communication question

Hello,

In my program, I create one NamingContextExt obj (one connection to
orbix naming server), and from that point, every object I need to
resolve - I use the same NamingContextExt.

My question: how can I know if the naming context reference is up and
valid, or if there is a communication problem and it is down?

Can I perforn a test to check the validity of the NamingContextExt
before I return the ncRef object? Are there a built in functions?
Is there some kind of special exception?

Thanks,
Asaf

P.S

My singleton which hold the NamingContextExt is:

package com.comverse.tcm.SCEConnector;

import com.comverse.tcm.vfit.ConfLoader;

import org.omg.CORBA.ORB;
import org.omg.CORBA.ShortHolder;
import org.omg.CORBA.StringHolder;
import org.omg.CORBA.UserException;
import org.omg.CosNaming.NameComponent;
import org.omg.CosNaming.NamingContextExt;
import org.omg.CosNaming.NamingContextExtHelper;
import org.omg.CosNaming.NamingContextPackage.*;

import SCE.VsCollector;
import SCE.VsCollectorHelper;

import com.comverse.model.Event;
import com.comverse.model.KeyModel;
import com.comverse.model.KeyModelInterface;
import com.comverse.model.Listener;

import com.comverse.cap.cifs.log.LogWriterIfc;
import com.comverse.cap.cifs.log.LogWriter;

public class NamingServiceHolder {

    private LogWriterIfc log =
LogWriter.getInstance(NamingServiceHolder.class);/* logger */

    private ConfLoader conf = null;

    private boolean isConnected;

	private static NamingServiceHolder instance = null;

	private static NamingContextExt ncRef = null;

    private NamingServiceHolder() {
    	isConnected = false;
    	conf = ConfLoader.getInstance();
		log.debug("Got new NamingServiceHolder");
    }

	public static NamingServiceHolder getInstance() {
		if (instance == null) {
			instance = new NamingServiceHolder();
		}
		return instance;
	}

    public boolean connect() {
		log.debug("Connecting to ORBIX server");
		String version = conf.getNamingServiceVersion();
		String ip = conf.getNamingServiceIP();
		int port = conf.getNamingServicePort();
		String namingServiceName = conf.getNamingServiceName();

		// create and initialize the ORB
		String[] array = null;
		ORB orb = ORB.init(array, null);

		// get the root naming context
		StringBuffer sb = new StringBuffer();
		sb.append("corbaloc:iiop:").append(version).append('@[EMAIL PROTECTED]
').append(ip).append(':').append(port).append('/').append(namingServiceName);
		String corbalocStr = sb.toString();
		log.debug("corbaloc String: " + corbalocStr);

		try {
		    org.omg.CORBA.Object objRef = orb.string_to_object(corbalocStr);
		    if(objRef == null) {
				log.error("Could not get object of the NamingService");
				isConnected = false;
				return false;
		    }
		    ncRef = NamingContextExtHelper.narrow(objRef);
		    log.debug("Got handle to the naming service, found ORBD");
		    isConnected = true;
			return true;
		}
		catch (org.omg.CORBA.COMM_FAILURE cf) {
		    log.error("Communication failure (probably problem with the
naming service): " + cf.toString());
		    isConnected = false;
		    return false;
		}
	}

	public NamingContextExt getNcRef() {
		return ncRef;
    }

    public boolean getIsConnected() {
		return isConnected;
    }
    
}