import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.Naming;
import java.rmi.MarshalledObject;
import java.rmi.activation.*;
import java.util.Properties;
import java.lang.Thread;
import java.lang.Runnable;
import java.io.File;
import java.io.FileInputStream;
import java.io.ObjectInputStream;

public class ActivatableWrapper extends Activatable 
   implements ActivatableUninstall, Runnable 
{
   private Thread t = null;
   protected long IDLE_TIME_IN_MINUTES = 1;

   public ActivatableWrapper(ActivationID id, 
      MarshalledObject data) 
   throws RemoteException 
   {
   // Register the object with the activation
   // system then export it on an
   // anonymous port
   super(id, 0);
   restore(data);
   t = new Thread(this);
   t.start();
   }

   // @param classname
   // The name of the class that implements
   // the remote interface(s) and extends the
   // java.rmi.activation.Activatable class 
   // @param codebase
   // A URL from where the class definition
   // will come when this object is requested
   // (activated). Important: don't forget
   // the trailing slash at the end of the
   // URL or your classes won't be found. 
   // @param policyfile
   // Because of the Java 2 security model, a
   // security policy should be specified for
   // the ActivationGroup Virtual Machine that will be
   // started by rmid.
   // @return 
   // The stub or null
   static public Remote install(String classname, String 
      codebase, String policyfile, MarshalledObject data)
   {
   try
   {
      Properties props = new Properties();
      props.put("java.security.policy",policyfile);

      // Create a new activation group descriptor
      ActivationGroupDesc.CommandEnvironment ace = null; 
      ActivationGroupDesc group = new 
         ActivationGroupDesc(props,ace);

      // Once the ActivationGroupDesc has been created, 
      // register it with the activation system to 
      // obtain its ID
      ActivationGroupID gid = 
         ActivationGroup.getSystem().registerGroup(group);

      // Now we need to explicitly create the group
      ActivationGroup.createGroup(gid,group,0);

      // Register the rmiobject with rmid
      // Auto restart
      ActivationDesc desc = 
         new ActivationDesc(gid,classname,codebase,data,true);

      // return a stub.
      return Activatable.register(desc);
   }
   catch(Exception e)
   {
      e.printStackTrace();
   }

   return null;
   }

  // The ActivatableShutdown interface implementation
   public boolean uninstall() throws RemoteException
   {
   return deactivate(true);
   }

   public void run()
   {
   while(true)
   {
      try
      {
      Thread.sleep(IDLE_TIME_IN_MINUTES*60000);
      boolean b = deactivate();
      if(b)
      {
         System.out.println("Deactivated object...");
         return;
      }
      }
      catch(Exception e)
      {
      System.out.println("Granted new life...");
         }
   }
   }

   protected void grantNewLife()
   {
   t.interrupt();
   }

   protected boolean deactivate()
   {
   return deactivate(false);
   }

   protected boolean deactivate(boolean forever)
   {
   try
   {
      if(forever)
      {
      Activatable.unregister(this.getID());
      return true;
      }
      else
      {
      return Activatable.inactive(this.getID());
      }
   }
   catch(Exception e)
   {
      e.printStackTrace();
      return false;
   }
   }

   private void restore(MarshalledObject data)
   {
   if(data == null)
      return;
   try
   {
      Object o = data.get();
      if(o instanceof java.lang.String)
      {
      String filename = (String)o;
      System.out.println("Recreating RMI Registry binding from
	     file:" + filename);
      File f = new File(filename);
      if(f.exists())
      {
         ObjectInputStream ois = new ObjectInputStream(
            new FileInputStream(f));
         String objectname = (String)ois.readObject();
         Remote stub = (Remote)ois.readObject();
         Naming.rebind(objectname, stub);
      }
      }
      else
      {
      System.out.println("Error: Corrupt data...");
      }
   }
   catch(Exception e)
   {
      e.printStackTrace();
   }
   }
}