weights java

abstract class Weight {
    public abstract int capacity();
}

class SimpleWeight extends Weight {
    private int capacity;


    public SimpleWeight(int capacity) {
        this.capacity = capacity;
    }

    @Override
    public int capacity() {
        return capacity;
    }
}

class DoubleWeight extends Weight {
    private Weight weight1, weight2;

    public DoubleWeight() {}
    public DoubleWeight(Weight weight1, Weight weight2) {
        this.weight1 = weight1;
        this.weight2 = weight2;
    }

    public void setWeight1(Weight w) {
        weight1 = w;
    }

    public void setWeight2(Weight w) {
        weight2 = w;
    }

    @Override
    public int capacity() {
        return weight1.capacity() + weight2.capacity();
    }
}

class MultipleWeight extends Weight {
    private Weight[] weights;

    public MultipleWeight(Weight[] weights) {
        this.weights = weights;
    }

    @Override
    public int capacity() {
        int sum = 0;
        for (int i = 0; i < weights.length; i++) {
            sum += weights[i].capacity();
        }
        return sum;
    }
}

class WeightsColection {
    private Weight[] weights;
    private int len;

    public WeightsColection(int maxLen) {
        weights = new Weight[maxLen];
    }

    public void add(Weight weight) {
        if (len == weight.length) {
            return;
        }
        weights[len++] = weight;
    }

    public double mean() {
        int sum = 0;
        for (int i = 0; i < len; i++) {
            sum += weights[i].capacity();
        }
        return (double)sum / len;
    }
}

public class Main {
    public static void main(String[] args) {
        SimpleWeight sw = new SimpleWeight(3);
        DoubleWeight dw = new DoubleWeight();
        dw.setWeight1(new SimpleWeight(5));
        dw.setWeight2(new SimpleWeight(10));
        MultipleWeight mw = new MultipleWeight(new Weight[]{sw, dw, new SimpleWeight(100)});
        System.out.println(mw.capacity());
        DoubleWeight dw2 = new DoubleWeight();
        dw2.setWeight1(new SimpleWeight(30));
        dw2.setWeight2(new SimpleWeight(40));
        WeightsColection wc = new WeightsColection(5);
        wc.add(new SimpleWeight(10));
        wc.add(dw2);
        wc.add(mw);
        System.out.println(wc.mean());//*/
    }
}