RTPExport problem
Hi, I'm a newbie to JMF and how to handle media file stream over RTP. What I need to do now is to receive a media stream from RTP, then play it and save it to a file at the same time. I have read throught the example and explanation on the Java Sun website, and here's what I think I'm gonna do:
- Use AVReceive's method to receive and play the stream.
- Use RTPExport's method to save the stream to a file.
- Merge the two file, using Clone to make copies of the data source, then pass to both threads.
However, I'm stuck at the step of understanding RTPExport concept. Somehow it's not woking properly. I use RTPExport with AVTransmit to transfer a sample .wav file.
Here's what I got:
java RTPExport -o file:temp.wav 192.168.137.54:10004/audio- create processor for: rtp://192.168.137.54:10004/audio
- set content descriptor to: WAV
- create DataSink for: file:temp.wav
start transcoding ...
...done RTPExporting.
The output file "temp.wav" has a size of only 8 bytes, no matter what the file sent to RTPExport. I have tried sending different type of file and saving in different format (like .mov) but the problem persists.
Does anyone have any idea how I could fix this?
Thanks in advance.
You might try setting the duration to something like 15 seconds and seeing if that affects the RTPExport stuff... more than likely, you're just having an issue with all of the shutdown events happening correctly.
Similar Messages
-
Problem with RTPExport output video files
Hi, I have a problem with RTPExport output video files. One side streams H263/RTP(AVTransmit2.java) and other write this steam to a file by RTPExport.java. When network conditions are ideal, output video file has same fps and same number of frames like original file. Problem occures, when theres packet lost in network, then output file has different fps,and also has less frames like original video(because it didnt write missing frames to file, and thats why it get shorter). Pls how can I achieve output file that will have the same fps like original one? How to write to file an identical copy of what I can see while receiveing video with AVReceive2.java? Its there a way to modifi rtpexport or avreceiver to do this? Thanks a lot!
Trubka wrote:
When network conditions are ideal, output video file has same fps and same number of frames like original file. Problem occures, when theres packet lost in network, then output file has different fps,and also has less frames like original video(because it didnt write missing frames to file, and thats why it get shorter). Okay, first off, the second file is smaller on purpose. RTP intentionally drops packets that are old/out of order in order to make sure real-time video stays as close to real time as it can. This is by design, so there's really nothing that can be done about it.
How to write to file an identical copy of what I can see while receiveing video with AVReceive2.java? Technically speaking, what you're getting in the RTPExport is exactly what you got on the receiving end. Any frames that are dropped during transmission will not be seen by the receiver, nor saved by the receiver.
Pls how can I achieve output file that will have the same fps like original one? I'm not 100% sure that you can, but, you can give the following idea a try. I make no guarentees that it'll work, but it should work for you...
[http://java.sun.com/javase/technologies/desktop/media/jmf/2.1.1/solutions/RTPConnector.html]
That example is an example of a "custom transport layer" for RTP connections. Essentially, it's some code that's handed the RTP packets on the transmission end, and it's expected to deliver those RTP packets on the other end. And it doesn't care about how they get from A to B, only that they do.
If you were to replace the UDP socket in that example with a TCP socket, you would be guarenteed not to drop packets due to network reasons. Every RTP packet you were handed by the transmitter, you would then hand to the receiver. There is no guarentee that none of the packets would be cast away as "old" by the RTP protocol itself, but there's also no guarentee any of them would be. It's a crap-shoot at best, but it's certainly worth a try. -
Hi all;
I tried to save incoming RTP Stream to a local disk using RTPExport, VideoRecoder, and JMStudio. it was fine using JMStudio, but however it gives some problem for other two. for example:
only audio track is saved/recorded audio, i tried to solve the problem by sending only video but then the video is saved with very poor quality, in other words, when i play the saved file, it plays with very high speed !
plz don't hesitate to give a hand
thanks in advanceThank you for trying to help. These file were imported by log and capture and were atomaticaly converted to prores 422 LT. I did not mess around with file names, as the names were given during the log and transfer proccess.
This is definetely a final cut bug.
The problem dissapeared (not solved though, as the reasons remain unknown) with the folowing way:
a) I open one of the backed up files and looked at my rough cut wich consists of sequencies.
b) By playing the 2 specific sequencies on the rough cut, there was no error in the edit.
c) By opening these 2 sequencies on the project browser, there was a different edit !!!!
d) By going back to the rough cut and double clicking on the nested sequence, I could see the original edit.
e) Now I had one specific sequence in the timeline, the same name, the identical sequence, opened in two different tabs. In one tab (the sequence that i entered to through the rough cut) the edit was the original, in the other tab (the one that i opened through the project browser) the edit was distorted !!!
f) I copied the clips of the original edit to a newly created sequence.
g) I deleted the old- problematic sequence
h) i repeated the process with the second sequence that was altered by final cut on its own will.
I hope this will help someone in a similar situation and I keep this question as unsolved, because in reality noone really knows - until now- the reason for this situation. Thank god it was solved. -
RTPExport using a new payload type
I'm interested in using the RTPExport example:
http://java.sun.com/products/java-media/jmf/2.1.1/solutions/RTPExport.html
But with a custom payload type. I tried to create a dummy RTPManager object with a call to addFormat() at the very beginning, but apparently that's not enough, as when the call is made to p.configure(), I get a message stating the payload type I'm using is not registered.
