Simple helper method(s) for Java.

ObjectUtil.java

package com.coolstuffs.util;

import javax.annotation.Nullable;

public class ObjectUtil {
	/**
	 * Similar to MySQL IFNULL(). If first parameter is null, second parameter will be
	 * returned--otherwise, first parameter will be returned. Think of this as the first
	 * parameter being the preferred value and the second parameter as the fall-back value.
	 *
	 * @param preferredValue
	 * @param fallbackValue
	 * @param <T>
	 * @return preferredValue if not null--fallbackValue, otherwise
	 */
	@Nullable
	public static <T> T ifNull(@Nullable final T preferredValue, @Nullable final T fallbackValue) {
		return firstNonnull(preferredValue, fallbackValue);
	}

	/**
	 * Returns the first nonnull parameter Think of the first parameter as being the preferred
	 * value and the remaining parameters as the fall-back values (in order of preference).
	 *
	 * @param values
	 * @param <T>
	 * @return The first nonnull parameter (or null if all are null)
	 */
	@SafeVarargs
	@Nullable
	public static <T> T firstNonnull(@Nullable final T... values) {
		if (values == null) {
			return null;
		}

		for (final T value : values) {
			if (value != null) {
				return value;
			}
		}

		return null;
	}
}

// ----- ----- ----- TESTS ----- ----- ----- //
// ----- ----- TESTS ----- TESTS ----- ----- //
// ----- ----- ----- TESTS ----- ----- ----- //

package com.coolstuffs.util;

import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.CsvSource;

import static org.assertj.core.api.Assertions.assertThat;

class ObjectUtilUnitTest {
	@ParameterizedTest
	@CsvSource(value = {
			",,", // Both params null--null expected
			"hello,hello,goodbye", // Neither param null--first param expected
			"hello,hello,", // First param nonnull--first param expected
			"goodbye,,goodbye", // First param null--second param expected
	})
	void ifNullStrings(final String expectedValue, final String param1, final String param2) {
		assertThat(ObjectUtil.ifNull(param1, param2)).isEqualTo(expectedValue);
	}

	@ParameterizedTest
	@CsvSource(value = {
			",,", // Both params null--null expected
			"1,1,2", // Neither param null--first param expected
			"1,1,", // First param nonnull--first param expected
			"2,,2", // First param null--second param expected
	})
	void ifNullIntegers(final Integer expectedValue, final Integer param1, final Integer param2) {
		assertThat(ObjectUtil.ifNull(param1, param2)).isEqualTo(expectedValue);
	}

	@ParameterizedTest
	@CsvSource(value = {
			",,,,,", // All params null--null expected
			"1,1,2,3,4,5", // No params null--first param expected
			"1,1,,,,", // First param nonnull--first param expected
			"2,,2,3,4,5", // First param null--second param expected
			"3,,,3,4,5", // First and second params null--third param expected
			"4,,,,4,5", // First, second and third params null--fourth param expected
			"5,,,,,5", // First, second, third and fourth params null--fifth param expected
	})
	void firstNonnullIntegers(final Integer expectedValue, final Integer param1, final Integer param2, final Integer param3, final Integer param4, final Integer param5) {
		assertThat(ObjectUtil.firstNonnull(param1, param2, param3, param4, param5)).isEqualTo(expectedValue);
	}
}