code: public boolean addMessagingClientFactory(IMessagingClientFactory factory) {
  
  		final String type = factory.getType();
  		this.logger.fine("Adding messaging client factory: " + type);
  		final boolean result = this.factories.putIfAbsent(type, factory) == null;
  		if (result)
  			notifyListeners(factory, true);
  
  		return result;
  	}
docs: Adds a messaging client factory to this registry, unless a similar one was already registered.
  @param factory the messaging client factory to add.
  @return {@code true} if the factory has been added, {@code false} if a factory with the same type was already registered.