERY s.a.l " + timezone);
timer.start();
public static void main(String args[])
FinalMachine finalmachine = new FinalMachine();
finalmachine.setSize(500, 500);
ImageIcon imageicon = new ImageIcon("images/pc.gif");
finalmachine.setIconImage(imageicon.getImage());
finalmachine.show();
public static String showTime(Locale locale)
java.util.Date date = new java.util.Date();
byte byte0 = 2;
DateFormat dateformat = DateFormat.getTimeInstance(byte0, locale);
String s = dateformat.format(date);
return s;
/* Thread loadData starts here */
class loadData extends Thread
public void run()
try {
 readMyFile();
catch( Exception x )
System.out.println("The following error occured in LoadData thread : "+x.toString() ); }
} // run() ends here
/* method read file inside thread loadData */
void readMyFile() {
String record = " ";
recCount = 0;
try {
 tem_file = new File("mydata.dat");
 data_file = new FileReader(tem_file);
 b_data_file = new BufferedReader( data_file );
 record = new String();
 while ( (record = b_data_file.readLine()) != null ) {
 dataBuffer[recCount] = Integer.parseInt(record);
 recCount += 1; }
 b_data_file.close();
 catch (IOException e) {
 System.out.println("Uh oh, got an IOException error!");
 e.printStackTrace();
 } // end of readMyFile()
} // thread loadData ends
mydata.dat
2
4
3
1
2
3
5
2
4
1
6
3
2
5
4
1
2
5
8
2
6
9
7
4
2
1
0
2
5
4
8
7
5
6
3
2
1
4
3
0
2
3
6
5
2
1
4
5
6
9
8
5
2
1
6
8
3
1
7
5