Thanks in advance for your help.I need a way to communicate a dynamic payload mapping to the Processor object. This is easily done with an RTPManager object, as in the AVCustom examples, but does not appear to be done as easily with a Processor. My requirements are very simple, I just need to use the RTPExport example, but with a dynamic payload type. Hope that clarifies my problem.
-
Problems with timeBase and addController to processors
I have a Slight problem getting the sync between multiple processors done.
I have programmed an application which receives multiple RTP streams from multiple computers. I am displaying them in real time, which works fine and without any problem.
I have synchronized nothing up to this point, as the video and audio is coming to the computer in a great time speed and everything seems fine.
However when trying to export the incoming streams to a file I have some problems.
I have used the Example RtpExport from the examples page
http://java.sun.com/products/java-media/jmf/2.1.1/solutions/RTPExport.html
and have extended the code so that every incoming stream is recorded in its own file.
The program works fine, except that there is a large difference in timing in the different files. I have now tried to set the time base of the processor P in the example equal to every processor, which creates timebase errors.
Then I have tried to add a controller of (p.addController(proce);) were proce is the first processor created. However this creates IncompatibleTimeBaseExceptions as well. Does anyone have any idea were to start!??
Thanks
Flow
ps: here is the error message
in ADDCONTROLLER incomming processor com.sun.media.processor.unknown.Handler@682406
in ADDCONTROLLER internal processor com.sun.media.processor.unknown.Handler@18105e8
javax.media.IncompatibleTimeBaseException
at com.sun.media.multiplexer.BasicMux.setTimeBase(BasicMux.java:636)
at com.sun.media.BasicSinkModule.setTimeBase(BasicSinkModule.java:52)
at com.sun.media.PlaybackEngine.setTimeBase(PlaybackEngine.java:1672)
at com.sun.media.BasicPlayer.setTimeBase(BasicPlayer.java:272)
at RtpReceiver.Doit.addcontroller(Doit.java:153)
at RtpReceiver.RTPExport.Create(RTPExport.java:133)
at RtpReceiver.RTPExport.<init>(RTPExport.java:88)
at RtpReceiver.AVReceiver.StartRecording(AVReceiver.java:103)
at RtpReceiver.Rx.actionPerformed(Rx.java:436)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:6038)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3260)
at java.awt.Component.processEvent(Component.java:5803)
at java.awt.Container.processEvent(Container.java:2058)
at java.awt.Component.dispatchEventImpl(Component.java:4410)
at java.awt.Container.dispatchEventImpl(Container.java:2116)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)
at java.awt.Container.dispatchEventImpl(Container.java:2102)
at java.awt.Window.dispatchEventImpl(Window.java:2429)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)
- create DataSink for: file:/C:/Documents and Settings/1.mov
start transcoding ...
size of i = 2
in ADDCONTROLLER incomming processor com.sun.media.processor.unknown.Handler@682406
in ADDCONTROLLER internal processor com.sun.media.processor.unknown.Handler@107108e
javax.media.IncompatibleTimeBaseException
at com.sun.media.multiplexer.BasicMux.setTimeBase(BasicMux.java:636)
at com.sun.media.BasicSinkModule.setTimeBase(BasicSinkModule.java:52)
at com.sun.media.PlaybackEngine.setTimeBase(PlaybackEngine.java:1672)
at com.sun.media.BasicPlayer.setTimeBase(BasicPlayer.java:272)
at RtpReceiver.Doit.addcontroller(Doit.java:153)
at RtpReceiver.RTPExport.Create(RTPExport.java:133)
at RtpReceiver.RTPExport.<init>(RTPExport.java:88)
at RtpReceiver.AVReceiver.StartRecording(AVReceiver.java:103)
at RtpReceiver.Rx.actionPerformed(Rx.java:436)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:6038)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3260)
at java.awt.Component.processEvent(Component.java:5803)
at java.awt.Container.processEvent(Container.java:2058)
at java.awt.Component.dispatchEventImpl(Component.java:4410)
at java.awt.Container.dispatchEventImpl(Container.java:2116)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)
at java.awt.Container.dispatchEventImpl(Container.java:2102)
at java.awt.Window.dispatchEventImpl(Window.java:2429)
at java.awt.Component.dispatchEvent(Component.java:4240)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)
- create DataSink for: file:/C:/Documents and Settings/2.mov
Edited by: FlowingAlong on Sep 21, 2007 8:07 AMWe don't have Virex or Norton software in the machine. We have Disk Warrior which was helpful in the past with other problems. Should I run another check using Disk Warrior?
We only have one machine which has three internal drives. We've experienced the same problems using each of the drives.
We do have some video stored in the system drive, but normally we don't use that drive. The system drive currently has 70GB availble, as do each of the other internal drives.
