Easy way to start a standalone JNDI server (and register some resources)

Question

For testing purposes, I'm looking for a simple way to start a standalone JNDI server, and bind my javax.sql.DataSource to "java:/comp/env/jdbc/mydatasource" programmatically.

The server should bind itself to some URL, for example: "java.naming.provider.url=jnp://localhost:1099" (doesn't have to be JNP), so that I can look up my datasource from another process. I don't care about which JNDI server implementation I'll have to use (but I don't want to start a full-blown JavaEE server).

This should be so easy, but to my surprise, I couldn't find any (working) tutorial.

Answer 1

The JDK contains a JNDI provider for the RMI registry. That means you can use the RMI registry as a JNDI server. So, just start rmiregistry, set java.naming.factory.initial to com.sun.jndi.rmi.registry.RegistryContextFactory, and you're away.

The RMI registry has a flat namespace, so you won't be able to bind to java:/comp/env/jdbc/mydatasource, but you will be able to bind to something so it will accept java:/comp/env/jdbc/mydatasource, but will treat it as a single-component name (thanks, @EJP).

I've written a small application to demonstrate how to do this: https://bitbucket.org/twic/jndiserver/src

I still have no idea how the JNP server is supposed to work.

Answer 2

I worked on the John´s code and now is working good.

In this version I'm using libs of JBoss5.1.0.GA, see jar list below:

• jboss-5.1.0.GA\client\jbossall-client.jar
• jboss-5.1.0.GA\server\minimal\lib\jnpserver.jar
• jboss-5.1.0.GA\server\minimal\lib\log4j.jar
• jboss-remote-naming-1.0.1.Final.jar (downloaded from http://search.maven.com)

This is the new code:

import java.net.InetAddress;
import java.util.Hashtable;
import java.util.concurrent.Callable;

import javax.naming.Context;
import javax.naming.InitialContext;

import org.jnp.server.Main;
import org.jnp.server.NamingBeanImpl;

public class StandaloneJNDIServer implements Callable<Object> {

public Object call() throws Exception {

    setup();

    return null;
}

@SuppressWarnings("unchecked")
private void setup() throws Exception {

    //configure the initial factory
    //**in John´s code we did not have this**
    System.setProperty(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");

    //start the naming info bean
    final NamingBeanImpl _naming = new NamingBeanImpl();
    _naming.start();

    //start the jnp serve
    final Main _server = new Main();
    _server.setNamingInfo(_naming);
    _server.setPort(5400);
    _server.setBindAddress(InetAddress.getLocalHost().getHostName());
    _server.start();

    //configure the environment for initial context
    final Hashtable _properties = new Hashtable();
    _properties.put(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
    _properties.put(Context.PROVIDER_URL,            "jnp://10.10.10.200:5400");

    //bind a name
    final Context _context = new InitialContext(_properties);
    _context.bind("jdbc", "myJDBC");

}

public static void main(String...args){

    try{

        new StandaloneJNDIServer().call();

    }catch(Exception _e){
        _e.printStackTrace();
    }

}
}

To have good logging, use this log4j properties:

log4j.rootLogger=TRACE, A1 
log4j.appender.A1=org.apache.log4j.ConsoleAppender 
log4j.appender.A1.layout=org.apache.log4j.PatternLayout 
log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

To consume the Standalone JNDI server, use this client class:

import java.util.Hashtable;

import javax.naming.Context;
import javax.naming.InitialContext;

/**
 * 
 * @author fabiojm - Fábio José de Moraes
 *
 */
public class Lookup {

public Lookup(){

}

@SuppressWarnings("unchecked")
public static void main(String[] args) {

    final Hashtable _properties = new Hashtable();

    _properties.put("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
    _properties.put("java.naming.provider.url",    "jnp://10.10.10.200:5400");

    try{
        final Context _context = new InitialContext(_properties);

        System.out.println(_context);
        System.out.println(_context.lookup("java:comp"));
        System.out.println(_context.lookup("java:jdbc"));

    }catch(Exception _e){
        _e.printStackTrace();
    }
}

}

Answer 3

Here's a code snippet adapted from JBoss remoting samples. The code that is in the samples (version 2.5.4.SP2 ) no longer works. While the fix is simple it took me more hours than I want to think about to figure it out. Sigh. Anyway, maybe someone can benefit.

package org.jboss.remoting.samples.detection.jndi.custom;

import java.net.InetAddress;  
import java.util.concurrent.Callable;

import org.jnp.server.Main;
import org.jnp.server.NamingBeanImpl;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class StandaloneJNDIServer implements Callable<Object> { 

    private static Logger logger = LoggerFactory.getLogger( StandaloneJNDIServer.class );

   // Default locator values - command line args can override transport and port
   private static String transport = "socket";
   private static String host = "localhost";
   private static int port = 5400;
   private int detectorPort = 5400;

    public StandaloneJNDIServer() {}

    @Override
    public Object call() throws Exception {

        StandaloneJNDIServer.println("Starting JNDI server... to stop this server, kill it manually via Control-C");

        //StandaloneJNDIServer server = new StandaloneJNDIServer();
        try {
            this.setupJNDIServer();

            // wait forever, let the user kill us at any point (at which point, the client will detect we went down)
            while(true) {
                Thread.sleep(1000);
            }
        }
        catch(Exception e) {
            e.printStackTrace();
        }

        StandaloneJNDIServer.println("Stopping JBoss/Remoting server");
        return null;

    }

    private void setupJNDIServer() throws Exception
    {
        // start JNDI server
        String detectorHost = InetAddress.getLocalHost().getHostName();

        Main JNDIServer = new Main();

 // Next two lines add a naming implemention into
 // the server object that handles requests. Without this you get a nice NPE.
        NamingBeanImpl namingInfo = new NamingBeanImpl();
        namingInfo.start();

        JNDIServer.setNamingInfo( namingInfo );
        JNDIServer.setPort( detectorPort );
        JNDIServer.setBindAddress(detectorHost);
        JNDIServer.start();
        System.out.println("Started JNDI server on " + detectorHost + ":" + detectorPort );
    }

    /**
     * Outputs a message to stdout.
     *
     * @param msg the message to output
     */
    public static void println(String msg)
    {
        System.out.println(new java.util.Date() + ": [SERVER]: " + msg);
    } 
}