code: public FutureOperation subscribeTicker(final BitfinexTickerSymbol tickerSymbol) 
  			throws BitfinexClientException {
  		
  		final FutureOperation future = new FutureOperation(tickerSymbol);
  		pendingSubscribes.registerFuture(future);
  		
  		final SubscribeTickerCommand command = new SubscribeTickerCommand(tickerSymbol);
  		client.sendCommand(command);
  		
  		return future;
  	}
docs: Subscribe a ticker
  @param tickerSymbol
  @return
  @throws BitfinexClientException