org.jgrapht.alg.util.UnorderedPair Maven / Gradle / Ivy
/*
* (C) Copyright 2003-2023, by Joris Kinable and Contributors.
*
* JGraphT : a free Java graph-theory library
*
* See the CONTRIBUTORS.md file distributed with this work for additional
* information regarding copyright ownership.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0, or the
* GNU Lesser General Public License v2.1 or later
* which is available at
* http://www.gnu.org/licenses/old-licenses/lgpl-2.1-standalone.html.
*
* SPDX-License-Identifier: EPL-2.0 OR LGPL-2.1-or-later
*/
package org.jgrapht.alg.util;
import java.io.*;
import java.util.*;
/**
* Generic unordered pair.
*
*
* Although the instances of this class are immutable, it is impossible to ensure that the
* references passed to the constructor will not be modified by the caller.
*
* @param the first element type
* @param the second element type
*
* @author Joris Kinable
*
*/
public class UnorderedPair
extends Pair
implements Serializable
{
private static final long serialVersionUID = -3110454174542533876L;
/**
* Create a new unordered pair
*
* @param a an element
* @param b another element
*/
public UnorderedPair(A a, B b)
{
super(a, b);
}
@Override
public String toString()
{
return "{" + first + "," + second + "}";
}
@Override
public boolean equals(Object o)
{
if (this == o)
return true;
else if (!(o instanceof UnorderedPair))
return false;
@SuppressWarnings("unchecked") UnorderedPair other = (UnorderedPair) o;
return (Objects.equals(first, other.first) && Objects.equals(second, other.second))
|| (Objects.equals(first, other.second) && Objects.equals(second, other.first));
}
@Override
public int hashCode()
{
int hash1 = first == null ? 0 : first.hashCode();
int hash2 = second == null ? 0 : second.hashCode();
return hash1 > hash2 ? hash1 * 31 + hash2 : hash2 * 31 + hash1;
}
/**
* Creates new unordered pair of elements pulling of the necessity to provide corresponding
* types of the elements supplied.
*
* @param a first element
* @param b second element
* @param the first element type
* @param the second element type
* @return new unordered pair
*/
public static UnorderedPair of(A a, B b)
{
return new UnorderedPair<>(a, b);
}
}