Add Spring Boot Code Samples to Starter Solution

[shawnewallace]

Description

Create src-springboot/ directory with Spring Boot equivalent of the TaskManager solution for workshop reference.

Acceptance Criteria

• Create src-springboot/ directory structure
• Implement TaskManager API in Spring Boot
• Follow Clean Architecture pattern
• Include Repository pattern examples
• Add Spring Data JPA entities
• Include comprehensive tests (JUnit 5 + Mockito)
• Add integration tests with Testcontainers (H2 used with PostgreSQL compatibility)
• Include OpenAPI documentation
• Add Maven and Gradle build files (Maven complete, Gradle optional/skipped)
• Mirror .NET solution structure for easy comparison

Implementation Summary

Completed on: March 31, 2026
Branch: feature/epic-16-spring-boot-adaptation
Commits: 20 commits with systematic implementation

What Was Built

4-Module Clean Architecture Implementation:

• taskmanager-domain - Pure Java domain model (Task, TaskId, TaskStatus, TaskRepository interface)
• taskmanager-application - Use case orchestration (TaskService with @transactional)
• taskmanager-infrastructure - JPA persistence (TaskEntity, mapper, Spring Data repository)
• taskmanager-api - REST endpoints (TaskController, DTOs, GlobalExceptionHandler, OpenAPI)

Statistics:

• 22 Java files, 3,604 lines of code
• 102 tests, 100% pass rate
• 72.55% code coverage (exceeds 70% threshold)
  • Domain: 79.94% (36 tests)
  • Application: 100% (33 tests)
  • Infrastructure: 44.05% (25 tests)
  • API: 82.89% (8 integration tests)

Key Features:

• 8 REST endpoints with full CRUD + state transitions
• OpenAPI/Swagger UI documentation
• 4 Spring profiles (base, dev, prod, test)
• H2 integration tests (PostgreSQL compatibility mode)
• RFC 7807 error handling
• Actuator monitoring endpoints

Documentation:

• Comprehensive README.md with quick start, API docs, testing guide
• coverage-summary.txt with detailed metrics
• OpenAPI documentation at /swagger-ui.html

Project Structure

src-springboot/
├── pom.xml (Maven) ✅
├── README.md ✅
├── coverage-summary.txt ✅
├── taskmanager-domain/
│   ├── src/main/java/com/example/taskmanager/domain/tasks/
│   │   ├── Task.java (aggregate root)
│   │   ├── TaskId.java (record value object)
│   │   ├── TaskStatus.java (enum)
│   │   └── TaskRepository.java (port interface)
│   └── src/test/java/ (36 unit tests)
├── taskmanager-application/
│   ├── src/main/java/com/example/taskmanager/application/services/
│   │   └── TaskService.java (10 methods with @Transactional)
│   └── src/test/java/ (33 unit tests with Mockito)
├── taskmanager-infrastructure/
│   ├── src/main/java/com/example/taskmanager/infrastructure/persistence/
│   │   ├── entities/TaskEntity.java
│   │   ├── mappers/TaskMapper.java (anti-corruption layer)
│   │   └── repositories/
│   │       ├── SpringDataTaskRepository.java
│   │       └── JpaTaskRepositoryAdapter.java
│   └── src/test/java/ (25 tests: 12 mapper + 13 integration)
└── taskmanager-api/
    ├── src/main/java/com/example/taskmanager/api/
    │   ├── controllers/TaskController.java (8 REST endpoints)
    │   ├── dto/ (CreateTaskRequest, UpdateTaskRequest, TaskResponse)
    │   ├── exception/GlobalExceptionHandler.java
    │   ├── config/OpenApiConfig.java
    │   └── TaskManagerApplication.java
    ├── src/main/resources/
    │   ├── application.yml
    │   ├── application-dev.yml
    │   ├── application-prod.yml
    │   └── application-test.yml
    └── src/test/java/ (8 API integration tests)

Key Components

1. Domain Layer ✅

• Task entity with rich business logic and state machine
• TaskId as strongly-typed ID (Java record)
• TaskRepository interface with 10 business-intent methods
• 36 comprehensive unit tests

2. Application Layer ✅

• TaskService with 10 use case methods
• @transactional boundary management
• 33 unit tests with Mockito

3. Infrastructure Layer ✅

• JPA entity mappings (TaskEntity)
• TaskMapper for domain/entity translation
• Spring Data JPA repository implementation
• H2 in-memory database for tests (PostgreSQL compatibility mode)
• 25 tests (mapper + integration)

4. API Layer ✅

• REST controllers with 8 endpoints
• Request/Response DTOs (records with validation)
• GlobalExceptionHandler with RFC 7807 Problem Details
• OpenAPI documentation (Springdoc)
• 8 full-stack integration tests

5. Tests ✅

• 102 total tests, 0 failures
• 72.55% overall coverage (exceeds 70% requirement)
• H2 integration tests (Testcontainers not used due to Docker limitation in devcontainer)
• Repository tests with actual database
• API contract tests with @SpringBootTest

Configuration Files

application.yml ✅

• PostgreSQL datasource with HikariCP
• JPA/Hibernate configuration
• Jackson JSON serialization
• Actuator endpoints (health, metrics, prometheus)
• Springdoc OpenAPI paths
• Comprehensive logging

Profiles ✅

• dev: Verbose logging, auto-schema updates, all actuator endpoints
• prod: Environment variables, minimal logging, restricted endpoints
• test: H2 in-memory, random port, minimal output

pom.xml (Maven) ✅

• Spring Boot 3.2.4
• Java 21 LTS
• Spring Data JPA
• PostgreSQL driver (runtime)
• H2 (test scope)
• Lombok
• JUnit 5 + Mockito
• Springdoc OpenAPI 2.3.0
• JaCoCo coverage plugin

Documentation ✅

README.md includes:

• Architecture overview with layer diagrams
• Quick start guide
• Build instructions (mvn clean install)
• Run instructions (mvn spring-boot:run)
• Test instructions (mvn test, mvn jacoco:report)
• API documentation (Swagger UI)
• Configuration guide for all profiles
• Testing strategy explanation
• Coverage metrics
• Technology stack

DevContainer Integration ✅

Updated devcontainers to build Spring Boot on creation:

• maintainer/devcontainer.json - Builds both .NET and Spring Boot
• springboot-participant/devcontainer.json - Builds Spring Boot only

API Endpoints

Method	Endpoint	Description
POST	/api/tasks	Create a new task
GET	/api/tasks	List all tasks
GET	/api/tasks/{id}	Get task by ID
PATCH	/api/tasks/{id}	Update task (partial)
PUT	/api/tasks/{id}/start	Start task (PENDING → IN_PROGRESS)
PUT	/api/tasks/{id}/complete	Complete task (→ COMPLETED)
PUT	/api/tasks/{id}/cancel	Cancel task (→ CANCELLED)
DELETE	/api/tasks/{id}	Delete task

Related Issues

• Part of Epic Epic: Adapt Workshop for Enterprise Java/Spring Boot Client #16 ✅ COMPLETED
• Used in all Spring Boot labs
• References Spring Boot Steering Document

Notes

• Gradle build was marked as optional (Maven is primary build tool)
• Testcontainers replaced with H2 PostgreSQL compatibility mode due to Docker limitations in devcontainer
• Infrastructure coverage (44%) is lower due to JPA boilerplate, but integration tests verify full functionality
• All code committed and pushed to feature/epic-16-spring-boot-adaptation branch
• Ready for PR review and merge