We have updated our FCP to 4.5, but should we trying re-installing it? -
Having problem storing incoming MU-LAW to PMC WAV file
Hi,
I am able to receive ULAW/rtp, 8000.0 Hz, 8-bit, Mono stream and play it using the Player class. What I need to do is to store the stream data into WAV file. I have followed the JMF tutorial to set the output file format. I can also create the WAV file no problem. But when I try to play the gnerated WAV file using Windows Media Player, it says : Windows Media Player cannot play the file. The Player might not support the fle type or might not support the codec that was used to compress the file.
Does anyone know what is wrong with my code?
I am attaching the code below:
stream = ((NewReceiveStreamEvent)evt).getReceiveStream();
DataSource ds = stream.getDataSource();
// Find out the formats.
RTPControl ctl = (RTPControl)ds.getControl("javax.media.rtp.RTPControl");
if (ctl != null){
System.err.println(" - Recevied new RTP stream: " + ctl.getFormat());
} else
System.err.println(" - Recevied new RTP stream");
if (participant == null)
System.err.println(" The sender of this stream had yet to be identified.");
else {
System.err.println(" The stream comes from: " + participant.getCNAME());
synchronized (dataSync) {
dataReceived = true;
dataSync.notifyAll();
ProcessorModel model = new ProcessorModel(ds,new Format[]{ }, new FileTypeDescriptor(FileTypeDescriptor.WAVE));
Processor processor = Manager.createRealizedProcessor(model);
boolean result = waitForState(processor, Processor.Configured);
if (result == false)
System.out.println("process is not configured");
TrackControl[] tracks = processor.getTrackControls();
if (tracks == null || tracks.length < 1)
System.out.println( "Couldn't find tracks in processor");
Format supported[];
Format chosen = null;
boolean atLeastOneTrack = false;
for (int i = 0; i < tracks.length; i++)
Format format = tracks.getFormat();
if (tracks[i].isEnabled())
supported = tracks[i].getSupportedFormats();
// Here we choose the ULAW format ...
if (supported.length > 0)
for(int k=0; k<supported.length; k++)
if(supported[k] instanceof AudioFormat)
String encoding = supported[k].getEncoding();
System.out.println("encoding = " + encoding);
if(encoding.indexOf("LINEAR") != -1)
chosen = supported[k];
break;
tracks[i].setFormat(chosen);
//tracks[i].setFormat(new AudioFormat(AudioFormat.LINEAR,8000,16,1));
System.err.println("Track " + i + " is set to transmit as: " + tracks[i].getFormat());
atLeastOneTrack = true;
} else
tracks[i].setEnabled(false);
} else
tracks[i].setEnabled(false);
if (!atLeastOneTrack)
System.out.println( "Couldn't set any of the tracks to a valid RTP format");
// create a player by passing datasource to the Media Manager
result = waitForState(processor, Controller.Realized);
if (result == false)
System.out.println( "Couldn't realize processor");
MediaLocator dest = new MediaLocator("file://c:\\tmp\\dddd.wav");
DataSink sink = Manager.createDataSink(processor.getDataOutput(), dest);
sink.open();
sink.start();
processor.start();
Thread.sleep(5000);
processor.stop();
sink.stop();
sink.close();
System.out.println("sink close");
Thank you very much in advance for all your help.
JBoutraspace wrote:
Hi,
I am able to receive ULAW/rtp, 8000.0 Hz, 8-bit, Mono stream and play it using the Player class. What I need to do is to store the stream data into WAV file. I have followed the JMF tutorial to set the output file format. I can also create the WAV file no problem. But when I try to play the gnerated WAV file using Windows Media Player, it says : Windows Media Player cannot play the file. The Player might not support the fle type or might not support the codec that was used to compress the file.
Does anyone know what is wrong with my code? Lots of things. As tbm pointed out, don't use a processor model. Use create a regular processor, and then create a ContentDescriptor object with all of the formatting you want, and set that on the Processor.
In your code "Here we choose the ULAW format", it doesn't appear that you're chosing ULAW. It appears you're chosing linear encoding. ULaw isn't linear, it's logarithmic, so certainly that's not the right format.
In the examples I've seen, the processor is started before the DataSink is started. You're doing this in reverse.
If you plan to configure a processor, do not get a realized one. That's like say "I'd like some ice cream", going out and buying ice-cream sandwiches and scraping out the ice cream...
You should disable all of the tracks except the ones you want data from. That means if it's not an audio format, you'll want to go ahead and disable it.
Without nitpicking anymore, I have no idea where your sample code came from, but it seems pretty useless. The best idea would be to take your code, delete it, and start over with the following code:
[http://java.sun.com/javase/technologies/desktop/media/jmf/2.1.1/solutions/RTPExport.java] -
I am trying to implement some kind of a server listening for requests. The listener part of the app, is a daemon thread that listens for connections and instantiates a handling daemon thread once it gets some. However, my problem is that i must be able to kill the listening thread at the user's will (say via a sto button). I have done this via the Sun's proposed way, by testing a boolean flag in the loop, which is set to false when i wish to kill the thread. The problem with this thing is the following...
Once the thread starts excecuting, it will test the flag, find it true and enter the loop. At some point it will LOCK on the server socket waiting for connection. Unless some client actually connects, it will keep on listening indefinatelly whithought ever bothering to check for the flag again (no matter how many times you set the damn thing to false).
