DCB States

Tracking Sequence

Tracking v3 incorporates polling at intervals based on current state, to reflect that some states should move quickly and others (such as LOANED) are unlikley to move for significant elapsed time.

This allows DCB to spread the load of circulation polling to improve system performance when dealing with several thousand in-flight requests.

See reference matrix at https://openlibraryfoundation.atlassian.net/wiki/spaces/DCB/pages/2870575137 .

State Model Diagrams

• The state model is generated using GraphViz

• The raw dot file can be found at https://dcb-dev.sph.k-int.com/statemodel/diagram/dot

• Images can be found at

  • https://dcb-dev.sph.k-int.com/statemodel/diagram/svg

  • https://dcb-dev.sph.k-int.com/statemodel/diagram/png

Prior State Model Iterations

Patron Request States

• SUBMITTED_TO_DCB - the patron has requested an item, it has been submitted to DCB

• PATRON_VERIFIED - the request has passed the validation phase

• RESOLVED - We’ve located an item

• NO_ITEMS_AVAILABLE_AT_ANY_AGENCY

• REQUEST_PLACED_AT_SUPPLYING_AGENCY - a request has been placed at the supplying agency

• REQUEST_PLACED_AT_BORROWING_AGENCY - a request has been placed for tracking at the patrons home system

• ERROR - There was an error

Supplier Request States

• PENDING - Hold placed, waiting for confirmation

• PLACED - Hold placed - we know the ID of the hold and the item

Fallback States

Context - see Slack

Broadly speaking, that will likely be something like:

• Available -> AVAILABLE

• Checked out -> CHECKED_OUT

• Unknown -> UNKNOWN

• Everything else to UNAVAILABLE

• No status (which shouldn’t happen) to Unknown

There are some quirky statuses that folks might want different mappings for:

• On order

• In process (because of the presence of In process (non-requestable) which implies the other kind of in process allows requests)

• In transit (which is ambiguous because we don’t know why it’s in transit)

• Intellectual item  (because I don’t know what that means)

The full list of statuses can be found here

State Models in DCB