public DiscoveryRegistry() 
{
        SystemInstance.get().setComponent(DiscoveryRegistry.class, this);
        SystemInstance.get().setComponent(DiscoveryAgent.class, this);
}

 public DiscoveryRegistry(DiscoveryAgent agent) 
{
        SystemInstance.get().setComponent(DiscoveryRegistry.class, this);
        SystemInstance.get().setComponent(DiscoveryAgent.class, this);
        addDiscoveryAgent(agent);
}

 public  void addDiscoveryAgent(DiscoveryAgent agent) 
{
        agents.add(agent);
        agent.setDiscoveryListener(this);
        for (URI uri : registered.values()) {
            try {
                agent.registerService(uri);
            } catch (IOException e) {
            }
        }
}

 public  void addDiscoveryListener(DiscoveryListener listener) 
{
        // get the listener caught up
        for (URI service : services.values()) {
            executor.execute(new ServiceAddedTask(listener, service));
        }
        listeners.add(listener);
}

 List<DiscoveryListener> getListeners() 
{
        return Collections.unmodifiableList(listeners);
}

 public Set<URI> getServices() 
{
        return new HashSet< URI >(services.values());
}

 public  void registerService(URI serviceUri) throws IOException 
{
        registered.put(serviceUri.toString(), serviceUri);
        for (DiscoveryAgent agent : agents) {
            agent.registerService(serviceUri);
        }
}

 public  void removeDiscoveryListener(DiscoveryListener listener) 
{
        listeners.remove(listener);
}

 public  void reportFailed(URI serviceUri) throws IOException 
{
        registered.remove(serviceUri.toString());
        for (DiscoveryAgent agent : agents) {
            agent.reportFailed(serviceUri);
        }
}

 public  void serviceAdded(URI service) 
{
        services.put(service.toString(), service);
        for (final DiscoveryListener discoveryListener : getListeners()) {
            executor.execute(new ServiceAddedTask(discoveryListener, service));
        }
}

 public  void serviceRemoved(URI service) 
{
        for (final DiscoveryListener discoveryListener : getListeners()) {
            executor.execute(new ServiceRemovedTask(discoveryListener, service));
        }
}

 public  void setDiscoveryListener(DiscoveryListener listener) 
{
        addDiscoveryListener(listener);
}

 public  void unregisterService(URI serviceUri) throws IOException 
{
        registered.remove(serviceUri.toString());
        for (DiscoveryAgent agent : agents) {
            agent.unregisterService(serviceUri);
        }
}