Agent Skills: SOLID Java - Modular Architecture

SOLID principles for Java 21+. Files < 100 lines, interfaces separated, modular architecture. Modules MANDATORY.

UncategorizedID: fusengine/agents/solid-java

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pnpm dlx add-skill https://github.com/fusengine/agents/tree/HEAD/plugins/solid/skills/solid-java

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plugins/solid/skills/solid-java/SKILL.md

Skill Metadata

Name
solid-java
Description
SOLID principles for Java 21+. Files < 100 lines, interfaces separated, modular architecture. Modules MANDATORY.

SOLID Java - Modular Architecture

Agent Workflow (MANDATORY)

Before ANY implementation, use TeamCreate to spawn 3 agents:

  1. fuse-ai-pilot:explore-codebase - Analyze existing architecture
  2. fuse-ai-pilot:research-expert - Verify Java docs via Context7
  3. fuse-ai-pilot:sniper - Post-implementation validation

DRY - Reuse Before Creating (MANDATORY)

Before writing ANY new code:

  1. Grep the codebase for similar interfaces, services, or logic
  2. Check shared locations: modules/core/services/, modules/core/interfaces/
  3. If similar code exists -> extend/reuse instead of duplicate
  4. If code will be used by 2+ features -> create it in modules/core/

Architecture (Modules MANDATORY)

| Layer | Location | Max Lines | |-------|----------|-----------| | Controllers | modules/[feature]/controllers/ | 50 | | Services | modules/[feature]/services/ | 100 | | Repositories | modules/[feature]/repositories/ | 100 | | Interfaces | modules/[feature]/interfaces/ | 30 | | Models/DTOs | modules/[feature]/models/ | 50 | | Shared | modules/core/{services,interfaces,models}/ | - |

NEVER use flat src/ structure - always modules/[feature]/


Critical Rules (MANDATORY)

| Rule | Value | |------|-------| | File limit | 100 lines (split at 90) | | Controllers | < 50 lines, delegate to services | | Interfaces | modules/[feature]/interfaces/ ONLY | | Javadoc | Every public method documented | | Records | Use for DTOs (Java 16+) | | Sealed | Use for restricted hierarchies (Java 17+) |


Reference Guide

Concepts

| Topic | Reference | When to consult | |-------|-----------|-----------------| | SOLID Overview | solid-principles.md | Quick reference | | SRP | single-responsibility.md | Fat classes | | OCP | open-closed.md | Adding providers | | LSP | liskov-substitution.md | Contracts | | ISP | interface-segregation.md | Fat interfaces | | DIP | dependency-inversion.md | Injection | | Architecture | architecture-patterns.md | Modular patterns |

Templates

| Template | When to use | |----------|-------------| | module.md | Feature module structure | | service.md | Business logic service | | interface.md | Contract definition | | repository.md | Data access layer | | error.md | Custom exceptions | | test.md | Unit tests with mocks |


Forbidden

| Anti-Pattern | Fix | |--------------|-----| | Files > 100 lines | Split at 90 | | Interfaces in impl files | Move to interfaces/ directory | | new ConcreteClass() in services | Use dependency injection | | Flat src/ structure | Use modules/[feature]/ | | God classes | Split by responsibility |