Creating custom modelers for intelligent instruments

At a glance

Project structure

Source bundle/
├── GoatList/
│   ├── AppDelegate.swift
│   ├── GoatTableViewController.swift
│   ├── Goat.swift
│   ├── GoatNames.swift
│   └── GoatTableViewCell.swift
└── MobileAgents/
    ├── MobileAgentPattern/
    │   └── MobileAgentTracing.swift
    └── GoatListAgents/
        ├── BackgroundProcessingStop.swift
        ├── DisplayAgent.swift
        ├── DisplayStop.swift
        ├── EditAgent.swift
        ├── GoatListReceivable.swift
        └── GoatListStop.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 6 project/configuration file(s) and 19 source declaration(s).

Overall architecture

flowchart LR
    N1["AppDelegate"]
    N2["GoatTableViewController"]
    N3["UIKit APIs"]
    N1 --> N2
    N2 --> N3

Reference code

GoatList/AppDelegate.swift:10 — architecture anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into Xcode.

Ownership and state

classDiagram
    AppDelegate o-- UIWindow : window
    GoatTableViewController *-- GoatListStop : goatListStop
    Goat *-- String : name
    GoatTableViewCell o-- UILabel : nameLabel

Ownership evidence

GoatList/AppDelegate.swift:13 — stored dependency or nearest verified ownership anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Class and protocol design

MobileAgents/MobileAgentPattern/MobileAgentTracing.swift:10 — representative type boundary

protocol DiagnosticCodeExpressable {
    func diagnosticsTypeCode() -> UInt32
}

The source explicitly defines local protocol relationships: BackgroundProcessingStop → MobileAgentStop, DisplayAgent → GoatListReceivable, DisplayStop → MobileAgentStop, EditAgent → GoatListReceivable, GoatListStop → MobileAgentStop, SortAgent → GoatListReceivable.

Access control

Reference code

GoatList/GoatNames.swift:12 — representative boundary

class GoatNames {
    // ...
    private static let goatNames = ["Happy Goat", "Silly Goat", "Hungry Goat", "Billy Goat",
                                    "Sleepy Goat", "Smart Goat", "Mountain Goat", "Goatee"]
    // ...
}

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: Controller: GoatTableViewController; Delegate: AppDelegate.
• Protocols: DiagnosticCodeExpressable, MockDelayable, GoatListReceivable, MobileAgentStop.
• Methods: addGoat, sortGoats, viewDidLoad, numberOfSections, tableView, setupInitialGoatList, diagnosticsTypeCode, injectMockDelay.
• Files: GoatList/AppDelegate.swift, GoatList/GoatTableViewController.swift, GoatList/Goat.swift, GoatList/GoatNames.swift, GoatList/GoatTableViewCell.swift, MobileAgents/GoatListAgents/BackgroundProcessingStop.swift.

Architecture takeaways

• AppDelegate is the main source-visible entry or composition anchor for this sample.
• Framework work reaches UIKit through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation