First "Hello World" Sample with SIMON 1.0.0¶

Interfaces¶

First of all, we need some interfaces which should be available on the respective remote-installation:

ServerInterface.java:

 1 package de.root1.simon.codesample.common;
 2 import de.root1.simon.SimonRemote;
 3 import de.root1.simon.exceptions.SimonRemoteException;
 4 
 5 public interface ServerInterface extends SimonRemote {
 6 
 7    public void login(ClientCallbackInterface clientCallback) throws SimonRemoteException;
 8 
 9 }

ClientCallbackInterface.java:

 1 package de.root1.simon.codesample.common;
 2 
 3 import de.root1.simon.SimonRemote;
 4 import de.root1.simon.exceptions.SimonRemoteException;
 5 
 6 public interface ClientCallbackInterface extends SimonRemote {
 7 
 8    public void callback(String text) throws SimonRemoteException;
 9 
10 } 

Implementations¶

Then we need the implementation for the server remote methods ...

ServerInterfaceImpl.java:

 1 package de.root1.simon.codesample.server;
 2 
 3 import de.root1.simon.Simon;
 4 import de.root1.simon.exceptions.SimonRemoteException;
 5 import de.root1.simon.codesample.common.ClientCallbackInterface;
 6 import de.root1.simon.codesample.common.ServerInterface;
 7 
 8 public class ServerInterfaceImpl implements ServerInterface {
 9 
10    private static final long serialVersionUID = 1L;
11 
12    public void login(ClientCallbackInterface clientCallback) throws SimonRemoteException {
13 
14       clientCallback.callback("This is the callback. " +
15          "Your address is "+
16          Simon.getRemoteInetSocketAddress(clientCallback).getAddress()+" "+
17          "and your are connected from port "+
18          Simon.getRemoteInetSocketAddress(clientCallback).getPort());
19 
20    }
21 }

And of course the callback methods that are available on the client side have the be implemented ...

ClientCallbackImpl.java:

 1 package de.root1.simon.codesample.client;
 2 
 3 import de.root1.simon.exceptions.SimonRemoteException;
 4 import de.root1.simon.codesample.common.ClientCallbackInterface;
 5 
 6 public class ClientCallbackImpl implements ClientCallbackInterface {
 7 
 8    private static final long serialVersionUID = 1L;
 9 
10    public void callback(String text) throws SimonRemoteException {
11 
12       System.out.println("This message was received from the server: "+text);
13 
14    }
15 } 

Server and Client¶

Now it's time to write the "server":

Server.java:

 1 package de.root1.simon.codesample.server;
 2 
 3 import java.io.IOException;
 4 import java.net.UnknownHostException;
 5 
 6 import de.root1.simon.Registry;
 7 import de.root1.simon.Simon;
 8 import de.root1.simon.exceptions.NameBindingException;
 9 
10 public class Server {
11 
12    public static void main(String[] args) 
13            throws UnknownHostException, IOException, NameBindingException {
14 
15       // create the serverobject
16       ServerInterfaceImpl serverImpl = new ServerInterfaceImpl();
17 
18       // create the server's registry ...
19       Registry registry = Simon.createRegistry(22222);
20 
21       // ... where we can bind the serverobject to
22       registry.bind("server", serverImpl);
23 
24       System.out.println("Server up and running!");
25 
26       // some mechanism to shutdown the server should be placed here
27       // this should include the following command:
28       // registry.unbind("server");
29    }
30 }

... last but not least: the "client":

Client.java:

 1 package de.root1.simon.codesample.client;
 2 
 3 import java.io.IOException;
 4 
 5 import de.root1.simon.Simon;
 6 import de.root1.simon.exceptions.LookupFailedException;
 7 import de.root1.simon.codesample.common.ServerInterface;
 8 
 9 public class Client {
10 
11    public static void main(String[] args) throws IOException, LookupFailedException {
12 
13       // create a callback object
14       ClientCallbackImpl clientCallbackImpl = new ClientCallbackImpl();
15 
16       // 'lookup' the server object
17       ServerInterface server = (ServerInterface) Simon.lookup("127.0.0.1", 22222, "server");
18 
19       // use the serverobject as it would exist on your local machine
20       server.login(clientCallbackImpl);
21 
22       // do some more stuff
23       // ...
24 
25       // and finally 'release' the serverobject to release to connection to the server
26       Simon.release(server);
27    }
28 }

That's all folks ... Quite easy, isn't it?