My question is this: Is there any real, non-theoretical, applied way to stop thread in java safely?
Thank you in advance,
LeftyThis was one solution from the socket programming forum, have you tried this??
public Thread MyThread extends Thread{
boolean active = true;
public void run(){
ss.setSoTimeout(90);
while (active){
try{
serverSocket = ss.accept();
catch (SocketTimeoutException ste){
// do nothing
// interrupt thread
public void deactivate(){
active = false;
// you gotta sleep for a time longer than the
// accept() timeout to make sure that timeout is finished.
try{
sleep(91);
}catch (InterruptedException ie){
interrupt();
} -
A problem with Threads and MMapi
I am tring to execute a class based on Game canvas.
The problem begin when I try to Play both a MIDI tone and to run an infinit Thread loop.
The MIDI tone "Stammers".
How to over come the problem?
Thanks in advance
Kobi
See Code example below:
import java.io.IOException;
import java.io.InputStream;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.media.Manager;
import javax.microedition.media.MediaException;
import javax.microedition.media.Player;
public class MainScreenCanvas extends GameCanvas implements Runnable {
private MainMIDlet parent;
private boolean mTrucking = false;
Image imgBackgound = null;
int imgBackgoundX = 0, imgBackgoundY = 0;
Player player;
public MainScreenCanvas(MainMIDlet parent)
super(true);
this.parent = parent;
try
imgBackgound = Image.createImage("/images/area03_bkg0.png");
imgBackgoundX = this.getWidth() - imgBackgound.getWidth();
imgBackgoundY = this.getHeight() - imgBackgound.getHeight();
catch(Exception e)
System.out.println(e.getMessage());
* starts thread
public void start()
mTrucking = true;
Thread t = new Thread(this);
t.start();
* stops thread
public void stop()
mTrucking = false;
public void play()
try
InputStream is = getClass().getResourceAsStream("/sounds/scale.mid");
player = Manager.createPlayer(is, "audio/midi");
player.setLoopCount(-1);
player.prefetch();
player.start();
catch(Exception e)
System.out.println(e.getMessage());
public void run()
Graphics g = getGraphics();
play();
while (true)
tick();
input();
render(g);
* responsible for object movements
private void tick()
* response to key input
private void input()
int keyStates = getKeyStates();
if ((keyStates & LEFT_PRESSED) != 0)
imgBackgoundX++;
if (imgBackgoundX > 0)
imgBackgoundX = 0;
if ((keyStates & RIGHT_PRESSED) != 0)
imgBackgoundX--;
if (imgBackgoundX < this.getWidth() - imgBackgound.getWidth())
imgBackgoundX = this.getWidth() - imgBackgound.getWidth();
* Responsible for the drawing
* @param g
private void render(Graphics g)
g.drawImage(imgBackgound, imgBackgoundX, imgBackgoundY, Graphics.TOP | Graphics.LEFT);
this.flushGraphics();
}You can also try to provide a greater Priority to your player thread so that it gains the CPU time when ever it needs it and don't harm the playback.
However a loop in a Thread and that to an infinite loop is one kind of very bad programming, 'cuz the loop eats up most of your CPU time which in turn adds up more delays of the execution of other tasks (just as in your case it is the playback). By witting codes bit efficiently and planning out the architectural execution flow of the app before start writing the code helps solve these kind of issues.
You can go through [this simple tutorial|http://oreilly.com/catalog/expjava/excerpt/index.html] about Basics of Java and Threads to know more about threads.
Regds,
SD
N.B. And yes there are more articles and tutorials available but much of them targets the Java SE / EE, but if you want to read them here is [another great one straight from SUN|http://java.sun.com/docs/books/tutorial/essential/concurrency/index.html] .
Edited by: find_suvro@SDN on 7 Nov, 2008 12:00 PM -
Hi all,
I would like to ask you for a help. I need to write a small program at my university. I started to write a midlet which function would be to countdown time for sports activities. I woul like to start a new thread - the one that counts down - and at the same time make the main thread sleep. After the "countdown" thread finishes, the main thread wakes up and waits for user input. The problem is that when the "countdown" thread finishes his work, I've got Uncaught exception java/lang/NullPointerException. error and the midlet halts.