Thank you Mr. jobuck, you helped me a lot, i wonder if you can provide me with a tutorial on how threads work and how runnables work too. i fixed the error ut old me about but still when i try to add another thread to my program i got an error saying that, i must decalre the new thread in a seperate file please can u have a look on what i have:
import java.awt.*;
import java.awt.event.*;
import java.text.DateFormat;
import java.util.*;
import javax.swing.*;
import java.sql.*;
import java.net.URL;
import java.io.*;
public class FinalMachine extends JFrame
private JPanel MainPanel, ThicknessPanel, MainManager,fieldsPanel, sub_panel;
private Container c;
private CardLayout CardManager;
private String timezone;
private static final int ONE_SECOND = 1000;
private JLabel welcome_label, label1, label2, label3,field_label;
private JTextField data_entry;
private JPanel thick_figure;
private int num_of_hits, next_index, recCount, read_flag;
private int dataBuffer[];
private FileReader data_file;
private BufferedReader b_data_file;
private File tem_file;
private Connection connection;
final int num_of_rec = 20;
public FinalMachine()
super("PHOENIX MACHINERY s.a.l");
/* load JDBC drivers */
try {
String url = "jdbc:odbc:DataEntry";
Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
 connection = DriverManager.getConnection( url );
 System.out.println( "Connection Suucessfull");
catch ( ClassNotFoundException cnfex ) {
// process ClassNotFoundExceptions here
cnfex.printStackTrace();
 System.out.println( "Connection UN Suucessfull");
catch ( SQLException sqlex ) {
// process SQLExceptions here
sqlex.printStackTrace();
 System.out.println( "Connection UN Suucessfull");
catch ( Exception ex ) {
// process remaining Exceptions here
ex.printStackTrace();
 System.out.println( "Connection UN Suucessfull");
/* Intializing global values */
dataBuffer = new int[60];
/* Start all threads */
/* Start filling data file in global array */
 loadData dataFile = new loadData();
 dataFile.start();
 setData setdata = new setData();
 setdata.start();
/* Adding control to window application */
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowevent)
// setDefaultCloseOperation(0);
 System.exit(0);
public void windowDeiconified(WindowEvent eve)
setState(0);
addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent componentevent)
setSize(500, 500);
Dimension dimension1 = Toolkit.getDefaultToolkit().getScreenSize();
if(dimension1.width == 800 && dimension1.height == 600)
setLocation(150, 25);
else
if(dimension1.width == 1024 && dimension1.height == 768)
setLocation(200, 100);
/* Setting the location of the application on the screen */
Dimension dimension = Toolkit.getDefaultToolkit().getScreenSize();
if(dimension.width == 800 && dimension.height == 600)
setLocation(150, 25);
else
if(dimension.width == 1024 && dimension.height == 768)
setLocation(200, 100);
/* Constructing the main menu */
 JMenuBar bar = new JMenuBar();
 setJMenuBar( bar );
 JMenu fileMenu = new JMenu( "File");
 fileMenu.setMnemonic( 'F' );
 JMenuItem mainItem = new JMenuItem( "Main page" );
 mainItem.setMnemonic( 'M' );
 mainItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 CardManager.show(MainManager, "main");
 fileMenu.add( mainItem );
 JMenuItem dataItem = new JMenuItem( "Database page" );
 dataItem.setMnemonic( 'D' );
 dataItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 CardManager.show(MainManager, "data_base");
 fileMenu.add( dataItem );
 JMenuItem printItem = new JMenuItem( "Print" );
 printItem.setMnemonic( 'P' );
 printItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 PrintUtilities.printComponent(MainManager);
 fileMenu.add( printItem );
 JMenuItem exitItem = new JMenuItem( "Exit" );
 exitItem.setMnemonic( 'P' );
 exitItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 System.exit(0);
 fileMenu.add( exitItem );
 bar.add( fileMenu );
 JMenu figureMenu = new JMenu( "Figures");
 figureMenu.setMnemonic( 'G' );
 JMenuItem thicknessItem = new JMenuItem( "Thickness" );
 thicknessItem.setMnemonic( 'T' );
 thicknessItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 CardManager.show(MainManager, "thickness");
 figureMenu.add( thicknessItem );
 bar.add( figureMenu );
 JMenu helpMenu = new JMenu( "Help");
 helpMenu.setMnemonic( 'H' );
 JMenuItem aboutItem = new JMenuItem( "About us" );
 aboutItem.setMnemonic( 'A' );
 aboutItem.addActionListener (
 new ActionListener() {
 public void actionPerformed( ActionEvent e )
 JOptionPane.showMessageDialog(null, "Engineer Bilal Haidar (Computer & "+ "Communication Engineering)\n\n All Rights Reserevd. @ 2002",
 "About me...", JOptionPane.PLAIN_MESSAGE);
 helpMenu.add( aboutItem );
 bar.add( helpMenu );
/* Initializing the panels */
c = getContentPane();
c.setLayout(new FlowLayout());
CardManager = new CardLayout();
MainManager = new JPanel(false);
MainManager.setLayout(CardManager);
c.add(MainManager);
javax.swing.border.Border border = BorderFactory.createEmptyBorder(10, 10, 5, 10);
MainPanel = new JPanel(false);
MainPanel.setLayout(new BoxLayout(MainPanel, 1));
MainPanel.setBorder(border);
