|  | // Copyright (c) 2019, the R8 project authors. Please see the AUTHORS file | 
|  | // for details. All rights reserved. Use of this source code is governed by a | 
|  | // BSD-style license that can be found in the LICENSE file. | 
|  |  | 
|  | package backport; | 
|  |  | 
|  | import java.util.OptionalDouble; | 
|  |  | 
|  | public final class OptionalDoubleBackportJava11Main { | 
|  |  | 
|  | public static void main(String[] args) { | 
|  | testIsEmpty(); | 
|  | } | 
|  |  | 
|  | private static void testIsEmpty() { | 
|  | OptionalDouble present = OptionalDouble.of(2d); | 
|  | assertFalse(present.isEmpty()); | 
|  |  | 
|  | OptionalDouble absent = OptionalDouble.empty(); | 
|  | assertTrue(absent.isEmpty()); | 
|  | } | 
|  |  | 
|  | private static void assertTrue(boolean value) { | 
|  | if (!value) { | 
|  | throw new AssertionError("Expected <true> but was <false>"); | 
|  | } | 
|  | } | 
|  |  | 
|  | private static void assertFalse(boolean value) { | 
|  | if (value) { | 
|  | throw new AssertionError("Expected <false> but was <true>"); | 
|  | } | 
|  | } | 
|  | } |