Listing 1: Managed part of a method invocation

object	Context.lookup( string name )
{
  //prepare the arguments
  int       hName = PinvokeHelper.toJavaString( name );

  //call the method
  string    cls = "javax/naming/Context";
  string    mname = "lookup";
  string    sig = "(Ljava/lang/String;)Ljava/lang/Object;";

  int       hResult = PinvokeHelper.callObjectMethod( this.Jobject,          
                        cls, mname, sig, hName );

  //prepare the result
  if( hResult == 0 )
    return null;
  else
    return FrameworkHelper.findBestProxyType( hResult );
}


Listing 2: PInvoke interface defined in PinvokeHelper

[DllImport("unmanagedlib")]
int  toJavaString( [MarshalAs(UnmanagedType.LPWStr)] string name );

[DllImport("unmanagedlib")]
int  callObjectMethod( int theObject,
                       [MarshalAs(UnmanagedType.LPWStr)] string cls,
                       [MarshalAs(UnmanagedType.LPWStr)] string mname, 
                       [MarshalAs(UnmanagedType.LPWStr)] string sig,
                       int arg );


Listing 3: Unmanaged part of a method invocation

extern "C" __declspec(dllexport) int __stdcall callObjectMethod(
                                                 int theObject,
                                                 LPWSTR cls,
                                                 LPWSTR mname,
                                                 LPWSTR sig,
                                                 int arg )
{
  char *	utfClassName = toUtf8( cls ); //utility function
  char *    utfMethodname = toUtf8( mname );
  char *    utfSig = toUtf8( sig );
  JNIEnv *  env = launchOrAttach(); //utility function
  jclass    clazz = env->FindClass( utfClassName );
  int	      methodID = env->GetMethodID(clazz, utfMethodname, utfSig );
  jobject   result = 0;

  result = env->CallObjectMethod( (jobject)theObject, methodID, arg );

  return result;
}

Listing 4: Configuration File XML snippet

<Codemesh>
	<JuggerNET>
		<Loader name="DefaultConfig" />
		<DefaultConfig.JvmSettings>
			<add key="Type" value="Codemesh.JuggerNET.SunJava2JvmLoader" />
			<add key="JVMPath" value="..\jre\bin\client\jvm.dll" />
			<add key="ClassPath" value="..\lib\myapp.jar" />
			<add key="MaximumHeapSize" value="256" />
		</DefaultConfig.JvmSettings>
	</JuggerNET>
</Codemesh>


Listing 5: MessageListener implementation

public class MyMessageListener : javax.jms.MessageListener
{
  public void	onMessage( Message m )
  {
    if( m is TextMessage )
	Console.WriteLine( "The message is {0}", m.getText() );
    Else
      Console.WriteLine( "Sorry, we only handle TextMessages" );
  }
}

Listing 6: MessageListener usage

public static void Main( string[] )
{
  …

  try
  {
    QueueConnectionFactory qcf = ctx.lookup( "QCF" );
    QueueConnection        qc = qcf.createQueueConnection();
    QueueSession           qs = qc.createQueueSession( false,  
                                       SessionImpl.AUTO_ACKNOWLEDGE );
    Queue                  q = ctx.lookup( "testqueue" );
    QueueReceiver          qrcv = qs.createReceiver( q );

    qrcv.setMessageListener( new MyMessageListener() );

    qc.start();

    …
  }
  catch( NamingException ne )
  {
  }
  catch( JMSException jmse )
  {
  }
  catch( Exception e )
  {
  }
}

Listing 7: Swing GUI from .NET

using System;
using Codemesh.JuggerNET;
using javax.swing;

public class SwingGUI
{
  public static void Main( string[] args )
  {
    string color = JOptionPane.showInputDialog( "Your color pick?" );

    Console.WriteLine( "Your favorite color is {0}", color );
  }
}

Listing 8: EJB access from .NET

using System;
using Codemesh.JuggerNET;
using com.codemesh.ejbtest;
using java.lang;
using java.util;
using javax.naming;

public class EJB
{
  public static void Main( string[] args )
  {
    try
    {
      InitialContext      ictx = new InitialContext();
      MyEJBHome           home = (MyEJBHome)ictx.lookup( "myejb" );

      if( home != null )
      {
        Date              date = home.getDeliveryDate();

        Console.WriteLine( "The delivery date is {0}", date );
      }
      else
        Console.WriteLine( "Couldn't find 'myejb'" );
    }
    catch( Exception e )
    {
      Console.WriteLine( "StackTrace: {0}", e.StackTrace );
      Console.WriteLine( "Message: {0}", e.Message );
    }
  }
}