Reading Input in a Client program

[JavaDude32]

I have a problem of freezing in my Client program when it attempts to read from a server. I've narrowed the problem down to one line I think, except I don't know how to fix it or why it's freezing. I've tried using a int as to make the code only try so many times, but it freezes in the while statement as the int (c) never prints to the screen. Any help or info on this would be very much appreciated.

while(((theLine = theReader.readLine()) != null) {
System.out.println(c);
theOutput.append("Server: " + theLine);
}

 

[JavaDude32]

Well in more testing of the program, the app is shown to freeze at the end, the server output will be read and displayed until it's last line and then the app freezes. Still looking for a cause. Thanks in advance for any advice.

 

[AdamRice32]

I'm not quite sure what you mean by "freezing" ... you should get some type of exception if the readLine() operation cannot be performed.

Have you tried expanding some of the code:

    String theLine = theReader.readLine();
    while( theLine != null )
    {
        System.out.println( c );
        theOutput.append( "Server: " + theLine );
        theLine = theReader.readLine();
    }

I'm thinking that maybe the condensed assignment in the while conditional is causing problems.

Best,
Adam Rice

 

[meadandale]

It kind of depends on what kind of server you are reading from. Generally, when talking to a java server, the server signals the end of output by sending a -1 which should cause the reader to terminate the read. This may not be occuring if you are talking to a C/C++ daemon which has a different protocol. I've encountered these sorts of issues when talking to Linux daemons such as Telnet.

A little more code and more info about what you are talking to would be helpful.

FWIW, there is nothing wrong with your assignment statement (sorry Adam 8^( )

 

[JavaDude32]

Okay, the purpose of the code there is to continually read input from a server and output to the client screen hence the reading of the input stream in the while statement, I've just thought of a way to possibly set the reading different. What I meant by freezing is that the client would stop reading and refuse to do anything else on the very last line of code. No error messages are reported from the catch part so I don't believe any exceptions are thrown. I don't believe is the server that is to blame as I have tested the client out on other servers and my own server(which works with other clients such as telnet). Thanks for the example AdamRice32, I'm going to try that instead to get the program to work, but I'm still in the dark as to why the program froze on the while statement.

Thanks
JavaDude32

 

[JavaDude32]

Here is a listing of all the code for the connection and reading process:

fConnect.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Integer myInt = new Integer(1);
int aPortNum = myInt.parseInt(thePort.getText());
String theAddress = theIp.getText();
try {
theSocket = new Socket(theAddress, aPortNum);
theReader = new BufferedReader(new InputStreamReader(theSocket.getInputStream()));

theWriter = new BufferedWriter(new OutputStreamWriter(theSocket.getOutputStream()));

fStatus.setText("Connected"
Status.setBackground(java.awt.Color.green);
} catch (IOException a) {
theOutput.append("\nException: " + a.getMessage());
fStatus.setText("Disconnected"
fStatus.setBackground(java.awt.Color.red);
}
try {
String theLine = theReader.readLine();
while(theLine != null) {
theOutput.append(theLine);
theLine = theReader.readLine();
} catch (Exception k) {
System.out.println("message: " + k.getMessage());
System.exit(0);
}
}
});