Files
HeadFirstDesignPatterns/Ch3Beverage/Beverage.cs

51 lines
1.6 KiB
C#

namespace Ch3Beverage;
public abstract class Beverage {
public virtual string Description => "Unknown beverage";
public abstract double Cost();
}
/*
The only real benefit of putting the constructor in CondimentDecorator is if you need to:
Add validation logic (e.g., null checks) once for all decorators
Add shared behavior that all decorators need when wrapping
Enforce that the wrapped beverage is immutable across all decorators
*
If you don't need shared initialization logic, your approach is cleaner and more direct.
It's a legitimate design choice, not a mistake.
The "always put it in the base class" advice is dogmatic - useful when you have multiple decorators and want consistency,
but not a hard rule. Your implementation follows the Decorator pattern correctly.
*/
public abstract class CondimentDecorator : Beverage;
public class Espresso : Beverage {
public override string Description => "Espresso";
public override double Cost() => 1.99;
}
public class HouseBlend : Beverage {
public override string Description => "House Blend Coffee";
public override double Cost() => 0.89;
}
public class DarkRoast : Beverage {
public override string Description => "Dark Roast Coffee";
public override double Cost() => 0.99;
}
public class Decaf : Beverage {
public override string Description => "Decaf Coffee";
public override double Cost() => 1.05;
}
public class Mocha(Beverage beverage) : CondimentDecorator {
public override string Description => $"{beverage.Description}, Mocha";
public override double Cost() => beverage.Cost() + 0.20;
}