Strategy Pattern

Create a common interface and multiple implementations. Choose a strategy by key or context.

interface TaxCalculator { public function for(int $cents): int; } final class NzTax implements TaxCalculator { /* ... / } final class AuTax implements TaxCalculator { / ... */ }

final class TaxFactory { public function __construct(private array $drivers) {} public function forCountry(string $code): TaxCalculator { return $this->drivers[$code]; } }

Register in a service provider and inject the factory where needed.