Visual Companions
Visual companions explain the scenario, design decisions, implementation structure, execution path, and technical problems of representative examples. The source repository and its Markdown designs remain the implementation reference.
Clinic appointment
clinic-appointment
Reference application designs for product composition, scheduling policies, appointment plans, and capacity management.
See how appointment plans, slot generation, capacity changes, and booking decisions remain consistent.
Open visual companion Clinic appointment Scheduling Policy FoundationFollow the scheduling policy model from source rules to validation, conflicts, and operational changes.
Open visual companion Clinic appointment Profile Change Reservation ReevaluationTrace a minimal profile-change event through fair dispatch, state decisions, and privacy-safe recovery for in-progress reservations.
Open visual companion Clinic appointment Product Scheduling ClassificationClassify product traits, separate product duration from clinic capacity, and inspect the validated booking contract.
Open visual companion Clinic appointment Package Product CompositionCompare repeated, composite, and choose-M-of-N packages while preserving item-level time, resources, and dependencies.
Open visual companion Clinic appointment Execution BOM to Appointment FlowFollow an immutable execution BOM through plan revisions, visit candidates, proposals, consent, and confirmed resource allocation.
Open visual companionbluetape4k workshop
bluetape4k-workshop
Complex example applications that connect domain decisions with event sourcing, concurrency control, payment, inventory, leader election, and recovery.
Trace voucher issuance and redemption through commands, immutable events, projections, and recovery.
Open visual companion bluetape4k workshop Concert Ticket Flash SaleFollow inventory, payment, refund, and ticket processing until the purchase reaches a consistent outcome.
Open visual companion bluetape4k workshop Kafka Outbox FallbackCompare how direct Kafka publication, timeout ambiguity, fallback persistence, relay recovery, and dead-letter handling change API, database, and event states.
Open visual companion bluetape4k workshop Leader Job Safety LabCompare lease overruns, network partitions, mixed-version rollouts, and non-fenceable effects to see where fencing tokens and idempotency stop stale work.
Open visual companionExposed workshop
exposed-workshop
Runnable examples of cache strategies built with Exposed and Redis, plus DDD boundaries verified with Spring Modulith.
Compare cache reads, updates, invalidation, and deferred database persistence across the local cache, Redis, and Exposed.
Open visual companion Exposed workshop DDD Modulith BoundariesSee how orders and shipping own separate persistence and communicate only through a published event contract.
Open visual companionbluetape4k leader
bluetape4k-leader
Distributed leader election with Redis/Lettuce locks, leases, takeover, bounded group capacity, and Spring Boot integration.
Follow one Redis-backed leader through lock acquisition, token ownership, lease expiry, takeover, auto-extension, and Spring interception.
Open visual companion bluetape4k leader LeaderGroupElector Slot CapacitySee how single-leader election expands to N lease-backed slots, including capacity, saturation, expiry, and later admission.
Open visual companionbluetape4k Exposed
bluetape4k-exposed
JetBrains Exposed extensions that make JDBC and R2DBC transaction ownership, repository boundaries, and framework integration explicit.
Compare JPA/Hibernate with Exposed, then trace caller-owned JDBC and coroutine R2DBC transaction boundaries across single- and multi-repository flows.
Open visual companion bluetape4k Exposed Spring Boot Exposed ActivationExplore the Spring Boot conditions that activate JDBC and R2DBC Exposed mappings, and the application-owned resources each path still requires.
Open visual companion