DataPort port = portItr.next();
for (Iterator<DataEdge> edgeItr = port.getEdges().iterator(); edgeItr.hasNext();) {
DataEdge edge = edgeItr.next();
// Remove the edge from from-port.
DataPort fromPort = edge.getFromPort();
fromPort.removeEdge(edge);
// remove the edge from this port. This is necessary so that
// type update works properly.
edgeItr.remove();
// Remove the edge from the graph.