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Overview

Direct Consortial Borrowing requests go through a largely deterministic sequence once successfully received:

  1. Preliminary States - ensure we have good data to propagate requests in downstream systems

    1. SUBMITTED_TO_DCB

    2. PATRON_VERIFIED

    3. RESOLVED

  2. Circulation Tracking - to track and synchronise downstream systems

    1. REQUEST_PLACED_AT_SUPPLYING_AGENCY

    2. CONFIRMED

    3. REQUEST_PLACED_AT_BORROWING_AGENCY

    4. PICKUP_TRANSIT

    5. RECEIVED_AT_PICKUP

    6. READY_FOR_PICKUP

    7. LOANED

    8. RETURN_TRANSIT

  3. Finishing States - to terminate and clean up traces of finished requests where possible

    1. Preliminary Finishing

      1. NOT_SUPPLIED_CURRENT_SUPPLIER

      2. NO_ITEMS_AVAILABLE_AT_ANY_AGENCY

    2. Circulation FInishing

      1. CANCELLED

    3. Happy Path Finishing

      1. COMPLETED

      2. FINALISED

    4. Unexpected Termination

      1. ERROR

Preliminary States

The initial sequence of states that a request goes through to verify a patron’s identity and resolve to an selectable item.

  • Until it completes this deterministic sequence, the request only exists in DCB and not in downstream systems.

  • There is no polling in these states.

DCB STATE

Max backoff / Next Poll interval / Next Step

DEV / TEST

Max backoff / Next Poll interval / Next Step

LIVE NOT USED

What tracking for next step in 2l process

What tracking for next step in 3l process

SUBMITTED_TO_DCB

None

None

Auto Triggers ValidatePatronTransition

Moves us to PATRON_VERIFIED

PATRON_VERIFIED

None

None

Auto Triggers PatronRequestResolutionStateTransition

Moves us to RESOLVED

RESOLVED

None

None

Auto Triggers PlacePatronRequestAtSupplyingAgencyStateTransition

Moves us to REQUEST_PLACED_AT_SUPPLYING_AGENCY

Circulation States

When a request has gone through preliminary verification and resolution states DCB attempts to place, update and track its progress in downstream systems.

  • Once the initial circulation state is entered, polling is triggered to handle state transitions based on the criteria defined

  • A request is expected to transition through each state in the given circulation sequence

    • this is the “happy path”

  • In rare scenarios, DCB may not always pick up all state transitions, depending on downstream system processing and polling intervals

    • in this case the request is flagged as out of sequence

    • this is not always fatal for a request - and they are often picked up again when they are in RETURN TRANSIT, the loan to patron having been skipped by DCB

DCB STATE

Max backoff / Next Poll interval / Next Step

DEV / TEST

Max backoff / Next Poll interval / Next Step

LIVE NOT USED

What tracking for next step in 2l process

What tracking for next step in 3l process

REQUEST_PLACED_AT_SUPPLYING_AGENCY

10ms

10ms

wait for SupplierRequest= CONFIRMED | TRANSIT → HandleSupplierRequestConfirmed

Moves us into the CONFIRMED state

CONFIRMED

10m

10m

Auto Triggers

PlacePatronRequestAtBorrowingAgencyStateTransition

Moves us to REQUEST_PLACED_AT_BORROWING_AGENCY

REQUEST_PLACED_AT_BORROWING_AGENCY

10m

1h

wait for SupplyingItem State = TRANSIT ->

HandleSupplierInTransit

Moves us to PICKUP_TRANSIT

PICKUP_TRANSIT

10m

1h

wait for BorrowingItem = RECEIVED | LOANED | ON_HOLD_SHELF Then

HandleBorrowerItemReceived moves us to RECEIVED_AT_PICKUP

RECEIVED_AT_PICKUP

10m

1h

wait for BorrowingItem = ON_HOLD_SHELF | LOANED

Then

HandleBorrowerItemOnHoldShelf moves us to READY_FOR_PICKUP

READY_FOR_PICKUP

10m

1h

wait for BorrowingItem = LOANED Then

HandleBorrowerItemLoaned moves us to LOANED

LOANED

10m

6h

wait for BorrowingItem = AVAILABLE | TRANSIT OR SupplierItem=AVAILABLE | SupplierRequest=CLOSED Then

HandleBorrowerRequestReturnTransit moves us to RETURN_TRANSIT

N.b. CLOSED==FOLIO Specific

N.b. Additional check needed here - item loaned other

RETURN_TRANSIT

10m

1h

SupplierItem = AVAILABLE | SupplierRequest=CLOSED Then

HandleSupplierItemAvailable moves us to COMPLETED

N.b. CLOSED==FOLIO Specific

N.b. Additional check needed here - item loaned other

Finishing States

When a request completes its cycle, or if it terminates prematurely, it enters a finishing state.

  • In most cases this indicates the end of the request, resulting in a finishing sequence

    • in the future, NOT_SUPPLIED_CURRENT_SUPPLIER will trigger a re-request

  • The finishing sequence may or may not involve clean up of virtual records, depending on whether the request

DCB STATE

Max backoff / Next Poll interval / Next Step

DEV / TEST

Max backoff / Next Poll interval / Next Step

LIVE NOT USED

What tracking for next step in 2l process

What tracking for next step in 3l process

Preliminary Finishing (follows a preliminary state before a request enters tracked circulation)

NOT_SUPPLIED_CURRENT_SUPPLIER

None

None

DCB-1230:

Auto Triggers: ResolveNextSupplierTransition

Moves us to NO_ITEMS_AVAILABLE_AT_ANY_AGENCY

NO_ITEMS_AVAILABLE_AT_ANY_AGENCY

None

None

TERMINAL STATE (For now)

Circulation Finishing (interrupts tracked circulation, and is typically manually instigated)

CANCELLED

None

None

DCB-1289:

Auto Triggers: FinaliseRequestTransition

moves us to FINALISED

Happy Path Finishing (follows directly after the end of tracked circulation)

COMPLETED

None

None

Auto Triggers: FinaliseRequestTransition

moves us to FINALISED

FINALISED

None

None

TERMINAL STATE

TERMINAL STATE

Unexpected Termination (can happen at any stage)

ERROR

None

None

TERMINAL STATE

TERMINAL STATE

Explanatory Notes

  • Max backoff / Next Poll interval / Next Step (see table below)

    • None: no downstream polling will happen

    • Time: add time period to now to calculate “Check Due Time” (not called that in code) when the next check should happen

  • Polling interval : (configured at an environment level in dcb-service config):

    • indicates how often to trigger a polling cycle generally, and then within each cycle, only check those items with states that have passed a Check Due Time

  • Force check update: check now regardless of Check Due Time

Changes

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