/** \file
 * \brief Declaration and implementation of the class PQNodeKey.
 *
 * \author Sebastian Leipert
 *
 * \par License:
 * This file is part of the Open Graph Drawing Framework (OGDF).
 *
 * \par
 * Copyright (C)<br>
 * See README.md in the OGDF root directory for details.
 *
 * \par
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * Version 2 or 3 as published by the Free Software Foundation;
 * see the file LICENSE.txt included in the packaging of this file
 * for details.
 *
 * \par
 * 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.
 *
 * \par
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, see
 * http://www.gnu.org/copyleft/gpl.html
 */

#pragma once

#include <ogdf/basic/pqtree/PQBasicKey.h>

namespace ogdf {

template<class T, class X, class Y>
class PQNode;

/**
 * The class template PQNodeKey is a derived class of class template
 * PQBasicKey. PQNodeKey is a concrete class.
 * It is constructed to store any kind of information of nodes of the
 * PQ-tree. It may be used for both internal nodes as well as leaves.
 *
 * The information is stored in #m_userStructInfo and
 * is assigned to a unique node in the PQ-tree. This
 * unique node can be identified with the #m_nodePointer of the
 * astract base class PQBasicKey. The
 * maintainance of this pointer is left to the user. By keeping the
 * responsibillity by the user, nodes with certain informations can
 * be identified and  accessed by her in constant time. This makes
 * the adaption of algorithms fast and easy.
 */
template<class T, class X, class Y>
class PQNodeKey : public PQBasicKey<T, X, Y> {
public:
	//! Stores the information. Has to be overloaded by the client.
	X m_userStructInfo;

	// Constructor
	explicit PQNodeKey(X info) : PQBasicKey<T, X, Y>() { m_userStructInfo = info; }

	// Destructor
	virtual ~PQNodeKey() { }

	//! Returns 0.
	virtual T userStructKey() { return nullptr; }

	//! Returns #m_userStructInfo.
	virtual X userStructInfo() { return m_userStructInfo; }

	//! Returns 0.
	virtual Y userStructInternal() { return 0; }
};

}
