Internals · Vidocq

For contributors: where the code lives and the rules it obeys. Users never need this page — the public surface is the Jakarta Validation API, nothing else.

Reactor layout

Module Purpose

Module	Purpose
`erasmus-api`	Aggregator that re-exposes the spec (`requires transitive jakarta.validation`). No forked API classes.
`erasmus-core`	The engine: bootstrap, metadata, 21 of the 22 built-in constraints (38 validators — `@Null` pending), interpolation.
`erasmus-codegen-apt`	APT processor generating per-bean static constraint dispatchers — M5, placeholder today.
`erasmus-codegen-maven-plugin`	Mojo generating dispatchers for third-party jars that cannot run the APT — M5.
`erasmus-cdi-vauban`	CDI beans + `@ValidateOnExecution` interceptor via Vauban — M7, placeholder.
`erasmus-jaxrs`	`ExceptionMapper<ConstraintViolationException>` → HTTP 400 for Cassini — M9, placeholder.
`erasmus-bench`	Placeholder for the JMH harness against Hibernate Validator — no sources yet (results will go to `BENCH.md`).
`erasmus-examples`	Placeholder for usage examples — no sources yet.
`erasmus-tck`	Official TCK runner, reactor-included only under `-Ptck` — M8.

erasmus-api

Aggregator that re-exposes the spec (requires transitive jakarta.validation). No forked API classes.

erasmus-core

The engine: bootstrap, metadata, 21 of the 22 built-in constraints (38 validators — @Null pending), interpolation.

erasmus-codegen-apt

APT processor generating per-bean static constraint dispatchers — M5, placeholder today.

erasmus-codegen-maven-plugin

Mojo generating dispatchers for third-party jars that cannot run the APT — M5.

erasmus-cdi-vauban

CDI beans + @ValidateOnExecution interceptor via Vauban — M7, placeholder.

erasmus-jaxrs

ExceptionMapper<ConstraintViolationException> → HTTP 400 for Cassini — M9, placeholder.

erasmus-bench

Placeholder for the JMH harness against Hibernate Validator — no sources yet (results will go to BENCH.md).

erasmus-examples

Placeholder for usage examples — no sources yet.

erasmus-tck

Official TCK runner, reactor-included only under -Ptck — M8.

Group id io.vidocq.erasmus, parent io.vidocq:vidocq-parent.

Encapsulation

erasmus-core exports nothing. Every class lives under io.vidocq.erasmus.core.internal.*; the only doorway is the provides ValidationProvider directive. This is the strictest possible Java Modules posture: user code cannot link against engine internals even by accident, which keeps every refactoring (including the M5 codegen swap) non-breaking by construction.

Engine parts

internal/ErasmusValidationProvider → ErasmusValidatorFactory → ErasmusValidator — the spec objects.
internal/metadata/ — BeanMetadata, ConstraintMetadataBuilder, field/method/property accessors. Built lazily per class, cached.
internal/constraints/BuiltinConstraints — the registry mapping the 21 implemented spec annotations to their 38 validators.
internal/ConstraintValidatorResolver — most-specific validator selection over generic interfaces (primitives boxed, UnexpectedTypeException on no match).
ErasmusMessageInterpolator + MinimalElExpression — bundle lookup (ValidationMessages, EN + FR) then the EL-subset pass.

House rules

The workspace-wide philosophy applies verbatim (see the repo’s CLAUDE.md):

zero third-party dependency — spec jar only;
strict Java Modules, no unjustified opens;
TDD — the engine grew test-first (grouped constraint test classes, bootstrap tests, authoring tests);
virtual-thread friendliness — no synchronized on hot paths, no ThreadLocal;
say Java Modules, never the abbreviation.

Testing strategy

The built-in validators are covered by 13 test classes, several grouping a constraint family (AssertBooleanValidatorTest, PositiveNegativeValidatorTest, DecimalMinMaxValidatorTest, PastFutureValidatorTest); custom-constraint authoring, bootstrap discovery, end-to-end validation, locale interpolation, and the EL subset have their own suites. From M5 on, the plan adds differential testing: every scenario runs on both the reflective path and the generated dispatchers, and the outputs must match.