Send ArrayList through UDP socket

I have the following 2D ArrayList
ArrayList<ArrayList<Integer>> myList = new ArrayList<ArrayList<Integer>>();How is it possible to send it through a UDP socket and then get it back?

Apart from adding implenents Serializable after the class name what else i have to do in order to add the arraylist to the datagramSocket?
For simple sockets i have found this
http://java.sun.com/developer/technicalArticles/ALT/sockets/ but
but it doesn't work for DatagramSocket
ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream()); throws an error "The method getOutputStream() is undefined for the type DatagramSocket"
Edit: It seems this site has the solution
http://www.nada.kth.se/~bishop/resources/javaSerial/index.html
Message was edited by:
[email protected]

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Problems sending bufferedimages through a socket

Hi everyone,
I've got a server program that takes a screen capture as a bufferedimage, and sends it through a socket to be saved by the client program. The programs work fine, however, whenever I'm transferring the image with the code at the bottom of this post, I notice that the collision LED on my network hub flashes and I can't figure out why (Obviously there's a collision, but I don't know what causes it or how to stop it from happening). I've googled a bit for collisions and bufferedimages, but have come up with El Zilcho. I've also gone through the IO tutorial and the Socket and BufferedImage API's, but havent learned anything to solve my problem.
Also, As it is now, if I want multiple images, I need to disconnect and reconnect repeatedly. I tried sending multiple bufferedimages throught the socket, but get the following exception:
java.lang.illegalargumentexception: im == null!Does anyone know of a way where I can send multiple bufferedimages through the socket without reconnecting every single time? Thanks
Server code:
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension screenSize = toolkit.getScreenSize();
Rectangle screenRect = new Rectangle(screenSize);
Robot robot = new Robot();
BufferedImage image = robot.createScreenCapture(screenRect));
ImageIO.write(image, "jpeg", fromClient.getOutputStream());
fromclient.shutdownOutput();
fromclient.close();Client code:
BufferedImage receivedImage = ImageIO.read(toServer.getInputStream)
toServer.close();Any help would be greatly appreciated. TIA
Jay

Have you tried.
ImageIO.write(image1, "jpeg", fromClient.getOutputStream());
ImageIO.write(image2, "jpeg", fromClient.getOutputStream());
ImageIO.write(image3, "jpeg", fromClient.getOutputStream());
ImageIO.write(image4, "jpeg", fromClient.getOutputStream());
ImageIO.write(image5, "jpeg", fromClient.getOutputStream());
ImageIO.write(image6, "jpeg", fromClient.getOutputStream());
ImageIO.write(image7, "jpeg", fromClient.getOutputStream());

Controlling sending rate over UDP socket

Hello,
After some NIO study, i finally managed to send and receive UDP data from a single thread. Here is my code
so far:
try {
      DatagramChannel channel = DatagramChannel.open();
      channel.configureBlocking(false);
     channel.socket().bind(localAddress);
      boolean flag = true;
      int LIMIT = 1000;
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      channel.register(selector, SelectionKey.OP_READ | SelectionKey.OP_WRITE);
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          while (iterator.hasNext()) {
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            iterator.remove();
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              buffer.flip();
              numbersRead++;
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    } // end catchThis thread both receives and send integers from/to my UDP echo server. Another thread acts as data generator and add data to ConcurentLinkedQueue. The sending thread poll the data from the queue and sends it.
Right now, the thread is sending at full speed.
I would like to know how i can control the sending rate ?
I would like to be able to specify a given rate like 50 packets per second, 100 packets per seconds...?
Of course i can always slow down the sending part by adding Thread.sleep(someValue) before or after sending..
but this way i am not sure what is the real rate achieved.
any advises would be welcome.
thanks
sepi
Edited by: sepi_seb on Dec 17, 2007 6:50 PM