Below you can find the code
import java.lang.*;
import java.util.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class intervals extends MIDlet implements CommandListener
public Display ekran;
private SweepCanvas sweeper;
private Form rundy;
private TextField round0, round1, round2, round3, round4, round5, round6, round7, round8;
private long czas,x;
private Command exitCommand;
private Command addRound;
private Command delRound;
private Command start;
private TextField repeat;
private Form odliczanie;
private Alert ostrz;
Licznik thread;
String test;
StringItem test1;
int parz,i,j,k;
static int l;
int ilrund;
int ilpowt;
Item sec;
long sec1;
public intervals()
rundy = new Form("Interwały sportowe");
exitCommand = new Command("Wyjście", Command.EXIT, 2);
addRound = new Command("Dodaj","Dodaj rundę", Command.ITEM,1);
delRound = new Command("Usuń","Usuń ostatnią rundę", Command.ITEM,1);
start = new Command("Start", Command.ITEM,1);
odliczanie = new Form("Odliczanie");
TextField dodaj(TextField kolej)
kolej=new TextField("Podaj czas (s) rundy "+parz,null, 4, TextField.NUMERIC);//stworzenie nowej instancji do wybierania czasu trwania rundy
if(rundy.size()==0)
rundy.insert(rundy.size(),kolej);
else
rundy.insert(rundy.size()-1, kolej);
return kolej;
void odliczanie(TextField round)
monitor m=new monitor();
k=Integer.parseInt(round.getString());
ekran.setCurrent(odliczanie);
thread=new Licznik(k,odliczanie);
thread.start();
ekran.setCurrent(rundy);
public void startApp()// throws MIDletStateChangeException
rundy.deleteAll();
repeat = new TextField("Podaj ilość powtórzeń",null,1,TextField.NUMERIC);
rundy.addCommand(addRound);
rundy.addCommand(exitCommand);
rundy.setCommandListener(this);
Canvas obrazek = new MyCanvas();
ekran = Display.getDisplay(this);
ekran.setCurrent(obrazek);
czas=System.currentTimeMillis();
while (System.currentTimeMillis()<czas+1000)
continue;
ekran.setCurrent(rundy);
public void pauseApp()
public void destroyApp(boolean unconditional)
notifyDestroyed();
public void commandAction(Command c, Displayable s)
if (c == exitCommand)
destroyApp(false);
notifyDestroyed();
else if(c==addRound)
if(rundy.size()==0)//Sprawdzenie ilości elementów w celu poprawnego wyświetlania liczby rund w formie
parz=1;
else
parz=rundy.size();
switch(parz)
case 1:
round0=dodaj(round0);break;
case 2:
round1=dodaj(round1);break;
case 3:
round2= dodaj(round2);break;
case 4:
round3=dodaj(round3);break;
case 5:
round4=dodaj(round4);break;
default:
ostrz=new Alert("Uwaga","Maksymalna liczba rund wynosi 9", null, AlertType.INFO);
ostrz.setTimeout(3000);
ekran.setCurrent(ostrz);
if(rundy.size()==1)
rundy.append(repeat);
rundy.addCommand(start);
rundy.addCommand(delRound);
else if(c==delRound)
if(rundy.size()!=0)
rundy.delete(rundy.size()-2);
if (rundy.size()==1)
rundy.deleteAll();
if(rundy.size()==0)
rundy.removeCommand(delRound);
rundy.removeCommand(start);
else if(c==start)
ilrund=rundy.size()-1;
if(this.repeat.size()>0)
ilpowt=Integer.parseInt(this.repeat.getString());
ekran = Display.getDisplay(this);
for (i=1; i<=ilpowt;i++)
odliczanie= new Form("Odliczanie");
for (j=0;j<ilrund;j++)
switch(j)
case 0:
odliczanie(round0);
break;
case 1:
odliczanie(round1);
break;
case 2:
odliczanie(round2);
break;
case 3:
odliczanie(round3);
break;
case 4:
odliczanie(round4);
break;
case 5:
odliczanie(round5);
break;
case 6:
odliczanie(round6);
break;
case 7:
odliczanie(round7);
break;
case 8:
odliczanie(round8);
break;
class Licznik extends Thread
int czas1,k;
Form forma;
monitor m;
public Licznik(int k,Form formap)
czas1=k;
forma=formap;
public synchronized void run()
while(czas1>0)
forma.deleteAll();
forma.append("Czas pozostały (s): "+czas1);
try{Thread.sleep(1000);} catch(InterruptedException e){e.printStackTrace();}
czas1--;
if(czas1<=0)
m.put();
}and monitor class
public class monitor
boolean busy=false;
synchronized void get()
if(!busy)
try
wait();
}catch(InterruptedException e){e.printStackTrace();}
notify();
synchronized void put()
if(busy)
try
wait();
}catch(InterruptedException e){e.printStackTrace();}
busy=true;
notify();
}Can anybody help me with this?Groovemaker,
Your Licznik class has a member m of type monitor, which has not been instantiated (in other words is null) hence, when calling m.put() you get NullPointerException. Please also mind, that using Thread.sleep(1000) is not an accurate way of measuring time.
If I may, please use recommended for Java class naming conventions - some of your names use lower case, while other don't which is confusing to the reader.
Daniel -
Problem with threads within applet
Hello,
I got an applet, inside this applet I have a singleton, inside this singleton I have a thread.
this thread is running in endless loop.
he is doing something and go to sleep on and on.
the problem is,
when I refresh my IE6 browser I see more than 1 thread.
for debug matter, I did the following things:
inside the thread, sysout every time he goes to sleep.
sysout in the singleton constructor.
sysout in the singleton destructor.
the output goes like this:
when refresh the page, the singleton constructor loading but not every refresh, sometimes I see the constructor output and sometimes I dont.
The thread inside the singleton is giving me the same output, sometime I see more than one thread at a time and sometimes I dont.
The destructor never works (no output there).
I don't understand what is going on.
someone can please shed some light?
thanks.
btw. I am working with JRE 1.1
this is very old and big applet and I can't convert it to something new.Ooops. sorry!
