public class Neuron {
    private double value;
    private double error;

    /**
     * Links to neurons in next layer
     */
    public ArrayList<Link> forward;

    /**
     * Links to neurons in previous layer
     */
    public ArrayList<Link> backward;

    /**
     * Constructor
     */
    public Neuron() {
        forward = new ArrayList<>();
        backward = new ArrayList<>();
    }

    public double getValue() { return value; }
    public void setValue(double v) { value = v; }
    public double getError() { return error; }
    public void setError(double e) { error = e; }
}

public class Link {
    static Random r = new Random();
    public Link() {
        weight = r.nextDouble();
    }
    public double weight;
    public Neuron prev, next;
}