hi
thanks for your reply.
I have some difficulties calculating the amount of time i need to sleep to achieve a proper sending speed.
basically it takes 16ms to send 20 requests so 1250req/s. Hoe can i regulate this accurately.
I added this kind of code in my sending part: Every 50 requests i execute this code.For some reason i get a divided by zero exception at the line marked in bold.
it happens at the second execution of this code.
     if(count == 50){
              count = 0;
              elapsedTime = System.currentTimeMillis() - startTime;
              System.out.println(elapsedTime);
              *sendingRate = (50 * 1000) / elapsedTime;*
              System.out.println("sending at:" + sendingRate + " req/s");
              if(sendingRate > speed){
                long diff = sendingRate - speed;
                long sleepTime = (diff * elapsedTime) / 50;
                try {
                  Thread.sleep(sleepTime);
                } catch (InterruptedException e) {
      }any comments are welcome
thanks
sebastien

I have to send messages through UDP multicast and unicast from same port. In Labview I tried that it throws error. I heard it is possible by means of Datagram (UDP unicast and multicast) Port Sharing. How can it be achieved in Labview?

I have to send UDP multicast and Unicast messages to a remote port from a single source/local port. I tried by opening UDP unicast and multicast in the same port and got the expected error. I tried by opening a unicast connection and sending unicast messages.After that when multicast messages has to send I closed unicast and opened multicast in the same port.This is not throwing any error. But my requirenment is to comminicate with another application in C ++ which recieves this data, throwing an error of lost connectivity and both the applications are not abled to communicate properly.
In the other application with C++ this is implemented using port sharing. So how port sharing can be implemented in labview so that I can send both multicast and unicast messages from the same port?
Thanks in advance

UDP is a sessionless protocol, meaning that anyone listening on the specified port CAN receive the data. CAN because as you noted there is no guarantee in the protocol that it will be received. And if you send the data not to a specific address but a multicast address not only one computer can receive it but in fact every computer on the same subnet listening to that multicast address and depending on the TTL of the packet also computers in neighbouring subnets, although that last one is not a very reliable operation since routers can be configured to drop multicast packages anyhow despite of a different TTL saying otherwise.
Accordingly there is no real way to make sure that a receiving UDP port is not already in use, since you don't build up a connection. UDP is more or less analogous to shouting your messages through a megaphone, and anyone listening on the right frequency (port) can hear it. You do bind the sender socket to a specific port number but that makes little difference.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions

Need to send 32 packet within 15ms through UDP

Hi all,
I need to send 32 packet within 15ms through UDP in labview 2012. Each packet carries 2560 bytes. If it can able to send all packet within 7 or 8 ms, then it should wait upto 15ms and again it should repeat the same.
Please, anyone help me.
My code is as below.
Thanks,
Attachments:
DAC_labview.zip ‏49 KB

I wouldn't go that far, Shane.
I think that there is some confusion/misunderstand around this topic.
YES, you can use LV to send data using UDP and TCP to other systems.
NO, UDP by itself does not ensure lossless data transfer. So UDP can lose packets. That is something which LV cannot influence by any means. TCP is a lossless protocol which should be used if you require the security.
NO, neither TCP nor UDP are deterministic. So even if the packages you are sending are sent within a time x ms, there is no one garantee of any means that this happens EVERY time. Sometime packages might take a multiple of this time.
NO, transfer times are not influenced by the sending PC at a primary level. It all depends on your network; if the network sucks, using UDP packages are lost. If using TCP, packages are resent, so it also depends on sender and receiver alike.
Norbert
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

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thank you....

[http://forums.sun.com/thread.jspa?forumID=11&threadID=390636] this may help you

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I have an application that sends/receives files through a socket. To do this, on the receiver side I have a BufferedInputStream from the socket, and a BufferedOutputStream to the file on disk.
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As you know I can't close any stream, ever.. because that closes the underlying socket (this seems stupid..?)Its not if you want to continuosly listen to the particular port.. like those of server, you need to use ServerSocket.
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The folowing examples are not the actual code implemented but provide an example of the condition under which the leak is seen.
set msg [udp_open]
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lappend clients "10.70.0.112 1234"
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any help would be appreciated.
Regards,
Robert.

