MediaManager-core/REFACTORING.md

Refactoring History—MediaManager Core

This document records the refactorings applied during development.

Refactoring #1: Connection Pool Implementation

Date: 2025-11-13 Commits: 22476abb27d95e88ae0439d97ef97467b6a4f985

Problem Identified

• Database connections were created multiple times
• No centralized control
• Possible resource leaks

Technique Applied

• Pattern: Singleton Pattern
• Refactoring: Extract Class + Introduce Singleton

Solution

Created DatabaseManager class that:

• Maintains single instance (Singleton)
• Manages connection pool
• Provides centralized getConnection() method

Result

• ✅ Single reusable connection
• ✅ Code centralized in one class
• ✅ Thread-safe
• ✅ Easier to test

Extracted Component

DatabaseManager - available in mediamanager-components

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Refactoring #2: Thread Pool for IPC

Date: 2025-11-14
Commits: f1071dca03da33f7355a6927497509b5aedaa4a2

Problem Identified

• New thread created for each IPC client
• Doesn't scale well
• Thread creation overhead

Technique Applied

• Pattern: Thread Pool Pattern
• Refactoring: Replace Thread Creation with Thread Pool

Solution

Implemented ExecutorService with:

• Fixed thread pool
• Thread reuse
• Ordered shutdown

Result

• ✅ Better performance
• ✅ Controlled resource usage
• ✅ Scalability

Extracted Component

IPCServer - available in mediamanager-components

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Refactoring #3: Graceful Shutdown

Date: 2025-11-13
Commits: 65e14930076db71a312feae373d6c5daee3c4d29,b7ff9d1e16c85bf986a770676827bee390f0d53c

Problem Identified

• Resources weren't released on exit
• Database connections remained open
• Thread pool didn't terminate correctly

Technique Applied

• Pattern: Shutdown Hook Pattern
• Refactoring: Introduce Shutdown Protocol

Solution

Implemented shutdown hooks that:

• Close database connections
• Terminate thread pools
• Release sockets
• In specific order with timeouts

Result

• ✅ Ordered cleanup
• ✅ No resource leaks
• ✅ Shutdown logging
• ✅ Timeout to prevent hanging

Extracted Component

Logic incorporated in DatabaseManager and IPCServer

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Applied Principles

• DRY (Don't Repeat Yourself): Elimination of duplicated code
• SOLID: Especially Single Responsibility Principle
• Design Patterns: Singleton, Thread Pool, Shutdown Hook
• Clean Code: Clear names, small methods, well-defined responsibilities