def __init__(self, processors, sendee=None, sending=True):
super(ChainProcessor, self).__init__(sendee, sending=sending)
processors = tuple(processors)
if not processors:
raise ValueError("expected at least one element in processors chain, got zero")
# front of the chain, where we push stuff
self.head = processors[0]
# create chain of processors, linking each processor's send function to
# each successor's process() function....
gb = GraphBuilder()
nodes, starts, ends = gb.add_graph(processors[0].graph)
assert len(starts) == 1 and len(ends) == 1
if len(processors) > 1:
succ_iter = iter(processors)
succ_iter.next()
for pred, succ in izip(processors, succ_iter):
pred.set_sendee(succ.process)
nodes, new_starts, new_ends = gb.add_graph(succ.graph)
gb.new_arc(ends[0], new_starts[0])
starts, ends = new_starts, new_ends
assert len(starts) == 1 and len(ends) == 1
assert succ == processors[-1]
# set up the list that will collect what the final element pushes
self.collector = list()
processors[-1].set_sendee(self.collector.append)
self._graph = FrozenGraph(gb)