Hi,
could you please tell me the package version number you are using?
You can obtain it by calling "package re udp".
thx

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<![CDATA[
import mx.controls.Alert;
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private var nextId:int;
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securityErrorHandler);
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<mx:HBox x="10" y="30" width="100%">
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dataProvider="{xml}">
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<mx:Array>
<mx:DataGridColumn headerText="Event Name"
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Hi all,
I am trying to receive some data through TCP Socket from the
server using XMLSocketClass. Ther server is responding with some
data. But I can't access this data in my application. Pls tell me
the reasons for not working of handler private function
dataHandler(event:DataEvent):void .
=============================================================================
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="
http://www.adobe.com/2006/mxml"
layout="absolute">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
import mx.collections.ArrayCollection;
import flash.display.Sprite;
import flash.events.Event;
import flash.events.DataEvent;
import flash.events.IOErrorEvent;
import flash.net.XMLSocket;
private var socket:XMLSocket;
private var nextId:int;
private var events:ArrayCollection = new ArrayCollection();
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public static var port:Number = 8002;
public var xml:XML;
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socket = new XMLSocket();
socket.addEventListener(DataEvent.DATA, dataHandler);
configureListeners(socket);
socket.connect(host, port);
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private function ioErrorHandler(event:IOErrorEvent):void {
trace("ioErrorHandler: " + event);
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trace("progressHandler loaded:" + event.bytesLoaded + "
total: " + event.bytesTotal);
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trace("dataHandler: " + event);
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var obj:Object = new Object();
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obj.timestamp = new Date().valueOf();
events.addItem(obj);
private function sendData():void
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var xmlfile:String =
"<command>SndIns<parameter1>0x06</parameter1><parameter2>0x00</parameter2><parameter3>0x7 1</parameter3><parameter4>0x0F</parameter4><parameter5>0x11</parameter5><parameter6>0xFF</ parameter6></command>";
socket.send(xmlfile);
Alert.show(xmlfile);
]]>
</mx:Script>
<mx:HBox width="80%" horizontalAlign="center">
<mx:TextInput id="txtData" name=""/>
<mx:Button id="btnConnect" label="Connect"
click="connectToServer();btnConnect.enabled = false"/>
<mx:Button id="btnSend" label="Send Data"
click="sendData()"/>

</mx:HBox>
<mx:HBox x="10" y="30" width="100%">
<mx:DataGrid width="80%" height="100%"
dataProvider="{xml}">
<mx:columns>
<mx:Array>
<mx:DataGridColumn headerText="Event Name"
dataField="eventName"/>
</mx:Array>
</mx:columns>
</mx:DataGrid>
</mx:HBox>
</mx:Application>

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(Sigh) Cross-posted, time-waster!
http://forum.java.sun.com/thread.jsp?thread=448691&forum=426&message=2034341
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getting the Input Stream data into a format
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I'm currently taking a web programming course in school. So far we've focused on implementing some very simply multiplayer games (othello, pong,...). As more of a convience than anything else i was looking to create some classes to provide stream functionality to UDP sockets. This way I could wrap the streams with DataInput/Output and ObjectInput/Output.
<br>
<br>
Because I feel pretty comfortable with conventional I/O my initial thought was to extend the ByteArray streams. I could code in an upper array size, explicit send()/receive(), and use queues to store packets to be swapped in and out when needed.
<br>
<br>
Intuitively this sounds like something that would be better handled by nio, but I don't really have a good grasp on nio's functionality. Are there any classes that intristically have these types of properties in the nio package?

Dear sir, first of all thank you for your reply, i am wondering if you can guide me to a place on the internet where i can have a sampl example of using UDP sockets in java implementing a timer to wait for reply, a cehcksum and other things could you ?

Cannot send email through yahoo on iPad 4, apple.smtp.mail.yahoo not available as of December 1, 2012

I am unable to send emails through yahoo on my ipad 4 wifi, just starting over the weekend. My 3 other non-yahoo email accounts are working fine on my ipad. When I try to send an email from the yahoo account, I receive the message that the connection to the outgoing mail server "apple.smtp.mail.yahoo" failed. I can send email through yahoo just fine on the web and on my computer through Thunderbird.

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Send ArrayList through UDP socket

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