/*
* 1.1 version.
*/
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import java.util.*;
public class TalkClientApplet extends Applet
implements Runnable,
ActionListener {
Socket socket;
BufferedWriter os;
BufferedReader is;
TextField portField, message;
TextArea display;
Button button;
int dataPort;
boolean trysted;
Thread receiveThread;
String host;
boolean DEBUG = false;
String newline;
public void init() {
//Get the address of the host we came from.
host = getCodeBase().getHost();
//Set up the UI.
GridBagLayout gridBag = new GridBagLayout();
GridBagConstraints c = new GridBagConstraints();
setLayout(gridBag);
message = new TextField("");
c.fill = GridBagConstraints.HORIZONTAL;
c.gridwidth = GridBagConstraints.REMAINDER;
gridBag.setConstraints(message, c);
message.addActionListener(this);
add(message);
display = new TextArea(10, 40);
display.setEditable(false);
c.weightx = 1.0;
c.weighty = 1.0;
c.fill = GridBagConstraints.BOTH;
gridBag.setConstraints(display, c);
add(display);
Label l = new Label("Enter the port (on host " + host
+ ") to send the request to:",
Label.RIGHT);
c.fill = GridBagConstraints.HORIZONTAL;
c.gridwidth = 1;
c.weightx = 0.0;
c.weighty = 0.0;
gridBag.setConstraints(l, c);
add(l);
portField = new TextField(6);
c.fill = GridBagConstraints.NONE;
gridBag.setConstraints(portField, c);
portField.addActionListener(this);
add(portField);
button = new Button("Connect");
gridBag.setConstraints(button, c);
button.addActionListener(this);
add(button);
newline = System.getProperty("line.separator");
}
public synchronized void start() {
if (DEBUG) {
System.out.println("In start() method.");
}
if (receiveThread == null) {
trysted = false;
portField.setEditable(true);
button.setEnabled(true);
os = null;
is = null;
socket = null;
receiveThread = new Thread(this);
receiveThread.start();
if (DEBUG) {
System.out.println(" Just set everything to null and started thread.");
}
} else if (DEBUG) {
System.out.println(" receiveThread not null! Did nothing!");
}
}
public synchronized void stop() {
if (DEBUG) {
System.out.println("In stop() method.");
}
receiveThread = null;
trysted = false;
portField.setEditable(true);
button.setEnabled(true);
notify();
try { //Close input stream.
if (is != null) {
is.close();
is = null;
}
} catch (Exception e) {} //Ignore exceptions.
try { //Close output stream.
if (os != null) {
os.close();
os = null;
}
} catch (Exception e) {} //Ignore exceptions.
try { //Close socket.
if (socket != null) {
socket.close();
socket = null;
}
} catch (Exception e) {} //Ignore exceptions.
}
public Insets getInsets() {
return new Insets(4,4,5,5);
}
public void paint(Graphics g) {
Dimension d = getSize();
Color bg = getBackground();
g.setColor(bg);
g.draw3DRect(0, 0, d.width - 1, d.height - 1, true);
g.draw3DRect(3, 3, d.width - 7, d.height - 7, false);
}
public synchronized void actionPerformed(ActionEvent event) {
int port;
if (DEBUG) {
System.out.println("In action() method.");
}
if (receiveThread == null) {
start();
}
if (!trysted) {
//We need to attempt a rendezvous.
if (DEBUG) {
System.out.println(" trysted = false. "
+ "About to attempt a rendezvous.");
}
//Get the port the user entered...
try {
port = Integer.parseInt(portField.getText());
} catch (NumberFormatException e) {
//No integer entered.
display.append("Please enter an integer below."
+ newline);
return;
}
//...and rendezvous with it.
rendezvous(port);
} else { //We've already rendezvoused. Just send data over.
if (DEBUG) {
System.out.println(" trysted = true. "
+ "About to send data.");
}
String str = message.getText();
message.selectAll();
try {
os.write(str);
os.newLine();
os.flush();
} catch (IOException e) {
display.append("ERROR: Applet couldn't write to socket."
+ newline);
display.append("...Disconnecting."
+ newline);
stop();
return;
} catch (NullPointerException e) {
display.append("ERROR: No output stream!"
+ newline);
display.append("...Disconnecting."
+ newline);
stop();
return;
}
display.append("Sent: " + str + newline);
}
}
synchronized void waitForTryst() {
//Wait for notify() call from action().
try {
wait();
} catch (InterruptedException e) {}
if (DEBUG) {
System.out.println("waitForTryst about to return. "
+ "trysted = " + trysted + ".");
}
return;
}
public void run() {
String received = null;
waitForTryst();
//OK, now we can send messages.
while (Thread.currentThread() == receiveThread) {
try {
//Wait for data from the server.
received = is.readLine();
//Display it.
if (received != null) {
display.append("Received: " + received
+ newline);
} else { //success but no data...
System.err.println("End of stream?");
return; //XXX
}
} catch (IOException e) { //Perhaps a temporary problem?
display.append("NOTE: Couldn't read from socket.\n");
return;
}
}
}
private void rendezvous(int port) {
//Try to open a socket to the port.
try {
socket = new Socket(host, port);
} catch (UnknownHostException e) {
display.append("ERROR: Can't find host: " + host
+ newline);
return;
} catch (IOException e) {
display.append("ERROR: Can't open socket on rendezvous port "
+ port + " (on host " + host + ")."
+ newline);
return;
}
//Try to open streams to read and write from the socket.
try {
os = new BufferedWriter(
new OutputStreamWriter(socket.getOutputStream()));
is = new BufferedReader(
new InputStreamReader(socket.getInputStream()));
} catch (IOException e) {
display.append("ERROR: Created data socket but can't "
+ "open stream on it."
+ newline);
display.append("...Disconnecting." + newline);
stop();
return;
}
if ((os != null) & (is != null)) {
if (DEBUG) {
System.out.println("Successful rendezvous.");
System.out.println("socket = " + socket);
System.out.println("output stream = " + os);
System.out.println("input stream = " + is);
}
//Let the main applet thread know we've successfully rendezvoused.
portField.setEditable(false);
button.setEnabled(false);
trysted = true;
notify();
} else {
display.append("ERROR: Port is valid but communication failed. "
+ "Please TRY AGAIN." + newline);
}
}
}
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