Hello World using JNDI (Example 2)

In this example, we will redo the client and server for the Hello World using JNDI but this time we will let the JNDI/COS provider create an ORB implicitly.

Notice that in the build file, we have set the JNDI naming factory for initial contexts to the JNDI/COS provider from JavaSoft.

   -Djava.naming.factory.initial=com.sun.jndi.cosnaming.CNCtxFactory

Hello Server

The Initial context factory implicitly creates the ORB so no explicit ORB.init() is required. Also when we created an RMI-IIOP object, the ORB started a keep alive thread that ensures that the VM does not exit when the "main thread" exits. So we do not need an explicit ORB.run() either.

package jndiCOS2;
                                                                           
import util.Util;
                                                                           
import helloWorld2.Hello;
import helloWorld2.HelloImpl;
                                                                           
import javax.naming.Context;
import javax.naming.InitialContext;
                                                                           
public class helloServer
{
    public static void main(String[] args)
    {
    |   try {
    |   |                                                                  
    |   |   // create a servant
    |   |   Hello hello = new HelloImpl();
    |   |                                                                  
    |   |   // get the root naming context
    |   |   Context ctx = new InitialContext(null);
    |   |                                                                  
    |   |   // bind the hello objref using JNDI
    |   |   ctx.rebind("hello", hello);
    |   |                                                                  
    |   |   // wait for invocations
    |   |   System.out.println("waiting for invocations ...");
    |   |                                                                  
    |   } catch (Exception ex) {
    |   |   ex.printStackTrace();
    |   }
    }
}

Hello Client

The initial context factory implicitly creates the ORB so no explicit ORB.init() is required.

package jndiCOS2;
                                                                           
import util.Util;
                                                                           
import helloWorld2.Hello;
                                                                           
import javax.naming.Context;
import javax.naming.InitialContext;
                                                                           
public class helloClient
{
    public static void main(String[] args)
    {
    |   try {
    |   |                                                                  
    |   |   // get the root naming context
    |   |   Context ctx = new InitialContext(null);
    |   |                                                                  
    |   |   // lookup the hello objref
    |   |   Hello hello = (Hello) ctx.lookup("hello");
    |   |                                                                  
    |   |   // invoke method on the object
    |   |   System.out.println(hello.sayHello());
    |   |                                                                  
    |   } catch (Exception ex) {
    |   |   ex.printStackTrace();
    |   }
    }
}

Hello Applet Client

package jndiCOS2;
                                                                           
import java.awt.Graphics;
import java.util.Hashtable;
                                                                           
import helloWorld2.Hello;
                                                                           
import javax.naming.Context;
import javax.naming.InitialContext;
                                                                           
public class helloApplet extends java.applet.Applet 
{
    private String _message = "";
                                                                           
    public void init() {
    |   try {
    |   |                                                                  
    |   |   // get the root naming context
    |   |   Context ctx = new InitialContext(null);
    |   |                                                                  
    |   |   // lookup the hello objref
    |   |   Hello hello = (Hello) ctx.lookup("hello");
    |   |                                                                  
    |   |   // invoke method on the object
    |   |   _message = hello.sayHello();
    |   |                                                                  
    |   } catch (Exception ex) {
    |   |   ex.printStackTrace();
    |   }
    }
                                                                           
    public void paint(Graphics g) 
    {
    |   g.drawString(_message, 25, 50);
    }
}