ThicknessPanel = new JPanel(false);
ThicknessPanel.setLayout(new BoxLayout(ThicknessPanel, 1));
ThicknessPanel.setBorder(border);
fieldsPanel = new JPanel(false);
fieldsPanel.setLayout( new BoxLayout( fieldsPanel,1));
fieldsPanel.setBorder(border);
sub_panel = new JPanel(false);
sub_panel.setLayout( new BoxLayout(sub_panel,0) );
sub_panel.setBorder(border);
thick_figure = new JPanel(false);
thick_figure.setBorder(border);
/* Filling the main panel */
JLabel jlmain = new JLabel("Main Page");
MainPanel.add(jlmain);
timezone = showTime(new Locale("en", "US"));
JLabel jltime = new JLabel(" " + timezone);
MainPanel.add(jltime);
MainManager.add(MainPanel, "main");
/* Filling the thickness panel */
num_of_hits = 0;
next_index = 0;
/* fill in with ero values for everything*/
/*display the figure*/
ThicknessPanel.add(thick_figure);
JLabel blanklabel = new JLabel(" ");
ThicknessPanel.add(blanklabel);
JButton build_fig = new JButton("Draw Figure");
build_fig.addActionListener(
 new ActionListener() { // anonymous inner class
 public void actionPerformed( ActionEvent e )
if ( num_of_hits == 0 )
/* draw figure based on first 20 points in the array */
next_index = num_of_rec;
else
if ( num_of_hits > 3 )
JOptionPane.showMessageDialog(null,"No more data to draw","Error Drawing",JOptionPane.ERROR_MESSAGE);
else
/* draw the figure starting the data from index 20*/
next_index = next_index + num_of_rec;
num_of_hits += 1;
ThicknessPanel.add(build_fig);
MainManager.add(ThicknessPanel, "thickness");
/* filling the database panel */
label1 = new JLabel(" ",SwingConstants.CENTER);
welcome_label = new JLabel(" Database Page ",SwingConstants.CENTER);
label2 = new JLabel(" ",SwingConstants.CENTER);
fieldsPanel.add( label1 );
fieldsPanel.add( welcome_label );
fieldsPanel.add( label2 );
field_label = new JLabel(" Enter your name: ");
data_entry = new JTextField( 10 );
sub_panel.add( field_label );
sub_panel.add( data_entry );
fieldsPanel.add( sub_panel );
JButton add_data = new JButton( "Add me" );
add_data.addActionListener(
 new ActionListener() { // anonymous inner class
 public void actionPerformed( ActionEvent e )
 try {
Statement statement = connection.createStatement();
 String get_field;
 get_field = data_entry.getText();
 String query = "INSERT INTO data (anyField) VALUES ('"+get_field+"')";
 int result1 = statement.executeUpdate( query );
 if ( result1 == 1 )
 JOptionPane.showMessageDialog(null, "Thanks for the info..."," Data Entry Success",JOptionPane.INFORMATION_MESSAGE);
 data_entry.setText(" ");
 else
 JOptionPane.showMessageDialog(null, "Sorry, your name was not added...","Data entry error",JOptionPane.ERROR_MESSAGE);
 catch ( SQLException sqlex ) {
 // process SQLExceptions here
 sqlex.printStackTrace();
 System.out.println( "Connection UN Suucessfull");
 catch ( Exception ex ) {
 // process remaining Exceptions here
 ex.printStackTrace();
 System.out.println( "Connection UN Suucessfull");
fieldsPanel.add(add_data);
MainManager.add(fieldsPanel, "data_base");
/* display time */
Timer timer = new Timer(1000, new ActionListener() {
public void actionPerformed(ActionEvent actionevent)
timezone = showTime(new Locale("en", "US"));
setTitle("PHOENIX MACHINERY s.a.l " + timezone);
timer.start();
public static void main(String args[])
FinalMachine finalmachine = new FinalMachine();
finalmachine.setSize(500, 500);
ImageIcon imageicon = new ImageIcon("images/pc.gif");
finalmachine.setIconImage(imageicon.getImage());
finalmachine.show();
public static String showTime(Locale locale)
java.util.Date date = new java.util.Date();
byte byte0 = 2;
DateFormat dateformat = DateFormat.getTimeInstance(byte0, locale);
String s = dateformat.format(date);
return s;
/* Thread loadData starts here */
public class loadData extends Thread
public void run()
try {
 readMyFile();
 read_flag = 1;
 notify();
catch( Exception x )
System.out.println("The following error occured in LoadData thread : "+x.toString() );
} // run() ends here
/* method read file inside thread loadData */
void readMyFile() {
String record = " ";
recCount = 0;
try {
 tem_file = new File("mydata.dat");
 data_file = new FileReader(tem_file);
 b_data_file = new BufferedReader( data_file );
 record = new String();
 while ( (record = b_data_file.readLine()) != null ) {
 dataBuffer[recCount] = Integer.parseInt(record);
 recCount += 1; }
 b_data_file.close();
 catch (IOException e) {
 System.out.println("Uh oh, got an IOException error!");
 e.printStackTrace();
 } // end of readMyFile()
} // thread loadData ends
public class setData extends Thread {
public void run()
try {
 while ( !read_flag ) {
 try { wait(); }
 catch( InterruptedException e ) {
 e.printStackTrace();
 } // end while
 for(int index = 0; index < 60; index++)
 System.out.println("Array["+index+"] = "+dataBuffer[index]);
catch( Exception x )
System.out.println("The following error occured in LoadData thread : "+x.toString() );
} // run() ends here
the only added thing is the setData thread, i want this thread to start printing out the array whenever, loadData thread has finished filling the data inside the array please i need ur help.

