The Observer pattern
Our worst fear is becoming a reality. Bumble Bikes has become so popular that Kitty and Phoebe are starting to have logistics problems. “Don’t get me wrong,” Phoebe said. “This is a good problem to have. We could be more profitable if we could optimize our shipping costs. The hardest part is the first mile. How can we be more efficient at getting our bikes to a national shipper’s depot?” Kitty arranged a Zoom call with ExFed, a small business owner who provides packing and shipping support as a service. Cathy, the ExFed representative near Phoebe’s factory in Dallas, and John, the representative based in Alpine, where Kitty’s factory was located, listened carefully to Bumble Bikes’ predicament.
“The key to a good logistics workflow,” Cathy said, “is to make sure every time a truck leaves your factory, it’s full of bikes. When the truck comes back, it should be full of...
