/**
 *
 * Implementing the NutritionFacts class using the Builder pattern.
 */
public class NutritionFactsBuilder {

    private final int servingSize;
    private final int servings;
    private final int calories;
    private final int fat;
    private final int sodium;
    private final int carbohydrate;
    private final int protein;
    
    public static class Builder{
        private final int servingSize;
        private final int servings;
        
        private int calories = 0;
        private int fat = 0;
        private int carbohydrate = 0;
        private int sodium = 0;
        private int protein = 0;
        
        public Builder(int servingSize, int servings){
            this.servingSize = servingSize;
            this.servings = servings;
        }
        
        public Builder calories(int a){
            calories = a;
            return this;
        }
        
        public Builder fat(int a){
            fat = a;
            return this;
        }
        
        public Builder carbohydrate(int a){
            carbohydrate = a;
            return this;
        }
        
        public Builder sodium(int a){
            sodium = a;
            return this;
        }
        
        public Builder protein(int a){
            protein = a;
            return this;
        }
        
        public NutritionFactsBuilder build(){
            return new NutritionFactsBuilder(this);
        }
    }
    
    private NutritionFactsBuilder(Builder builder){
        servingSize = builder.servingSize;
        servings = builder.servingSize;
        calories = builder.calories;
        fat = builder.fat;
        sodium = builder.sodium;
        carbohydrate = builder.carbohydrate;
        protein = builder.protein;
    }

    public static void main(String[] args) {
        // Sample usage
        NutritionFactsBuilder cocaCola = 
        new NutritionFactsBuilder.Builder (240, 8).
        calories(100).sodium(35).carbohydrate(27).build();

        // Advantages:
        // Client code is easy to write and read
        // Like constructor, can impose invariants
        // No inconsistent state exposed to client
        // Fine for immutable objects

        // Note:  If Builder pattern is appropriate, start with
	// Builder model.  When evolving to Builder model, it is
        // not possible to get rid of obsolete constructors or factories
    }

}