/**
 * This file is part of d:swarm graph extension.
 *
 * d:swarm graph extension 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 3 of the License, or
 * (at your option) any later version.
 *
 * d:swarm graph extension 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 d:swarm graph extension.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.dswarm.graph.delta.match.model.util;

import java.util.Collection;
import java.util.HashSet;
import java.util.Optional;
import java.util.Set;

import org.dswarm.graph.delta.match.model.CSEntity;
import org.dswarm.graph.delta.match.model.ValueEntity;

/**
 * @author tgaengler
 */
public final class CSEntityUtil {

	public static Optional<? extends Collection<ValueEntity>> getValueEntities(final Optional<? extends Collection<CSEntity>> csEntities) {

		if (!csEntities.isPresent() || csEntities.get().isEmpty()) {

			return Optional.empty();
		}

		final Set<ValueEntity> valueEntities = new HashSet<>();

		for (final CSEntity csEntity : csEntities.get()) {

			valueEntities.addAll(csEntity.getValueEntities());
		}

		return Optional.of(valueEntities);
	}
}
