Java Question

podgeen

I am writing a client server application which exchanges objects over a
socket connection. A new thread is started for each client connection
and
ObjectInputStream.readObject is used to receive the object. Once this
object is processed the server must check from more messages until it
receives a disconnect message. I do this using the following code:


while(disconnect!=true)
{
try {
SphinxMessage msg = (SphinxMessage)ois.readObject();
this.processNormalMessage(msg);
}catch(IOException e3) { /*do nothing*/ }
catch (ClassNotFoundException cnfe2){
System.out.println(" readobject cnfe");
cnfe2.printStackTrace();
}
}

How can i make ObjectInputStream.readObject() block until it receives
a message because at the moment it is continously looping calling
readObject and catching the exception.
Any help or suggestions would be appreciated.
David.

podgeen

anyone?

lynchie

This is some quick code I whipped up to show that readObject does block. I dont know how your code is not blocking. Run this example to verify that it does block

SERVER

import java.net.*;
import java.io.*;

public class Server {

public Server() {
}
public static void main(String[] args) throws Exception
{
ServerSocket ss = new ServerSocket(12345);
Socket s = ss.accept();
ObjectOutputStream out = new ObjectOutputStream(s.getOutputStream());

out.writeObject(new String("FIRST"));
Thread.sleep(10000);
out.writeObject(new String("SECOND"));
Thread.sleep(10000);
out.writeObject(new String("CLOSE"));
Thread.sleep(10000);

out.close();
s.close();
ss.close();
}
}

CLIENT

import java.net.*;
import java.io.*;


public class Client {

public Client() {
}
public static void main(String[] args) throws Exception
{
Socket ss = new Socket("localhost",12345);
ObjectInputStream in = new ObjectInputStream(ss.getInputStream());
while(true)
{
System.out.println(".");
Object o = in.readObject();
//As soon as the above line is called execution is blocked in the
//current thread. As the server is pausing for 10 seconds, if the //code was not blocking, you would see loads of . and .. being //print out
System.out.println("..");
System.out.println(o.getClass().getName());
String s = (String) o;
System.out.println(s);
if(s.equalsIgnoreCase("CLOSE"))
break;
}
in.close();
ss.close();
}
}

L8er,
Lynchie

podgeen

i havent tried your code but i got it blocking yesterday, there was a problem with the client i was using to test the server and it was messing up the input stream. Thanks for your help.