/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE
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* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
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* add the following below this CDDL HEADER, with the fields enclosed
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* by brackets "[]" replaced with your own identifying information:
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* Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*
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*
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* Copyright 2013 ForgeRock AS
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*/
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package org.opends.server.util;
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/**
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* Ordered pair of various objects.
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*
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* @param <F>
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* type of the first pair element
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* @param <S>
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* type of the second pair element
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*/
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public class Pair<F, S>
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{
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/** An empty Pair. */
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public static final Pair<?, ?> EMPTY = Pair.of(null, null);
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/** The first pair element. */
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private final F first;
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/** The second pair element. */
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private final S second;
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/**
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* Default ctor.
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*
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* @param first
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* the first element of the constructed pair
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* @param second
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* the second element of the constructed pair
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*/
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private Pair(F first, S second)
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{
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this.first = first;
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this.second = second;
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}
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/**
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* Factory method to build a new Pair.
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*
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* @param first
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* the first element of the constructed pair
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* @param second
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* the second element of the constructed pair
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* @param <F>
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* type of the first pair element
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* @param <S>
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* type of the second pair element
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* @return A new Pair built with the provided elements
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*/
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public static <F, S> Pair<F, S> of(F first, S second)
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{
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return new Pair<F, S>(first, second);
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}
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/**
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* Returns an empty Pair matching the required types.
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*
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* @param <F>
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* type of the first pair element
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* @param <S>
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* type of the second pair element
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* @return An empty Pair matching the required types
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*/
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@SuppressWarnings("unchecked")
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public static <F, S> Pair<F, S> empty()
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{
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return (Pair<F, S>) EMPTY;
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}
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/**
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* Returns the first element of this pair.
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*
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* @return the first element of this pair
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*/
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public F getFirst()
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{
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return first;
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}
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/**
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* Returns the second element of this pair.
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*
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* @return the second element of this pair
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*/
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public S getSecond()
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{
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return second;
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}
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/** {@inheritDoc} */
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@Override
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public int hashCode()
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{
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final int prime = 31;
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int result = 1;
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result = prime * result + ((first == null) ? 0 : first.hashCode());
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result = prime * result + ((second == null) ? 0 : second.hashCode());
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return result;
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}
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/** {@inheritDoc} */
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@Override
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public boolean equals(Object obj)
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{
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if (this == obj)
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return true;
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if (obj == null)
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return false;
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if (getClass() != obj.getClass())
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return false;
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Pair<?, ?> other = (Pair<?, ?>) obj;
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if (first == null)
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{
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if (other.first != null)
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return false;
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}
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else if (!first.equals(other.first))
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return false;
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if (second == null)
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{
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if (other.second != null)
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return false;
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}
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else if (!second.equals(other.second))
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return false;
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return true;
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}
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/** {@inheritDoc} */
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@Override
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public String toString()
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{
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return "Pair [" + first + ", " + second + "]";
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}
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}
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