source: src/main/java/agents/anac/y2016/farma/etc/Pair.java

package agents.anac.y2016.farma.etc;

import java.util.HashMap;
import java.util.Map;

class Pair<F, S> {
        public final F first;
        public final S second;

        Pair(F first, S second) {
                this.first = first;
                this.second = second;
        }

        @Override
        public boolean equals(Object obj) {
                if (!(obj instanceof Pair))
                        return false;
                Pair pair = (Pair) obj;
                return (first.equals(pair.first) && second.equals(pair.second));
        }

        @Override
        public int hashCode() {
                return first.hashCode() ^ second.hashCode();
        }

        public static void main(String[] args) {
                Map<Pair<Integer, Integer>, String> map = new HashMap<Pair<Integer, Integer>, String>();

                Pair pair = new Pair(1, 2);
                Pair pair2 = new Pair(1, 2);
                map.put(pair, "a");

                if (map.containsKey(pair2)) {
                        System.out.println("equal");
                } else {
                        System.out.println("not equal");
                }
        }
}