I did.
public void start() {
public void stop() {
public void destroy() {
try {
resetAll();
Configuration.closeConnection();
QuoteItem.closeConnection();
} finally {
try {
super.finalize();
} catch (Throwable e) {
e.printStackTrace();
} -
Problem with Threads and a static variable
I have a problem with the code below. I am yet to make sure that I understand the problem. Correct me if I am wrong please.
Code functionality:
A timer calls SetState every second. It sets the state and sets boolean variable "changed" to true. Then notifies a main process thread to check if the state changed to send a message.
The problem as far I understand is:
Assume the timer Thread calls SetState twice before the main process Thread runs. As a result, "changed" is set to true twice. However, since the main process is blocked twice during the two calls to SetState, when it runs it would have the two SetState timer threads blocked on its synchronized body. It will pass the first one, send the message and set "changed" to false since it was true. Now, it will pass the second thread, but here is the problem, "changed" is already set to false. As a result, it won't send the message even though it is supposed to.
Would you please let me know if my understanding is correct? If so, what would you propose to resolve the problem? Should I call wait some other or should I notify in a different way?
Thanks,
B.D.
Code:
private static volatile boolean bChanged = false;
private static Thread objMainProcess;
protected static void Init(){
objMainProcess = new Thread() {
public void run() {
while( objMainProcess == Thread.currentThread() ) {
GetState();
objMainProcess.setDaemon( true );
objMainProcess.start();
public static void initStatusTimer(){
if(objTimer == null)
objTimer = new javax.swing.Timer( 1000, new java.awt.event.ActionListener(){
public void actionPerformed( java.awt.event.ActionEvent evt){
SetState();
private static void SetState(){
if( objMainProcess == null ) return;
synchronized( objMainProcess ) {
bChanged = true;
try{
objMainProcess.notify();
}catch( IllegalMonitorStateException e ) {}
private static boolean GetState() {
if( objMainProcess == null ) return false;
synchronized( objMainProcess ) {
if( bChanged) {
SendMessage();
bChanged = false;
return true;
try {
objMainProcess.wait();
}catch( InterruptedException e ) {}
return false;
}Thanks DrClap for your reply. Everything you said is right. It is not easy to make them alternate since SetState() could be called from different places where the state could be anything else but a status message. Like a GREETING message for example. It is a handshaking message but not a status message.
Again as you said, There is a reason I can't call sendMessage() inside setState().
The only way I was able to do it is by having a counter of the number of notifies that have been called. Every time notify() is called a counter is incremented. Now instead of just checking if "changed" flag is true, I also check if notify counter is greater than zero. If both true, I send the message. If "changed" flag is false, I check again if the notify counter is greater than zero, I send the message. This way it works, but it is kind of a patch than a good design fix. I am yet to find a good solution.
Thanks,
B.D. -
Problem with threads running javaw
Hi,
Having a problem with multi thread programming using client server sockets. The program works find when starting the the application in a console using java muti.java , but when using javaw multi.java the program doesnt die and have to kill it in the task manager. The program doesnt display any of my gui error messages either when the server disconnect the client. all works find in a console. any advice on this as I havent been able to understand why this is happening? any comment would be appreciated.
troy.troy,
Try and post a minimum code sample of your app which
does not work.
When using javaw, make sure you redirect the standard
error and standard output streams to file.
Graeme.Hi Graeme,
I dont understand what you mean by redirection to file? some of my code below.
The code works fine under a console, code is supposed to exit when the client (the other server )disconnects. the problem is that but the clientworker side of the code still works. which under console it doesnt.
public class Server{
ServerSocket aServerSocket;
Socket dianosticsSocket;
Socket nPortExpress;
ClientListener aClientListener;
LinkedList queue = new LinkedList();
int port = 0;
int clientPort = 0;
String clientName = null;
boolean serverAlive = true;
* Server constructor generates a server
* Socket and then starts a client threads.
* @param aPort socket port of local machine.
public Server(int aPort, String aClientName, int aClientPort){
port = aPort;
clientName = aClientName;
clientPort = aClientPort;
try{
// create a new thread
aServerSocket = new ServerSocket(port) ;
// connect to the nPortExpress
aClientListener = new ClientListener(InetAddress.getByName(clientName), clientPort, queue,this);
// aClientListener.setDaemon(true);
aClientListener.start();
// start a dianostic port
DiagnosticsServer aDiagnosticsServer = new DiagnosticsServer(port,queue,aClientListener);
// System.out.println("Server is running on port " + port + "...");
// System.out.println("Connect to nPort");
catch(Exception e)
// System.out.println("ERROR: Server port " + port + " not available");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Server port " + port + " not available", JOptionPane.ERROR_MESSAGE);
serverAlive = false;
System.exit(1);
while(serverAlive&&aClientListener.hostSocket.isConnected()){
try{
// connect the client
Socket aClient = aServerSocket.accept();
//System.out.println("open client connection");
//System.out.println("client local: "+ aClient.getLocalAddress().toString());
// System.out.println("client localport: "+ aClient.getLocalPort());
// System.out.println("client : "+ aClient.getInetAddress().toString());
// System.out.println("client port: "+ aClient.getLocalPort());
// make a new client thread
ClientWorker clientThread = new ClientWorker(aClient, queue, aClientListener, false);
// start thread
clientThread.start();
catch(Exception e)
//System.out.println("ERROR: Client connection failure");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Client connection failure", JOptionPane.ERROR_MESSAGE);
}// end while
} // end constructor Server
void serverExit(){
JOptionPane.showMessageDialog(null, "Server ","ERROR: nPort Failure", JOptionPane.ERROR_MESSAGE);
System.exit(1);
}// end class Server
*** connect to another server
public class ClientListener extends Thread{
InetAddress hostName;
int hostPort;
Socket hostSocket;
BufferedReader in;
PrintWriter out;
boolean loggedIn;
LinkedList queue; // reference to Server queue
Server serverRef; // reference to main server
* ClientListener connects to the host server.
