jatin puri

Thanks a lot

Can some one please suggest a good advanced book on Concurrent Processes. Iam a bit confused in which one to follow.

Hi Steve, First of all Happy Diwali (Diwali is the biggest festival here in India)
I think i have found the solution to the problem. THe data is completely received. The thing it that can you please explain System.out.println(). Because the problem is if i make 2 threads and run them i

import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.SocketException; import java.util.concurrent.LinkedBlockingQueue; import java.util.logging.Level; import java.util.logging.Logger; class E { LinkedBlockingQueue<DatagramPacket> li = new LinkedBlockingQueue<DatagramPacket>(); DatagramPacket packet = new DatagramPacket(new byte[8210],8210); DatagramPacket packet2; public static void main(String args[]) { new E().go2(); } void go2() { new Thread(new Foo()).start(); new Thread(new Fo()).start(); } int j,k; class Fo implements Runnable { public void run() { DatagramSocket so = null; try { so = new DatagramSocket(9001); } catch (SocketException ex) { System.err.println("Error"); } while(true){ try { k++; so.receive(packet); synchronized(li) { li.add(packet);} if(k==20)// ie if i receive 20 packets then break { break; } } catch(Exception ex) { System.err.println("error"); } } } } class Foo implements Runnable { public void run() { int i=0; System.out.print("check "); while(true) { try { if(li.size()>0) { i++; synchronized(li){ packet2 = li.remove();} j= k-i; System.out.println(j+" "+new String(packet2.getData())); if(i==20) { break; } } else { Thread.sleep(100); System.out.print("slept"+ " ");.....................................................................................................[1] }} catch (InterruptedException ex) { Logger.getLogger(E.class.getName()).log(Level.SEVERE, null, ex); } }System.out.println("\n"+j); } } }
This code only receives the data,
to send packets you can use the below code
import java.io.IOException; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.net.SocketException; import java.net.UnknownHostException; import java.util.Random; public class prac7 { public static void main (String[] args) throws SocketException, UnknownHostException, IOException, InterruptedException { new prac7().go(); } void go() throws SocketException, UnknownHostException, IOException, InterruptedException { DatagramSocket s= new DatagramSocket(); String as = " hey what is the matter"; DatagramPacket p = new DatagramPacket(as.getBytes(),as.length(),InetAddress.getByName("127.0.0.1"),9001); while(true) { s.send(p); Thread.sleep(100); } } }

Now Run the 1st code and wait for around 20-30 sec to execute the 2nd code.why is it that [1] is not printed when 1st code is implemented and only after 2nd code runs the output is shown.
Similarly in my problem i have found that all the data is arriving but it is not printing on screen.

Thanks a lot of help.
The socket is an reference for DatagramSocket, and socket.receive(packet) is an inbuilt method which copies information from the packet which it receives from the network and puts the data in packet along with other information like destination address etc.
The reason why i dont execute retrieving the data in the the other thread is, because as you know in UDP there is no internal buffer, hence as soon as the packet arrives from the network it should be received or there will be a packet loss. Hence if i include the code which retrieves data from list and processes it, a lot of processor power will go into that (as in creation of jpacket there are a lot of algorithms implemented in it according to the data in packet).
So in the mean time iam loosing a lot of data. I actually tried that. That way i was almost loosing 50% of the packets.

PS: I have attached the code . Please help if you can
In the file. First say 'in' is an instance of SocketInputStream().
in.activate() is called which initiates a new Thread which only collects packets from network and add's it to the list.
Later when in.readData() is called : It removes packets from the list and later does calculation on that.
package protocolapi.packetandsocket; import java.io.IOException; import java.io.InputStream; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.util.LinkedList; import java.util.concurrent.LinkedBlockingQueue; import java.util.logging.Level; import java.util.logging.Logger; /** * * @author Jatin */ public class SocketInputStream extends InputStream { private Jpacket jpacket; private Runnable receiver; private Thread receiver_thread; private JpacketType ptype; private JSocket mothersocket; private DatagramSocket socket; private Variables var; private DatagramPacket packet2=new DatagramPacket(new byte[8210],8210); void setJsocket(JSocket aThis) { mothersocket = aThis; socket = mothersocket.getActualSocket(); } @Override /** * @return The length of the data */ public int read() throws IOException { byte[] buf=readData(); return buf.length; } /** * Method to get the data from Stream * @return The byte array of data * @throws IOException */ public byte[] readData() throws IOException { byte buf[]=null; while(true) { if(var.getLinkedBlockingQueue().size()>0) { packet2=(DatagramPacket) var.getLinkedBlockingQueue().poll(); System.out.println(packet2); buf = packet2.getData(); System.out.println(packet2.getLength()+ " the size "); jpacket = new Jpacket(buf); break; } else { try { Thread.sleep(80); } catch (InterruptedException ex) { Logger.getLogger(SocketInputStream.class.getName()).log(Level.SEVERE, null, ex); } } } return buf; } public void activate()//activate should be called only once or else should throw an exception { receiver = new ReceivingThread(); receiver_thread = new Thread(receiver); //receiver_thread.setPriority(Thread.MAX_PRIORITY); receiver_thread.start(); var = new Variables(); } private class ReceivingThread implements Runnable { public void run() { DatagramPacket packet =new DatagramPacket(new byte[8210],8210); while(true) { try { socket.receive(packet); var.getLinkedBlockingQueue().add(packet); } catch (IOException ex) { Logger.getLogger(SocketInputStream.class.getName()).log(Level.SEVERE, null, ex); } } } } }

Iam stuck in this problem and have spent almost 5-6 hours in it.
In the project i am implementing TCP over UDP.
When stream.activate() is called the following new Thread is implemented
socket.receive(packet); list.add(packet); //List is LinkedBlockingQueue. THe functions is basically whenever it the server receives any packet, it stores in the lsit and later other Thread removes from it
Now the main Thread checks if list has any packets in it
It implements the following code. Basically it checks if there list has any packets in it, if it has it get's the packet and then processes. But some how it doesnt proceed
byte buf[]=null; while(true) { if(list.size()>0) { packet2=(DatagramPacket) list.poll(); System.out.println(packet2); buf = packet2.getData(); //........................................................................[1] System.out.println(packet2.getLength()+ " the size "); jpacket = new Jpacket(buf); break; } else { try { Thread.sleep(80); .....
Now the problem is as soon as the process reaches [1], it doesnt proceed forward. It cant be deadlock as their is nothing for deadlock.

hello!When in the below code if iam using a local address instead of yahoo.com,it is executing well,but if iam not using a local address then it is giving a java.net.SocketException.I use a proxy connection and i have set my proxy for java .pl help

import java.net.*; import java.io.*; import java.io.*; public class URLReader { public static void main(String[] args) throws Exception { URL yahoo = new URL("http://www.yahoo.com/"); BufferedReader in = new BufferedReader( new InputStreamReader( yahoo.openStream())); String inputLine; while ((inputLine = in.readLine()) != null) System.out.println(inputLine); in.close(); } }