【26】java的组合与继承

public class Plate {

    public Plate(int i){
        System.out.println("Plate constructor");
    }
}

public class DinnerPlate extends Plate {

    public DinnerPlate(int i){
        super(i);
        System.out.println("DinnerPlage constructor");
    }
}

public class Utensil {

    public Utensil(int i){
        System.out.println("Utensil constructor");
    }
}

public class Spoon extends Utensil {

    public Spoon(int i){
        super(i);
        System.out.println("Spoon constructor");
    }
}

public class Fork extends Utensil {

    public Fork(int i){
        super(i);
        System.out.println("Fork constructor");
    }
}

public class Knife extends Utensil {

    public Knife(int i){
        super(i);
        System.out.println("Knife constructor");
    }
}

public class Custom {

    public Custom(int i){
        System.out.println("Custom constructor");
    }
}

public class PlaceSetting extends Custom {//继承

    Spoon spoon;//组合
    Knife knife;//组合
    Fork fork;//组合
    DinnerPlate dPlate;//组合
    
    public PlaceSetting(int i){
        super(i + 2);//先初始化父类
        
        spoon = new Spoon(i + 3);//再初始化组合类
        knife = new Knife(i + 4);//再初始化组合类
        fork = new Fork(i + 5);//再初始化组合类
        dPlate = new DinnerPlate(i + 6);//再初始化组合类
        
        System.out.println("PlaceSetting constructor");
    }
    
    public static void main(String args[]){
        new PlaceSetting(666);
    }
}
//总之，先初始化父类，再初始化组合类，如果组合类同样有父类，也会先初始化，最后初始化自己