if (output == null)
if (outputChannel == null)
    public void connectGraph()    {        // do I even have anything to do?        if (srcs.isEmpty())            return;        // yep, create an input array of appropriate size        input = new Channel[srcs.size()];        // yep, go through my members and connect them all with        // ChannelConnectFilter        int inputIndx = 0;        ListIterator iter = srcs.listIterator();        while (iter.hasNext())            {                // connect the input streams:                Stream s = (Stream)iter.next();                // it is possible for a stream to be null - if I'm doing a                // weighted joiner and I really don't have the stream!                if (s != null)                    {                        s.setupOperator();                        // retrieve the output of this filter, which will be an                        // input to this joiner                        Channel channel = s.getOutputChannel();                        input[inputIndx] = channel;                        // if it is not a sink, make sure that it produces data                        // of the same kind as everything else in this Joiner                        if (channel != null)                            {                                // handle input channel                                if (output == null)                                    {                                        output = new Channel(channel);                                        output.setSource(this);                                    }                                else                                    {                                        // check that the input types agree                                        assert channel.getType().getName().equals(                                                                                  output.getType().getName());                                    }                                // now connect the channel to me                                channel.setSink(this);                            }                    }                inputIndx++;            }    }