Two roles of user objects

• Supplier vs. Consumer

  • who has data and who wants data
  • data always go from suppliers to consumers

• Active vs. Inactive participant

  • active guys (“PullConsumer” and “PushSupplier”) do not need many methods because they actively call methods of passive guys
  • passive guys (“PushConsumer” and “PullSupplier”) need to have methods that are called; they are designed as “callback” objects

Notes: