---
title: Modeling Quality 3
categories: demo
toc: false
...

Specifying individual contributions of features to quality and defining formulas for total variant quality.

```clafer
abstract Car
    ABS : ComfortFeature ?
        [cost = 2]
        [mass = 1]
        [comfort = 1]        
    xor Transmission : Feature
        [cost = 0]
        [mass = 0]        
        Automatic : FuelFeature
            [fuel = 2]
            [mass = 1]            
            [comfort = 2]
            [cost = 4]     
        Manual : FuelFeature
            [fuel = 0]
            [mass = 1]            
            [comfort = 1]
            [cost = 3]
    FCA : FuelFeature ?
        [fuel = 2]
        [mass = 2] 
        [comfort = 4]
        [cost = 5]        
        xor Sensor : Feature
            [cost = 0]
            [mass = 0]
            Radar : Feature
                [cost = 3]
                [mass = 1]
            Lidar : Feature
                [cost = 5]
                [mass = 1]            
        xor Alert : Feature ?
            [cost = 0]
            [mass = 0]
            Haptic : ComfortFeature
                [comfort = 4]
                [cost = 2]
                [mass = 1]
            Audible : ComfortFeature
                [comfort = 2]
                [cost = 1]
                [mass = 1]
    CC : FuelFeature ?
        [fuel = 1]
        [mass = 1]
        [comfort = 3]
        [cost = 4]
        ACC : FuelFeature ?
            [fuel = 2]
            [mass = 2]
            [comfort = 6]
            [cost = 3]
    [ ACC => FCA]
    
    total_cost : integer = sum Feature.cost
    total_comfort : integer = sum ComfortFeature.cost
    total_fuel : integer = sum FuelFeature.cost
    total_mass : integer = sum FuelFeature.mass
```


Defining quality attributes.

* basic feature with `cost` and `mass`.

```clafer
abstract Feature
    cost: integer
    mass: integer
```

* feature that impacts `comfort`

```clafer
abstract ComfortFeature : Feature
    comfort: integer
```

* feature that impacts `fuel` consumption

```clafer
abstract FuelFeature : ComfortFeature
    fuel: integer
```

[Modeling Quality 4]()