service — domain service scaffold

Generate the domain service that owns an entity's transaction boundary and is the only way the rest of the system touches its persistence.

Authority: AGENTS.md is binding. Review with kotlin-spring-review; tests with test-authoring.

Where it goes

• The domain module (the persistence-owning module), package com.example.domain.<domain>.service. No public keyword.
• open class <Name>Service — open so Spring can proxy @Transactional.

Skeleton (see order/service/OrderService.kt)

@Service
@Transactional(readOnly = true)
open class <Name>Service(
    private val <name>JdbcRepository: <Name>JdbcRepository,
    private val <name>Repository: <Name>EntityRepository,
) {
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    open fun bulkUpsert(models: List<<Name>>) {
        <name>JdbcRepository.upsert(models)
    }

    open fun findBy<Field>(<field>: Collection<String>): List<<Name>> {
        if (<field>.isEmpty()) return emptyList()
        return <name>Repository.findBy<Field>In(<field>).map(<Name>Mapper::toModel)
    }
}

Rules (MUST)

• open class annotated @Service. Class-level @Transactional(readOnly = true) is the default; write methods are open fun with @Transactional(propagation = Propagation.REQUIRES_NEW) (so writes self-commit, decoupled from a batch chunk's resourceless transaction or a Kafka listener context).
• Constructor injection only. Map at the boundary via the mapper; the service holds models, not entities. JSON/serialization is the service's job, not the repository's.
• Return empty collections early on empty input (avoid a needless DB hit).
• For generated single-parameter Kotlin lambdas, use it unless a nested lambda needs an explicitly named inner parameter to disambiguate scope. Preserve API-required names for multi-parameter lambdas.

Hard constraints (build/ArchUnit fail otherwise)

• No field injection (@Autowired field) anywhere under the application root package — constructor only (InjectionStyleArchTest).
• Controllers/listeners reach persistence through the service, never the repository (ControllerRepositoryAccessArchTest). Keep the service the single entry point.
• Required beans use no @ConditionalOnMissingBean — fail fast at boot if misconfigured.

Verify

Auto-detect the build system (gradle/maven/npm/pnpm/yarn) and run the domain module's compile/build task.

Related

[[entity]] · [[repository]] · [[mapper]]

Knowledge base

• reference/principles.md — service-layer constitution (transaction boundary, readOnly default, propagation, idempotency, exception translation).
• reference/kb/INDEX.md — task → KB routing table.