Structures · Coordination
OrderedCollection
Give one queued job to one worker without duplicate ownership.
Set the Eagle Creek problem first
The ranger queue contains one bridge inspection while three hikers request it.
Each person carries a work queue card. When a person makes a change, they copy it onto a acquire slip with the identity, path, sequence, or acceptance evidence that the rule needs. The demo shows both the local record and the note that travels.
An ordinary local edit names a position or value. That name can become
stale while another client works. Watershed's ordered_collection_kernel
uses this structure's rule to produce one shared result.
A OrderedCollection applies this rule to the shared record.
Run the conflict
Alice and Bob act before either receives the other operation. Carol stays connected as the third replica and confirms the converged view.
Three Eagle Creek clients
OrderedCollection authored race
The ranger queue contains one bridge inspection while three hikers request it.
Watershed ruleThe sequencer grants each queued item to the first accepted acquire.
Alice
Work queue card Queue: inspect bridge
Acquire slip Acquire next job requester Alice · awaits sequence
Bob
Work queue card Queue: inspect bridge
Acquire slip Acquire next job requester Bob · awaits sequence
Carol
Work queue card Queue: inspect bridge
Acquire slip Acquire next job requester Carol · awaits sequence
- Queue: inspect bridge
Enable JavaScript to run the race. The expected result remains in the lesson.
Ready: Queue: inspect bridge
Read the result
Accept one acquire. Bob and Carol cannot receive the same job.
The demo models the authored race from Watershed's public structure examples. The lesson keeps the conflict rule visible before exposing its metadata or protocol.