Table of Contents

Class GameSystem

Namespace
Core.Systems
Assembly
Core.dll

ENGINE LAYER - Base class for all game systems with standardized lifecycle

Responsibilities:

  • Define standard system lifecycle (Initialize, Shutdown, Save, Load)
  • Enforce dependency validation before initialization
  • Prevent re-initialization and initialization of missing dependencies
  • Provide consistent logging for system operations

Architecture:

  • Pure mechanism, no game-specific knowledge
  • Systems declare dependencies explicitly via GetDependencies()
  • Initialization order determined by dependency graph
  • All state changes go through standard lifecycle methods

Usage (Game Layer): public class EconomySystem : GameSystem { public override string SystemName => "Economy";

protected override IEnumerable{GameSystem} GetDependencies()
{
    yield return timeManager;
    yield return provinceSystem;
}

protected override void OnInitialize()
{
    // Dependencies guaranteed to be initialized here
    timeManager.OnMonthlyTick += CollectTaxes;
}

}

Benefits:

  • No load order bugs (dependencies validated)
  • No circular dependency crashes (detected at startup)
  • Easy testing (mock dependencies)
  • Save/load support (standard serialization hooks)
  • Self-documenting (dependencies explicit)
public abstract class GameSystem : MonoBehaviour
Inheritance
object
GameSystem
Derived

Properties

IsInitialized

Whether this system has been initialized Systems cannot be used until initialized

public bool IsInitialized { get; }

Property Value

bool

SystemName

Unique name for this system (used in logging and debugging)

public abstract string SystemName { get; }

Property Value

string

Methods

EnsureInitialized()

Check if this system is ready to be used Systems should check this before performing operations

protected void EnsureInitialized()

GetDependencies()

Get all systems this system depends on Dependencies must be initialized before this system Override to declare dependencies (return empty if none) Internal visibility allows SystemRegistry to access for dependency resolution

protected virtual IEnumerable<GameSystem> GetDependencies()

Returns

IEnumerable<GameSystem>

Initialize()

Initialize this system (call after all dependencies initialized) Validates dependencies before calling OnInitialize()

public void Initialize()

LogSystem(string)

Log a system-specific message Prefixes message with system name for easier debugging

protected void LogSystem(string message)

Parameters

message string

LogSystemError(string)

Log a system-specific error

protected void LogSystemError(string message)

Parameters

message string

LogSystemWarning(string)

Log a system-specific warning

protected void LogSystemWarning(string message)

Parameters

message string

OnDestroy()

Unity lifecycle - automatically shutdown on destroy

protected virtual void OnDestroy()

OnInitialize()

Perform system-specific initialization All dependencies guaranteed to be initialized when this is called Override to set up system state, subscribe to events, etc.

protected abstract void OnInitialize()

OnLoad(SaveGameData)

Load system state from save data Override to deserialize system state for save/load

protected virtual void OnLoad(SaveGameData saveData)

Parameters

saveData SaveGameData

OnSave(SaveGameData)

Save system state to save data Override to serialize system state for save/load

protected virtual void OnSave(SaveGameData saveData)

Parameters

saveData SaveGameData

OnShutdown()

Perform system-specific shutdown Override to clean up resources, unsubscribe events, etc.

protected virtual void OnShutdown()

Shutdown()

Shutdown this system cleanly Unsubscribe from events, release resources, etc. Called before scene unload or game exit

public void Shutdown()

Subscribe<T>(EventBus, Action<T>)

Subscribe to an event using a specific EventBus. Useful when not using GameState.Instance.

protected void Subscribe<T>(EventBus eventBus, Action<T> handler) where T : struct, IGameEvent

Parameters

eventBus EventBus
handler Action<T>

Type Parameters

T

Subscribe<T>(Action<T>)

Subscribe to an event with automatic cleanup on shutdown. No need to manually unsubscribe - handled automatically.

Usage: protected override void OnInitialize() { Subscribe{MonthlyTickEvent}(HandleMonthlyTick); } // No OnShutdown override needed for unsubscription

protected void Subscribe<T>(Action<T> handler) where T : struct, IGameEvent

Parameters

handler Action<T>

Type Parameters

T
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