DDD4j Project Creator

When to use this skill

CRITICAL: This skill should ONLY be triggered when the user explicitly mentions creating a ddd4j project, initializing ddd4j project, or setting up ddd4j-boot project.

ALWAYS use this skill when the user mentions:

• Creating a ddd4j project (explicitly mentions “ddd4j”)
• Initializing ddd4j-boot project
• Setting up ddd4j project structure
• Creating ddd4j project scaffolding
• 创建 ddd4j 项目 (explicitly mentions “ddd4j”)
• 初始化 ddd4j 项目 (initialize ddd4j project)
• ddd4j-boot 项目创建 (create ddd4j-boot project)

Trigger phrases include:

• “创建 ddd4j 项目” (create ddd4j project) – must include “ddd4j”
• “初始化 ddd4j 项目” (initialize ddd4j project) – must include “ddd4j”
• “创建 ddd4j-boot 项目” (create ddd4j-boot project) – must include “ddd4j”
• “使用 ddd4j 创建项目” (create project using ddd4j)
• “ddd4j 项目脚手架” (ddd4j project scaffolding)

DO NOT trigger this skill for:

• Generic DDD projects without mentioning ddd4j
• JPA/Hibernate projects
• Other ORM frameworks
• Generic project initialization without ddd4j context
• “创建 DDD 项目” without “ddd4j” (too generic)
• “初始化项目” without “ddd4j” (too generic)

About DDD4j Boot

DDD4j Boot is a Java microservice development scaffold based on Domain-Driven Design (DDD) principles. It is built with Spring Boot 3.5.x and uses lightweight ddd-4-java and cqrs-4-java libraries to implement Domain-Driven Design, Command Query Responsibility Segregation (CQRS), and Event Sourcing.

Core Design Principles

• Domain-Driven Design (DDD): Strategic design through bounded contexts, tactical design with entities, value objects, aggregates, domain services, repositories, and domain events
• Command Query Responsibility Segregation (CQRS): Separation of read and write models, independent optimization
• Event Sourcing: State changes recorded as event sequences, supporting complete history and state reconstruction
• Diamond Architecture (COLA): Adapter → Application → Domain ← Infrastructure four-layer architecture

Key Features

• Complete DDD layered architecture supporting COLA V5 pattern
• Lightweight DDD implementation based on ddd-4-java and cqrs-4-java
• Technology stack integration: Spring Boot 3.5.x, MyBatis Plus, Jackson, Guava, Swagger, SaToken
• Dual stack support: WebMVC (traditional Servlet) and WebFlux (reactive)
• Domain model base capabilities: BaseEntity, BaseRepository, BaseService
• Domain event support with built-in event publishing mechanism
• Anti-Corruption Layer (ACL) for external service integration
• Unified exception handling mechanism

Project Types Supported

1. Single-Module Monolith (单体单模块)

适用场景: 中小型应用，单个业务领域，团队规模 5-15 人

特点:

• 单一 Maven 模块
• 所有层（interfaces, application, domain, infrastructure）在同一模块内
• 适合快速开发和部署

2. Multi-Module Monolith (单体多模块)

适用场景: 中大型应用，多个业务域，团队规模 15-50 人

特点:

• 多个 Maven 模块，按业务域划分
• 每个业务域包含完整的 DDD 四层架构
• 共享 common 模块
• 统一 BOM 和依赖管理

3. Microservices (单体微服务)

适用场景: 大型电商平台，多个业务域，团队规模 50+ 人

特点:

• 每个服务独立部署
• 服务间通过 RPC 和消息队列通信
• 每个服务内部按 DDD 四层架构组织
• 独立的数据库和配置

How to use this skill

CRITICAL: This skill should ONLY be triggered when the user explicitly mentions creating a ddd4j project. Do NOT trigger for generic DDD project creation requests without ddd4j context.

For New DDD4j Project Creation

1. Identify the project type from user requirements:

   • Single-module monolith → single-module
   • Multi-module monolith → multi-module
   • Microservices → microservices

2. Load the appropriate example from the examples/ directory:

   • examples/single-module.md – Single-module monolith structure
   • examples/multi-module.md – Multi-module monolith structure
   • examples/microservices.md – Microservices structure
   • examples/architecture-patterns.md – DDD, Hexagonal, Clean, COLA V5 patterns

3. Collect project information:

   • groupId: Maven group ID (e.g., com.github.hiwepy or io.ddd4j.base)
   • artifactId: Maven artifact ID (e.g., ddd4j-douyin or my-ddd4j-service)
   • version: Project version (e.g., 1.0.0-SNAPSHOT)
   • parentVersion: Parent POM version (e.g., 2023.0.x.20251205-SNAPSHOT or reference to ddd4j-boot-parent)
   • packageBase: Base package name (e.g., io.ddd4j.douyin or com.example.service)
   • modules: List of business modules (for multi-module/microservices)
   • architecture: Architecture pattern (DDD Classic, Hexagonal, Clean, COLA V5)
   • ddd4jBootVersion: DDD4j Boot version (if using ddd4j-boot-bom)

4. Generate project structure:

   • Create directory structure based on selected type
   • Generate pom.xml files (parent and modules)
   • Create package-info.java files for each module
   • Generate .gitignore, LICENSE, mvnw, mvnw.cmd
   • Create basic directory structure with src/main/java and src/test/java

5. Save to project directory:

   • Default location: Save directly to the command execution directory (same level as the command)
   • Directory creation: Automatically create the project directory structure if it doesn’t exist
   • File naming: Use descriptive names based on project type and module names

