LP2esame1

package com.company;
import java.util.*;
import java.lang.*;
import java.io.*;

class A {
    public String f(Object x, int n) { return "A1"; }
    public String f(A x, int n) { return "A2:" + n; }
    public String f(A x, double n) { return "A3:" + x.f(x, (int) n); }
    private String f(B x, int n) { return "A4"; }
}

class B extends A {
    public String f(B x, double n) { return "B2:" + f((A) x, 2); }
    public String f(A x, double n) { return "B1:" + n; }
    public String f(A x, int n) { return "B3"; }
}

enum Nutrient{
    FAT, CARBO, PROTEIN;
}

class NutrInfo implements Comparable<NutrInfo>{

    public double kcal;
    public EnumMap<Nutrient, Double> vals = new EnumMap<Nutrient, Double>(Nutrient.class);

    NutrInfo(double kcal){
        this.kcal = kcal;
    }

    @Override
    public int compareTo(NutrInfo o) {
        return (int)(kcal - o.kcal);
    }

    public void setNutrient(Nutrient n, double val){
        vals.put(n, val);
    }

    public static Comparator<NutrInfo> comparatorBy(final Nutrient n){
        return new Comparator<NutrInfo>() {
            @Override
            public int compare(NutrInfo o1, NutrInfo o2){
                return (int)(o1.vals.get(n) - o2.vals.get(n));
            }
        };
    }
}

class Exchanger<T> {

    T val1 = null;
    T val2 = null;

    public synchronized T exchange(T val) throws InterruptedException{
        if (val1 == null) {
            val1 = val;
            this.wait();
            return val2;
        }
        else if (val2 == null) {
            val2 = val;
            this.notifyAll();
            return val1;
        }
        else throw new RuntimeException();
    }
}

public class Main {

    public static <K,V> Map<K,V> subMap(Map<K,V> m, Collection<?> c){
        HashMap<K,V> map = new HashMap<K,V>();
        for(K key: m.keySet()){
            if (c.contains(key)){
                map.put(key, m.get(key));
            }
        }
        return map;
    }

    public static void main(String[] args) throws InterruptedException{

        //eser1
        B beta = new B();
        A alfa = beta;
        System.out.println(alfa.f(null, 2L));
        System.out.println (beta. f (beta, 5.0) );
        System.out.println(12 & 2);

        //eser2
        NutrInfo x = new NutrInfo(500);
        x.setNutrient(Nutrient.FAT, 12.0);
        x.setNutrient(Nutrient.CARBO, 20.0);
        x.setNutrient(Nutrient.PROTEIN, 15.0);
        Comparator<NutrInfo> c = NutrInfo.comparatorBy(Nutrient.FAT);
        for (Double val : x.vals.values()) System.out.print(val.toString() + "\n");

        //eser3
        final Exchanger<String> e = new Exchanger<String>();
        Thread t = new Thread(){
            @Override
            public void run(){
                try {
                    String a = e.exchange("ciao\n");
                    System.out.print(a);
                }
                catch(Exception e){
                    System.out.print(e.getMessage());
                }
            }
        };
        t.start();
        String a = e.exchange("Pippo\n");
        System.out.print(a);
        try {
            e.exchange("Error!");
        } catch (RuntimeException e1){
            System.out.print("Ok\n");
        }
        t.join();

        //eser4
        Collection<Object> col = new LinkedList<Object>();
        for (Object o : x.vals.keySet()){
            col.add(o);
        }
        col.add(1);
        col.add(666L);
        col.add(666.666);
        for(Nutrient key : subMap(x.vals, col).keySet()){
            System.out.print(key.toString() + "\n");
        }

    }

}