* @param aHostName is the name of the host eg server name or IP address.
* @param aHostPort is a port number of the host.
* @param aLoginName is the users login name.
public ClientListener(InetAddress aHostName, int aHostPort,LinkedList aQueue,Server aServer) // reference to Server queue)
hostName = aHostName;
hostPort = aHostPort;
queue = aQueue;
serverRef = aServer;
// connect to the server
try{
hostSocket = new Socket(hostName, hostPort);
catch(IOException e){
//System.out.println("ERROR: Connection Host Failed");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Connection to nPort Failed", JOptionPane.ERROR_MESSAGE);
System.exit(0);
} // end constructor ClientListener
** multi client connection server
ClientWorker(Socket aSocket,LinkedList aQueue, ClientListener aClientListener, boolean diagnostics){
queue = aQueue;
addToQueue(this);
client = aSocket;
clientRef = aClientListener;
aDiagnostic = diagnostics;
} // end constructor ClientWorker
* run method is the main loop of the server program
* in change of handle new client connection as well
* as handle all messages and errors.
public void run(){
boolean alive = true;
String aSubString = "";
in = null;
out = null;
loginName = "";
loggedIn = false;
while (alive && client.isConnected()&& clientRef.hostSocket.isConnected()){
try{
in = new BufferedReader(new InputStreamReader(client.getInputStream()));
out = new PrintWriter(new OutputStreamWriter(client.getOutputStream()));
if(aDiagnostic){
out.println("WELCOME to diagnostics");
broadCastDia("Connect : diagnostics "+client.getInetAddress().toString());
out.flush();
else {
out.println("WELCOME to Troy's Server");
broadCastDia("Connect : client "+client.getInetAddress().toString());
out.flush();
String line;
while(((line = in.readLine())!= null)){
StringTokenizer aStringToken = new StringTokenizer(line, " ");
if(!aDiagnostic){
broadCastDia(line);
clientRef.sendMessage(line); // send mesage out to netExpress
out.println(line);
out.flush();
else{
if(line.equals("GETIPS"))
getIPs();
else{
clientRef.sendMessage(line); // send mesage out to netExpress
out.println(line);
out.flush();
} // end while
catch(Exception e){
// System.out.println("ERROR:Client Connection reset");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR:Client Connection reset", JOptionPane.ERROR_MESSAGE);
try{
if(aDiagnostic){
broadCastDia("Disconnect : diagnostics "+client.getInetAddress().toString());
out.flush();
else {
broadCastDia("Disconnect : client "+client.getInetAddress().toString());
out.flush();
// close the buffers and connection;
in.close();
out.close();
client.close();
// System.out.println("out");
// remove from list
removeThreadQueue(this);
alive = false;
catch(Exception e){
// System.out.println("ERROR: Client Connection reset failure");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Client Connection reset failure", JOptionPane.ERROR_MESSAGE);
}// end while
} // end method run
* method run - Generates io stream for communicating with the server and
* starts the client gui. Run also parses the input commands from the server.
public void run(){
boolean alive = true;
try{
// begin to life the gui
// aGuiClient = new ClientGui(hostName.getHostName(), hostPort, loginName, this);
// aGuiClient.show();
in = new BufferedReader(new InputStreamReader(hostSocket.getInputStream()));
out = new PrintWriter(new OutputStreamWriter(hostSocket.getOutputStream()));
while (alive && hostSocket.isConnected()){
String line;
while(((line = in.readLine())!= null)){
System.out.println(line);
broadCast(line);
} // end while
} // end while
catch(Exception e){
// System.out.println("ERRORa Connection to host reset");
JOptionPane.showMessageDialog(null, (e.toString()),"ERROR: Connection to nPort reset", JOptionPane.ERROR_MESSAGE);
try{
hostSocket.close();
}catch(Exception a){
JOptionPane.showMessageDialog(null, (a.toString()),"ERROR: Exception", JOptionPane.ERROR_MESSAGE);
alive = false;
System.exit(1);
} // end method run -
Problem with Threads and "plase wait..."-Window
Hi everyone,
I have a problem that I'm not able to solve in any way... I have a time-consuming task (a file decryption) which I execute in a separate thread; I've used the SwingWorker class, like suggested by sun-tutorial, and it works right. The problem is that I have to wait that the decryption have finished before continuing with program-execution. Therefore I would like to display a "please wait"-window while the task runs. I've tryed all the possible ways I know but the problem is always the same: the waitWindow is displayed empty, the bounds are painted but the contents no; it's only painted when the decrypt-task has finished. Please help me, I have no more resources....
decrypt-file code:
public class DecryptFile {
private String cryptedFileNameAndPath;
private ByteArrayInputStream resultStream = null;
// need for progress
private int lengthOfTask;
private int current = -1;
private String statMessage;
public DecryptFile(String encZipFileNameAndPath) {
cryptedFileNameAndPath = encZipFileNameAndPath;
//Compute length of task...
