Simple client/server advice (chat processing)
Hello.
I'm working on a chat server for a game that I'm developing, and currently I have been able to get the server to send and receive messages through telnet, and I am now working on giving it a GUI.
From the GUI, I can send messages but the DataInputStream seems to be confusing me. What I need to do is monitor the input stream to add text to the text area when a message is sent to the server. Because I don't want to have a while loop constantly running readLine, I would like to know how I can monitor the stream efficiently.
Is there a simple way to do this that I am missing?
By the way, here is the code I'm using to start the input stream: (it will be run from the init method on startup)
private DataInputStream input;
publicvoid startInputStream(){
// uses addLine method to add text to chat box
try{
input =new DataInputStream(client.getInputStream());
}
catch (IOException e){
System.out.println(e);
}
}
Ok, another question...
The client closes the connection to the server after sending it's first message and that seems to be preventing the messages from being added to the text box. If not, then my variables aren't being initialized correctly (I don't like not being able to declare variables from try/catch if you want to use them later).
Here's the full code to my client. If you need the server code, I got it from http://www.acm.org/crossroads/xrds6-1/ovp61.html . Sorry about it's messiness but NetBeans doesn't exactly help with that :P (I did try to keep the connecting code in a somewhat logical order).
So I'm hoping some one will notice bad variable declaration or an obvious error?
/*
* chatWindow.java
*
* Created on February 21, 2007, 10:24 PM
*/
package mazerunner;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.net.*;
/**
*
* @author timothyb89
*/
public class chatWindow extends javax.swing.JFrame {
/** Creates new form chatWindow */
public chatWindow() {
initComponents();
connect("na");
}
private void addLine(String text) {
String oldText = textField.getText();
String newText = oldText += text + "\n";
//sets new text
textField.setText(newText);
}
private Socket client;
public void connect(String user) {
// creates new socket, connects to server
try {
client = new Socket("timothyb89.homelinux.org", 4321);
}
catch (IOException ex) {
ex.printStackTrace();
}
}
private PrintStream output;
public void sendMessage(String text) {
// sends text to the server to broadcast to clients
try {
output = new PrintStream(client.getOutputStream());
output.print(text);
output.close();
}
catch (IOException e) {
System.out.println(e);
}
}
private DataInputStream input;
public void startInputStream() {
// uses addLine method to add text to chat box
try {
input = new DataInputStream(client.getInputStream());
}
catch (IOException e) {
System.out.println(e);
}
// monitors server for messages (if only there was a better way...)
String addText;
try {
while ((addText = input.readLine()) != null) {
addLine(addText);
//System.out.println("echo: " + in.readLine());
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
private void initComponents() {
jScrollPane1 = new javax.swing.JScrollPane();
textField = new javax.swing.JTextArea();
textToSend = new javax.swing.JTextField();
jButton1 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
textField.setColumns(20);
textField.setRows(5);
jScrollPane1.setViewportView(textField);
textToSend.addKeyListener(new java.awt.event.KeyAdapter() {
public void keyPressed(java.awt.event.KeyEvent evt) {
textToSendKeyPressed(evt);
}
});
jButton1.setText("Send");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(textToSend, javax.swing.GroupLayout.DEFAULT_SIZE, 376, Short.MAX_VALUE)
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 376, Short.MAX_VALUE)
.addComponent(jButton1, javax.swing.GroupLayout.DEFAULT_SIZE, 376, Short.MAX_VALUE))
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 220, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(textToSend, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton1)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
pack();
}
private void textToSendKeyPressed(java.awt.event.KeyEvent evt) {
// will implement sending on press of enter key (need key code for enter key)
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
sendMessage(textToSend.getText());
connect("na");
textToSend.setText("");
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new chatWindow().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea textField;
private javax.swing.JTextField textToSend;
// End of variables declaration
}
And finally, about my having to connect() every time, my socket seems to close after sending a message and I think it could be interfering with my line listener.
EDIT: I realized that I never ran the startInputStream code thus it never ran, so I ran it and remembered I needed to be using a thread for it. And it was at that time that I realized that I couldn't access any variables from my chatWindow class in my thread class.
I seem to be efficiently managing to confuse myself...
