10.3.2 Looking up the Connector Server with the Jini Lookup Service

The following code extract is taken from the Client class in the Jini lookup service examples directory.

Example 10–8 Looking up the Connector Server with the Jini Lookup Service

public class Client { 
 
   private static boolean debug = false; 
   public static ServiceRegistrar getRegistrar() 
       throws IOException, ClassNotFoundException, MalformedURLException { 
       final String jurl = 
                  System.getProperty("jini.lookup.url","jini://localhost"); 
       final LookupLocator lookup = new LookupLocator(jurl); 
       final ServiceRegistrar registrar = lookup.getRegistrar(); 
       if (registrar instanceof Administrable) 
               debug("Registry is administrable."); 
       return registrar; 
 } 
 
   public static List lookup(ServiceRegistrar registrar, 
           String name) throws IOException { 
       final ArrayList list = new ArrayList(); 
       final Class[] classes = new Class[] {JMXConnector.class}; 
       final Entry[] serviceAttrs = new Entry[] { 
           new net.jini.lookup.entry.Name(name) 
   }; 
    
   ServiceTemplate template = 
        new ServiceTemplate(null,classes,serviceAttrs); 
   ServiceMatches matches = 
        registrar.lookup(template, Integer.MAX_VALUE); 
   for(int i = 0; i < matches.totalMatches; i++) { 
        debug("Found Service: " + matches.items[i].serviceID); 
        if (debug) { 
           if (matches.items[i].attributeSets != null) { 
                   final Entry[] attrs = matches.items[i].attributeSets; 
                   for (int j = 0; j < attrs.length ; j++) { 
                       debug("Attribute["+j+"]=" + attrs[j]); 
               } 
           } 
        } 
 
 
        if(matches.items[i].service != null) { 
            JMXConnector c = (JMXConnector)(matches.items[i].service); 
            debug("Found a JMXConnector: " + c); 
            list.add(c); 
        } 
   } 
   return list; 
} 
 
[...] 

Example 10–8 shows how the connector client obtains a pointer to the Jini lookup service with a call to lookup.getRegistrar(). The client then obtains the list of the connectors registered as entries in the Jini lookup service with the agent name name. Unlike in the SLP example, the agent name you pass to Client when it is launched must be either an exact match of an existing agent name, or null, in which case the Jini lookup service will look up all the agents.

Once the list of connectors has been obtained, in code that is not shown here, the client connects to the MBean server started by Server, and retrieves the list of all the MBeans registered in it.