private ListenerSupport<Listener> getListeners(
		ConnectionType connectionType) {

		synchronized (m_listenerMap) {
			final ListenerSupport<Listener> original =
				m_listenerMap.get(connectionType);

			if (original != null) {
				return original;
			}
			else {
				final ListenerSupport<Listener> newList =
					new ListenerSupport<Listener>();

				m_listenerMap.put(connectionType, newList);
				return newList;
			}
		}
	}
Get the listener list for a particular connection type.
ngrinder-core/src/main/java/net/grinder/communication/Acceptor.java