ComparisonUtils.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.openflamingo.mapreduce.util;

import java.util.Iterator;

/**
 * Simple helper class for comparisons and equality checking
 */
public class ComparisonUtils {

	/**
	 * Do not construct this object
	 */
	private ComparisonUtils() {
	}

	/**
	 * Compare elements, sort order and length
	 *
	 * @param <T>    Type of iterable to compare.
	 * @param first  First iterable to compare.
	 * @param second Second iterable to compare.
	 * @return True if equal, false otherwise.
	 */
	public static <T> boolean equal(Iterable<T> first, Iterable<T> second) {
		return equal(first.iterator(), second.iterator());
	}

	/**
	 * Compare elements, sort order and length
	 *
	 * @param <T>    Type of iterable to compare.
	 * @param first  First iterable to compare.
	 * @param second Second iterable to compare.
	 * @return True if equal, false otherwise.
	 */
	public static <T> boolean equal(Iterator<T> first, Iterator<T> second) {
		while (first.hasNext() && second.hasNext()) {
			T message = first.next();
			T otherMessage = second.next();
			/* element-wise equality */
			if (!(message == null ? otherMessage == null :
				message.equals(otherMessage))) {
				return false;
			}
		}
		/* length must also be equal */
		return !(first.hasNext() || second.hasNext());
	}
}