# GKComponentSystem Manages periodic update messages for all component objects of a specified class. ``` class GKComponentSystem where ComponentType : GKComponent ``` ## Overview A [`GKComponentSystem`](/documentation/GameplayKit/GKComponentSystem) object manages periodic update messages for components in a game that uses Entity-Component architecture. Use a component system to perform per-frame logic for all components of a specific class without traversing your game’s object hierarchy to dispatch update messages. Each [`GKComponentSystem`](/documentation/GameplayKit/GKComponentSystem) object manages components of a specific [`GKComponent`](/documentation/GameplayKit/GKComponent) subclass. You create a component system with the [`init(componentClass:)`](/documentation/GameplayKit/GKComponentSystem/init(componentClass:)) initializer, specifying the component class it will work with. Then, you register the components used by the entities in your game with the [`addComponent(_:)`](/documentation/GameplayKit/GKComponentSystem/addComponent(_:)) or [`addComponent(foundIn:)`](/documentation/GameplayKit/GKComponentSystem/addComponent(foundIn:)) methods. The component system will then forward any component-specific messages it receives to all registered instances of its component class. The most important of the component-specific messages is the [`update(deltaTime:)`](/documentation/GameplayKit/GKComponentSystem/update(deltaTime:)) method. Call this method from your game’s update/render loop—that is, from a method such as (SpriteKit) or (SceneKit), or from a (iOS) or (macOS) timer in a custom rendering engine. The component system then forwards to the [`update(deltaTime:)`](/documentation/GameplayKit/GKComponent/update(deltaTime:)) method of all the [`GKComponent`](/documentation/GameplayKit/GKComponent) subclass instances it manages, allowing those objects to perform per-frame update logic. For more information on Entity-Component architecture, read [Entities and Components](https://developer.apple.com/library/archive/documentation/General/Conceptual/GameplayKit_Guide/EntityComponent.html#//apple_ref/doc/uid/TP40015172-CH6) in [GameplayKit Programming Guide](https://developer.apple.com/library/archive/documentation/General/Conceptual/GameplayKit_Guide/index.html#//apple_ref/doc/uid/TP40015172). ## Topics ### Creating a Component System [`- initWithComponentClass:`](/documentation/GameplayKit/GKComponentSystem/init(componentClass:)) Initializes a component system to manage components of the specified class. ### Managing a List of Components [`componentClass`](/documentation/GameplayKit/GKComponentSystem/componentClass) The class of components managed by the component system. [`components`](/documentation/GameplayKit/GKComponentSystem/components) The component system’s list of components. [`- addComponent:`](/documentation/GameplayKit/GKComponentSystem/addComponent(_:)) Adds a component instance to the component system. [`- addComponentWithEntity:`](/documentation/GameplayKit/GKComponentSystem/addComponent(foundIn:)) Adds any instances of the component system’s component class in the specified entity to the component system. [`- removeComponent:`](/documentation/GameplayKit/GKComponentSystem/removeComponent(_:)) Removes the specified component instance from the component system. [`- removeComponentWithEntity:`](/documentation/GameplayKit/GKComponentSystem/removeComponent(foundIn:)) Removes any instances of the component system’s component class in the specified entity from the component system. ### Performing Periodic Updates [`- updateWithDeltaTime:`](/documentation/GameplayKit/GKComponentSystem/update(deltaTime:)) Tells all component instances managed by the system to perform their custom periodic actions. ### Accessing Components With Subscript Syntax [`- objectAtIndexedSubscript:`](/documentation/GameplayKit/GKComponentSystem/subscript(_:)) Returns the component at the specified index in the system’s list of components. ### Instance Methods [`- classForGenericArgumentAtIndex:`](/documentation/GameplayKit/GKComponentSystem/classForGenericArgument(at:)) ## Relationships ### Conforms To [`Hashable`](/documentation/Swift/Hashable) [`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible) [`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol) [`CVarArg`](/documentation/Swift/CVarArg) [`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible) [`NSFastEnumeration`](/documentation/Foundation/NSFastEnumeration) [`Equatable`](/documentation/Swift/Equatable) ### Inherits From [`NSObject-swift.class`](/documentation/ObjectiveC/NSObject-swift.class) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)