/*
 * Copyright 2017-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.data.mongodb.core.aggregation;

import java.util.ArrayList;
import java.util.List;

import org.springframework.data.domain.Range;
import org.springframework.util.Assert;

/**
 * Utility methods for aggregation operation implementations.
 *
 * @author Oliver Gierke
 */
interface AggregationUtils {

	/**
	 * Converts the given {@link Range} into an array of values.
	 *
	 * @param range must not be {@literal null}.
	 * @return
	 */
	public static List<Long> toRangeValues(Range<Long> range) {

		Assert.notNull(range, "Range must not be null!");

		List<Long> result = new ArrayList<Long>(2);
		result.add(range.getLowerBound().getValue()
				.orElseThrow(() -> new IllegalArgumentException("Lower bound of range must be bounded!")));
		range.getUpperBound().getValue().ifPresent(it -> result.add(it));

		return result;
	}
}
