Lab JK SB Fulfillment
John's alternate state machine for fulfillment:
The broker object gets its own set of suspend and cancel related states as well (not shown). From these state transitions, we can derive a new set of roles and exchanges. Roles: Placer Places the original request, and waits for it to be complete. May have an order manager Broker Chooses a lab, or holds the request until the patient chooses a lab. May mediate communications subsequently Fulfiller Accepts the request, and then carries out the activities to fulfill what was asked
Initiator Name Information Request State Transitions Promise State Transition Before After Before After Placer Request Request identity Patient identity Clinician Identity Test list Initial Seeking Initial Deciding Placer Modify Request identity Patient Identity New Test list No change No Change – either Accept or Reject needed Placer Suspend Request identity Patient Identity Waiting Suspended In Progress Suspended Placer Unsuspend Request identity Patient Identity Suspended Waiting Suspended In Progress Placer Cancel Request Identity Patient Identity Reason No change No Change – either Accept or Reject needed Fulfiller Refusal Request Identity Patient Identity Reason for Refusal Seeking Refused Deciding Rejected Fulfiller Accept Request Identity Patient Identity Predicted Delivery Time? Seeking Waiting Deciding Working Fulfiller Accept Modify Request Identity Patient Identity Waiting | Complete Waiting In Progress | Complete In Progress Fulfiller Reject Modify Request Identity Patient Identity Reason No Change No Change Fulfiller Accept Cancel Request Identity Patient Identity Waiting Canceled In Progress Canceled Fulfiller Reject Cancel Request Identity Patient Identity Reason No Change No Change Fulfiller Complete Request Identity Patient Identity Waiting Complete Working Complete Fulfiller Failed Request Identity Patient Identity Reason for Failure Waiting Aborted Waiting Failed
The broker plays the roles of both placer and fulfiller. It has the same exchanges, though the state transitions and the consequential workflow differ. However there are few broker specific exchanges. In the mode where the broker holds the request waiting for a patient to attend a laboratory, we need an exchange to allow the laboratory to find any outstanding requests for that patient. For the broker mode where the broker holds an auction for the request, we could implement it using the exchanges described above, but that leads to an odd workflow. Given the exchanges above, when the broker receives a request, it would hand the request on to all participants of the auction, who would all then ‘accept’ the request. The broker would pick the best offer, and cancel all the others. Perhaps the others may refuse to cancel, but that would be pretty pointless. This is possible, but it doesn’t really match what’s going on, and it’s going to at least cause confusion for the implementers. So it’s better to define specific exchanges. Initiator Name Information Promise State Transitions Broker State Transition Before After Before After Fulfiller Query Patient identity Initial Searching No Change Broker Query Response Patient identity (Request Info)n No Change No Change Broker Auction Request identity Patient identity Clinician Identity Test list Initial Costing No Change Placer Bid Request identity Cost Costing Bid Wait for outcome of Auction