For Existing Project Validation

1. Analyze project structure:

   • Scan project directory for Maven modules
   • Identify layer structure (interfaces, application, domain, infrastructure)
   • Check package naming conventions
   • Verify directory organization

2. Identify project type:

   • Single-module: Single pom.xml at root, all layers in one module
   • Multi-module: Parent pom.xml with multiple modules, each module has complete layers
   • Microservices: Multiple services, each with independent structure

3. Validate against standards:

   • Check DDD layer compliance
   • Verify dependency direction (interfaces → application → domain ← infrastructure)
   • Validate package naming ({basePackage}.{module}.{layer})
   • Check for required directories (src/main/java, src/test/java)
   • Verify package-info.java files exist

4. Generate validation report:

   • List identified issues
   • Provide recommendations
   • Suggest fixes for non-compliant structures

Output Format and File Saving

When generating a project structure, follow this response structure:

1. Save the files first: Create the project structure directly in the command execution directory

   • The project will be created at the same level as where the command is executed
   • Generate all required files and directories (pom.xml, src/, etc.)
   • Use the artifactId as the project root directory name

2. Inform the user: Tell them where the files were saved

3. Display the structure: Show the generated directory structure in a code block

Example Response Structure:

• First line: “I’ve created the DDD project structure and saved it to ./{artifactId}/ in the current directory.”
• Then show the structure wrapped in a code block:
  • Start with: three backticks + text + newline
  • Then the directory structure
  • End with: three backticks + newline

Critical Requirements:

• Always save project files directly to the command execution directory (same level)
• Use artifactId as the project root directory name
• Create the directory structure automatically if it doesn’t exist
• Generate complete project structure with all required files
• Follow Maven and DDD conventions strictly

Project Structure Standards

Package Naming Convention

For multi-module projects:

{basePackage}.{moduleName}.{layerName}

Examples:

• io.ddd4j.douyin.api.domain – API module, domain layer
• io.ddd4j.douyin.api.application – API module, application layer
• io.ddd4j.douyin.api.interfaces – API module, interfaces layer
• io.ddd4j.douyin.api.infrastructure – API module, infrastructure layer

Required Files

Every module must have:

• pom.xml – Maven configuration
• src/main/java/{package}/package-info.java – Package documentation
• src/test/java/ – Test directory structure
• .gitignore – Git ignore rules (at root)
• LICENSE – License file (at root)
• mvnw, mvnw.cmd – Maven wrapper (at root)

Layer Dependencies

Correct dependency direction:

interfaces → application → domain ← infrastructure

Rules:

• Domain layer must not depend on any other layer
• Infrastructure layer implements domain layer interfaces
• Application layer depends on domain layer
• Interfaces layer depends on application layer

Architecture Patterns

The skill supports four architecture patterns:

1. DDD Classic Layered Architecture (DDD 经典分层架构)

   • Layers: interfaces, application, domain, infrastructure
   • Reference: docs/1、DDD 经典分层架构目录结构.md and examples/architecture-patterns.md#ddd-classic

2. Hexagonal Architecture (六边形架构)

   • Ports and Adapters pattern
   • Reference: docs/2、六边形架构详细目录结构参考.md and examples/architecture-patterns.md#hexagonal

3. Clean Architecture (整洁架构)

   • Entities, Use Cases, Interface Adapters
   • Reference: docs/3、整洁架构详细目录结构参考.md and examples/architecture-patterns.md#clean

4. COLA V5 (菱形架构)

   • Adapter → App → Domain ← Infrastructure
   • Reference: docs/4、COLA V5 架构详细目录结构参考.md and examples/architecture-patterns.md#cola-v5

Validation Rules

When checking existing projects, validate:

1. Structure Compliance:

   • ✓ Correct layer organization
   • ✓ Proper module separation
   • ✓ Package naming conventions

2. Dependency Rules:

   • ✓ Domain layer has no external dependencies
   • ✓ Infrastructure implements domain interfaces
   • ✓ Correct dependency direction

3. File Organization:

   • ✓ Required directories exist
   • ✓ package-info.java files present
   • ✓ Maven configuration correct

4. Naming Conventions:

   • ✓ Package names follow convention
   • ✓ Module names are descriptive
   • ✓ Layer names are standard

Examples

See the examples/ directory for:

• single-module.md – Complete single-module monolith example
• multi-module.md – Complete multi-module monolith example (based on ddd4j-douyin structure)
• microservices.md – Complete microservices example
• architecture-patterns.md – All four architecture patterns with detailed structures

Keywords

English keywords: ddd4j, ddd4j-boot, ddd4j project, create ddd4j project, initialize ddd4j project, ddd4j project creator, ddd4j project scaffolding, ddd4j-boot project, ddd4j project structure, ddd4j-boot initialization, ddd4j microservice, ddd4j monolith

Chinese keywords (中文关键词): ddd4j, ddd4j-boot, ddd4j 项目, 创建 ddd4j 项目, 初始化 ddd4j 项目, ddd4j 项目创建, ddd4j 项目脚手架, ddd4j-boot 项目, ddd4j 项目结构, ddd4j-boot 初始化, ddd4j 微服务, ddd4j 单体应用

IMPORTANT: All keywords must include “ddd4j” to avoid false triggers. Generic terms like “DDD 项目” (DDD project) or “创建项目” (create project) without “ddd4j” should NOT trigger this skill.