/*
 * Copyright (C) 2021 Daniel Dietsch (dietsch@informatik.uni-freiburg.de)
 * Copyright (C) 2014-2021 Matthias Heizmann (heizmann@informatik.uni-freiburg.de)
 * Copyright (C) 2021 University of Freiburg
 *
 * This file is part of the ULTIMATE Util Library.
 *
 * The ULTIMATE Util Library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * The ULTIMATE Util Library 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the ULTIMATE Util Library. If not, see <http://www.gnu.org/licenses/>.
 *
 * Additional permission under GNU GPL version 3 section 7:
 * If you modify the ULTIMATE Util Library, or any covered work, by linking
 * or combining it with Eclipse RCP (or a modified version of Eclipse RCP),
 * containing parts covered by the terms of the Eclipse Public License, the
 * licensors of the ULTIMATE Util Library grant you additional permission
 * to convey the resulting work.
 */
package de.uni_freiburg.informatik.ultimate.util.datastructures.relation;

/**
 * Base class for a tuple that does not provide any getters. Useful for implementing tuples as return type.
 *
 * @author Daniel Dietsch (dietsch@informatik.uni-freiburg.de)
 * @author Matthias Heizmann
 *
 */
public abstract class BaseTuple<E1, E2> {

	protected E1 mFirstElement;
	protected E2 mSecondElement;

	public BaseTuple(final E1 first, final E2 second) {
		super();
		mFirstElement = first;
		mSecondElement = second;
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((mFirstElement == null) ? 0 : mFirstElement.hashCode());
		result = prime * result + ((mSecondElement == null) ? 0 : mSecondElement.hashCode());
		return result;
	}

	@Override
	public boolean equals(final Object obj) {
		if (this == obj) {
			return true;
		}
		if (obj == null) {
			return false;
		}
		if (!(obj instanceof BaseTuple)) {
			return false;
		}
		final BaseTuple<?, ?> other = (BaseTuple<?, ?>) obj;
		if (mFirstElement == null) {
			if (other.mFirstElement != null) {
				return false;
			}
		} else if (!mFirstElement.equals(other.mFirstElement)) {
			return false;
		}
		if (mSecondElement == null) {
			if (other.mSecondElement != null) {
				return false;
			}
		} else if (!mSecondElement.equals(other.mSecondElement)) {
			return false;
		}
		return true;
	}

	@Override
	public String toString() {
		return "[" + mFirstElement + ", " + mSecondElement + "]";
	}
}