source: anac2020/BlingBling/src/main/java/geniusweb/blingbling/Ranknet/Pair.java@ 14

package geniusweb.blingbling.Ranknet;

import java.util.Objects;

public class Pair<A, B> {
        
        public final A fst;
        public final B snd;
        
        public Pair(A fst, B snd) {
                this.fst = fst;
                this.snd = snd;
        }
        
        public String toString() {
                return "Pair[" + fst + "," + snd + "]";
        }
        
        public boolean equals(Object other) {
                return
                        other instanceof Pair<?,?> &&
                        Objects.equals(fst, ((Pair<?,?>)other).fst) &&
                        Objects.equals(snd, ((Pair<?,?>)other).snd);
        }
        
        public int hashCode() {
                if (fst == null) return (snd == null) ? 0 : snd.hashCode() + 1;
                else if (snd == null) return fst.hashCode() + 2;
                else return fst.hashCode() * 17 + snd.hashCode();
        }
        
        public static <A,B> Pair<A,B> of(A a, B b) {
                return new Pair<>(a,b);
        }
}