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Apache Commons telnet connection with a continuous command

Hi all.

Im currently trying to write an application that connects to a telnet server and tails a log file.
What I hope to achieve is to check new data as it arrives, record timings of various jobs and play an audible alert when certain phrases are picked up in the file.

I have created a telnet class to send and receive data using the Apache Commons libraries, this class works perfectly. I am able to use the application as an interface to the server, send commands and display the output.
The problem I am having is that when the tail -f command is issued, it never gets to the end of the output so the method never returns control to the main class. If a command like 'ls' is issued there is no problems.

I have a suspicion that the answer may be to use threads and have the command run in a seperate thread which can be killed when desired, but I know very little about threads. Does this seem a reasonable approach?

What I would really like if possible is a way of doing essentially the following:

Code:

while (connected)

{

    if(newDataReceived)

    {

          parseNewData();

          appendNewDataToTextArea();

    }

}

and to have that running until the disconnect button is pressed, thus ending the loop.
I have seen an SSH/Telnet class that seems to have a method that does essentially this (I believe it's a commercial offering by JScape), but the budget for this project is 0 and they want $599 for licencing.

If anyone has any advice on this then I would be grateful.

Thanks,
Chris

Can you post some code and show which method is not returning? I assume you are using org.apache.commons.net.telnet?

The method that is being used to send the command is:

Code:

public String sendCommand(String command)

    {

        try

        {

            write(command);

            return readUntil(prompt + " ");

        }

        catch (Exception e)

        {

            e.printStackTrace();

        }

        return null;

    }

The write method it refers to is:
[CODE]
public void write(String value)
{
try
{
out.println(value);
out.flush();
}
catch (Exception e)
{
e.printStackTrace();
}
}
[/CODE}

Which is called by:

Code:

aOpenConnection = new AbstractAction("Open Connection")

        {



            public void actionPerformed(ActionEvent e)

            {

                try

                {

                  telnetConn =  new Telnet(SERVER, USER, PASSWORD);

                    outputPane.setText(telnetConn.sendCommand("tail -f " + LOGFILE));

                }

                catch (Exception ex)

                {

                    ex.printStackTrace();

                }

            }

        };

The code itself probably isn't particularly great, this is just a proof-of-concept program which will be refined if I can prove it works, and therefore justify spending works time on developing it.