public final U first;

public final V second;

public static<U, V> Pair<U, V> makePair(U first, V second) {

return new Pair<U, V>(first, second);

}

private Pair(U first, V second) {

this.first = first;

this.second = second;

}

@Override

public boolean equals(Object o) {

if (this == o) return true;

if (o == null || getClass() != o.getClass()) return false;

Pair pair = (Pair) o;

return !(first != null ? !first.equals(pair.first) : pair.first != null) && !(second != null ? !second.equals(pair.second) : pair.second != null);

}

@Override

public int hashCode() {

int result = first != null ? first.hashCode() : 0;

result = 31 * result + (second != null ? second.hashCode() : 0);

return result;

}

public Pair<V, U> swap() {

return makePair(second, first);

}

@Override

public String toString() {

return "(" + first + "," + second + ")";

}

@SuppressWarnings({"unchecked"})

public int compareTo(Pair<U, V> o) {

int value = ((Comparable<U>)first).compareTo(o.first);

if (value != 0)

return value;

return ((Comparable<V>)second).compareTo(o.second);

}