import java.rmi.*;
import java.net.*;

public class HelloClient {

  public static void main(String args[]) {
    
    // Get the url of the HelloServer    
    String urlServerStr = "";
    if( (args.length > 1) ||
        (args.length == 1 && !args[0].startsWith("rmi:")) ) {
         System.err.println(
             "Usage: java HelloClient [rmi://host.domain:port/helloServer]");
              System.exit(1);
    }
    else if ( args.length == 0 ) {
      urlServerStr = "rmi://localhost/helloServer";
    }
    else {
      urlServerStr = args[0];
    }
    
    // Starts Security Manager to download stub_class and execute it !
    if( System.getSecurityManager() == null ) {
      System.setSecurityManager(new RMISecurityManager());
    }

    try {
      Hello h = (Hello)Naming.lookup(urlServerStr);

      String message = h.sayHello();
      System.out.println("\n HelloClient: msg from server -> " + message);
    } 
    catch (MalformedURLException e) {
      System.out.println(urlServerStr + " is not a valid RMI URL" + 
                         e.getMessage());
      e.printStackTrace();
    } 
    catch (RemoteException e) {
      System.out.println("Remote object threw exception " + e.getMessage());
      e.printStackTrace();
    } 
    catch (NotBoundException e) {
      System.out.println("Could not find the requested remote object: " + 
                         e.getMessage());
      e.printStackTrace();
    } 
    catch (Exception e) {
      System.out.println("Exception in main: " + e);
      e.printStackTrace();
    }
  }
}