--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/dancres/jini/util/ServiceLocator.java	Sat Mar 21 11:00:06 2009 +0000
@@ -0,0 +1,172 @@
+package org.dancres.jini.util;
+
+import net.jini.lookup.entry.Name;
+import net.jini.core.entry.Entry;
+import net.jini.discovery.DiscoveryListener;
+import net.jini.discovery.DiscoveryEvent;
+import net.jini.discovery.LookupDiscovery;
+import net.jini.core.discovery.LookupLocator;
+import net.jini.core.lookup.ServiceRegistrar;
+import net.jini.core.lookup.ServiceTemplate;
+import java.rmi.RMISecurityManager;
+import java.rmi.RemoteException;
+
+/** 
+ * ServiceLoactor is a simple wrapper class over Jini's LookupDiscover.
+ * It which returns the first matching instance of a service either via
+ * unicast or multicast discovery
+ */
+
+public class ServiceLocator{
+
+    static {
+        if (System.getSecurityManager() == null) {
+            System.setSecurityManager(new RMISecurityManager());
+        }
+    }
+
+    private Object _proxy;
+    private Object _lock=new Object();
+    private ServiceTemplate _template;
+
+    /**
+     *  Locates a service via Unicast discovery
+     * @param lusHost The name of the host where a Jini lookup service is running
+     * @param serviceClass The class object representing the interface of the service
+     * @throws MalformedURLException
+     * @throws IOException
+     * @throws ClassNotFoundException
+     * @return The proxy to the discovered service  
+     */    
+    public static Object getService(String lusHost,Class serviceClass)
+        throws java.net.MalformedURLException,java.io.IOException,ClassNotFoundException{
+    
+        LookupLocator loc=new LookupLocator("jini://"+lusHost);
+        ServiceRegistrar reggie=loc.getRegistrar();
+        ServiceTemplate tmpl=new ServiceTemplate(null, new Class[]{serviceClass},null);
+        return reggie.lookup(tmpl);
+        
+    }
+    /**
+     *
+     * @param lusHost
+     * @param serviceClass
+     * @param serviceName
+     * @return proxy or <code>null</code>
+     * @throws java.net.MalformedURLException
+     * @throws java.io.IOException
+     * @throws ClassNotFoundException
+     */
+    public static Object getService(String lusHost,Class serviceClass,
+                                    String serviceName)
+        throws java.net.MalformedURLException,java.io.IOException,
+               ClassNotFoundException{
+
+        Class [] types=new Class[]{serviceClass};
+        Entry [] entry=null;
+
+        if(serviceName!=null){
+            entry=new Entry[]{new Name(serviceName)};
+        }
+
+        ServiceTemplate _template = new ServiceTemplate(null,types,entry);
+        LookupLocator loc=new LookupLocator("jini://"+lusHost);
+        ServiceRegistrar reggie=loc.getRegistrar();
+
+        return reggie.lookup(_template);
+    } 
+    /**
+     * Locates the first matching service via multicast discovery
+     * @param serviceClass The class object representing the interface of the service
+     * @throws IOException
+     * @throws InterruptedException
+     * @return  */    
+    public static Object getService(Class serviceClass)
+        throws java.io.IOException,InterruptedException{
+            
+        return getService(serviceClass,null,Long.MAX_VALUE);    
+    }
+    /**
+     * Locates the first matching service via multicast discovery
+     * @param serviceClass The class object representing the interface of the service
+     * @param waitTime How to wait for the service to be discovered
+     * @throws IOException
+     * @throws InterruptedException
+     * @return  */    
+    public static Object getService(Class serviceClass,long waitTime)
+        throws java.io.IOException,InterruptedException{
+            
+        return getService(serviceClass,null,waitTime);    
+    }
+    /**
+     * Locates the first matching service via multicast discovery
+     * @param serviceClass The class object representing the interface of the service
+     * @param serviceName The Name attribute of the service
+     * @throws IOException
+     * @throws InterruptedException
+     * @return  */    
+    public static Object getService(Class serviceClass,String serviceName,long waitTime)
+        throws java.io.IOException,InterruptedException{
+    
+        ServiceLocator sl=new ServiceLocator();
+        return sl.getServiceImpl(serviceClass,serviceName,waitTime);
+    }
+
+   
+    private Object getServiceImpl(Class serviceClass,String serviceName,long waitTime)
+        throws java.io.IOException,InterruptedException{
+        
+                
+         Class [] types=new Class[]{serviceClass};        
+         Entry [] entry=null;
+         
+         if(serviceName!=null){
+            entry=new Entry[]{new Name(serviceName)};
+        }
+
+         _template=new ServiceTemplate(null,types,entry);
+
+        LookupDiscovery disco=
+            new LookupDiscovery(LookupDiscovery.ALL_GROUPS);
+
+        disco.addDiscoveryListener(new Listener());
+        
+                
+        
+       synchronized(_lock){
+            _lock.wait(waitTime);               
+       }
+       
+		disco.terminate();
+		if(_proxy==null){
+			throw new InterruptedException("Service not found within wait time");
+		}
+		return _proxy;
+        
+    }
+     class Listener implements DiscoveryListener {
+        //invoked when a LUS is discovered       
+        public void discovered(DiscoveryEvent ev) {
+            ServiceRegistrar[] reg = ev.getRegistrars();
+            for (int i=0 ; i<reg.length && _proxy==null ; i++) {
+                findService(reg[i]);
+            }
+        }
+             
+        public void discarded(DiscoveryEvent ev) {
+        }
+    }
+     private void findService(ServiceRegistrar lus) {
+        
+        try {
+            synchronized(_lock){               
+                _proxy=lus.lookup(_template);
+                if(_proxy!=null){                 
+                    _lock.notifyAll();
+                }
+            }
+        }catch(RemoteException ex) {           
+            ex.printStackTrace(System.err);
+        }
+    }
+}