| Methods Summary |
|---|
| void | broadcastMessage(java.lang.String message)
message = user + ": " + message; // Pre-pend the speaker's name
try {
chatServer.broadcastMessage(message);
}
catch (RemoteException e) {
// Remote exception, report it and abandon the broadcast
System.out.println("Remote exception: " + e.getMessage());
}
catch (Exception e) {
// Some other exception, report it and abandon the broadcast
System.out.println("General exception: " +
e.getClass().getName() + ": " + e.getMessage());
}
|
| private ChatServer | getChatServer()
try {
Registry registry =
LocateRegistry.getRegistry(getCodeBase().getHost(), getRegistryPort());
Object obj = registry.lookup(getRegistryName());
return (ChatServer)obj;
}
catch (java.rmi.UnknownHostException e) {
// Don't know the registry host, try to exit
System.out.println("Host unknown in url: " + e.getMessage());
System.exit(1);
}
catch (NotBoundException e) {
// Can't find our object, try to exit
System.out.println("Name not bound: " + e.getMessage());
System.exit(1);
}
catch (ClassCastException e) {
// The object wasn't a ChatServer, try to exit
System.out.println(getRegistryName() + " was not a ChatServer:" +
e.getMessage());
System.exit(1);
}
catch (RemoteException e) {
// General RMI problem, try to exit
System.out.println("Remote exception: " + e.getMessage());
System.exit(1);
}
catch (Exception e) {
// Some other problem, try to exit
System.out.println("General exception: " +
e.getClass().getName() + ": " + e.getMessage());
System.exit(1);
}
return null; // return null if the exit() doesn't work
|
| java.lang.String | getNextMessage()
String nextMessage = null;
while (nextMessage == null) {
try {
nextMessage = chatServer.getNextMessage();
}
catch (RemoteException e) {
// Remote exception, report and wait before trying again
System.out.println("Remote Exception:" + e.getMessage());
try { Thread.sleep(1000); } catch (InterruptedException ignored) { }
}
}
return nextMessage + "\n";
|
| private java.lang.String | getRegistryName()
String name = getParameter("name");
return (name == null ? "ChatServlet" : name);
|
| private int | getRegistryPort()
try { return Integer.parseInt(getParameter("port")); }
catch (NumberFormatException ignored) { return Registry.REGISTRY_PORT; }
|
| public boolean | handleEvent(java.awt.Event event)
switch (event.id) {
case Event.ACTION_EVENT:
if (event.target == input) {
broadcastMessage(input.getText());
input.setText("");
return true;
}
}
return false;
|
| public void | init()
// Check if this applet was loaded directly from the filesystem.
// If so, explain to the user that this applet needs to be loaded
// from a server in order to communicate with that server's servlets.
URL codebase = getCodeBase();
if (!"http".equals(codebase.getProtocol())) {
System.out.println();
System.out.println("*** Whoops! ***");
System.out.println("This applet must be loaded from a web server.");
System.out.println("Please try again, this time fetching the HTML");
System.out.println("file containing this servlet as");
System.out.println("\"http://server:port/file.html\".");
System.out.println();
System.exit(1); // Works only from appletviewer
// Browsers throw an exception and muddle on
}
// Get the remote chat server
chatServer = getChatServer();
// Register ourselves as one of its clients
registerWithChatServer(chatServer);
// Get this user's name from an applet parameter set by the servlet
// We could just ask the user, but this demonstrates a
// form of servlet->applet communication.
user = getParameter("user");
if (user == null) user = "anonymous";
// Set up the user interface...
// On top, a large TextArea showing what everyone's saying.
// Underneath, a labeled TextField to accept this user's input.
text = new TextArea();
text.setEditable(false);
label = new Label("Say something: ");
input = new TextField();
input.setEditable(true);
setLayout(new BorderLayout());
Panel panel = new Panel();
panel.setLayout(new BorderLayout());
add("Center", text);
add("South", panel);
panel.add("West", label);
panel.add("Center", input);
|
| private void | registerWithChatServer(ChatServer server)
try {
UnicastRemoteObject.exportObject(this);
server.addClient(this);
}
catch (RemoteException e) {
// General RMI problem, try to exit
System.out.println("Remote exception: " + e.getMessage());
System.exit(1);
}
catch (Exception e) {
// Some other problem, try to exit
System.out.println("General exception: " +
e.getClass().getName() + ": " + e.getMessage());
System.exit(1);
}
|
| public void | setNextMessage(java.lang.String message)
text.appendText(message + "\n");
|
