Collecting Network Connection Metrics

At a glance

Project structure

Source bundle/
├── Connection Metrics/
│   ├── Connection Metrics/
│   │   ├── AppDelegate.swift
│   │   ├── ViewController.swift
│   │   ├── ConnectionProbe.swift
│   │   ├── Base.lproj/
│   │   │   ├── LaunchScreen.storyboard
│   │   │   └── Main.storyboard
│   │   └── Info.plist
│   └── Connection Metrics.xcodeproj/
│       ├── .xcodesamplecode.plist
│       └── project.pbxproj
└── Configuration/
    └── SampleCode.xcconfig

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 5 source declaration(s).

Overall architecture

flowchart LR
    N1["AppDelegate"]
    N2["ViewController"]
    N3["Network APIs"]
    N1 --> N2
    N2 --> N3

Reference code

Connection Metrics/Connection Metrics/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 Network.

Ownership and state

classDiagram
    AppDelegate o-- UIWindow : window
    ViewController o-- ConnectionProbe : currentProbe
    ViewController o-- UISegmentedControl : typeChooser
    ViewController o-- UILabel : hostLabel

Ownership evidence

Connection Metrics/Connection Metrics/AppDelegate.swift:12 — 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

Connection Metrics/Connection Metrics/ConnectionProbe.swift:19 — representative type boundary

protocol ConnectionProbeDelegate: AnyObject {
    func reportComplete(_ report: Result<NWConnection.EstablishmentReport, NWError>)
}

The source explicitly defines local protocol relationships: ViewController → ConnectionProbeDelegate.

Access control

Reference code

Connection Metrics/Connection Metrics/ConnectionProbe.swift:28 — representative boundary

    private let endpoint: NWEndpoint
    private let probeType: ProbeType
    private weak var delegate: ConnectionProbeDelegate?
    var useLegacyTLSVersion: Bool = false
    var disableOptimisticDNS: Bool = false

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: ViewController; Delegate: AppDelegate, ConnectionProbeDelegate.
• Protocols: ConnectionProbeDelegate.
• Methods: runProbe, probeTypeChanged, tableView, resolutionDescription, reportComplete, makeParameters, start, cancel.
• Files: Connection Metrics/Connection Metrics/AppDelegate.swift, Connection Metrics/Connection Metrics/ViewController.swift, Connection Metrics/Connection Metrics/ConnectionProbe.swift.

Architecture takeaways

• AppDelegate is the main source-visible entry or composition anchor for this sample.
• Framework work reaches Network, 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