💡 Strategy Pattern
Tags: swift, programming, computerscience, architecture
Published: 2022-12-13 17:49:27


![Strategy Pattern](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/4nyqubo7q2z5jcoojsar.png)

---

The strategy pattern is used to create an interchangeable family of algorithms from which the required process is chosen at run-time.

Github https://github.com/sergeyleschev/design-patterns

**Example**
```swift
struct TestSubject {
    let pupilDiameter: Double
    let blushResponse: Double
    let isOrganic: Bool
}

protocol RealnessTesting: AnyObject {
    func testRealness(_ testSubject: TestSubject) -> Bool
}

final class VoightKampffTest: RealnessTesting {
    func testRealness(_ testSubject: TestSubject) -> Bool {
        return testSubject.pupilDiameter < 30.0 || testSubject.blushResponse == 0.0
    }
}
final class GeneticTest: RealnessTesting {
    func testRealness(_ testSubject: TestSubject) -> Bool {
        return testSubject.isOrganic
    }
}
final class BladeRunner {
    private let strategy: RealnessTesting
    init(test: RealnessTesting) { self.strategy = test }
    func testIfAndroid(_ testSubject: TestSubject) -> Bool {
        return !strategy.testRealness(testSubject)
    }
}
```
**Usage**
```swift
let rachel = TestSubject(pupilDiameter: 30.2,
                         blushResponse: 0.3,
                         isOrganic: false)

// Deckard is using a traditional test
let deckard = BladeRunner(test: VoightKampffTest())
let isRachelAndroid = deckard.testIfAndroid(rachel)

// Gaff is using a very precise method
let gaff = BladeRunner(test: GeneticTest())
let isDeckardAndroid = gaff.testIfAndroid(Rachel)
```
Sources: [Github](https://github.com/sergeyleschev/design-patterns/tree/main/Strategy)
> **_Behavioral_**
In software engineering, behavioral design patterns are design patterns that identify common communication patterns between objects and realize these patterns. By doing so, these patterns increase flexibility in carrying out this communication.
Source: [wikipedia.org](https://en.wikipedia.org/wiki/Behavioral_pattern)

---

🐝 [Chain Of Responsibility](https://dev.to/sergeyleschev/swift-design-patterns-chain-of-responsibility-4bbd)
👫 [Command Pattern](https://dev.to/sergeyleschev/swift-design-patterns-command-pattern-3044)
🎶 [Interpreter Pattern](https://dev.to/sergeyleschev/swift-design-patterns-interpreter-pattern-390a)
🍫 [Iterator Pattern](https://dev.to/sergeyleschev/swift-design-patterns-iterator-pattern-405o)
💐 [Mediator Pattern](https://dev.to/sergeyleschev/swift-design-patterns-mediator-pattern-4299)
💾 [Memento Pattern](https://dev.to/sergeyleschev/swift-design-patterns-memento-pattern-chp)
👓 [Observer Pattern](https://dev.to/sergeyleschev/swift-design-patterns-observer-pattern-44fc)
🐉 [State Pattern](https://dev.to/sergeyleschev/swift-design-patterns-state-pattern-5ej4)
💡 [Strategy Pattern](https://dev.to/sergeyleschev/swift-design-patterns-strategy-pattern-143c)
📝 [Template Method](https://dev.to/sergeyleschev/swift-design-patterns-template-method-1c2o)
🏃 [Visitor Pattern](https://dev.to/sergeyleschev/swift-design-patterns-visitor-pattern-4hl5)
🌰 [Abstract Factory](https://dev.to/sergeyleschev/swift-design-patterns-abstract-factory-3ppa)
👷 [Builder Pattern](https://dev.to/sergeyleschev/swift-design-patterns-builder-pattern-3609)
🏭 [Factory Method](https://dev.to/sergeyleschev/swift-design-patterns-factory-method-5c6e)
🔂 [Monostate Pattern](https://dev.to/sergeyleschev/swift-design-patterns-monostate-pattern-574i)
🃏 [Prototype Pattern](https://dev.to/sergeyleschev/swift-design-patterns-prototype-pattern-n25)
💍 [Singleton](https://dev.to/sergeyleschev/swift-design-patterns-singleton-3c8b)
🔌 [Adapter Pattern](https://dev.to/sergeyleschev/swift-design-patterns-adapter-pattern-1040)
🌉 [Bridge Pattern](https://dev.to/sergeyleschev/swift-design-patterns-bridge-pattern-1ee2)
🌿 [Composite Pattern](https://dev.to/sergeyleschev/swift-design-patterns-composite-pattern-1koj)
🍧 [Decorator Pattern](https://dev.to/sergeyleschev/swift-design-patterns-decorator-pattern-2c6p)
🎁 [Facade Pattern](https://dev.to/sergeyleschev/swift-design-patterns-facade-pattern-130a)
🍃 [Flyweight Pattern](https://dev.to/sergeyleschev/swift-design-patterns-flyweight-pattern-6ko)
☔ [Protection Proxy](https://dev.to/sergeyleschev/swift-design-patterns-protection-proxy-3kpc)
🍬 [Virtual Proxy](https://dev.to/sergeyleschev/swift-design-patterns-virtual-proxy-2bbg)

---

**Contacts**
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