Example Class Specification

The examples below demonstrate the expected structure and level of detail for internal code contracts.

These are not informal notes — they model the documentation standard required for your project.

warning

These should match your class diagrams from the System Architecture document. If your implementation changes, these must be updated to reflect the current design.

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Example: UserService

Class Overview

Class Name: UserService Purpose: Encapsulates business logic for user account management, including validation, persistence, and audit logging.

Responsibilities:

• Validate incoming user data
• Persist user records
• Enqueue onboarding side effects
• Emit audit logs

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Fields

Field	Type	Visibility	Description
userRepository	UserRepository	private	Handles data persistence
logger	Logger	private	Records audit and diagnostic logs

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Public Methods

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createUser(req: CreateUserRequest): User

Description: Creates and persists a new user account.

Preconditions:

• req.email is a valid email format
• req.password satisfies complexity rules
• Email must not already exist in the system

Postconditions:

• A new User record is persisted
• A welcome email event is enqueued
• Audit log entry is recorded

Throws:

• ValidationException — if input fails validation
• DuplicateUserException — if email already exists

Example Usage:

UserService svc = new UserService(userRepository, logger);
User user = svc.createUser(
    new CreateUserRequest("a@b.com", "P@ssw0rd")
);