Does Spring's AbstractController reuse threads?

Hello all,
I am planning on using a ThreadLocal<ProxySelector> so each time I call a WS a different proxy is used.
For that, each time AbstractController returns a thread I want to have a thread that is unique.
Is this the case with AbstractController, or are threads re-used?
Thank you, Dimitris

Why are you not asking this in the Spring forum?
http://forum.springsource.org/forum.php
Over there you'll find hundreds of developers using Spring, over here - if you're lucky a few and they might miss your thread because you're posting in an off-topic forum (this has nothing to do with webservices).

Thread Pool in JRT

Hi All,
1) the first question is what is the recommended way to allocate thread poll in rt system??
2) what is the best way to do:
-if my mission take a long time can i just suspend the thread and than resume it again (is it possible at all??)
or the other option is to return it to the pool and get it again and again.
im asking the second question from the view of performance and low latency .
i assumed that each time i return the thread to the pool and than active it again it will "cost" cpu time.
hope my question is clear enough.
TIA
Gabi

Hi Gabi,
I'm not completely clear on your questions. You can create a thread pool in a RT system the same basic way as in non-RT but you need to deal with priorities correctly. One way to do this would be to have the pool threads run at maximum priority normally and then drop to the actual priority of a submitted work task. Another model is to split the pool into groups based on priority, so effectively there is a work queue per priority-level and a group of threads to service each pool. This second model is used in the Real-time CORBA "lanes" approach. Designing an effective thread pool is a non-trivial task (take a look at the java.util.concurrent Thread PoolExecutor) and dealing with RT priorities and RT latency issues makes it even more complex.
Alternatively rather than use an explicit thread pool consider whether you can convert the design to one using AsyncEvents and AsyncEventHandlers.
Question 2 I don't really understand. Pool threads typically block on a queue waiting for work tasks to appear. But you can also have a non-terminating task that effectively picks up its own work from elsewhere - eg a task that reads from a socket to get the next "job" to process. Any interaction between threads is going to cost CPU time, whether a pool is involved or not, but yes there will be overhead associated with a pool, just as there is starting and terminating a thread, or performing any kind of thread coordination/synchronization.
Regards,
David Holmes

Assertion failed: poll() is a blocking call and cannot be called on the Service thread

