/*
|
* CDDL HEADER START
|
*
|
* The contents of this file are subject to the terms of the
|
* Common Development and Distribution License, Version 1.0 only
|
* (the "License"). You may not use this file except in compliance
|
* with the License.
|
*
|
* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
|
* or http://forgerock.org/license/CDDLv1.0.html.
|
* See the License for the specific language governing permissions
|
* and limitations under the License.
|
*
|
* When distributing Covered Code, include this CDDL HEADER in each
|
* file and include the License file at legal-notices/CDDLv1_0.txt.
|
* If applicable, add the following below this CDDL HEADER, with the
|
* fields enclosed by brackets "[]" replaced with your own identifying
|
* information:
|
* Portions Copyright [yyyy] [name of copyright owner]
|
*
|
* CDDL HEADER END
|
*
|
*
|
* Copyright 2013-2014 ForgeRock AS
|
*/
|
package com.forgerock.opendj.util;
|
|
import java.util.Comparator;
|
|
/**
|
* Ordered pair of arbitrary objects.
|
*
|
* @param <F>
|
* type of the first pair element
|
* @param <S>
|
* type of the second pair element
|
*/
|
public final class Pair<F, S> {
|
|
private static final class ComparablePairComparator
|
<F extends Comparable<F>, S extends Comparable<S>>
|
implements Comparator<Pair<F, S>> {
|
/** {@inheritDoc} */
|
@Override
|
public int compare(Pair<F, S> o1, Pair<F, S> o2) {
|
final int compareResult = o1.getFirst().compareTo(o2.getFirst());
|
if (compareResult == 0) {
|
return o1.getSecond().compareTo(o2.getSecond());
|
}
|
return compareResult;
|
}
|
}
|
|
/** An empty Pair. */
|
public static final Pair<?, ?> EMPTY = Pair.of(null, null);
|
|
/**
|
* {@link Comparator} for {@link Pair}s made of {@link Comparable} elements.
|
*/
|
@SuppressWarnings("rawtypes")
|
public static final Comparator COMPARATOR = new ComparablePairComparator();
|
|
/** The first pair element. */
|
private final F first;
|
|
/** The second pair element. */
|
private final S second;
|
|
/**
|
* Creates a pair.
|
*
|
* @param first
|
* the first element of the constructed pair
|
* @param second
|
* the second element of the constructed pair
|
*/
|
private Pair(F first, S second) {
|
this.first = first;
|
this.second = second;
|
}
|
|
/**
|
* Factory method to build a new Pair.
|
*
|
* @param first
|
* the first element of the constructed pair
|
* @param second
|
* the second element of the constructed pair
|
* @param <F>
|
* type of the first pair element
|
* @param <S>
|
* type of the second pair element
|
* @return A new Pair built with the provided elements
|
*/
|
public static <F, S> Pair<F, S> of(F first, S second) {
|
return new Pair<F, S>(first, second);
|
}
|
|
/**
|
* Returns an empty Pair matching the required types.
|
*
|
* @param <F>
|
* type of the first pair element
|
* @param <S>
|
* type of the second pair element
|
* @return An empty Pair matching the required types
|
*/
|
@SuppressWarnings("unchecked")
|
public static <F, S> Pair<F, S> empty() {
|
return (Pair<F, S>) EMPTY;
|
}
|
|
/**
|
* Returns a comparator for Pairs of comparable objects.
|
*
|
* @param <F>
|
* type of the first pair element
|
* @param <S>
|
* type of the second pair element
|
* @return a comparator for Pairs of comparable objects.
|
*/
|
@SuppressWarnings("unchecked")
|
public static <F extends Comparable<F>, S extends Comparable<S>>
|
Comparator<Pair<F, S>> getPairComparator() {
|
return COMPARATOR;
|
}
|
|
/**
|
* Returns the first element of this pair.
|
*
|
* @return the first element of this pair
|
*/
|
public F getFirst() {
|
return first;
|
}
|
|
/**
|
* Returns the second element of this pair.
|
*
|
* @return the second element of this pair
|
*/
|
public S getSecond() {
|
return second;
|
}
|
|
/** {@inheritDoc} */
|
@Override
|
public int hashCode() {
|
final int prime = 31;
|
int result = 1;
|
result = prime * result + ((first == null) ? 0 : first.hashCode());
|
result = prime * result + ((second == null) ? 0 : second.hashCode());
|
return result;
|
}
|
|
/** {@inheritDoc} */
|
@Override
|
public boolean equals(Object obj) {
|
if (this == obj) {
|
return true;
|
}
|
if (!(obj instanceof Pair)) {
|
return false;
|
}
|
Pair<?, ?> other = (Pair<?, ?>) obj;
|
if (first == null) {
|
if (other.first != null) {
|
return false;
|
}
|
} else if (!first.equals(other.first)) {
|
return false;
|
}
|
if (second == null) {
|
if (other.second != null) {
|
return false;
|
}
|
} else if (!second.equals(other.second)) {
|
return false;
|
}
|
return true;
|
}
|
|
/** {@inheritDoc} */
|
@Override
|
public String toString() {
|
return "Pair [" + first + ", " + second + "]";
|
}
|
|
}
|
