10.2.1 Registering the Connector Server with SLP

Example 10–1 shows the registration of a connector server's URL with the SLP lookup service's Advertiser. This code is taken from the Server class in the SLP example directory.

Example 10–1 Registering the Connector Server's Address with the SLP Advertiser

public class Server { 
   public final static int JMX_DEFAULT_LEASE = 300; 
   public final static String JMX_SCOPE = "DEFAULT"; 
 
   private final MBeanServer mbs; 
   public Server() { 
       mbs = MBeanServerFactory.createMBeanServer(); 
   } 
    
[...] 

   public static void register(JMXServiceURL jmxUrl, String name) 
     throws ServiceLocationException { 
     ServiceURL serviceURL = 
          new ServiceURL(jmxUrl.toString(), 
                         JMX_DEFAULT_LEASE); 
     debug("ServiceType is: " + serviceURL.getServiceType()); 
     Vector attributes = new Vector(); 
     Vector attrValues = new Vector(); 
     attrValues.add(JMX_SCOPE); 
     ServiceLocationAttribute attr1 = 
          new ServiceLocationAttribute("SCOPE", attrValues); 
     attributes.add(attr1); 
     attrValues.removeAllElements(); 
     attrValues.add(name); 
     ServiceLocationAttribute attr2 = 
          new ServiceLocationAttribute("AgentName", attrValues); 
     attributes.add(attr2); 
     final Advertiser slpAdvertiser = 
          ServiceLocationManager.getAdvertiser(Locale.US); 
     slpAdvertiser.register(serviceURL, attributes); 
      
   }  
 
[...] 

Examining this code excerpt, we see that the SLP lease JMX_DEFAULT_LEASE is set to a default lease of 300 seconds, which corresponds to the length of time the URL will be registered, and the initial creation of the MBean server mbs with a call to MBeanServerFactory.createMBeanServer(). In code that is not shown here, an SLP advertiser slpAdvertiser, and an SLP service URL url are defined. The slpAdvertiser is used to register the service URL in the SLP lookup service.

The service URL jmxUrl is the address of the connector server, and is obtained by a call to the getAddress() method of JMXConnectorServer when the connector server is started.

The SLP lookup attribute, namely the agent name under which the connector server address is to be registered (name), is then specified by the SLP class ServiceLocationAttribute. The AgentName attribute is mandatory, but other optional attributes, such as ProtocolType, AgentHost, and Property can also be registered in the SLP lookup service.

Finally, the JMX connector server address is registered in the SLP advertiser service with a call to the register() method of the Advertiser interface, with the serviceURL and the attributes passed in as parameters.

Now that the connector server's address has been advertised, the connector server itself is created and registered with SLP, as shown in Example 10–2.

Example 10–2 Registering the Connector Server in the SLP Lookup Service

[...] 
 
   public JMXConnectorServer rmi(String url) throws 
     IOException, 
     JMException, 
     NamingException, 
     ClassNotFoundException, 
     ServiceLocationException { 
     JMXServiceURL jurl = new JMXServiceURL(url); 
     final HashMap env = new HashMap(); 
     // Environment map attributes 
     [...] 
 
  
     JMXConnectorServer rmis = 
        JMXConnectorServerFactory.newJMXConnectorServer(jurl, env, mbs); 
     final String agentName = System.getProperty("agent.name", 
                                                 "DefaultAgent"); 
     start(rmis, agentName); 
 
     return rmis; 
  } 
 
   public void start(JMXConnectorServer server, String agentName) 
      throws IOException, ServiceLocationException { 
      server.start(); 
      final JMXServiceURL address = server.getAddress(); 
      register(address,agentName); 
   } 
    

The service URL jurl is constructed from the string url that will be included in the command used to launch the Server at the command line. An RMI connector server named rmis is then created with the system properties defined by the environment map and the address jurl.

The connector server is then started, and the RMI connector server address is registered in the SLP lookup service under the name agentName. Subsequent code not shown here creates a corresponding JMXMP connector server named jmxmp, that is also registered with the SLP service.