Hi
We are getting a strange issue, the application successfully joins the cluster but after start failing with following exception.
The cluster have three nodes storage disabled web-logic and two standalone coherence JVM's, we are using distributed cache with Local scheme
<Error> (thread=DistributedCache, member=4): Assertion failed: poll() is a blocking call and cannot be called on the Service thread
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.poll(Grid.CDB:5)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.poll(Grid.CDB:11)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$BinaryMap.get(PartitionedCache.CDB:26)
at com.tangosol.util.ConverterCollections$ConverterMap.get(ConverterCollections.java:1655)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$ViewMap.get(PartitionedCache.CDB:1)
at com.tangosol.coherence.component.util.SafeNamedCache.get(SafeNamedCache.CDB:1)
at com.thehartford.pi.core.referencedata.dao.cachedaoimpl.ReferenceCacheDAOImpl.getReferenceData(Unknown Source)
at com.thehartford.pi.core.caching.cachestore.ReferenceCacheStore.load(Unknown Source)
at com.tangosol.net.cache.ReadWriteBackingMap$CacheLoaderCacheStore.load(ReadWriteBackingMap.java:6132)
at com.tangosol.net.cache.ReadWriteBackingMap$CacheStoreWrapper.loadInternal(ReadWriteBackingMap.java:5616)
at com.tangosol.net.cache.ReadWriteBackingMap$StoreWrapper.load(ReadWriteBackingMap.java:4698)
at com.tangosol.net.cache.ReadWriteBackingMap.get(ReadWriteBackingMap.java:717)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$Storage.get(PartitionedCache.CDB:10)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache.onGetRequest(PartitionedCache.CDB:23)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$GetRequest.run(PartitionedCache.CDB:1)
at com.tangosol.coherence.component.net.message.requestMessage.DistributedCacheKeyRequest.onReceived(DistributedCacheKeyRequest.CDB:12)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.onMessage(Grid.CDB:34)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.onNotify(Grid.CDB:33)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.PartitionedService.onNotify(PartitionedService.CDB:3)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache.onNotify(PartitionedCache.CDB:3)
at com.tangosol.coherence.component.util.Daemon.run(Daemon.CDB:42)
at java.lang.Thread.run(Thread.java:722)
ERROR 2013-09-20 09:06:42,515 : [2013-09-20 09:06:42.515/8740.228 Oracle Coherence GE 3.7.1.0 <Error> (thread=DistributedCache, member=4): Assertion failed: poll() is a blocking call and cannot be called on the Service thread
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.poll(Grid.CDB:5)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.poll(Grid.CDB:11)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$BinaryMap.get(PartitionedCache.CDB:26)
at com.tangosol.util.ConverterCollections$ConverterMap.get(ConverterCollections.java:1655)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$ViewMap.get(PartitionedCache.CDB:1)
at com.tangosol.coherence.component.util.SafeNamedCache.get(SafeNamedCache.CDB:1)
at com.thehartford.pi.core.referencedata.dao.cachedaoimpl.ReferenceCacheDAOImpl.getReferenceData(Unknown Source)
at com.thehartford.pi.core.caching.cachestore.ReferenceCacheStore.load(Unknown Source)
at com.tangosol.net.cache.ReadWriteBackingMap$CacheLoaderCacheStore.load(ReadWriteBackingMap.java:6132)
at com.tangosol.net.cache.ReadWriteBackingMap$CacheStoreWrapper.loadInternal(ReadWriteBackingMap.java:5616)
at com.tangosol.net.cache.ReadWriteBackingMap$StoreWrapper.load(ReadWriteBackingMap.java:4698)
at com.tangosol.net.cache.ReadWriteBackingMap.get(ReadWriteBackingMap.java:717)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$Storage.get(PartitionedCache.CDB:10)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache.onGetRequest(PartitionedCache.CDB:23)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache$GetRequest.run(PartitionedCache.CDB:1)
at com.tangosol.coherence.component.net.message.requestMessage.DistributedCacheKeyRequest.onReceived(DistributedCacheKeyRequest.CDB:12)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.onMessage(Grid.CDB:34)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.onNotify(Grid.CDB:33)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.PartitionedService.onNotify(PartitionedService.CDB:3)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.partitionedService.PartitionedCache.onNotify(PartitionedCache.CDB:3)
at com.tangosol.coherence.component.util.Daemon.run(Daemon.CDB:42)

Hi
The problem is that you are making a re-entrant call back into a cache service from the service thread or worker thread of a cache service. This is a bad thing to do as you risk deadlocking your cluster by consuming all of the threads in the service. From the stack trace it looks like you are doing a get on a cache which is calling through to a cache store which is then doing a get on another cache.
For example, you have done a "get" on a cache, that has now consumed a worker thread (call it Thread-1), that thread is calling the cache store which is doing a get on another cache in the same cache service so will now consume another thread (call it Thread-2) so you now have two threads in use, Thread-1 will not return until Thread-2 completes. Now say you had 2 worker threads on your cache service and two "get" calls came in at the same time, Get-1 and Get-2. Both worker threads are now in use so when Get-1 calls the cache store to do a get on the other cache then it has to wait for a worker thread to become free to process the get. The same applies to Get-2, it is calling the cache store and waiting for a thread to become free. The problem is no threads will become free as they are all waiting. Hopefully that is a clear enough explanation of why you get the warning.
Read this Constraints on Re-entrant Calls - 12c (12.1.2) This is for 12.1.2 but the same applies for any Coherence version.
JK

Creating Thread Pool with Executors.newFixedThreadPool(poolSize)

