SuperAPI AI Directory
Partner with us中文AI newsFavorites
Skillsddd4j-javalin-data

ddd4j-javalin-data

Data & analytics

View repository

Updated 10-15 21:48

About this skill

ddd4j-javalin Data

Overview

Covers MyBatis, JPA/PostgreSQL, Repository, transactions, EMF, EventStore, Projection, and Outbox uniformly. Confirm the maintenance line with ddd4j-javalin-version-selection first, then read the current branch source.

When to Use

  • Wiring MyBatis or JPA/PostgreSQL repositories, transactions, and the Repository SPI into a ddd4j-javalin service on 6.7.x, 7.1.x, or 7.2.x.
  • Assigning lifecycle ownership for the JPA EntityManagerFactory, EventStore, Projection, and Outbox, including initialization order and reverse-order rollback on partial startup failure.
  • Contributing real database availability to aggregated readiness, and wiring drain plus idempotent close for data resources.
  • Running real database round-trip tests: transactions, conflicts, Projection advancement, and Outbox delivery.

When NOT to Use

Do not use this skill when:

  • The aggregate model, Repository SPI signature, or event contracts are being designed — use ddd4j-core instead. Install: npx skills add full-stack-skills/ddd4j-skills --skill ddd4j-core.
  • Outbox message transport is the question (MQ consumers, publishers, ack/retry) — use ddd4j-javalin-mq instead. Install: npx skills add full-stack-skills/ddd4j-skills --skill ddd4j-javalin-mq.
  • Route-level payload validation or error responses are the question — use ddd4j-javalin-web instead. Install: npx skills add full-stack-skills/ddd4j-skills --skill ddd4j-javalin-web; for lifecycle participant mechanics use ddd4j-javalin-runtime.
  • A cross-capability review or release gate is needed — use ddd4j-javalin-production-hardening instead. Install: npx skills add full-stack-skills/ddd4j-skills --skill ddd4j-javalin-production-hardening.
  • Spring Boot, Quarkus, or Spring Cloud data wiring is the question — use ddd4j-boot-data, ddd4j-quarkus-data, or ddd4j-cloud-data instead, for example Install: npx skills add full-stack-skills/ddd4j-skills --skill ddd4j-boot-data.
  • The project is generic JPA/MyBatis without ddd4j — do not use this skill; use java-skills instead, since the ddd4j Repository/EventStore contracts do not exist there.

Trigger Keywords

English: MyBatis, JPA, PostgreSQL, repository, transactions, EventStore, Outbox, EntityManagerFactory

Chinese: MyBatis, JPA, PostgreSQL, Repository, transactions, EventStore, Outbox, data source integration

Core Scope

MyBatis, JPA/PostgreSQL, Repository, transactions, EMF, EventStore, Projection, Outbox.

Core Rules

  1. 6.7.x, 7.1.x, and 7.2.x each keep their own Javalin/JDK/Maven/POM contract.
  2. Javalin 6 versus 7 API differences are aligned by behavior, not copied mechanically.
  3. Report configuration, startup, HTTP, containers, CI, and publishing in layers.
  4. Context/Subject/resources are cleaned on success, exception, and async terminal states.
  5. Production dependencies need real readiness, shared CAS, explicit CORS, and idempotent close.

Capability Boundaries

✅ Strong At

  • Implementation choice for data access and Javalin adaptation.
  • Lifecycle, configuration, and behavior boundaries.
  • Differences across the three maintenance lines.

⚠️ Needs Input

  • Target branch, POM, and Javalin version.
  • Business behavior, dependencies, and deployment mode.
  • Current source/test/CI evidence.

❌ Out of Scope

  • Copying Javalin 6 code directly to 7.
  • Substituting smoke tests for real behavior.
  • Unauthorized releases or production changes.

Workflow

Step 1: Confirm the source of truth

Fix the maintenance line with ddd4j-javalin-version-selection, then locate the data module, its EntityManagerFactory wiring, and the database tests in the current checkout.

Step 2: Select the access stack

Choose MyBatis or JPA/PostgreSQL and confirm the Repository implementations and transaction boundaries. Confirm the initialization order of EventStore, Projection, and Outbox against the aggregate lifecycle.

Step 3: Manage the data lifecycle

Confirm the EntityManagerFactory, schedulers, and listeners each have exactly one owner registered as a lifecycle participant. Verify drain, idempotent close, and that the database contributes to aggregated readiness.

Step 4: Test with a real database

Run real database round-trips — transactions, conflicts, Projection advancement, Outbox delivery — plus startup failure and rollback behavior. In-memory substitutes and skipped containers must be reported as BLOCKED/SKIPPED, not green.

Step 5: Report the data state

Produce a single report: chosen stack with configuration keys and connection handling, lifecycle owners and shutdown order, tests executed with evidence state per tier, and risks with proposed fixes and missing inputs.

Gotchas

  • The JPA EntityManagerFactory must have exactly one lifecycle owner — two owners close it twice, zero owners leak it across embedded-test restarts.
  • A Repository method existing on the interface is not behavior: an unoverridden default method surfaces as UnsupportedOperationException from the registered adapter at first use.
  • Outbox delivery and the business transaction are separate concerns — a DB commit never proves the event was delivered, and an MQ ack never proves the row committed.
  • Readiness must reflect real database availability; a hardcoded READY converts a DB outage into request storms instead of load-shedding.
  • EMF/EventStore/Projection/Outbox initialization order decides rollback on partial failure — a later participant failing must close the earlier ones in reverse order.
  • The maintenance lines do not change MyBatis/JPA semantics, but the per-line JDK contract does — 7.2.x-only Java syntax must not leak into the 6.7.x/7.1.x baselines.

Output and Exceptions

When input is missing, output "missing: target line/implementation/configuration; how to provide: supply the POM and acceptance behavior", and continue safe read-only checks.

Deep Reference

Privacy and Security

Never output tokens, cookies, OIDC secrets, or database or private repository credentials.

This skill does not access, collect, store, or transmit any user data, credentials, or keys; database examples use only desensitized fictitious data.

Quick Start

  • "Use $ddd4j-javalin-data to analyze the implementation and configuration my current project should adopt."
  • "Use $ddd4j-javalin-data to review existing usage against the current source."
  • "Use $ddd4j-javalin-data to return an implementation choice, evidence state, and remaining risk."

Audience and Customization

  • Developers: provide the target maintenance line, POM, capabilities, and acceptance behavior.
  • Architects: specify a read-only boundary review, compatibility, or migration target.
  • Testers / release engineers: specify the required evidence levels; do not auto-expand to release or production operations.

Customize the target framework, allowed implementations, excluded modules, compatibility requirements, and output evidence level. When input is insufficient, give a tentative verdict first, then list "missing: specific item; how to provide: required path or configuration".

FAQ

  1. Are skills organized by Maven artifact? No — by the user-facing capability domain.
  2. Can I copy another maintenance line directly? No — verify the version and source first.
  3. Does a class existing in source prove the capability works? No — registration and behavior evidence are also required.
  4. How do I report tests that did not run? Mark NOT RUN or BLOCKED.
  5. Can the skill commit or release automatically? Only after explicit user authorization.
  6. What if the implementation is missing? Describe the missing module or evidence; do not invent APIs.