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///////////////////////////////////////////////////////////////////////////////
// For information as to what this class does, see the Javadoc, below. //
// Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, //
// 2007, 2008, 2009, 2010, 2014, 2015, 2022 by Peter Spirtes, Richard //
// Scheines, Joseph Ramsey, and Clark Glymour. //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation; either version 2 of the License, or //
// (at your option) any later version. //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program; if not, write to the Free Software //
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA //
///////////////////////////////////////////////////////////////////////////////
package edu.cmu.tetrad.graph;
/**
* An unordered pair of nodes.
*
* @author Tyler Gibson
* @version $Id: $Id
*/
public class NodePair {
/**
* The "First" node.
*/
private final Node first;
/**
* The "second" node.
*/
private final Node second;
/**
* Constructor for NodePair.
*
* @param first a {@link edu.cmu.tetrad.graph.Node} object
* @param second a {@link edu.cmu.tetrad.graph.Node} object
*/
public NodePair(Node first, Node second) {
if (first == null) {
throw new NullPointerException("First node must not be null.");
}
if (second == null) {
throw new NullPointerException("Second node must not be null.");
}
this.first = first;
this.second = second;
}
//============================== Public methods =============================//
/**
* Getter for the field first.
*
* @return a {@link edu.cmu.tetrad.graph.Node} object
*/
public Node getFirst() {
return this.first;
}
/**
* Getter for the field second.
*
* @return a {@link edu.cmu.tetrad.graph.Node} object
*/
public Node getSecond() {
return this.second;
}
/**
* hashCode.
*
* @return a int
*/
public int hashCode() {
return this.first.hashCode() + this.second.hashCode();
}
/**
* {@inheritDoc}
*/
public boolean equals(Object o) {
if (o == this) {
return true;
}
if (!(o instanceof NodePair thatPair)) {
return false;
}
// return this.first.equals(thatPair.first) && this.second.equals(thatPair.second) || this.first.equals(thatPair.second) && this.second.equals(thatPair.first);
return (this.first == thatPair.first && this.second == thatPair.second) || (this.first == thatPair.second && this.second == thatPair.first);
}
/**
* toString.
*
* @return a {@link java.lang.String} object
*/
public String toString() {
return "{" + this.first + ", " + this.second + "}";
}
}