I am creating a server socket and want a Thread pool to limit the number of threads created for serving each clients. I have written a code:
private ExecutorService threadPool;
//Creating a Thread Pool for handling new sessions
threadPool=ThreadPool.createSessionThreadPool(poolSize);
and in my main listen logic:
serverSocket = new ServerSocket(listenPort);
clientSocket = serverSocket.accept();
                    threadPool.execute(new Runnable(){
                         public void run(){
                              handleConnection();
and in handleConnection I am trying to read the inputstream in a while loop:
public void handleConnection(){
BufferedReader in=null;
in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
while (true) {
if((fullCommandString = in.readLine()) ==null){
wait(); // I assume that this wait will block the thread and keep the thread back in to the pool.
                    System.out.println(Thread.currentThread().getName() + " received the message");
                    System.out.println("echo: " + fullCommandString);
                    out.println("230 reply back \r\n");
why don't it keep the thread back in the pool when I call the wait() ? Is it since the thread is still active in reading the input stream? If so can any one hepl me with a snippet which will keep the thread back in the pool when there is noting on the input stream to read.

Hi,
The call to wait does not return the thread pool back to the pool. The thread will be associated with your runnable as long as your run method hasn't returned.
It looks like you instead want to use NIO if you want to use a few threads to handle many clients.
Kaj

Primitive data changes visible to other threads?

I thought that if one thread changes an instance variable, the change may not be visible to other threads if synchronization is not used.
Today I read that primitive types whose assignment is atomic are an exception. Is that correct?
Maybe I'm not clear about the original idea. Is it simply that another thread might be in the middle of a method where the old value is in use? Or is it more complex than that? For some reason, I had it in my head that each thread somehow maintains its own "view" of memory.
Thanks,
Krum

I think you are mixing two different things here.
The assignment of most types are atomic. They either contain a value or not. This does not nessecarly mean that they are written to the main memory, they could still be in the thread-local memory area. Once they are being transfered, the transferation will also be atomic. Example of non-atomic is that longs and doubles are assigned the first 32 bits and then the rest of the 32 bits. This would for instance if two threads wrote to the shared memory, you could end up with the first 32 bits belonging to the change made in thread 1 and the last 32 bits belonging to thread 2.
So, for a method that is not declared synchronous but assigns one single value before returning is "thread" safe in the aspect that one thread will manipulate the data on at the time. This does not however guarantee order. So, thread 1 can enter the method but not do the assignment, thread 2 enters the method, does the assignment that is imidiatly written over by thread 1. Synchronous would make sure that thread 2 could not enter until thread one written it's change.
There is a reserved keyword 'volatile' in java that has the purpose of warning JVM's that a variable is not allowed to be stored in thread-local memory space, but as far as I know, no JVM implements this functionality properly.
What the article states is that if you only do one assignment or return it will be executed atomically as long as we are not using long or double. It is a bit braver than I would say, since technically an reference assignment can be atomically assigned before the object is actually created (se articles from Doug Lea about the failure of double-checked locking ) and therefor some thread problem could occur as it might use an object before it is actually there.
Regards,
Peter Norell

How to stop an execution from a method and thread?

1,
public void method(){
if( something is true)
//I want to stop this method
//or if something is false, go on
blablablablabla
}Does any one know how to solve the above??
2,
Thread t = new Thread(){
public void run(){
if( something is true)
//I want to stop and kill this Thread
//or if something is false, go on
blablablablabla
}Again, how do I solve the above??
I know this is very simple, but I just hit a wall when I encounter this on making a program for my project.
please help
thanks alot

warnerja, for the method, I have tried "return" but
it does not work... will it work on the run method of
thread object??
Secondly, doesn't "break" keyword only stops the
execution of a loop/condition, but not the method's
scope??yes. break breaks the loop. I thought your method doesnt have any other code except the condition.
use return with thread.

Does a reentrant dll call monopolize the calling thread?

