class Element:
def __init__(self):
self.downstream_elements = CList()
- self.upstream_elements = CList()
self.master = None
self.source = None
self.master = downstream
def connectUpstream(self, upstream):
- self.upstream_elements.append(upstream)
- self.source = upstream # for single-source elements (i.e., most of them.)
+ assert self.source is None
+ self.source = upstream
self.changed()
def connect(self, upstream):
# we should not disconnect from upstream if
# there are still elements depending on us.
assert len(self.downstream_elements) == 0, "there are still downstream elements left"
-
- # disconnect all upstream elements from us
- for upstream in self.upstream_elements:
- upstream.disconnectDownstream(self)
+ self.source.disconnectDownstream(self)
def disconnectDownstream(self, downstream):
self.downstream_elements.remove(downstream)
# default action: push downstream
def changed(self, *args, **kwargs):
self.downstream_elements.changed(*args, **kwargs)
+
+ def reconnectUpstream(self, new_upstream):
+ assert self.source is not None
+ self.source = new_upstream
wrap_around = property(lambda self: self.__wrap_around, setWrapAround)
def selectionChanged(self):
- self.upstream_elements.selectionChanged(self.index)
+ self.source.selectionChanged(self.index)
def getIndex(self):
if self.instance is None: