Implement Use Case

Instructions

Implement the use case $ARGUMENTS using Vaadin for the UI layer and jOOQ for data access. Don't create tests – there are the karibu-test and playwright-test skills for that.

If the Vaadin and jOOQ MCP servers are configured, check them for guidance; otherwise rely on your own knowledge and the documentation links below.

DO NOT

• Create test classes (use dedicated testing skills instead)
• Use fetchInto(SomeDto.class) for projected queries — use Records.mapping(SomeDto::new) instead

Workflow

1. Read the use case specification from docs/use_cases/
2. Read the entity model from docs/entity_model.md
3. Check existing code for patterns and conventions
4. Implement the data access layer using jOOQ
5. Verify the data access layer compiles and follows existing patterns
6. Implement the Vaadin view following existing patterns
7. Wire up the view with the data access layer
8. Verify the full implementation compiles successfully

jOOQ result mapping

When a query projects columns into a DTO, Java record, or any immutable class, map the result with org.jooq.Records.mapping(...) and a constructor reference. Do not use fetchInto(Dto.class) — it uses reflection and is not checked against the projection at compile time.

import org.jooq.Records;

// List
List<PersonDto> persons = ctx
    .select(PERSON.ID, PERSON.FIRST_NAME, PERSON.LAST_NAME, PERSON.EMAIL)
    .from(PERSON)
    .fetch(Records.mapping(PersonDto::new));

// Single (optional) row
Optional<PersonDto> person = ctx
    .select(PERSON.ID, PERSON.FIRST_NAME, PERSON.LAST_NAME, PERSON.EMAIL)
    .from(PERSON)
    .where(PERSON.ID.eq(id))
    .fetchOptional(Records.mapping(PersonDto::new));

// Stream
try (Stream<PersonDto> stream = ctx
        .select(PERSON.ID, PERSON.FIRST_NAME, PERSON.LAST_NAME, PERSON.EMAIL)
        .from(PERSON)
        .fetchStream()
        .map(Records.mapping(PersonDto::new))) {
    ...
}

The order of the projected columns must match the constructor parameter order of the target type — the compiler will enforce this.

Exception: when fetching a generated table record without projection (ctx.selectFrom(PERSON).fetchInto(Person.class) using the generator-produced POJO), the generated into mapper is fine.

Resources

• If configured, use the Vaadin MCP server for component documentation (https://mcp.vaadin.com/docs)
• If configured, use the jOOQ MCP server for query DSL reference (https://jooq-mcp.martinelli.ch/mcp)
• If configured, use the JavaDocs MCP server for API documentation (https://www.javadocs.dev/mcp)
• See the MCP setup rule to configure these optional servers