code: @Override
  	public void shutdown(IAggregator aggregator) {
  		final String sourceMethod = "shutdown"; //$NON-NLS-1$
  		final boolean isTraceLogging = log.isLoggable(Level.FINER);
  		if (isTraceLogging) {
  			log.entering(sourceClass, sourceMethod, new Object[] { aggregator });
  		}
  		aggregator = null;
  		for (IServiceRegistration reg : registrations) {
  			reg.unregister();
  		}
  		registrations.clear();
  
  		if (isTraceLogging) {
  			log.exiting(sourceClass, sourceMethod);
  		}
  	}
docs: /* (non-Javadoc)
  @see com.ibm.jaggr.core.IShutdownListener#shutdown(com.ibm.jaggr.core.IAggregator)