我的配对版本。这也处理比较。PS:大部分代码取自AOSP。
package util;
import java.util.Objects;
public class Pair<F extends Comparable<F>, S extends Comparable<S>>
implements Comparable<Pair<F, S>> {
public final F first;
public final S second;
/**
* Constructor for a Pair.
*
* @param first the first object in the Pair
* @param second the second object in the pair
*/
public Pair(F first, S second) {
this.first = first;
this.second = second;
}
/**
* Checks the two objects for equality by delegating to their respective
* {@link Object#equals(Object)} methods.
*
* @param o the {@link Pair} to which this one is to be checked for equality
* @return true if the underlying objects of the Pair are both considered
* equal
*/
@Override
public boolean equals(Object o) {
if (!(o instanceof Pair)) {
return false;
}
Pair<?, ?> p = (Pair<?, ?>) o;
return Objects.equals(p.first, first) && Objects.equals(p.second, second);
}
/**
* Compute a hash code using the hash codes of the underlying objects
*
* @return a hashcode of the Pair
*/
@Override
public int hashCode() {
return (first == null ? 0 : first.hashCode()) ^ (second == null ? 0 : second.hashCode());
}
/**
* Convenience method for creating an appropriately typed pair.
*
* @param a the first object in the Pair
* @param b the second object in the pair
* @return a Pair that is templatized with the types of a and b
*/
public static <A extends Comparable<A>, B extends Comparable<B>> Pair<A, B> create(A a, B b) {
return new Pair<>(a, b);
}
@Override
public int compareTo(Pair<F, S> that) {
int cmp = this.first.compareTo(that.first);
if (cmp == 0)
cmp = this.second.compareTo(that.second);
return cmp;
}
}