Java Networking

C

Chase Preuninger

I have been having trouble with my file transfer program that I have
been writing over the past few weeks. It makes p2p to transfer files
and the two sides update each over based upon string being sent over
one port (5013) and the actual data being sent over another (5012).
This works great except for when the user on the receiving side
accepts the download the update only makes it to the user on the other
side 20% of the time. Bellow I have provided the class that manages
the socket.


//This manages the connection for the receiving side
package com.cpsoft.filetransfer.net;

import java.net.*;
import java.io.*;
import java.util.*;
import com.cpsoft.filetransfer.*;
import java.util.*;

public class SocketIO
{
private Socket s;
private Writer out;
private Scanner in;
private InListener listener;
public SocketIO(Socket s) throws Exception
{
this.s = s;
try
{
s.setTcpNoDelay(true);
s.setSendBufferSize(5);
out = new OutputStreamWriter(s.getOutputStream(),
"UTF-8");
in = new Scanner(this.s.getInputStream());
}
catch(Exception ex)
{
throw ex;
}
listener = new InListener();
listener.start();
}
public void SendUpdate(Update u)
{
try
{
out.write(u.toString());
out.flush();
}
catch (IOException ex)
{
ex.printStackTrace();
}
}
private ArrayList updateEvents = new ArrayList();
public void addUpdateListener(UpdateListener l)
{
updateEvents.add(l);
}
private class InListener extends Thread
{
public InListener()
{
super();
setPriority(Thread.MAX_PRIORITY);
}
public void run()
{
while(!interrupted())
{
if(in.hasNext())
{
try
{
Update u = Update.parseString(in.nextLine());
if(u.getStatus().equals(Update.ACCEPT))
{
for(int i = 0; i < updateEvents.size(); i+
+)

((UpdateListener)updateEvents.get(i)).AcceptUpdateReceieved(u);
}
else if(u.getStatus().equals(Update.CANCEL))
{
for(int i = 0; i < updateEvents.size(); i+
+)

((UpdateListener)updateEvents.get(i)).CancelUpdateReceieved(u);
}
else if(u.getStatus().equals(Update.DONE))
{
for(int i = 0; i < updateEvents.size(); i+
+)

((UpdateListener)updateEvents.get(i)).DoneUpdateReceieved(u);
}
else if(u.getStatus().equals(Update.REQUEST))
{
for(int i = 0; i < updateEvents.size(); i+
+)

((UpdateListener)updateEvents.get(i)).RequestUpdateReceieved(u);
}
else if(u.getStatus().equals(Update.DECLINE))
{
for(int i = 0; i < updateEvents.size(); i+
+)

((UpdateListener)updateEvents.get(i)).DeclineUpdateReceieved(u);
}
for(int i = 0; i < updateEvents.size(); i++)

((UpdateListener)updateEvents.get(i)).UpdateReceieved(u);
}
catch(Exception ex)
{
continue;
}
}
}
}
}
public void close()
{
try
{
listener.interrupt();
if(!s.isClosed())
s.close();
}
catch(Exception ex)
{

}
}
}



//Socket used on send side
package com.cpsoft.filetransfer.net;

import com.cpsoft.filetransfer.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
import java.util.*;

public class SendUpdateSocket extends Socket
{
public PrintWriter out;
public Scanner in;
private Thread inbound;

public SendUpdateSocket(InetAddress host, int port) throws
IOException
{
super(host, port);
}
public SendUpdateSocket()
{
super();
}
private ArrayList updateListeners = new ArrayList();

public void connect(SocketAddress endpoint) throws IOException
{
super.connect(endpoint);
inbound = new InboundManager();
out = new PrintWriter(getOutputStream());
in = new Scanner(getInputStream());
inbound.start();
setTcpNoDelay(true);
}
public void addUpdateListener(UpdateListener u)
{
updateListeners.add(u);
}
public void SendUpdate(Update u)
{
out.println(u.toString());
out.flush();
}
public void close() throws IOException
{
super.close();
inbound.interrupt();
}
private class InboundManager extends Thread
{
public InboundManager()
{
super();
setPriority(Thread.MAX_PRIORITY);
}
public void run()
{
System.out.println("RUNNING");
while(!interrupted())
{
if(in.hasNext())
{
try
{
Update u = Update.parseString(in.nextLine());
if(u.getStatus().equals(Update.ACCEPT))
{
for(int i = 0; i < updateListeners.size();
i++)

((UpdateListener)updateListeners.get(i)).AcceptUpdateReceieved(u);
}
else if(u.getStatus().equals(Update.CANCEL))
{
for(int i = 0; i < updateListeners.size();
i++)

((UpdateListener)updateListeners.get(i)).CancelUpdateReceieved(u);
}
else if(u.getStatus().equals(Update.DONE))
{
for(int i = 0; i < updateListeners.size();
i++)

((UpdateListener)updateListeners.get(i)).DoneUpdateReceieved(u);
}
else if(u.getStatus().equals(Update.REQUEST))
{
for(int i = 0; i < updateListeners.size();
i++)

((UpdateListener)updateListeners.get(i)).RequestUpdateReceieved(u);
}
else if(u.getStatus().equals(Update.DECLINE))
{
for(int i = 0; i < updateListeners.size();
i++)

((UpdateListener)updateListeners.get(i)).DeclineUpdateReceieved(u);
}
for(int i = 0; i < updateListeners.size(); i+
+)

((UpdateListener)updateListeners.get(i)).UpdateReceieved(u);
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
}
}
}
}
 
A

Andrew Thompson

Chase said:
I have been having trouble with my file transfer program that I have
been writing over the past few weeks. ...

For the best chance of getting help, I recommend you
1) Post an SSCCE*. The two classes can be incorporated into
one source file by reducing the access from public to 'default',
moving the imports to the top, getting rid of the package
statement (not entirely necessary, but easier), and fixing
(shortenning) those dozen lines that line-wrap**.
2) Ask a specific question.

* <http://www.physci.org/codes/sscce.html>
** A tool to help check line width ..
<http://www.physci.org/twc.jnlp>
Try to keep it under 62 chars width for usenet code
postings.

--
Andrew Thompson
http://www.athompson.info/andrew/

Message posted via JavaKB.com
http://www.javakb.com/Uwe/Forums.aspx/java-general/200711/1
 
A

Andrew Thompson

Chase said:
I have been having trouble with my file transfer program that I have
been writing over the past few weeks. ...

As a general tip - never 'swallow' exceptions in code that
is breaking inexplicably.

e.g. This..

catch(Exception ex)
{

}

..should be..

catch(Exception ex)
{
// be very noisy about what went wrong
ex.printStackTrace();
}

--
Andrew Thompson
http://www.athompson.info/andrew/

Message posted via JavaKB.com
http://www.javakb.com/Uwe/Forums.aspx/java-general/200711/1
 
G

Gordon Beaton

I have been having trouble with my file transfer program that I have
been writing over the past few weeks. It makes p2p to transfer files
and the two sides update each over based upon string being sent over
one port (5013) and the actual data being sent over another (5012).
This works great except for when the user on the receiving side
accepts the download the update only makes it to the user on the
other side 20% of the time.

Exactly what happens in the other 80%? Does the connection fail? Is
the file truncated or corrupted by the transfer? Do you get an
exception? Be specific.

AFAICT you are using a PrintWriter to send the file. Unless you're
sending pure text, you really should be using a FileOutputStream.

At first glance I'm unable to follow the logic in the code you've
posted, and I'm not even sure I can see where you transfer any data.
Post a concise example and describe the steps.

/gordon


--
 

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