// 0 for indeterminate
lengthOfTask = 0;
public ByteArrayInputStream getDecryptedInputStream() {
return this.resultStream;
* Called from ProgressBarDemo to start the task.
public void go() {
current = -1;
final SwingWorker worker = new SwingWorker() {
public Object construct() {
return new ActualTask();
worker.start();
* Called from ProgressBarDemo to find out how much work needs
* to be done.
public int getLengthOfTask() {
return lengthOfTask;
* Called from ProgressBarDemo to find out how much has been done.
public int getCurrent() {
return current;
public void stop() {
current = lengthOfTask;
* Called from ProgressBarDemo to find out if the task has completed.
public boolean done() {
if (current >= lengthOfTask)
return true;
else
return false;
public String getMessage() {
return statMessage;
* The actual long running task. This runs in a SwingWorker thread.
class ActualTask {
ActualTask () {
current = -1;
statMessage = "";
resultStream = AIUtil.getInputStreamFromEncZip(cryptedFileNameAndPath); //here the decryption happens
current = 0;
statMessage = "";
}The code that calls decryption and displays waitWindow
final WaitSplash wS = new WaitSplash("Please wait...");
final DecryptFile cryptedTemplate = new DecryptFile (this.templateFile);
cryptedTemplate.go();
while (! cryptedTemplate.done()) {
try {
wait();
} catch (Exception e) { }
this.templateInputStream = cryptedTemplate.getDecryptedInputStream();
wS.close();Thanks, thanks, thanks in advance!
EdoardoMaybe you can try setting the priority of the long-running thread to be lower? so that the UI will be more responsive...
-
im using jdk 1.6 with java wtk 2.1
ya i know..
2.1 is a jdk1.4 source
but im using souce as 1.4 during compiliation so thats not the prob
this is my code
package org.learn;
import javax.microedition.midlet.MIDlet;
import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.Display;
public class thtest extends MIDlet
Thread t;
public void startApp()
Alert a=new Alert("hello");
a.setString("hello");
Alert b=new Alert("world");
b.setString("world");
Display d = Display.getDisplay(this );
d.setCurrent(a);
t=Thread.currentThread();
try{
t.sleep(10000);
catch (Exception e){}
d.setCurrent(b);
public void pauseApp()
public void destroyApp(boolean unconditional)
its just supposed to pause between the alerts using threads
however when i run it using the wtk, the emulator run properly but when i launch the app, it stops executing giving me this:
"Error verifying method org/learn/thtest startApp()V
Approximate bytecode offset 49: Inconsistent or missing stackmap at target
%the stack info%
Execution completed.
437782 bytecodes executed
9 thread switches
486 classes in the system (including system classes)
2506 dynamic objects allocated (73832 bytes)
2 garbage collections (60652 bytes collected)
Execution completed.
437782 bytecodes executed
9 thread switches
486 classes in the system (including system classes)
ALERT: java/lang/VerifyError: org/learn/thtest.
2506 dynamic objects allocated (73832 bytes)
2 garbage collections (60652 bytes collected)
please can someone help me out with this, is it an error on my part or do i have to set some option.Hi gandalf123,
First, Thread.sleep is a static method, so you don't need to create a Thread object to use it.
I think the problem is due to the fact you don't preverify your midlet.
More over, you don't need to double post your question. -
Problem with threads and camera.
Hi everybody!
I've a problem with taking snapshot.
I would like to display a loading screen after it take snapshot ( sometimes i
have to wait few seconds after i took snapshot. Propably photo is being taken in time where i have to wait).
I was trying to use threads but i didn't succeed.
I made this code:
display.setCurrent(perform);
new Thread(new Runnable(){
public void run() {
while((!performing.isShown()) && (backgroundCamera.isShown())){
Thread.yield();
notifyAll();
}).start();
new Thread(new Runnable(){
public void run() {
try {
this.wait();
} catch(Exception e) {
exceptionHandler(e);
photo = camera.snapshot();
display.setCurrent(displayPhoto);
}).start();This code is sometimes showing performing screen but sometimes no.
I don't know why. In my opinion performing.isShown() method isn't working correctly.
Does anyone have some idea how to use threads here?Hi,
I've finally managed to work this fine.
The code:
Object o = new Object();
display.setCurrent(perform);
new Thread(new Runnable(){
public void run() {
while(!performing.isShown()){
Thread.yield();
synchronized(o) {
o.notify();
}).start();
new Thread(new Runnable(){
public void run() {
try {
synchronized(o) {
o.wait(1);
} catch(Exception e) {
exceptionHandler(e);
photo = camera.snapshot();
display.setCurrent(displayPhoto);
}).start();
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