If I understand thing correctly, threading for a dll call is the same as threading for a vi whose execution priority is set to subroutine.
To review threading in subvis:
(1) the thread in which a subroutine-execution-priorty-vi call is made is monopolized by the subroutine-execution-priorty-vi since labview cannot time slice the thread.
(2) if the subroutine-execution-priority-vi is not reentrant, then other threads that call the vi may be suspended because they are competing for the same code resource.
(3) if the subroutine-execution-priority-vi is reentrant, then other threads may call the vi simultaneously. However, within any particular thread the vi must complete because of point (1).
In
sum, the OS timeslices between the threads, and labVIEW timeslices within the threads. If a vi's execution priority is set to subroutine, then the thread under which it is running is monopolized by the vi. Yes?
A reentrant dll call would be equivalent to a reentrant subvi call in which the subvi's execution priority is set to subroutine. Yes?
If the above is correct then this should also be correct:
Using an API call to return the thread ID, you could use the the thread ID at the front and back side of a dll call, as well as in a message library function callable from a dll, to theoretically message labVIEW upon the dll return. The message would be uniquely identifiable because a dll call cannot be superceded by another dll call from within the same thread. Yes?
I'm not saying that it would be particularly efficient to do so, only that it could be done. And depending on the messaging, it could be a useful option in the dll call configuration dialog box.
In consider
ation of "magic",
Kind Regards,
Eric

Eric,
I'm not sure I understand exactlly what you are trying to do here.
If you want LV to react to a dll error, why don't you just pass a return
code that's not zero? Then, back in LV, read the return code. If it's not
zero, create an error, and pass this to the rest of the code. The rest of
the code is (or should, following good programming practise) has an error
in, and the code will not execute if the input error is TRUE. It does not
even have to be the return code, it could be any input value. The input
values can be changed in the code, and the modified value is returnd to
LabVIEW.
If you want to generate an error, and put it into a buffer to be read later
on in LV, you'll have to synchronise the code. This is the consequence for a
construction like this, and is the same for several windows API's
(GetLastError, etc.). the buffer will stay in memory, untill all instances
of the dll are released from LV memory.
BTW: A dll could create another thread. This thread can run on the
background, like the good old TRS's in dos. (A thread like this could even
call a LabVIEW VI that is build in a dll, just like any other api.)
BTW: A thread created by a dll can be made to be automatically released when
the thread is detatched, or when the process is detached. This is important,
because LV will crash if the dll is removed from memory, but the thread is
not stopped properly.
Regards,
Wiebe.
"Eric6756" wrote in message
news:[email protected]...
> Greg,
>
> As I think I lost you in the point of this line of questions, let me
> back up.
>
> A couple of week ago I asked the following question, "Is there a
> labVIEW library call that can be made from a dll to tell labVIEW to
> abort the calling vi thread?" To that question you made the following
> statement:
>
> "... and I doubt that there is a function to do that from a DLL as the
> DLL could be arbitrarily deep down the stack and the function called
> would have to magically find the VI that it wants to abort. And don't
> forget that DLLs can be called by multiple VIs at the same time."
>
> You seem to be saying here that what I'm asking for is not possible.
> And having thought about this for a while, I didn't understand why
> not.
>
> For the moment I'm going to ignore the caveat you just put into the
> dll calling presumptions I've made and assume the dll is going to
> execute synchronously within a thread. As the original question
> suggests, the objective here is to message labVIEW from a dll to
> provide the same functionallity as a CIN, namely return an error code
> to labVIEW from a dll.
>
> A library function could do this as follows:
>
> First, the library function would have two modes; set error, and
> return error
>
> (1) set error:
>
> 1.1 get the set error caller thread ID from API
> 1.2 get the passed in error
> 1.3 store the error and associated thread ID locally
>
> (2) return error
> 2.1 get return error caller thread ID from API
> 2.2 locate the error, if any, associated with thread ID
> 2.3 return the error and clear it locally
>
> Now, if a dll encountered an error that it wanted labview to deal
> with, it would call the error function to set the error code. When
> the dll call returns control to labVIEW, labVIEW could call the
> function to return the error. This of course works only if the dll
> call is synchronous within a thread. Obviously, if the dll releases
> the thread before it returns, then more than one dll call can be made
> from the thread and the presumption that an error could be uniquely
> associated with a thread is itself an error.
>
> Having looked at your reply again, I think though your answering a
> different question than I asked. I just wanted a function to message
> labVIEW to abort the vi chain, I don't want to abort a vi chain from
> within the dll. It is a feature of CIN calls which I wanted in dll
> calls.
>
> That a dll call may not be synchronous within a thread throws a wrench
> in the works. Apparently I've just chased down a dead end.
>
> Hey, but thanks for the wrench...
> Kind Regards,
> Eric

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